JP7069643B2 - Signal processing equipment, signal processing methods and signal processing programs - Google Patents

Description

The present invention relates to a signal processing system, a signal processing apparatus, a signal processing method and a signal processing program.

In the above technical field, in Non-Patent Document 1, in order to measure the distance to a target object, a sound wave is transmitted, a sound wave reflected from the target object is received, and the received sound wave waveform and the transmitted sound wave waveform are mutual. A method for measuring distance with a correlation function has been published.

Tomoharu Sato, Shinnosuke Hirata, Minoru Kurosawa, Takashi Katagiri "Multi-channel pulse compression in ultrasonic distance measurement using M-sequence code" Proceedings of the Acoustic Society September 2008 Lecture materials Yasunari Yokota Signal processing Part 3 Unsteady signal analysis / cepstrum analysis (http://www.ykt.info.gifu-u.ac.jp/sp3.pdf)

However, in the technique described in the above document, since the intervals having similar frequency modulation waveforms are correlated with each other, in the correlation function, in addition to the peak of the true correlation, a side lobe or a grating lobe is used. There was a peak called. These sidelobes and grating lobes can be confirmed by a display called the ambiguity function, but the grating lobes that occur at each period of frequency modulation may have a height comparable to the true correlation peak. , Leading to false positives.

An object of the present invention is to provide a technique for solving the above-mentioned problems.

In order to achieve the above object, the signal processing device according to the present invention is
A signal processing device provided with a transmission waveform generation means for generating a transmission waveform with smooth frequency modulation.
The transmission waveform generation means has a bandwidth changing means for generating the transmission waveform whose frequency changes non-repetitively by changing the bandwidth of the frequency modulation.
The bandwidth changing means modulates and changes the bandwidth of the frequency modulation with a smoothly changing waveform, and includes a sine wave as the smoothly changing waveform .
Further, in order to achieve the above object, the signal processing apparatus according to the present invention is
A signal processing device provided with a transmission waveform generation means for generating a transmission waveform with smooth frequency modulation.
The transmission waveform generation means has a bandwidth changing means for generating the transmission waveform whose frequency changes non-repetitively by changing the bandwidth of the frequency modulation.
The bandwidth changing means modulates the frequency modulation bandwidth to narrow and then widen, or widens and then narrows the frequency modulation bandwidth.
Further, in order to achieve the above object, the signal processing apparatus according to the present invention is
A signal processing device provided with a transmission waveform generation means for generating a transmission waveform with smooth frequency modulation.
The transmission waveform generation means has a bandwidth changing means for generating the transmission waveform whose frequency changes non-repetitively by changing the bandwidth of the frequency modulation.
The bandwidth changing means modulates so that the center of the bandwidth of the frequency modulation moves.
Further, in order to achieve the above object, the signal processing apparatus according to the present invention is
A signal processing device provided with a transmission waveform generation means for generating a transmission waveform with smooth frequency modulation.
The transmission waveform generation means has a bandwidth changing means for generating the transmission waveform whose frequency changes non-repetitively by changing the bandwidth of the frequency modulation.
The bandwidth changing means moves the timing at which the bandwidth of the frequency modulation changes.
Further, in order to achieve the above object, the signal processing apparatus according to the present invention is
A signal processing device provided with a transmission waveform generation means for generating a transmission waveform with smooth frequency modulation.
The transmission waveform generation means has a bandwidth changing means for generating the transmission waveform whose frequency changes non-repetitively by changing the bandwidth of the frequency modulation.
The bandwidth changing means modulates the frequency modulation so that the bandwidth change is repeated at least twice.
Further, in order to achieve the above object, the signal processing apparatus according to the present invention is
A signal processing device provided with a transmission waveform generation means for generating a transmission waveform with smooth frequency modulation.
The transmission waveform generation means has a bandwidth changing means for generating the transmission waveform whose frequency changes non-repetitively by changing the bandwidth of the frequency modulation.
The bandwidth changing means modulates the bandwidth of the frequency modulation with at least two waveforms.

In order to achieve the above object, the signal processing method according to the present invention
It is a signal processing method of a signal processing apparatus including a transmission waveform generation step of generating a transmission waveform with smooth frequency modulation.
The transmission waveform generation step includes a bandwidth change step for generating the transmission waveform in which the frequency changes non-repetitively by changing the bandwidth of the frequency modulation.
In the bandwidth changing step, the bandwidth of the frequency modulation is modulated and changed by a smoothly changing waveform, and a sine wave is included as the smoothly changing waveform .

In order to achieve the above object, the signal processing program according to the present invention is
A signal processing program that causes a computer to execute a transmission waveform generation step that generates a transmission waveform with smooth frequency modulation.
The transmission waveform generation step has a bandwidth change step for generating the transmission waveform in which the frequency changes non-repetitively by changing the bandwidth of the frequency modulation .
In the bandwidth change step, the bandwidth of the frequency modulation is modulated and changed by a smoothly changing waveform, and a computer including a sine wave as the smoothly changing waveform is executed.

According to the present invention, it is possible to suppress the generation of grating lobes and detect an object with high accuracy.

It is a block diagram which shows the structure of the signal processing apparatus which concerns on 1st Embodiment of this invention. It is a block diagram which shows the structure of the signal processing apparatus which concerns on 1st Embodiment of this invention. It is a block diagram which shows the functional structure of the signal processing apparatus which concerns on 2nd Embodiment of this invention. It is a block diagram which shows the structure of the signal processing system which includes the signal processing apparatus which concerns on 2nd Embodiment of this invention. It is a figure which shows the spectrogram of the transmission waveform which concerns on 2nd Embodiment of this invention. It is a figure which shows the 2D display of the self-ambiguity function of the transmission waveform which concerns on 2nd Embodiment of this invention. It is a figure which shows the 3D display of the self-ambiguity function of the transmission waveform which concerns on 2nd Embodiment of this invention. It is a block diagram which shows the functional structure of the transmission waveform generation part in the signal processing apparatus which concerns on a prerequisite technique. It is a figure which shows the spectrogram of the transmission waveform which concerns on a prerequisite technique. It is a figure which shows the 2D display of the self-ambiguity function of the transmission waveform which concerns on a prerequisite technique. It is a figure which shows the 3D display of the self-ambiguity function of the transmission waveform which concerns on a prerequisite technique. It is a block diagram which shows the hardware composition of the signal processing apparatus which concerns on 2nd Embodiment of this invention. It is a figure which shows the structure of the transmission waveform generation table which concerns on 2nd Embodiment of this invention. It is a flowchart which shows the processing procedure of the signal processing apparatus which concerns on 2nd Embodiment of this invention. It is a figure which shows the spectrogram of the transmission waveform which concerns on 3rd Embodiment of this invention. It is a figure which shows the 2D display of the self-ambiguity function of the transmission waveform which concerns on 3rd Embodiment of this invention. It is a figure which shows the 3D display of the mutual ambiguity function of the transmission waveform which concerns on 3rd Embodiment of this invention. It is a figure which shows the spectrogram of the transmission waveform which concerns on 3rd Embodiment of this invention. It is a figure which shows the 2D display of the self-ambiguity function of the transmission waveform which concerns on 3rd Embodiment of this invention. It is a figure which shows the spectrogram of the transmission waveform which concerns on 4th Embodiment of this invention. It is a figure which shows the 2D display of the self-ambiguity function of the transmission waveform which concerns on 4th Embodiment of this invention. It is a figure which shows the spectrogram of the transmission waveform which concerns on 5th Embodiment of this invention. It is a figure which shows the 2D display of the self-ambiguity function of the transmission waveform which concerns on 5th Embodiment of this invention. It is a figure which shows the spectrogram of the transmission waveform which concerns on 6th Embodiment of this invention. It is a figure which shows the 2D display of the self-ambiguity function of the transmission waveform which concerns on 6th Embodiment of this invention. It is a block diagram which shows the functional structure of the signal processing apparatus which concerns on 7th Embodiment of this invention. It is a figure which shows the spectrogram of the transmission waveform which concerns on 7th Embodiment of this invention. It is a figure which shows the 2D display of the self-ambiguity function of the transmission waveform which concerns on 7th Embodiment of this invention. It is a figure which shows the spectrogram of the transmission waveform which concerns on 7th Embodiment of this invention. It is a figure which shows the 2D display of the self-ambiguity function of the transmission waveform which concerns on 7th Embodiment of this invention. It is a block diagram which shows the functional structure of the signal processing apparatus which concerns on 8th Embodiment of this invention. It is a figure which shows the spectrogram of the transmission waveform which concerns on 8th Embodiment of this invention. It is a figure which shows the 3D display of the self-ambiguity function of the transmission waveform which concerns on 8th Embodiment of this invention. It is a block diagram which shows the functional structure of the signal processing apparatus which concerns on 9th Embodiment of this invention. It is a figure which shows the spectrogram of the transmission waveform which concerns on 9th Embodiment of this invention. It is a figure which shows the 2D display of the self-ambiguity function of the transmission waveform which concerns on 9th Embodiment of this invention. It is a block diagram which shows the functional structure of the signal processing apparatus which concerns on 10th Embodiment of this invention. It is a figure which shows the spectrogram of the transmission waveform which concerns on 11th Embodiment of this invention. It is a block diagram which shows the structure of the signal processing system which includes the signal processing apparatus which concerns on 12th Embodiment of this invention. It is a block diagram which shows the functional structure of the synthesis part which concerns on 12th Embodiment of this invention. It is a figure explaining the processing outline of the signal processing system including the signal processing apparatus which concerns on 12th Embodiment of this invention. It is a figure explaining the processing outline of the signal processing system including the signal processing apparatus which concerns on 12th Embodiment of this invention. It is a figure which shows the other field which can use this invention.

Hereinafter, embodiments of the present invention will be described in detail exemplary with reference to the drawings. However, the components described in the following embodiments are merely examples, and the technical scope of the present invention is not intended to be limited thereto.

[First Embodiment]
The signal processing device 100 as the first embodiment of the present invention will be described with reference to FIGS. 1A and 1B. The signal processing device 100 is a device that generates a transmission waveform for detecting an object.

As shown in FIG. 1A, the signal processing device 100 includes a transmission waveform generation unit 101 and a bandwidth changing unit 102. The transmission waveform generation unit 101 generates a frequency-modulated transmission waveform in order to generate a modulated wave whose frequency changes non-repetitively. The bandwidth changing unit 102 changes the bandwidth of frequency modulation in the transmission waveform generation unit 101.

As shown in FIG. 1B, the transmission waveform generation unit 101 includes an initial phase designation unit 111, a frequency modulation waveform generation unit 112, and a bandwidth change unit 102. The bandwidth changing unit 102 includes a frequency designating unit 121, a modulated wave generating unit 122, and a modulated wave generating unit 122. The frequency modulation waveform generation unit 112 receives the initial phase designation from the initial phase designation unit 111, and generates a transmission waveform by sinusoidal frequency modulation (hereinafter referred to as SFM) based on the frequency information from the frequency designation unit 121. .. For the frequency designation unit 121, a sine wave that controls the modulation of the SFM is provided from the modulation wave generation unit 122, and a modulation wave that changes the bandwidth is provided from the modulation wave generation unit 123.

According to the present embodiment, by changing the bandwidth of the frequency modulation, the height of the correlation function in the phase which is an integral multiple of the frequency modulation cycle is suppressed, so that the generation of the grating lobe is suppressed and the object is detected with high accuracy. Can be done.

[Second Embodiment]
Next, the signal processing apparatus according to the second embodiment of the present invention will be described. The signal processing apparatus according to the present embodiment controls the bandwidth of the frequency modulation corresponding to the maximum frequency of the frequency to be added to the center frequency by time-varying control, so that the height of the correlation function in the phase of an integral multiple of the frequency modulation cycle can be determined. suppress.

<< Explanation of prerequisite technology >>
Before explaining the signal processing apparatus of this embodiment, the configuration and operation of the prerequisite technique and its problems will be described in order to clarify its characteristics.

First, SFM will be described. SFM is a waveform obtained by frequency-modulating a sine wave with a sine wave. The resonance frequency of the transmitting element is set as the carrier frequency, and the frequency is modulated by a sine wave having a frequency lower than the carrier frequency. It is called a waveform or modulated wave with a frequency lower than this carrier frequency. In SFM, the modulated wave is a sine wave. The range of frequency modulation is set so as not to deviate significantly from the resonance frequency of the transmitting element. The waveform generated by this SFM has less burden on the carrier transmission element, and can increase the power of the signal.

The equation (1) for generating the frequency f1 (ti) for generating the SFM is shown in equation (1), and the equation (2) shows an example of a pseudo program that generates a waveform by the equation. Here, * is multiplication, ti is the sample number (that is, time), f1 is the frequency of the modulated sine wave (transmission signal), fc is the center frequency, beta0 is the bandwidth, pi is the circumference ratio, and M is the length of the waveform. Modulation repeated in the meantime The number of sinusoidal modulations and len represent the length of the signal. sig (ti) is a transmission waveform, phi is a phase, fs is a sampling frequency, 1i is an imaginary unit, and exp is a complex exponential function. The same applies to other mathematical formulas and pseudo-programs for symbols and variables that are not specified.

(Functional configuration of signal processing device)
FIG. 5 is a block diagram showing a functional configuration of a transmission waveform generation unit 501 in a signal processing device according to a prerequisite technique.

The SFM transmission waveform is generated by the frequency modulation waveform generation unit 211. The frequency modulation waveform generation unit 211 receives the initial phase designation from the initial phase designation unit 212, and generates an SFM transmission waveform based on the frequency information from the bandwidth designation unit 502. The bandwidth designation unit 502 includes a frequency designation unit 503 and a modulated wave generation unit 204. The frequency designation unit 503 has an addition unit 231 and a multiplication unit 532.

The modulation wave generation unit 204 generates a sine wave that controls the modulation of the SFM with an amplitude of “1” and sends it to the multiplication unit 532 of the frequency designation unit 503. The multiplication unit 532 multiplies the sine wave received from the modulation wave generation unit 204 by the bandwidth beta and sends the sine wave to the addition unit 231. The addition unit 231 adds the center frequency fc to the waveform received from the multiplication unit 532, and sends it as frequency information to the frequency modulation waveform generation unit 211.

(Spectrogram of transmitted waveform)
FIG. 6A is a diagram showing a spectrogram 610 of a transmission waveform according to a prerequisite technique. Here, exemplary, the center frequency fc is 1 GHz, the modulation bandwidth beta0 is plus or minus 5 MHz, the waveform length is 100 μSec, and the number of repetitions M is 16.5. The sampling frequency fs was set to 3 GHz. The waveform length len is 300,000 samples. The horizontal axis is time and the vertical axis is frequency. You can see on the spectrogram that the frequency draws a sine wave. That is, the spectrogram represents a change in the frequency of the transmitted signal.

Since SFM has a sharp peak in the correlation function, the position detection accuracy is high. Also, the Doppler detection capability is not low. Therefore, it is used in radar and the like. However, since there is a correlation in the section where the frequency modulation waveforms are similar, a peak called a side lobe or a grating lobe is generated in the correlation function in addition to the peak of the true correlation. These sidelobes and grating lobes may have a height comparable to the true correlation peak in an environment with environmental noise, leading to false positives.

ここでA(τ,v)は曖昧度関数、τは時間差、vは周波数偏移量（ドップラー効果）、U(t)は波形を時刻tについて表現したものである。*は複素共役、eは対数の底、iは虚数単位、πは円周率をそれぞれ表す。 This sidelobes and grating lobes are confirmed by a display called the auto ambiguity function. The self-ambiguity function is defined by the equation (3), for example, as described in [Non-Patent Document 2].

Here, A (τ, v) is the ambiguity function, τ is the time difference, v is the frequency shift amount (Doppler effect), and U (t) is the waveform expressed for time t. * Is the complex conjugate, e is the base of the logarithm, i is the imaginary unit, and π is the pi.

(Two-dimensional display of self-ambiguity function)
FIG. 6B is a diagram showing a two-dimensional display 620 of the self-ambiguity function of the transmission waveform according to the prerequisite technique. In FIG. 6B, the vertical axis represents frequency deviation (corresponding to moving speed), the horizontal axis represents time difference (corresponding to distance), and brightness is the value of the correlation function. Tracing on the horizontal axis passing through the origin, the density becomes a correlation function when the moving speed of the target object is “0”. Ideally, there should be a bright (high) part only in the center and a low part otherwise. It can be seen that FIG. 6B is close to the ideal when looking only at the region near the central portion. However, some peaks other than the origin on the vertical axis are sidelobes. Not expensive enough to be a problem here.

(Three-dimensional display of self-ambiguity function)
FIG. 6C is a diagram showing a three-dimensional display 630 of the self-ambiguity function of the transmission waveform according to the prerequisite technique. In FIG. 6C, there are some high peaks other than the origin on the horizontal axis. These peaks are the grating lobes. The grating lobe has a height close to the true peak (center in this figure) and can be mistakenly detected. This will result in erroneous measurement of the position (distance) of the target object.

<< Explanation of the present embodiment >>
Hereinafter, the present embodiment for solving the above problems will be described in detail. In this embodiment, the method of changing the frequency of the modulated sine wave of SFM is further modulated. As a method of changing the frequency of the modulated sine wave in the present embodiment, it is desirable to make a smooth change. Smooth changes include gradually narrowing and then widening the modulation bandwidth, gradually widening and then narrowing, gradually narrowing, gradually widening, and gradually increasing the overall bandwidth. There are methods such as gradually lowering the entire bandwidth, gradually changing both wide and narrow bandwidth and high and low bandwidth.

本実施形態では、帯域幅を変調することによって、波形の相関が変化する。その結果、自己曖昧度関数に単独ピークを有する、すなわち、検知対象物体の速度や位置の精度を高めることができる。また、自己曖昧度関数において、グレーティングローブが低くなり、位置や速度の検知精度が高められる自己曖昧度関数が得られるという効果が得られる。また、任意関数の変更により、相互曖昧度関数(Cross ambiguity function)の小さい波形、すなわち相互相関の少ない波形を得ることが可能となる。したがって、時間軸対周波数軸の枠（以下、時間周波数タイルと称す）における波形の選択肢を増やすことができるという効果が得られる。 The equation for generating the transmission waveform of this embodiment is shown in Equation (4). Compared with the equation (1) of the prerequisite technique, the bandwidth beta0 of the frequency f1 was a constant, whereas the equation (4) is characterized in that the bandwidth beta (ti) changes with time. ..

In this embodiment, the waveform correlation changes by modulating the bandwidth. As a result, it is possible to have a single peak in the self-ambiguity function, that is, to improve the accuracy of the velocity and position of the object to be detected. Further, in the self-ambiguity function, it is possible to obtain an effect that the grating lobe is lowered and the self-ambiguity function is obtained in which the detection accuracy of the position and the speed is improved. Further, by changing the arbitrary function, it becomes possible to obtain a waveform having a small cross ambiguity function, that is, a waveform having little cross-correlation. Therefore, it is possible to obtain the effect of increasing the choice of waveforms in the frame of the time axis vs. the frequency axis (hereinafter referred to as the time frequency tile).

前提技術の式（１）と比較して、周波数f1の帯域幅beta0が定数であったのに対し、式（５）では、｛(c1+c2*cos(2*pi*ti/(len)))/(c1+c2)｝の項によって時間的に変化する。波形全体での帯域幅の最大値はbeta0のまま変わらない。式（４）におけるＭu(ti)を定数Ｍにした形になっている。 (Specific example of this embodiment)
As a specific example of this embodiment, a transmission waveform in the case of gradually narrowing and then widening will be described as an example. The equation that generates the transmission waveform in this specific example is shown in equation (5).

Compared with equation (1) of the prerequisite technique, the bandwidth beta0 of frequency f1 was a constant, whereas in equation (5), {(c1 + c2 * cos (2 * pi * ti / (len)) )) / (C1 + c2)} changes over time. The maximum bandwidth of the entire waveform remains beta0. Mu (ti) in the equation (4) is a constant M.

<< Functional configuration of signal processing equipment >>
FIG. 2 is a block diagram showing a functional configuration of the signal processing device 200 according to the present embodiment. In addition, in FIG. 2, the same reference number is assigned to the same functional configuration as in FIG. 5 of the prerequisite technique.

The signal processing device 200 includes a transmission waveform generation unit 201. The transmission waveform generation unit 201 includes a frequency modulation waveform generation unit 211, an initial phase designation unit 212, and a bandwidth change unit 202. The bandwidth changing unit 202 includes a frequency designating unit 203, a modulated wave generating unit 204, and a modulated wave generating unit 205. Further, the frequency designation unit 203 includes an addition unit 231 and a multiplication unit 232.

The SFM transmission waveform of this embodiment is generated by the frequency modulation waveform generation unit 211. The frequency modulation waveform generation unit 211 receives the initial phase designation from the initial phase designation unit 212, and generates an SFM transmission waveform based on the frequency information from the bandwidth change unit 202. The modulation wave generation unit 204 generates a sine wave that controls the modulation of the SFM with an amplitude of “1” and sends it to the multiplication unit 232 of the frequency designation unit 203. The multiplication unit 232 multiplies the sine wave received from the modulation wave generation unit 204 by the changing bandwidth beta1 (ti) from the modulation wave generation unit 205, and sends the sine wave to the addition unit 231. The addition unit 231 adds the center frequency fc to the waveform received from the multiplication unit 232 and sends it to the frequency modulation waveform generation unit 211 as frequency information.

<< Configuration of signal processing system >>
FIG. 3 is a block diagram showing a configuration of a signal processing system 300 including a signal processing device 200 as a transmitter according to the present embodiment.

As shown in FIG. 3, the signal processing system 300 receives a signal processing device 200 that transmits a transmission signal 331 as a transmitter and a reflection signal 332 obtained by reflecting the transmission signal 331 on the target object 330. It is equipped with a machine 350. The receiver 350 detects the existence of the target object 330 and the distance to the target object 330 based on the correlation between the transmission signal 331 and the reflection signal 332.

The signal processing device 200 as a transmitter includes a transmission waveform generation unit 201, a wireless transmission unit 301, and a transmission antenna 302. The receiver 350 includes a receiving antenna 352, a wireless receiving unit 353, a correlation calculation unit 354, an absolute value generation unit 355, and an output unit 356.

The transmission waveform generation unit 201 generates a transmission waveform and sends it to the wireless transmission unit 301, and also sends the transmission waveform to the correlation calculation unit 354. The wireless transmission unit 301 performs frequency conversion or the like on the transmission waveform, converts it into a wireless signal, and transmits it from the transmission antenna 302. The radio reception unit 353 receives the reflection signal 332 obtained by reflecting the transmission signal 331 on the target object 330 via the reception antenna 352, performs frequency conversion of the received radio signal, and performs a desired frequency. It is sent to the correlation calculation unit 354 as a received waveform of the band. The correlation calculation unit 354 calculates the cross-correlation function between the transmission waveform and the reception waveform and sends it to the absolute value generation unit 355. The existence of the target object 330 and the distance to the target object 330 are detected based on the cross-correlation function output from the output unit 356 by the absolute value generation unit 355.

In the present embodiment, the transmitter is used as a signal processing device, but a device in which a transmitter and a receiver are integrated or a device composed of some constituent groups thereof is used as a signal processing device. May be good.

(Spectrogram of transmitted waveform)
FIG. 4A is a diagram showing a spectrogram 410 of the transmission waveform according to the present embodiment. The spectrogram 410 is a spectrogram of the transmission waveform generated according to the equation (5). Here, c1 = 2 and c2 = 1. In FIG. 4A, it can be seen that the spectrogram (frequency change) has sinusoidal modulation as in SFM, but the bandwidth of the frequency change gradually narrows and then widens.

(Two-dimensional display of self-ambiguity function)
FIG. 4B is a diagram showing a two-dimensional display 420 of the self-ambiguity function of the transmission waveform according to the present embodiment.

(Three-dimensional display of self-ambiguity function)
FIG. 4C is a diagram showing a three-dimensional display 430 of the self-ambiguity function of the transmission waveform according to the present embodiment.

4B and 4C are self-ambiguity functions of the waveform of the spectrogram of FIG. 4A, and the effect of the present embodiment is analyzed from the ambiguity function. Compared with the ambiguity function of SFM shown in FIGS. 6B and 6C, it can be seen that the vicinity of the origin is high and the correlation coefficient in other parts is small. Looking at the correlation function along the horizontal axis passing through the origin, we can see that there are almost no sidelobes or grating lobes. Even if you look at the correlation function along the vertical axis passing through the origin, there are few points where the correlation function other than the origin is high. This ambiguity function means that false positives can be reduced.

<< Hardware configuration of signal processing device >>
FIG. 7 is a block diagram showing a hardware configuration of the signal processing device 200 according to the present embodiment. FIG. 7 shows a configuration when the functional component of the signal processing device 200 is executed by software.

In FIG. 7, the CPU (Central Processing Unit) 710 is a processor for arithmetic control, and the functional components of FIGS. 2 and 3 are realized by executing a program. There may be a plurality of CPU 710s corresponding to each function. The ROM (Read Only Memory) 720 stores fixed data and programs such as initial data and programs. The network interface 730 controls communication with other devices via the network.

The RAM (Random Access Memory) 740 is a random access memory used by the CPU 710 as a temporary storage work area. The RAM 740 secures an area for storing data necessary for realizing the present embodiment. The transmission waveform generation table 741 is a table used to generate the transmission waveform of the present embodiment. The transmission waveform generation table 741 includes a transmission waveform generation parameter 742 used to generate a transmission waveform, a modulation frequency 743 generated using the transmission waveform generation parameter 742, and a transmission waveform generation parameter 742 and a modulation frequency 743. The generated transmission waveform 744 and the generated transmission waveform 744 are stored. The transmission radio data 745 is data for transmission radio generated corresponding to the transmission waveform 744. The input / output data 746 is data that is input / output to / from the input / output device including the wireless transmission unit 301 via the input / output interface 760. The transmission / reception data 747 is data for transmission / reception to / from another device via the network interface 730.

The storage 750 stores a database, various parameters, and the following data or programs necessary for realizing the present embodiment. The modulation frequency generation algorithm 751 is an algorithm that generates a modulation frequency 743 from the transmission waveform generation parameter 742. The transmission waveform generation algorithm 752 is an algorithm that generates a transmission waveform from the transmission waveform generation parameter 742 and the modulation frequency 743.

The following programs are stored in the storage 750. The signal processing device control program 753 is a program that controls the entire processing of the signal processing device 200 of the present embodiment. The modulation frequency generation module 754 is a module that generates the modulation frequency 743 from the transmission waveform generation parameter 742 according to the modulation frequency generation algorithm 751. The transmission waveform generation module 756 is a module that generates a transmission waveform from the transmission waveform generation parameter 742 and the modulation frequency 743 according to the transmission waveform generation algorithm 752. The wireless transmission module 757 is a module that controls transmission of a transmission waveform signal from the wireless transmission unit 301.

The input / output interface 760 provides an interface for controlling data input / output with an input / output device. In the present embodiment, the input / output interface 760 is connected to a wireless transmission unit 301 that transmits a signal to the transmission antenna 302. If the signal processing device 200 also has a function of detecting an object by receiving a reflected signal, a receiving antenna and a wireless receiving unit may be connected. The input / output interface 760 may be further connected to a display unit 761 and an operation unit 762 in order to monitor and operate the operation of the signal processing device 200.

The RAM 740 and the storage 750 of FIG. 7 do not show programs or data related to the general-purpose functions of the signal processing device 200 and other feasible functions.

(Transmission waveform generation table)
FIG. 8 is a diagram showing the configuration of the transmission waveform generation table 741 according to the present embodiment. The transmission waveform generation table 741 is used to generate the transmission waveform of the present embodiment. In FIG. 8, the same reference numbers are assigned to the same components as those in FIG. 7.

The transmission waveform generation table 741 stores the transmission waveform generation parameter 742, the modulation frequency 743, and the transmission waveform 744. The transmission waveform generation parameter 742 includes a center waveform fc, a bandwidth beta1 (ti), a number of iterations Mu (ti), a signal length (len), and an initial phase (phi). It also includes the maximum bandwidth beta0, which is the parameter 845 for generating the bandwidth beta1 (ti), and the bandwidth change parameters c1 and c2.

<< Processing procedure of signal processing device >>
FIG. 9 is a flowchart showing a processing procedure of the signal processing device 200 according to the present embodiment. This flowchart is executed by the CPU 710 of FIG. 7 using the RAM 740 to realize the functional components of FIGS. 2 and 3.

In step S901, the signal processing apparatus 200 acquires the parameter 845 for changing the bandwidth. Then, in step S903, the signal processing apparatus 200 generates the bandwidth beta1 (ti) by using the parameter 845 for changing the bandwidth. The signal processing device 200 acquires the transmission waveform generation parameter 742 in step S905. Then, in step S907, the signal processing apparatus 200 executes the generation processing of the frequency (f1 (ti)) of the modulated sine wave according to the equation (5). Next, in step S909, the signal processing apparatus 200 executes the generation of the transmission waveform (sig (ti)) according to the program of the equation (2). Then, in step S911, the signal processing device 200 performs wireless transmission processing according to the transmission waveform (sig (ti)).

According to the present embodiment, the generation of the grating lobe is suppressed by changing the frequency (f1 (ti)) of the modulated sine wave with time to change the bandwidth of the frequency modulation and suppressing the height of the correlation function. It is possible to detect an object with high accuracy.

That is, as shown in Eq. (5), by changing the amplitude beta1 (ti) of the modulated sine wave with time, the modulation bandwidth appearing in the spectrogram of FIG. 4A is continuously changed. , This complex change changes the ambiguity function in the desired direction.

The waveform of the present embodiment can easily create a waveform that can be easily distinguished from other waveforms by slightly changing the parameters, and has the effect of increasing the choice of waveforms within the time-frequency frame.

ここで、U1(t)とU2(t)とは相互相関をとる波形である。U1(t)とU2(t)とが同一である場合が自己曖昧度関数である。曖昧度関数は、時間の軸（time）と周波数偏移量（doppler）の軸を有する。 In order to show this, whether or not the waveform of FIG. 4A is easily distinguishable from other waveforms is evaluated by a function called the mutual ambiguity function expressed by the following equation (6), and it is sufficiently easy to distinguish. confirmed.

Here, U1 (t) and U2 (t) are cross-correlated waveforms. The self-ambiguity function is when U1 (t) and U2 (t) are the same. The ambiguity function has an axis of time and an axis of frequency offset (doppler).

The difference between equation (3) and equation (6) is that different functions U1 and U2 are used as U. Equivalent to calculating the reciprocal similarity between another function U1 and U2. If this value is small overall, it means that U1 and U2 are dissimilar, that is, distinguishable, even if they are staggered or have a Doppler effect.

Since the waveform of FIG. 4A and LFM (Linear Frequency Modulation) or CW (continuous wave) are significantly different in the shape of the spectrogram of the waveform, the mutual ambiguity function is less than "0.1" in all cases. This means that it is easy to distinguish waveforms. It is possible to use the waveform of FIG. 4A as one of the options in the frame of time frequency, and the increase in the options means that it is possible to process many waveforms separately even when they are received at the same time. It means that the effect can be obtained.

When the waveform of the present embodiment is used, it is easy to distinguish by the cross-correlation function even when there is only one frame of time frequency.

[Third Embodiment]
Next, the signal processing apparatus according to the third embodiment of the present invention will be described. The signal processing apparatus according to the present embodiment is different from the second embodiment in that the number of times (M) of repeated modulation sine wave modulation is changed during the length of the waveform. Since other configurations and operations are the same as those in the second embodiment, the same configurations and operations are designated by the same reference numerals and detailed description thereof will be omitted.

<< First Example of the present embodiment >>
This embodiment is a case where the modulation speed is changed. The equation is the same as the equation (5), but the modulation speed is slowed down by setting M to "11.5".

(Spectrogram of transmitted waveform)
FIG. 10A is a diagram showing a spectrogram 1010 of a transmission waveform according to the present embodiment. From FIG. 10A, it can be seen that the repetition cycle becomes longer and the number of frequency upper limits decreases.

(Two-dimensional display of self-ambiguity function)
FIG. 10B is a diagram showing a two-dimensional display 1020 of the self-ambiguity function of the transmission waveform according to the present embodiment. In the self-ambiguity function of FIG. 10B, a slight peak can be seen at a place where the Doppler is high, but the velocity of the object at this time is extremely high as Mach 4, which is not a problem in practical use. That is, it is possible to reduce the modulation speed according to the speed of the object.

(Three-dimensional display of mutual ambiguity function)
FIG. 10C is a diagram showing a three-dimensional display 1030 of the mutual ambiguity function of the transmission waveform according to the present embodiment. At first glance, the waveform of the second embodiment and the waveform of the present embodiment are very similar, but when looking at FIG. 10C showing their mutual ambiguity functions, it can be seen that the maximum is about "0.1" and they can be distinguished. In FIG. 10C, the scale is changed (10 times higher sensitivity) to make the figure easier to see.

<< Second Example of the present embodiment >>
In the second example, the speed of the modulated sine wave is further reduced as compared with the first example. This is the case where the number of repetitions M of the equation (5) is set to “4.5”.

(Spectrogram of transmitted waveform)
FIG. 11A is a diagram showing a spectrogram 1110 of the transmission waveform according to the present embodiment. From FIG. 11A, it can be seen that the number of repetitions is small.

(Two-dimensional display of self-ambiguity function)
FIG. 11B is a diagram showing a two-dimensional display 1120 of the self-ambiguity function of the transmission waveform according to the present embodiment. In FIG. 11B, there is a place where the value of the ambiguity function is large around the vertical axis plus or minus 5 km / sec, but if there is no possibility that the object to be detected moves at such a speed, there is a possibility of false detection. Is few.

According to the present embodiment, by slowing down the modulation speed, a large number of waveform candidates that can be put in the time frequency frame can be obtained, and the effect that the choices in the time-frequency frame are further increased can be obtained.

[Fourth Embodiment]
Next, the signal processing apparatus according to the fourth embodiment of the present invention will be described. The signal processing apparatus according to the present embodiment is different from the second embodiment and the third embodiment in that the timing for narrowing the bandwidth is changed. Since other configurations and operations are the same as those of the second embodiment or the third embodiment, the same configurations and operations are designated by the same reference numerals and detailed description thereof will be omitted.

ここで、繰り返しの速さＭは“11.5”とした。 Similar to the second embodiment, the present embodiment gradually narrows and then widens the bandwidth of the modulated sine wave, but the timing of narrowing is different. The equation for changing the timing is shown in equation (7). In beta (ti) that determines the modulation width, the timing is off due to the term (pi / 4). The amount that determines the timing of shifting does not have to be limited to (pi / 4).

Here, the repetition speed M is set to "11.5".

(Spectrogram of transmitted waveform)
FIG. 12A is a diagram showing a spectrogram 1210 of a transmission waveform according to the present embodiment. Comparing FIG. 12A with FIG. 4A, it can be seen that the timing at which the modulation bandwidth is narrowed is different.

(Two-dimensional display of self-ambiguity function)
FIG. 12B is a diagram showing a two-dimensional display 1220 of the self-ambiguity function of the transmission waveform according to the present embodiment. Comparing FIGS. 12B and 4B, it can be seen that the self-ambiguity functions are almost the same and the same effect is obtained.

According to the present embodiment, even if the timing of gradually narrowing the bandwidth of the modulated sine wave is changed, the height of the correlation function can be suppressed to suppress the generation of the grating lobe and detect the object with high accuracy. can.

[Fifth Embodiment]
Next, the signal processing apparatus according to the fifth embodiment of the present invention will be described. The signal processing apparatus according to the present embodiment is different from the second to fourth embodiments in that the bandwidth is gradually widened and then narrowed. Since other configurations and operations are the same as those of the second to fourth embodiments, the same configurations and operations are designated by the same reference numerals and detailed description thereof will be omitted.

ここでは、一例としてＭ=11.5、c1=2、c2=1とした。 The present embodiment is characterized in that the bandwidth of the modulated sine wave is gradually widened and then narrowed. The equation that generates the waveform is shown in Equation (8). Compared with the equation (5), the positive and negative signs of c2 are different.

Here, as an example, M = 11.5, c1 = 2, and c2 = 1.

(Spectrogram of transmitted waveform)
FIG. 13A is a diagram showing a spectrogram 1310 of a transmission waveform according to the present embodiment. As can be seen from FIG. 13A, the bandwidth of the modulated sine wave is gradually widened and then narrowed.

(Two-dimensional display of self-ambiguity function)
FIG. 13B is a diagram showing a two-dimensional display 1320 of the self-ambiguity function of the transmission waveform according to the present embodiment. As can be seen from FIG. 14B, the ambiguity function is almost the same as that of the second embodiment, so that the same effect can be obtained.

According to the present embodiment, even if the bandwidth of the modulated sine wave is gradually widened and then narrowed, the height of the correlation function is suppressed to suppress the generation of the grating lobe and detect the object with high accuracy. can.

[Sixth Embodiment]
Next, the signal processing apparatus according to the sixth embodiment of the present invention will be described. The signal processing apparatus according to the present embodiment is different from the second to fifth embodiments in that the number of times of increase / decrease in bandwidth is increased. Since other configurations and operations are the same as those of the second to fifth embodiments, the same configurations and operations are designated by the same reference numerals and detailed description thereof will be omitted.

この式（９）と式（５）とを比較すると、式（５）では、波形長の間の帯域幅の増減の回数が１回であったのに対して、式（９）では、波形長の間に帯域幅がＲ回増減する。 The present embodiment is characterized in that the speed of the modulated sine wave is further increased as compared with the second embodiment. The equation for generating the transmission waveform of this embodiment is shown in Equation (9).

Comparing the equation (9) and the equation (5), in the equation (5), the number of times of increase / decrease of the bandwidth during the waveform length was once, whereas in the equation (9), the waveform. Bandwidth increases or decreases R times during the length.

(Spectrogram of transmitted waveform)
FIG. 14A is a diagram showing a spectrogram 1410 of a transmission waveform according to the present embodiment. Here, M is set to "16.5" and R is set to "3", and as can be seen from the spectral gram of FIG. 14A, the number of times the modulation width of the modulated sine wave is increased or decreased is three times. Further, it can be seen that the maximum value of the bandwidth of the entire waveform is maintained at plus or minus 5 MHz.

(Two-dimensional display of self-ambiguity function)
FIG. 14B is a diagram showing a two-dimensional display 1420 of the self-ambiguity function of the transmission waveform according to the present embodiment. From FIG. 14B, it can be seen that a desired form of self-ambiguity function with a peak only in the center is obtained.

According to the present embodiment, since it is asymmetric even if similar waveforms are repeated, it is possible to suppress the generation of grating lobes and detect an object with high accuracy by suppressing the height of the correlation function.

[7th Embodiment]
Next, the signal processing apparatus according to the seventh embodiment of the present invention will be described. The signal processing apparatus according to the present embodiment is different from the second to sixth embodiments in that the modulation speed is changed in addition to the change in the modulation width. Since other configurations and operations are the same as those in the second embodiment, the same configurations and operations are designated by the same reference numerals and detailed description thereof will be omitted.

本実施形態における変調正弦波の周波数の変化のさせ方として、滑らかな変化にしていくことが望ましい。滑らかな変化として、徐々に速くしていく、徐々に遅くしていく、徐々に速くしたのち遅くする、徐々に遅くしたのち速くする、などの方法があるが、ここではまず、徐々に速くしていく場合を例に説明する。その一例として、Ｍ0=7、Ｍ1=2.5、M2=2、Ｍ3=0とした。 The present embodiment is characterized in that not only the bandwidth of the modulated sine wave is changed, but also the modulation speed of the modulated sine wave is changed. The equation for generating the transmission waveform of the first example of the present embodiment is shown in the equation (10). In the equation (10), the constant M in the equation (5) of the second embodiment is changed to the time-varying function Mu (ti) in order to change the velocity of the modulated sine wave. Here, Mu (ti) is a cubic polynomial of ti, but higher-order polynomials, exponential functions, logarithmic functions, trigonometric functions, and other arbitrary functions can be used. The effect of the velocity change of the modulated sine wave has the effect of reducing the mutual ambiguity function, further increasing the variation.

As a method of changing the frequency of the modulated sine wave in the present embodiment, it is desirable to make a smooth change. Smooth changes include gradual speeding up, gradual slowing down, gradual speeding up and then slowing down, gradual slowing down and then speeding up, etc. The case will be described as an example. As an example, M0 = 7, M1 = 2.5, M2 = 2, and M3 = 0.

<< Functional configuration of signal processing equipment >>
FIG. 15 is a block diagram showing a functional configuration of the signal processing device 1500 according to the seventh embodiment of the present invention. In FIG. 15, the same reference numbers are assigned to the functional components similar to those in FIG. 2, and duplicate description will be omitted.

The difference between FIGS. 15 and 2 is that the modulation speed in the modulation wave generation unit 204 is further modulated by the modulation speed Mu (ti) generated by the modulation speed generation unit 1506. As a result, the equation (10) is realized.

(Spectrogram of transmitted waveform)
FIG. 16A is a diagram showing a spectrogram 1610 of a transmission waveform according to the present embodiment. It can be seen that the modulation bandwidth of the spectrogram gradually increases and then decreases, but the frequency of the sine wave, which represents the frequency change of the spectrogram, gradually increases.

(Two-dimensional display of self-ambiguity function)
FIG. 16B is a diagram showing a two-dimensional display 1620 of the self-ambiguity function of the transmission waveform according to the present embodiment. It can be seen that, as compared with the ambiguity function of the second embodiment shown in FIGS. 4B and 4C, the vicinity of the origin is higher and the correlation coefficient in other parts is smaller. Looking at the correlation function along the horizontal and vertical axes passing through the origin, we can see that there are almost no sidelobes or grating lobes. That is, this ambiguity function means that false positives can be reduced.

本例においても、徐々に速くしていく場合を例に説明する。その一例として、Ｍ0=7、Ｍ1=2.5、M2=2、Ｍ3=0とした。 The equation for generating the transmission waveform of the second example of the present embodiment is shown in the equation (11). In the equation (11), the constant M in the equation (8) of the fifth embodiment is changed to the time-varying function Mu (ti) in order to change the velocity of the modulated sine wave. Here, Mu (ti) is a cubic polynomial of ti, but higher-order polynomials, exponential functions, logarithmic functions, trigonometric functions, and other arbitrary functions can be used. The effect of the velocity change of the modulated sine wave has the effect of reducing the mutual ambiguity function, further increasing the variation.

Also in this example, the case of gradually increasing the speed will be described as an example. As an example, M0 = 7, M1 = 2.5, M2 = 2, and M3 = 0.

(Spectrogram of transmitted waveform)
FIG. 17A is a diagram showing a spectrogram 1710 of a transmission waveform according to the present embodiment. It can be seen that the modulation bandwidth of the spectrogram gradually decreases and then increases, but the frequency of the sine wave, which represents the frequency change of the spectrogram, gradually increases.

(Two-dimensional display of self-ambiguity function)
FIG. 17B is a diagram showing a two-dimensional display 1720 of the self-ambiguity function of the transmission waveform according to the present embodiment. It can be seen that, as compared with the ambiguity function of the fifth embodiment shown in FIGS. 13B and 13C, the vicinity of the origin is higher and the correlation coefficient in other parts is smaller. Looking at the correlation function along the horizontal and vertical axes passing through the origin, we can see that there are almost no sidelobes or grating lobes. That is, this ambiguity function means that false positives can be reduced.

In the present embodiment, an example in which the modulation speed is gradually increased is shown, but there are also methods such as gradually slowing down, gradually increasing the speed and then slowing down, and gradually slowing down and then speeding up. , Has the same effect.

According to the present embodiment, by changing the modulation speed in addition to the change in the modulation width, the height of the correlation function can be further suppressed, so that the generation of the grating lobe can be suppressed and the object can be detected with high accuracy.

That is, as shown in the equations (10) and (11), the angular frequency representing the frequency modulation f1 of the sine wave is changed by a higher-order function with respect to the time ti / len. By continuously and unidirectionally changing the frequency of the modulation appearing in the spectrogram (here, the direction in which the frequency increases), the ambiguity function is changed in the desired direction.

[Eighth Embodiment]
Next, the signal processing apparatus according to the eighth embodiment of the present invention will be described. The signal processing apparatus according to the present embodiment is different from the second to seventh embodiments in that it moves the center of the modulation width. Since other configurations and operations are the same as those in the second embodiment, the same configurations and operations are designated by the same reference numerals and detailed description thereof will be omitted.

この式（１２）は、式（１）と比較して、変調の帯域幅をbeta0からbeta1に変更し、さらに“beta2*cos(2*pi*M2*ti/(len))”による新たな変調を加えた形である。Ｍ2は新たに加えた変調の回数である。beta1+beta2 = beta0とすることで、波形全体での帯域幅の最大値はbeta0に保つことができる。 The signal generation method according to the present embodiment is characterized in that the center of the modulation band of the SFM moves. The formula (12) representing the frequency for generating the transmission waveform of the present embodiment is shown. Others are the same as the previous equations, so detailed explanations of the same symbols and variables will be omitted.

This equation (12) changes the modulation bandwidth from beta0 to beta1 as compared with equation (1), and is newly added by "beta2 * cos (2 * pi * M2 * ti / (len))". It is a modulated form. M2 is the number of newly added modulations. By setting beta1 + beta2 = beta0, the maximum bandwidth of the entire waveform can be kept at beta0.

<< Functional configuration of signal processing equipment >>
FIG. 18 is a block diagram showing a functional configuration of the signal processing device 1800 according to the present embodiment. In FIG. 18, the same reference numbers are assigned to the functional components similar to those in FIG. 5, and duplicate description will be omitted.

The difference between FIG. 18 and FIG. 5 is that in the frequency designation unit 1803 of the bandwidth changing unit 1802, the addition unit 231 of FIG. 5 is replaced with the addition unit 1831 of 3 inputs, and the modulation wave generation unit 2807 is generated there. A modulated wave obtained by multiplying the modulated wave by the bandwidth beta2 by the multiplication unit 1833 is newly input. As a result, new modulation is added.

(Spectrogram of transmitted waveform)
FIG. 19A is a diagram showing a spectrogram 1910 of a transmission waveform according to the present embodiment. Here, beta1 = 10/3 [MHz], beta2 = 5/3 [MHz], and M2 = 1/2. It can be seen that the maximum value of the bandwidth of the entire waveform is maintained at plus or minus 5 MHz. Similar to SFM, the spectrogram (frequency change) has a sinusoidal modulation, but it can be seen that the entire bandwidth of the sinusoidal wave representing the frequency change is gradually reduced. Since the modulated sine wave is further modulated, there are few parts where the curves of the modulated sine wave match. This reduces the cross-correlation.

(Three-dimensional display of self-ambiguity function)
FIG. 19B is a diagram showing a three-dimensional display 1920 of the self-ambiguity function self-ambiguity function of the transmission waveform according to the present embodiment. High sidelobes and grating lobes do not appear in the self-ambiguity function of FIG. 19B. Compared with the ambiguity function of SFM shown in FIGS. 6B and 6C, it can be seen that the vicinity of the origin is high and the correlation coefficient in other parts is small. Even if you look at the correlation function along the vertical axis passing through the origin, there are few points where the correlation function other than the origin is high. This ambiguity function means that the false detection of the target object is small and the error of the distance measurement to the target object can be reduced, which is a desirable form.

According to the present embodiment, the height of the correlation function can be suppressed by moving the center of the modulation width without changing the modulation width, the generation of the grating lobe can be suppressed, and the object can be detected accurately. Can be done.

[9th Embodiment]
Next, the signal processing apparatus according to the ninth embodiment of the present invention will be described. The signal processing apparatus according to the present embodiment is different from the second embodiment to the eighth embodiment in that the modulation width and the center are modulated. Since other configurations and operations are the same as those in the second embodiment, the same configurations and operations are designated by the same reference numerals and detailed description thereof will be omitted.

In this embodiment, both the modulation width and the center of the modulated sine wave are further modulated. The equation for generating the waveform of this embodiment is shown in Equation (13).

<< Functional configuration of signal processing equipment >>
FIG. 20 is a block diagram showing a functional configuration of the signal processing device 2000 according to the present embodiment. In FIG. 20, the same reference number is assigned to the same functional component as in FIG. 2 or FIG. 18, and duplicate description will be omitted.

The difference between FIG. 20 and FIG. 2 is that in the frequency designation unit 2003 of the bandwidth changing unit 2002, the addition unit 231 of FIG. 2 is replaced with the addition unit 1831 of 3 inputs, and the modulation wave generation unit 2807 is generated there. A modulated wave obtained by multiplying the modulated wave by the bandwidth beta2 by the multiplication unit 1833 is newly input. As a result, new modulation is added.

(Spectrogram of transmitted waveform)
FIG. 21A is a diagram showing a spectrogram 2110 of a transmission waveform according to the present embodiment. As can be seen from the spectral gram of FIG. 21A, both the modulation width and the center of the modulated sine wave are further modulated. It can also be seen that the maximum value of the bandwidth of the entire waveform is maintained at plus or minus 5 MHz.

(Two-dimensional display of self-ambiguity function)
FIG. 21B is a diagram showing a two-dimensional display 2120 of the self-ambiguity function of the transmission waveform according to the present embodiment. From FIG. 21B, it can be seen that a desired form of self-ambiguity function with a peak only in the center of plus or minus 10 km / sec or less on the Doppler axis is obtained.

According to the present embodiment, by moving the center of the modulation width in addition to the change of the modulation width, the height of the correlation function is suppressed, so that the generation of the grating lobe is suppressed and the object is detected with high accuracy. Can be done.

[10th Embodiment]
Next, the signal processing apparatus according to the tenth embodiment of the present invention will be described. The signal processing apparatus according to the present embodiment is different from the second embodiment to the tenth embodiment in that it shows a more generalized configuration. Since other configurations and operations are the same as those of the second to ninth embodiments, the same configurations and operations are designated by the same reference numerals and detailed description thereof will be omitted.

In the above embodiment, not only the frequency change of the modulated sine wave may be smoothed, but also the frequency change may not be smooth. It is clear that the modulation waveform for frequency modulation may be another waveform other than a sine wave, such as a triangular wave or a trapezoidal wave. The equation that generates the waveform is the above-mentioned equation (4). Further, as in Eq. (14), it is possible to increase the number of terms to complicate the modulation.

When the frequency modulation is fast, the spectrum is widened and there are many frequency components that exceed the modulation bandwidth. It should be noted that the spread of the spectrum may be a burden on the transmitting element, or frequency components exceeding the allowable band may be generated and interfere with other devices. In order to suppress the spread of the spectrum, in order to suppress the spread of the spectrum at the start and end of the waveform or at the sudden change part of the modulated waveform, not only windowing (taper processing, also called Raised Cosine processing) but also through a band limiting filter May be good.

<< Functional configuration of signal processing equipment >>
FIG. 22 is a block diagram showing a functional configuration of the signal processing devices 2210 and 2220 according to the present embodiment. In FIG. 22, the same reference number is assigned to the same functional component as in FIG. 2 or 15, and duplicate description will be omitted.

The difference between FIG. 22 and FIG. 15 is that the frequency designation unit 203 of the bandwidth change unit 202 is replaced with the frequency designation unit 2203 of the bandwidth change unit 2202, and the addition unit 231 is replaced with the addition unit 2231 of a plurality of inputs. The input is now added. Further, it has a plurality of modulation blocks including a modulation wave generation unit 204, a modulation wave generation unit 205, a modulation speed generation unit 1506, and a multiplication unit 232, and sends modulation information to the addition unit 2231. This difference allows complex modulations to be applied, resulting in a self-ambiguity function producing more desirable waveforms or a larger number of candidate waveforms with smaller mutual ambiguity functions. ..

According to the present embodiment, by suppressing the height of the correlation function by combining various modulation waveforms and changing the modulation width, it is possible to suppress the generation of the grating lobe and detect the object with high accuracy.

[11th Embodiment]
Next, the signal processing apparatus according to the eleventh embodiment of the present invention will be described. Compared with the second to eleventh embodiments, the signal processing apparatus according to the present embodiment has a transmission waveform over a plurality of vertical and horizontal tiles with the time and frequency transmission waveforms in the above embodiment as one tile. Is different. Since other configurations and operations are the same as those of the second to tenth embodiments, the same configurations and operations are designated by the same reference numerals and detailed description thereof will be omitted.

In the above embodiment, the present embodiment has been described in one time-frequency tile, but a case where there are many time-frequency tiles will be described.

The equation for generating the waveform of the present embodiment is represented by, for example, the equation (15). That is, the center frequency is changed with time.

(Spectrogram of transmitted waveform)
FIG. 23 is a diagram showing a spectrogram 2300 of the transmission waveform according to the present embodiment.

The upper part of FIG. 23 is a schematic spectrogram of the first example of the transmission waveform in the present embodiment, and is arranged in a tile shape in the spectrogram. There are a plurality of time frequency frames as transmission waveforms, and the waveforms of the second to eleventh embodiments or the conventional waveforms are assigned to the plurality of time frequency frames. The increased waveform variation within the time-frequency tile makes it possible to distinguish and process more types of transmitted waveforms.

The middle part of FIG. 23 is a schematic spectrogram of the second example of the transmission waveform in the present embodiment, and is tiled with a taper at both ends to gradually attenuate the value. Taper processing is used to ensure that adjacent time-frequency tiles overlap in time. Taper processing is to gradually increase the amplitude at the beginning of the waveform and gradually decrease the amplitude at the end of the waveform, so that the wideband component generated at the beginning and end of the waveform, that is, the connection part of the time-frequency tile, is removed. This is a process to reduce. Since the amplitude is small at the beginning and end of the waveform in the taper processing, the time-frequency tile can be packed in the time direction by overlapping these time intervals. As a result, it is possible to further increase the distinguishable transmission waveforms by providing more time-frequency tiles within the same time.

The lower part of FIG. 23 is a schematic spectrogram of the third example of the transmission waveform in the present embodiment, and the spectrograms are smoothly connected between adjacent tiles. That is, the time-frequency tiles are adjacent, and in the waveform in the time-frequency tile, the last frequency in the time in the tile is the same as the first frequency in the next time-frequency tile. .. Since the frequencies are smoothly connected and there is no sudden change in amplitude, wideband components are unlikely to occur at the connection part of the time-frequency tile. The waveform in the time-frequency tile does not have to be tapered. Although the combination of time-frequency tiles is limited, it is not necessary to apply a taper, so a large amount of power can be transmitted. The transmission waveform within the time frequency frame in the third example is designed with restrictions so that the frequency can be smoothly connected to the adjacent time frequency frame. If you can allow the overlap of time and frequency frames, you can easily design it by simply connecting.

According to this embodiment, in many time-frequency tiles, by suppressing the height of the correlation function, it is possible to suppress the generation of grating lobes and detect an object with high accuracy.

[12th Embodiment]
Next, a signal processing system including the signal processing device according to the twelfth embodiment of the present invention will be described. The signal processing system according to the present embodiment is different from the second to eleventh embodiments described above in that the configuration of the receiver is devised. Since other configurations and operations are the same as those of the second to eleventh embodiments, the same configurations and operations are designated by the same reference numerals and detailed description thereof will be omitted.

<< Configuration of signal processing system >>
FIG. 24A is a block diagram showing a configuration of a signal processing system 2400 including the signal processing device 200 according to the present embodiment. In FIG. 24, the same reference numbers are assigned to the functional components similar to those in FIG.

The receiver 2450 includes a wireless reception unit 353, a correlation processing unit 2454, a correlation processing unit 2455, a synthesis unit 2456, and a receiving antenna 352. The correlation processing units 2454 and 2455 generate different correlation waveforms based on the transmission waveform or transmission waveform information, calculate the cross-correlation function between the received waveform and each correlation waveform, and send it to the synthesis unit 2456. .. Each correlation waveform is generated from the transmission waveform, and sampling and the like are synchronized. The synthesis unit 2456 outputs the synthesized cross-correlation function from the output unit 356. Although the detection of the target object is not shown in FIG. 24A, the position and the moving speed of the target object are detected from the output of the cross-correlation function from the output unit 356 without being affected by the moving speed.

(Synthesis part)
FIG. 24B is a block diagram showing a functional configuration of the synthesis unit 2456 according to the present embodiment.

In the left figure of FIG. 24B, the synthesis unit 2456 has an absolute value generation unit 2481 and 2482 and an addition unit 2483, and receives a cross-correlation function from the correlation processing unit 2454 and 2455 to take an absolute value of each. Then, the synthesized cross-correlation function is output from the output unit 356.

In the right figure of FIG. 24B, the synthesis unit 2456 has absolute value generation units 2481 and 2482, a subtraction unit 2485, and an absolute value generation unit 2486, and receives a cross-correlation function from the correlation processing units 2454 and 2455. The absolute value of each is taken, and the combined cross-correlation function is output from the output unit 356.

<< Outline of processing of signal processing system >>
25A and 25B are diagrams for explaining the processing outline of the signal processing system 2400 including the signal processing device 200 according to the present embodiment.

(Mutual ambiguity function connection in Doppler velocity direction)
FIG. 25A is a diagram illustrating a processing outline of the signal processing system 2400 when the synthesis unit 2456 according to the present embodiment has the configuration shown in the left figure of FIG. 24B. In FIG. 25A, the relationship between the transmission waveform and the two correlation waveforms will be described schematically by representing the ambiguity function.

As the transmission waveform, as shown in the left figure (a) of FIG. 25A, the waveform of the present embodiment in which the region where the value of the self-ambiguity function 2510 is large is concentrated at doppler = 0 and time = 0 to form an island is used. ..

The self-ambiguity function is a mutual ambiguity function when a transmission waveform is used as the correlation waveform, but when a frequency-corrected waveform obtained by applying the Doppler effect to the transmission waveform is used as the correlation waveform, the island is It is formed in a place shifted by the amount of the Doppler effect applied. In the generation of the correlation waveform, the correlation waveform is generated so that a plurality of islands formed at the shifted locations appear. When generating the correction waveform, if the amount of Doppler shift is not sufficiently separated, the correction waveforms interfere with each other and the islands are not arranged side by side. Therefore, if the amount of frequency correction is appropriately designed, a mutual ambiguity function in which distant islands are lined up can be obtained as shown in the central figures (b) and (c) of FIG. 25A.

In the present embodiment, two correlation waveforms are generated in which a mutual ambiguity function is obtained in which islands separated by alternating Doppler shift amounts are arranged at different positions. The mutual ambiguity functions 2522A and 2522B between the two correlated waveforms and the received waveform are the two central figures (b) and (c) of FIG. 25A. If the amount of frequency correction is properly designed, islands can be formed in places that complement each other, as shown in the central figures (b) and (c) of FIG. 25A.

The processing and effect of the synthesis of the present embodiment will be described with reference to the following right figure (d) of FIG. 25A. In the synthesis process of the present embodiment, the absolute values of the two cross-correlation functions calculated from the received waveform and the two correlation waveforms are taken and added. Since the cross-correlation function is a complex number, it interferes if it is added as it is, but the problem of interference can be reduced by adding the absolute value. As a result, as shown in the right figure (d) of FIG. 25A, an ambiguity function 2530 obtained by simply adding the central figures (b) and (c) of FIG. 25A is obtained. It can be seen that the ambiguity function 2530 in the right figure (d) of FIG. 25A is substantially straight in the vertical direction and is not easily affected by the vertical axis, that is, the Doppler effect. This indicates that the time time, that is, the distance on the horizontal axis can be correctly detected even when there is the Doppler effect.

(Mutual ambiguity function Doppler velocity direction zero gap generation)
FIG. 25B is a diagram illustrating a processing outline of the signal processing system 2400 when the synthesis unit 2456 according to the present embodiment has the configuration shown in the right figure of FIG. 24B. In FIG. 25B, the same reference numbers are assigned to the same components as those in FIG. 25A.

As the transmission waveform, as shown in the left figure (a) of FIG. 25B, the waveform of the present embodiment in which the region where the value of the self-ambiguity function 2510 is large is concentrated at doppler = 0 and time = 0 to form an island is used. ..

The self-ambiguity function is a mutual ambiguity function when a transmission waveform is used as the correlation waveform, but when a frequency-corrected waveform obtained by applying the Doppler effect to the transmission waveform is used as the correlation waveform, the island is It is formed in a place shifted by the amount of the Doppler effect applied. In the present embodiment, in the generation of the correlation waveform used by the plurality of correlation processing units, when each island is formed at a position shifted in the opposite direction in the Doppler direction and the absolute value is taken and subtracted, the Doppler zero A correlation waveform is generated such that a gap in which the value of the ambiguity function is equal to or less than the threshold is formed in the range including.

(B) and (c) of FIGS. 25B show the mutual ambiguity functions 2542A and 2542B between the correlation waveform used in the correlation processing unit and the transmission waveform. If the amount of frequency correction is properly designed, it is possible to form islands having symmetrical shapes as shown in FIG. 25B (b) and FIG. 25B (c).

The processing and effect of the synthesis of the present embodiment will be described with reference to the following right figure (d) of FIG. 25B. In the synthesis process of the present embodiment, the absolute values of the two cross-correlation functions calculated from the received waveform and the two correlation waveforms are taken and subtracted. Since the cross-correlation function is a complex number, it interferes if it is subtracted as it is, but the problem of interference can be reduced by subtracting the absolute value. As a result, as shown in the right figure (d) of FIG. 25B, an ambiguity function 2550 obtained by simply subtracting the central views (b) and (c) of FIG. 25B is obtained. In the ambiguity function 2550 shown in the right figure (d) of FIG. 25B, a gap in which the value of the ambiguity function is equal to or less than the threshold value is formed in the range including Doppler zero. That is, in the ambiguity function of (d) in FIG. 25B, a reflective object having a horizontal axis of 0 (zero) and a horizontal axis of 0 (zero) is not detected near doppler = 0. Understand. In addition, reflective objects other than those with velocities near 0 (zero) can detect the correct time, that is, the distance.

Since the formation of this gap generates an output signal that does not include the detection signal of a low-speed object including Doppler zero, that is, a low-speed object including stationary, the low-speed object already including stationary is excluded in the post-processing. It suffices to process the received signal, which simplifies and speeds up the processing. Further, as shown in FIG. 25B (a), there are a plurality of waveforms in which the self-ambiguity function forms an island and the cross-correlation function and the mutual ambiguity function between the waveforms become small. By using these waveforms, it is possible to obtain the effect that they can be operated in the same frequency band.

According to the present embodiment, the transmission waveform of the present embodiment can be used to seamlessly detect an object in a wide speed range, or to detect only a moving object.

[Other embodiments]
By generating the transmission waveform of the present embodiment, it is possible to superimpose the transmission waveform so far. Since each transmitted waveform is a waveform that can be easily distinguished, it is easy to separate them even if they are superimposed. It is also possible to properly design the ease of distinction by combining superpositions. In particular, when a waveform with the modulation direction reversed is superimposed, in addition to the effect of the present invention, the ambiguity function becomes symmetric in the velocity direction with respect to the axis of velocity 0 (zero), and the correlation function is synthesized. This has the effect of facilitating processing such as lowering the sensitivity to a specific speed. Further, in the above embodiment, the SFM waveform is used as the transmission waveform that changes the bandwidth, but the present invention is not limited to these waveforms. Other phase-modulated signals may be used.

Further, FIG. 26 is a diagram showing other fields in which the present invention can be used. As shown in FIG. 26, the object detection methods described above include a technique 2610 for robots to pass each other without colliding with each other, a vehicle collision avoidance technique 2620, an artificial satellite collision avoidance technique, and an observation technique on the earth 2630. Can be used for. However, the present invention is not limited to these, and can be used for monitoring intruders in offices and the like, and for detecting human movements in gymnasiums. The present invention can be used for both an object detection method using radio waves in the air and an object detection method using sound waves in the air or water, but is more suitable for object detection using sound waves because of the frequency of the transmitted wave. The present invention can be applied to the principle of a distance detection method using a sound wave called Active Sonar in underwater monitoring such as a harbor. Therefore, if the center frequency (carrier frequency), waveform time length, modulated wave frequency, frequency correction amount, etc. suitable for the sound wave are appropriately set, the effect of the present invention can be obtained in the same manner. As described above, by using the present invention in the distance detection, it is possible to detect a moving object with a small error in the distance measurement.

Further, although the invention of the present application has been described with reference to the embodiments, the invention of the present application is not limited to the above-described embodiment. Various changes that can be understood by those skilled in the art can be made within the scope of the present invention in terms of the configuration and details of the present invention. Also included in the scope of the present invention are systems or devices in which the different features contained in each embodiment are combined in any way. That is, the same effect can be obtained by arbitrarily combining the changes in the bandwidth of each of the above embodiments.

Further, the present invention may be applied to a system composed of a plurality of devices, or may be applied to a single device. Furthermore, the present invention is also applicable when the signal processing program that realizes the functions of the embodiment is supplied directly or remotely to the system or device. Therefore, in order to realize the functions of the present invention on a computer, a program installed on the computer, a medium containing the program, and a WWW (World Wide Web) server for downloading the program are also included in the scope of the present invention. .. In particular, at least a non-transitory computer readable medium containing a program for causing a computer to execute the processing steps included in the above-described embodiment is included in the scope of the present invention.

[Other expressions of the embodiment]
Some or all of the above embodiments may also be described, but not limited to:
(Appendix 1)
In order to generate a modulated wave whose frequency changes non-repetitively, a transmission waveform generation means that generates a transmission waveform in which frequency modulation is smoothly performed, and a transmission waveform generation means.
In the transmission waveform generation means, a bandwidth changing means for changing the bandwidth of the frequency modulation, and a bandwidth changing means.
A signal processing device.
(Appendix 2)
The signal processing apparatus according to Appendix 1, wherein when the transmission waveform generation means generates an SFM (Sinusoidal Frequency Modulation) waveform whose frequency is modulated by a sine wave, the SFM waveform is further modulated by the bandwidth changing means.
(Appendix 3)
The signal processing apparatus according to Appendix 1 or 2, wherein the frequency modulation bandwidth is modulated and changed by a smoothly changing waveform.
(Appendix 4)
The signal processing apparatus according to any one of Supplementary note 1 to 3, wherein the frequency modulation bandwidth is modulated by a sine wave and changed.
(Appendix 5)
The signal processing apparatus according to Appendix 4, wherein the modulation bandwidth of the frequency modulation is modulated by a sine wave whose speed changes.
(Appendix 6)
The signal processing apparatus according to any one of Supplementary note 1 to 5, wherein the frequency modulation bandwidth is narrowed and then widened.
(Appendix 7)
The signal processing apparatus according to any one of Supplementary note 1 to 5, wherein the frequency modulation bandwidth is widened and then narrowed.
(Appendix 8)
The signal processing apparatus according to Appendix 6 or 7, wherein the change in the bandwidth of the frequency modulation is modulated so as to be repeated at least twice.
(Appendix 9)
The signal processing apparatus according to any one of Supplementary note 1 to 8, wherein the center of the bandwidth of the frequency modulation is modulated so as to move.
(Appendix 10)
The signal processing apparatus according to any one of Supplementary note 1 to 9, which moves the timing at which the bandwidth of the frequency modulation changes.
(Appendix 11)
The signal processing apparatus according to any one of Supplementary note 1 to 10, which modulates the frequency modulation bandwidth with at least two waveforms.
(Appendix 12)
A signal processing method that changes the bandwidth of the frequency modulation when a transmission waveform that is smoothly frequency-modulated is generated in order to generate a modulated wave whose frequency changes non-repetitively.
(Appendix 13)
In order to generate a modulated wave whose frequency changes non-repetitively, a transmission waveform generation step is included to generate a transmission waveform with smooth frequency modulation.
The transmission waveform generation step is a signal processing program to be executed by a computer, which has a bandwidth changing step for changing the bandwidth of the frequency modulation.
(Appendix 14)
Equipped with transmitter and receiver,
The transmitter is
In order to generate a modulated wave whose frequency changes non-repetitively, a transmission waveform generation means that generates a transmission waveform in which frequency modulation is smoothly performed, and a transmission waveform generation means.
In the transmission waveform generation means, a bandwidth changing means for changing the bandwidth of the frequency modulation, and a bandwidth changing means.
A transmission means for transmitting the signal of the transmission waveform and
Have,
The receiver is
A receiving means for receiving the reflected signal in which the signal of the transmitted waveform is reflected by the target object,
Correlation calculation means for calculating the correlation function between the transmission waveform and the waveform of the reflection signal, and
An object detection means for detecting the target object based on the correlation function,
Signal processing system with.

Claims (10)

A signal processing device provided with a transmission waveform generation means for generating a transmission waveform with smooth frequency modulation.
The transmission waveform generation means has a bandwidth changing means for generating the transmission waveform whose frequency changes non-repetitively by changing the bandwidth of the frequency modulation.
The bandwidth changing means is a signal processing device that modulates and changes the bandwidth of the frequency modulation with a smoothly changing waveform, and includes a sine wave as the smoothly changing waveform . The signal processing device according to claim 1 , wherein the bandwidth changing means changes the modulation bandwidth of the frequency modulation by modulating it with a sine wave whose speed changes. A signal processing device provided with a transmission waveform generation means for generating a transmission waveform with smooth frequency modulation.
The transmission waveform generation means has a bandwidth changing means for generating the transmission waveform whose frequency changes non-repetitively by changing the bandwidth of the frequency modulation.
The bandwidth changing means is a signal processing device that narrows and widens the bandwidth of the frequency modulation, or widens and then narrows the bandwidth of the frequency modulation. A signal processing device provided with a transmission waveform generation means for generating a transmission waveform with smooth frequency modulation.
The transmission waveform generation means has a bandwidth changing means for generating the transmission waveform whose frequency changes non-repetitively by changing the bandwidth of the frequency modulation.
The bandwidth changing means is a signal processing device that modulates the frequency modulation so that the center of the bandwidth moves. A signal processing device provided with a transmission waveform generation means for generating a transmission waveform with smooth frequency modulation.
The transmission waveform generation means has a bandwidth changing means for generating the transmission waveform whose frequency changes non-repetitively by changing the bandwidth of the frequency modulation.
The bandwidth changing means is a signal processing device that moves the timing at which the bandwidth of the frequency modulation changes. A signal processing device provided with a transmission waveform generation means for generating a transmission waveform with smooth frequency modulation.
The transmission waveform generation means has a bandwidth changing means for generating the transmission waveform whose frequency changes non-repetitively by changing the bandwidth of the frequency modulation.
The bandwidth changing means is a signal processing device that modulates the frequency modulation so that the bandwidth change is repeated at least twice. A signal processing device provided with a transmission waveform generation means for generating a transmission waveform with smooth frequency modulation.
The transmission waveform generation means has a bandwidth changing means for generating the transmission waveform whose frequency changes non-repetitively by changing the bandwidth of the frequency modulation.
The bandwidth changing means is a signal processing device that modulates the bandwidth of the frequency modulation with at least two waveforms. One of claims 1 to 7 , wherein when the transmission waveform generation means generates an SFM (Sinusoidal Frequency Modulation) waveform whose frequency is modulated by a sine wave, the SFM waveform is further modulated by the bandwidth changing means. The signal processing device according to the section . It is a signal processing method of a signal processing apparatus including a transmission waveform generation step of generating a transmission waveform with smooth frequency modulation.
The transmission waveform generation step includes a bandwidth change step for generating the transmission waveform in which the frequency changes non-repetitively by changing the bandwidth of the frequency modulation.
In the bandwidth changing step, a signal processing method in which the bandwidth of the frequency modulation is modulated and changed by a smoothly changing waveform, and a sine wave is included as the smoothly changing waveform . A signal processing program that causes a computer to execute a transmission waveform generation step that generates a transmission waveform with smooth frequency modulation.
The transmission waveform generation step has a bandwidth change step for generating the transmission waveform in which the frequency changes non-repetitively by changing the bandwidth of the frequency modulation .
In the bandwidth change step, a signal processing program for causing a computer to modulate and change the bandwidth of the frequency modulation with a smoothly changing waveform and include a sine wave as the smoothly changing waveform .

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