JP3466908B2 - Marine radar using shortwave or ultrashortwave - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [0001] BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous wave
Wave transmission and reception in the ocean by transmitting and receiving several modulated waves
Shortwave and oceanographic information
Is related to marine radar using ultrashort waves. [0002] 2. Description of the Related Art A marine radar of this type is shown in FIG.
Marine radars 61 are conventionally known. This ocean leh
DA 61 measures wave information using Bragg scattering mechanism
The so-called pulsed chirp Doppler radar
The transmission frequency within a certain frequency band
And transmit and receive at an appropriate speed.
By changing, Bragg resonance scattering by waves etc.
The frequency of the received signal and the
Based on the difference between the transmitted signal frequency and the
It is configured to be able to measure the distance, speed, etc. concrete
As shown in FIG.
Is a transmitting unit 62 for generating and transmitting a transmission signal,
Receiving section 63 for demodulating the signal and transmitting and receiving signals
A transmission / reception switching circuit 64 for switching and a station for reception
Frequency f1 as a reference for generating the local oscillation signal and the transmission signal
A reference signal generator 65 for oscillating the reference signal Sref of the
Signal processing unit that measures various marine information based on the signal
66 and an antenna 67. [0003] The transmitting section 62 has a Phase-Locked-Loop-Osclla
tor (hereinafter also referred to as “PLO”) circuit
The reference signal S generated by the reference signal generator 65
The transmission frequency modulation wave Sf of the frequency f2 is synchronized with the ref.
PLO times for generating transmission wave signal generated by phase synchronization method
Path 71 and a transmission of the frequency f3 which is also constituted by a PLO circuit.
Transmit local signal generation to generate trust local signal STL
Raw PLO circuit 72 and transmission wave signal generating PLO circuit 7
1 and the local signal for transmission.
Transmission local output from the signal generation PLO circuit 72
By mixing the signal STL with the transmission signal STX,
The transmission mixer circuit 73 to be generated and the transmission signal STX are
And a power amplifying circuit 74 for amplifying. [0004] On the other hand, the receiving section 63 is composed of a PLO circuit.
The reference signal Sref output from the reference signal generator 65
Synchronize and generate local signal SRL for reception at frequency f4
Reception local signal generation circuit 81, antenna 67,
Received signal SRX input via transmission / reception switching circuit 64
And the frequency output from the transmission wave signal generating PLO circuit 71.
The first intermediate frequency signal is generated by mixing the
Receiving first mixer circuit 82 and first intermediate frequency signal
A first intermediate frequency amplifying circuit 83 for amplifying the first intermediate frequency;
By mixing the signal and the reference signal Sref,
(2) Second mixer circuit 84 for reception generating intermediate frequency signal
And a second intermediate frequency amplifier circuit for amplifying the second intermediate frequency signal
85 and the signal generated by the reception local signal generation circuit 81.
The received local signal SRL and the second intermediate frequency signal.
And a detection circuit 86 for detecting by singing.
I have. The marine radar 61 generates a transmission wave signal.
PLO circuit 71 sweeps out a predetermined frequency range per second
By shaking, a frequency modulated wave Sf is generated. Next
The transmission mixer circuit 73 generates the generated frequency modulated wave S
f and the transmission local signal STL by mixing
And generates a transmission signal STX. In this case, the transmission signal STX
Is intermittent by a control signal output from a control unit (not shown).
And is output to the power amplifying circuit 74.
Next, the power amplification circuit 74 converts the transmission signal STX to a predetermined gain.
Circuit for transmitting / receiving transmission signal STX after power amplification
64. On the other hand, the transmission / reception switching circuit 64
The transmission signal STX is activated according to the switching signal output from the control unit.
Output to the antenna 67 and during the transmission suspension period.
A receiving unit for receiving the reception signal SRX received by the antenna 67;
63. [0006] In the receiving section 63, the
Frequency due to resonant resonance scattering and Doppler shift
The shifted received signal SRX is input and received by the receiving unit 63.
First mixer circuit 82 receives the received signal SRX and the frequency-modulated wave.
Sf and the first intermediate frequency.
Convert to one intermediate frequency signal. After this, the first intermediate frequency signal
Is converted to a second intermediate frequency signal of the second intermediate frequency.
Thereafter, detection is performed by the detection circuit 86. As a result,
A measurement signal SM is generated, and the generated measurement signal SM is
The signal is output to the signal processing unit 66. Thereafter, the signal processing unit 66
Is included in the measurement signal SM by the FFT operation.
Extract the signal level of each frequency component
Doppler echo from resonant wave component wave in several components
Based on this, it measures distance and speed to the waves. [0007] However, this conventional method
The marine radar 61 includes a transmitting unit 62, a receiving unit 63, and a signal.
Of the marine radar 61 as a whole including the signal processing unit 66
A function to self-diagnose whether the function is operating normally
Information is measured correctly
The problem is that self-diagnosis cannot be
You. In this case, the contents of the self-diagnosis include transmission
The signal STX is received by the receiving unit 63,
FFT calculation for the processing unit 66 based on the measurement signal SM
And if it can be determined whether the result of the operation is normal
Good. However, in the configuration using the ocean radar 61,
If the received signal STX is received as it is, the received signal SRX
Is (f2 + f3), the first mixer for reception
Circuit 82, second mixer circuit 84 for reception, and detection circuit
86, the frequency of the measurement signal SM
The frequency is ((f2 + f3)-(f2 + f4 + f1))
Becomes In this case, the frequency f of the transmission local signal STL
3, the frequency f1 of the reference signal Sref and the reception local
Since the sum of the frequencies f4 of the signal SRL is equal to each other,
The frequency of the measurement signal SM is 0 Hz. As a result,
Evaluation of the characteristics of the unit 62, the receiving unit 63, and the signal processing unit 66
Can't do it. On the other hand, the reception local signal generation circuit 81
Frequency of transmission local signal SRL or local signal for transmission
Frequency of transmission local signal STL of generating PLO circuit 72
May be slightly shifted. However, temporarily
A configuration to shift the frequency of the reception local signal SRL is adopted.
If used, the PLO of the reception local signal generation circuit 81
The oscillation frequency is changed to the frequency of the PLO circuit 71 for generating the transmission wave signal.
It is necessary to synchronize with the number modulation wave Sf and shift it slightly.
is there. Therefore, P of reception local signal generation circuit 81
LO is converted to the received local signal SRL in a few frequency steps.
Must be configured to generate This place
Frequency splicing according to the slight frequency step
Is included in the measurement signal SM, and the signal processing unit 66
The problem that FFT operation with high accuracy by
is there. The present invention has been made to solve such a problem.
Short-wave, which is capable of performing high-precision fault diagnosis.
Or to provide marine radars using ultrashort waves
And [0011] Means for Solving the Problems In order to achieve the above object,
The marine radar using shortwave or ultrashortwave according to the invention is a continuous wave.
Oscillation frequency control for transmitting frequency modulated wave for transmission
The transmission oscillator that generates according to the control data,
Transmitting a transmission signal based on the transmitted frequency modulated wave for transmission.
And a predetermined frequency synchronized with the transmitting frequency modulated wave.
The reception frequency modulated wave shifted by the wave number
A receiving oscillator that generates according to the oscillation frequency control data;
Intermittently transmitting the transmission signal, and a transmission pause time
Measurement of ocean information by receiving received signals
In marine radar using waves or ultrashort waves,The two
The step frequency in each of the frequency modulated waves
The corresponding step frequency data to the corresponding frequency modulation for transmission.
Frequency or the highest oscillation frequency of the receiving modulated wave
Each reference oscillation frequency data corresponding to the oscillation frequency
Both oscillation frequencies are calculated by adding or subtracting, respectively.
An oscillation frequency control unit that generates data is provided,Both oscillations
Section is a direct digital synth
Each of the transmission frequencies comprises a sizer.
Modulated waveandAny one of the frequency modulation waves for reception
One of them is shifted by a predetermined frequency from the frequency at the time of measurement
And the transmission signal output from the transmission unit is directly
Interference reception and fault diagnosis can be performed based on the received signal
It is characterized by comprising. In this marine radar, a transmission signal is based.
Frequency modulated wave for transmission and reception for receiving received signal
Frequency modulated wave for direct digital
Generated by the synthesizer. In this case, the director
Digital synthesizers are generally
Is provided. Therefore, the wave
To read waveform data from a shape memory at high speed
More accurate transmission frequency independent of temperature and humidity
Modulation wave and frequency modulation wave for reception can be generated.
You. For this reason, for example, reception frequency modulation wave or transmission
The frequency modulation wave for
Shift by receiving the transmitted signal directly
A signal corresponding to the frequency difference can be received.
Therefore, the transmitter and the receiver are operating normally
It is possible to reliably diagnose whether or not a failure has occurred. Also,
By performing an FFT operation on the received signal,
By comparing the measured value with the
It is also possible to diagnose failures. [0013]Also,Frequency modulated wave for transmission and frequency for reception
Direct digital system as an oscillation source of wave number modulated wave
Waveform data from the waveform memory as long as the synthesizer is used.
Various methods can be used for reading the data. An example
For example, by sequentially specifying the addresses of the waveform memory,
However, it is possible to generate a frequency modulation wave. This short
For marine radars using waves or ultrashort waves, the oscillation frequency control
The control unit controls the frequency modulation wave for transmission and the frequency modulation wave for reception.
Direct digital synthesizer as oscillation source
The lowest oscillation as reference oscillation frequency data
Step to vibration frequency data or maximum oscillation frequency data
By sequentially adding or subtracting frequency data,
Generate oscillation frequency control data. Therefore, the waveform memo
ROM for storing the read address from the
Can be eliminated, reducing equipment costs.
In addition, the size of the device can be reduced. [0014] BRIEF DESCRIPTION OF THE DRAWINGS FIG.
Ocean radar using VHF transmission signal
An embodiment applied to a radar will be described. First, an outline of the marine radar will be described.
You. Ocean radar is based on the Black Resonance Mechanism,
Resonant waves that resonate with the transmitted signal as irradiated radar waves
Based on Doppler echo from component wave, surface current and wave
Ocean information such as wave height, period and wave direction can be measured
It is configured. The sea surface current and the wave direction of the waves
Because it is expressed in the amount of a vector, as an actual radar system
Consists of two marine radars, each marine radar
As vector quantities based on ocean information measured by
Measure. The marine radar 1 is an FMICW (Frequency
Modulated Interrupted ContinuousWave Method)
It is configured to be able to measure ocean information, as shown in FIG.
As described above, the signal generator 2, the power amplifier 3, the receiver 4, the signal
Diagnosis of failures arranged in the processing unit 5 and the operation unit not shown
Switch 6. The signal generation unit 2 is a transmission unit according to the present invention.
A frequency modulated wave for transmission and reception according to the present invention
Sine wave signal corresponding to the
It generates a signal from a credit bureau, and generates a reference signal.
Raw circuit 11, 81.5 MHz PLO circuit 12 (hereinafter P
LO circuit 12), transmission wave signal generation circuit 13,
Multiplying circuit 14, modulation circuit 15, receiving station signal generation circuit 1
6. Multiplier circuit 17, 9.1 MHz PLO circuit 18
And a control circuit 19).
It has. Here, the reference signal generating circuit 11
High stability crystal oscillator that oscillates fixed oscillation of HZ reference signal Sref
And the generated reference signal Sref is a PLO
The circuit 12, a second intermediate frequency amplifier circuit described later in the receiving unit 4
33 and the PLO circuit 18. PLO circuit
12 is composed of a Phase-Locked-Loop-Oscllator circuit.
And the reference signal Sre output from the reference signal generation circuit 11.
81.5 MHz read pulse signal S using f as a reference signal
Oscillates fixedly. The transmission wave signal generation circuit 13 operates for 0.25 seconds.
Within the sweep time, 20.875 MHz to 21.025 MH
Sweep sine wave signal of z with step frequency of 0.5Hz
Circuit which is a direct
Digital synthesizer (hereinafter also referred to as "DDS")
And a low-pass filter. here
In the transmission wave signal generation circuit 13, the DDS is
19 in accordance with the transmission frequency control data DTXf output from
The waveform data stored in the built-in waveform memory.
Data is read out in synchronization with the read pulse signal Sp, and a low-pass
Filter removes harmonic components of read waveform signal
By doing so, the frequency is half of the transmission frequency fTX.
Output a sinusoidal signal. The multiplication circuit 14 includes a transmission wave signal generation circuit 13
By doubling the sine wave signal output from
When the transmission frequency fTX is 41.75MHz to 42.05MHz
And outputs a continuous wave transmission signal STX to the modulation circuit 15.
You. The modulation circuit 15 controls the transmission output from the control circuit 19
The transmission signal STX is pulse-modulated according to the switching signal ST, and
The adjusted transmission signal STX is output to the power amplifier 3. concrete
In the meantime, as shown in FIG.
In accordance with the signal ST, at the sweep time TC of 0.25 sec.
A transmission signal STX is continuously generated for 244 μS as a communication period.
After output, the transmission signal continues for 244 μS
Exchange these operations, such as stopping the output of STX.
Repeat each other. The signal generated by the receiving station oscillating signal generator 16 is used for normal measurement.
In synchronization with the sweep oscillation of the transmission wave signal generation circuit 13,
0.5 Hz step frequency within 0.25 second sweep time
Positive number from 15.6475 MHz to 15.7975 MHz
A circuit for sweeping and oscillating a sinusoidal signal, comprising a DDS
And a pass filter. Where received
In the local oscillation signal generation circuit 16, the DDS
According to the receiving station frequency control data DRXf output from the
Waveform data stored in the built-in waveform memory
Read in synchronization with the read pulse signal Sp,
Filter removes harmonic components of the read waveform signal
As a result, a sine wave signal that is the basis of the
Power. Note that the receiving station signal generation circuit 16 will be described later.
At the time of failure diagnosis, the oscillation frequency is
40.33 Hz lower sine wave signal, ie 15.6474
Sine of 5967 MHz to 15.797495967 MHz
Sweep oscillates a wave signal. The multiplying circuit 17 is a receiving station generated signal generating circuit 1
6 by doubling the sine wave signal output from
Generate a local signal SCH of trust. Note that the multiplication circuit 17
Means that during normal measurement, the frequency is 31.295 MHz to 3
Generates a 1.595 MHz local oscillation signal, which is used for fault diagnosis.
Has a frequency of 31.2491934 MHz to 31.5
A local signal of 949934 MHz is generated. PLO times
Road 18 is composed of a Phase-Locked-Loop-Oscllator circuit.
And the reference signal Sre output from the reference signal generation circuit 11.
8. f is used as a reference signal and becomes a basis of a received local signal.
A high frequency signal of 1 MHz is oscillated fixedly. The control circuit 19 includes a transmission wave signal generation circuit 13
And the oscillation frequency for the reception station oscillation signal generation circuit 16.
Control, transmission switching control for modulation circuit 15, and fault diagnosis
Switching control of the failure diagnosis switching circuit 23 described later in
And communication with the signal processing unit 5 and the like. Control circuit
19, specifically, as shown in FIG.
And a calculation result of the CPU 41
The RAM 42 for temporarily storing and the operation program of the CPU 41
ROM 43 for storing gram and the like, and adders 44 to 47
And Here, the transmission wave signal performed by these
Signal generating circuit 13 and receiving station generated signal generating circuit 16
The oscillation frequency control will be described. In this control process
Is stored in the ROM 43 first.
The lowest oscillation frequency data DTM of the transmission wave signal generation circuit 13
Output to one input of adder 45 and clock C
L is output to the adders 44 and 45. This allows the adder
45 transmits the lowest oscillation frequency data DTM to the transmission frequency control data.
The signal is output to the transmission wave signal generation circuit 13 as the data DTXf. Next
The CPU 41 calculates the unit of the oscillation frequency during the sweep.
Step frequency corresponding to the step frequency that is the change frequency
After outputting the wave number data DTS to the adder 44, the clock C
L is output. As a result, the adder 45 becomes
Frequency data DTS output from the
The wave number data DTM is added, and the added data is used as the oscillation frequency.
It is output as number control data DTXf. These addition processes
Is performed every 800 ns, and as a result, as shown in FIG.
The signal wave generation circuit 13 operates from the lowest oscillation frequency fmin to the highest
When switching the frequency up to high oscillation frequency fmax, 800 ns
0.5 Hz which is the step frequency fstep every Tstep
Oscillates to a higher oscillation frequency. In addition,
The CPU 41 also uses the signal for the transmission signal
In the same manner as the oscillation signal of
The data DRM is output, and the
It outputs the top frequency data DRS. This allows the receiving station
The signal generation circuit 16 operates from the lowest oscillation frequency fmin to the highest
Up to oscillation frequency fmax, 800ns frequency switching time
0.5 Hz, which is the step frequency fstep, for each Tstep
Sweep oscillation is performed so that the oscillation frequency becomes high. Thus, the oscillation frequency control data DTR
By generating f and DRXf, general waveform data
The following advantages compared to the method using a read ROM
Occurs. That is, in a general method, the waveform reading R
Requires a certain amount of memory as OM,
In contrast to the soaring price and the size of the equipment,
In adder 1, adders 44 to 47 output from CPU 41.
The minimum oscillation frequency data DTM and DRM
Waveform reading because data DTS and DRS only need to be added
ROM can be eliminated, resulting in lower equipment costs
The size and the size of the device can be reduced. Also, the lowest
Oscillation frequency data DTM, DRM and step frequency data
By appropriately setting the DTS and DRS, the transmission wave signal
For the raw circuit 13 and the receiving station signal generation circuit 16,
Arbitrarily set the frequency and step frequency of the oscillation signal.
Can be specified. The power amplification unit 3 includes a power amplification circuit 21 and a transmission
A reception switching circuit 22 and a failure diagnosis switching circuit 23 are provided.
ing. Here, the power amplification circuit 21 is
The power of the transmitted transmission signal is amplified to a predetermined power.
The transmission / reception switching circuit 22 outputs an output from the control circuit 19.
In response to the transmission control signal ST
Transmission / reception switching control. The failure diagnosis switching circuit 23 includes:
It consists of a coaxial relay.
Output the received signal SRX from the
In accordance with the transmission control signal Sf from the control circuit 19,
Therefore, the modulation circuit 1 is used instead of the reception signal SRX from the antenna.
The transmission signal STX output from 5 is output to the reception unit 4. The receiving section 4 includes a high-frequency amplifier circuit 31 and a first
Inter-frequency amplifier circuit 32, second intermediate frequency amplifier circuit 33, detection
A circuit 34 and a 1/20 frequency dividing circuit 35 are provided. This
Here, the high-frequency amplifier circuit 31 converts the received signal SRX into a predetermined signal.
And amplify. The first intermediate frequency amplification circuit 32 receives the received signal
By mixing SRX and the local oscillation signal SCH, 1
Is converted to a first intermediate frequency signal of 0.455 MHz,
One intermediate frequency signal is amplified with a predetermined gain. 2nd intermediate frequency
The amplifier circuit 33 includes a first intermediate frequency signal and a reference signal Sref.
By mixing the second intermediate frequency of 455 kHz.
And converts the second intermediate frequency signal to a predetermined gain.
Amplify with The detection circuit 34 includes a 1/20 frequency dividing circuit 35.
The 9.1MHz oscillation signal is divided by 20 to generate
455 KHz local signal and second intermediate frequency signal generated
And 200Hz or less by mixing
Generate the measurement signal SM below and send the measurement signal SM.
Output to the signal processing unit 5. The signal processing unit 5 is based on the measurement signal SM.
Extraction of resonance wave component wave by FFT calculation
Then, based on the extracted resonant wave component waves,
Analyze marine information such as speed. As a specific configuration
, The signal processing unit 5, as shown in FIG.
A / D converter 51 for analog-to-digital conversion of M
And the measurement data output from the A / D conversion circuit 51
An FFT operation circuit 52 for performing an FFT operation based on the
The operation data calculated by the operation circuit 52 is stored.
RAM 53 and various oceans measured based on the calculation data
The information and various data in the calculation process are stored in the LCD panel 55.
And a CPU 54 for displaying the information. Next, a fault diagnosis operation in the marine radar 1
The overall operation will be described mainly. First, an outline of the operation during normal measurement will be described.
I will tell. First, the multiplier circuit 14 generates the transmission wave signal.
Doubling the oscillation signal generated by the path 13
Then, a transmission signal STX is generated. Next, the modulation circuit 15
Is the power after pulse modulation of the generated transmission signal STX
Output to the amplifier 3. Next, the transmission / reception switching circuit 22
Output transmission signal STX to antenna according to transmission control signal ST
I do. As a result, the transmission signal STX is launched toward the sea surface.
As well as being scattered by waves on the sea surface,
Undergoes a Doppler shift. Next, the transmission signal STX
The scattered signal scattered in the opposite direction to the irradiation direction is sent to the antenna.
Therefore, it is received. In this case, the received
The received signal SRX is transmitted to the transmission / reception switching circuit 22 and
Input to the high frequency amplifier circuit 31 via the diagnostic switching circuit 23
After being amplified by the high-frequency amplifier circuit 31,
The signal is output to the intermediate frequency amplifier circuit 32. Then the received signal
SRX is supplied to the first intermediate frequency amplifying circuit 32 for the first intermediate frequency.
After being converted into a wave signal, the second intermediate frequency amplifying circuit 33
Therefore, the signal is converted to the second intermediate frequency signal, and finally the detection
The signal is converted into a measurement signal SM by a path 34. After this,
The signal processing unit 5 calculates the wave speed based on the measurement signal SM.
And so on. On the other hand, at the time of failure diagnosis, the switching switch
When the switch 6 is operated and the switching signal SS is input, the control circuit
The CPU 41 of the path 19 outputs the lowest oscillation frequency control data DT
M, step frequency data DTS and step frequency data
For data DRS, data with the same content as during normal measurement
Output and the minimum oscillation frequency control data DRM
40.33 Hz lower than the normal local signal frequency
The data which oscillates is output. At the same time, the CPU 41
Is a switching signal for failure diagnosis to the switching circuit 23 for failure diagnosis.
The signal Sf is output. This causes the transmission signal STX to fail.
Input to the high frequency amplifier circuit 31 via the diagnostic switching circuit 23
Is forced. As a result, in the receiving unit 4, the input transmission signal
STX was converted into first and second intermediate frequency signals, and the converted
The detection circuit 34 detects the second intermediate frequency signal. This place
The transmission wave signal generation circuit 13 and the reception station
High accuracy independent of temperature and humidity as the oscillation source of the path 16
Is used, the signal generator 2 and the receiver
When the communication unit 4 is operating normally, the measurement signal SM
Is always shifted by the receiving station signal generation circuit 16.
Signal in accordance with the frequency that was switched, that is, 8 in this example.
A low frequency signal of 0.66 Hz is generated. Then this
The measurement signal SM is output to the signal processing unit 5. This result
As a result, check the output frequency and amplitude value of the measurement signal SM.
Thus, the gain of the signal generator 2 and the receiver 4
About whether it is operating normally or not with high accuracy
Can be used for fault diagnosis. Next, the signal processing unit 5 performs the A / D conversion
The road 51 converts the measurement signal SM into an analog signal every 0.25 seconds.
Generates measurement data by digital conversion
Then, the data is output to the FFT operation circuit 52. FFT operation circuit 5
2 performs FFT operation on the measurement data with a resolution of 4 Hz
By this, the spectrum distribution of the measurement signal SM is obtained,
The obtained speckle data is stored in the RAM 53. this
In the case, the FFT operation is performed with a resolution of 4 Hz,
Specifically, as shown in FIG.
Cloth. In addition, this spectrum is equivalent to ocean radars 1 to 4
Bragg caused by waves at a distance of 0 km
This corresponds to wave information based on resonance scattering. Then, CPU
54 is based on the spectrum data, as shown in FIG.
From the start of the self-diagnosis shown in FIG.
Spectrum data at the same distance
Collect numbers, sort them in chronological order, and sort them
The new spectrum data is stored in the RAM 53. What
In this case, the time is not limited to 500 seconds, for example,
For example, from the start of self-diagnosis to the elapse of 224 seconds
Change the number of series data and the generation time of measurement data as appropriate.
Can be Next, the FFT operation circuit 52
Based on the spectrum data newly stored in M53
By performing the FFT operation again, as shown in FIG.
Doppler spectrum corresponding to the moving speed of the scattered waves
And the obtained Doppler spectrum data is stored in RAM5.
Store it in 3. Next, the CPU 54 stores the
Based on stored Doppler spectrum data
The resulting spectral distribution of FIG.
Let me show you. According to the figure, the frequency is set to ± 0.66 Hz.
It can be seen that a ppra spectrum exists. This
In the case of, the Doppler spectrum expected to be measured in advance
The overall operation of the signal processing unit 5
Can be diagnosed. Thus, this
According to the marine radar 1, the signal generator 2, the receiver 4,
It is possible to automatically perform a failure diagnosis on the signal processing unit 5.
it can. In this case, the failure diagnosis is performed, for example, once a day.
Preferably to start the first measurement of the day.
It is more preferable to carry out before carrying out. The present invention is limited to the above embodiment.
The configuration is not specified, and the configuration can be appropriately changed. example
For example, the transmission / reception frequency and the sweep time are indicated in this embodiment.
The values are not limited to the values shown, but may be changed as appropriate for the purpose of measurement.
be able to. Further, the signal generator 2, the power amplifier 3, and the
The configuration of the receiving unit 4 can also be changed as appropriate. [0035] As described above,According to the present inventionShortwave or
According to marine radar using ultrashort waves, direct
Using a digital synthesizer as the oscillation source
And the receiving oscillator, and output from the transmitting unit.
By directly receiving the transmitted transmission signal and performing fault diagnosis,
Ensure that the transmitter and receiver are working properly
In addition to being able to diagnose failures with high accuracy,
By comparing the measured value to the expected measured value,
The failure diagnosis can also be reliably performed for the measuring section. Also,thisOcean using shortwave or ultrashortwave
According to the radar, the oscillation frequency control unit controls the frequency of both oscillation units.
Each step frequency corresponding to the step frequency in the modulated wave
The wave number data is converted into a frequency modulation wave for transmission and a frequency modulation for reception.
Corresponds to the lowest or highest harmonic oscillation frequency
Add or subtract sequentially to each reference oscillation frequency data
To generate both oscillation frequency data,
Cost and the size of the device can be reduced.
You.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an electrical block diagram of a marine radar according to an embodiment of the present invention. FIG. 2 is a block diagram of a control circuit according to the embodiment of the present invention. FIG. 3 is a block diagram of a signal processing unit according to the embodiment of the present invention. FIG. 4 is an explanatory diagram for explaining an oscillation operation of the transmission wave signal generation circuit and the reception station oscillation signal generation circuit according to the embodiment of the present invention. FIG. 5 is an explanatory diagram for explaining a transmission / reception operation in the marine radar according to the embodiment of the present invention. FIG. 6 is a spectrum density diagram showing a result of FFT operation by an FFT operation circuit of a signal processing unit at the time of a self-diagnosis, showing a relationship between a spectrum density and a frequency. FIG. 7 is a relationship diagram showing a relationship between a spectrum level and an elapsed time rearranged in time series by a CPU of a signal processing unit. FIG. 8 is an explanatory diagram illustrating a relationship between a frequency and a level of a Doppler spectrum obtained by an FFT operation circuit. FIG. 9 is an electrical block diagram of a conventionally known marine radar. [Description of Signs] 1 Ocean radar 2 Signal generator 4 Receiver 5 Signal processor 13 Transmission wave signal generator 16 Receiver signal generator 19 Control circuit

Continuation of the front page (56) References JP-A-8-292273 (JP, A) JP-A-6-102342 (JP, A) JP-A-10-10227 (JP, A) JP-A-3-262990 (JP) JP-A-60-22681 (JP, A) JP-A-61-50283 (JP, U) JP-A-57-138076 (JP, U) JP-A-7-502591 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) G01S ⁷ /00-7/42 G01S 13/00-13/95

Claims (1)

(1) A transmission oscillating unit that generates a transmission frequency modulated wave that is a continuous wave according to transmission oscillation frequency control data, and a transmission oscillation unit that generates the transmission frequency modulated wave. A transmission unit that transmits a transmission signal based on the transmission frequency modulation wave, and a reception oscillation unit that generates a reception frequency modulation wave shifted by a predetermined frequency according to the reception oscillation frequency control data in synchronization with the transmission frequency modulation wave. Comprising, intermittently transmitting the transmission signal,
In a marine radar using a short wave or an ultrashort wave for measuring marine information by receiving a reception signal during a transmission suspension time, a step frequency in each of the frequency modulated waves of both the oscillation units is used.
Each step frequency data corresponding to the wave number is
Up to the lowest oscillation frequency of the wave number modulated wave and the receiving modulated wave.
Or the reference oscillation frequency data corresponding to the maximum oscillation frequency
By adding or subtracting to
An oscillation frequency control unit for generating oscillation frequency data, wherein both of the oscillation units are each provided with a direct digital synthesizer as an oscillation source, and any of the transmission frequency modulation wave and the reception frequency modulation wave Or at least one of which is shifted by a predetermined frequency from the frequency at the time of measurement, directly receives the transmission signal output from the transmission unit, and is configured to be able to execute a failure diagnosis based on the received signal. Marine radar using shortwave or ultrashortwave.