JPH0675104B2 - Radar signal processing method and device, and chainness determination method suitable therefor - Google Patents

Description

TECHNICAL FIELD The present invention relates to radar signal processing for transmitting a pulse signal to a target and receiving a reflected signal from the target to acquire information such as the position and shape of the target. A method and apparatus.

2. Description of the Related Art Conventionally, there is known a radar signal processing device that transmits a pulse signal to a target, receives a reflection signal of the pulse signal from the target, and obtains information such as the position and shape of the target.

FIG. 6 shows an example of the configuration of the radar signal processing device.

The apparatus shown in this figure has a pulse signal 10 applied to a target 10.
It includes an antenna 12 and a transmitting / receiving circuit 14 for transmitting 0 and receiving a reflected signal 102, and an indicator 16 for displaying information such as the position and shape of the target 10 extracted from the reflected signal 102. That is, the device shown in this figure is a so-called pulse radar, and the pulse signal is targeted as a radio wave in a microwave band such as an X band or an S band.
Sent to 10.

FIG. 7 shows the operating principle of the device shown in FIG.

In FIG. 7, the antenna 12 shown in FIG. 6 rotates in the direction of the arrow. At this time, the target 10 is hit several times per one rotation. For example, if the rotation speed of the antenna 12 is 20 rotations / minute, the transmission repetition frequency is 1000 Hz, and the beam width θ is about 1 degree, the target 10 (target
10 is considered as a point target) about 8 times / 1
Only the rotation will be a hit.

FIG. 8 shows the structure of an apparatus according to a conventional example.

The device shown in FIG. 8 is a circuit built in the transmission / reception circuit 14, and is a circuit for converting a reception signal supplied from the antenna 12 into data and outputting the data.

The device shown in this figure judges whether or not a predetermined threshold level is exceeded at each sampling timing of a received signal, and outputs a judgment result as a binary value, and a threshold circuit 18 and the threshold circuit. The binary value output from 18 is written according to the threshold clock, and at the same time, the judgment result of the previous sweep of the same sampling timing is read out, and the threshold circuit.
18 includes a cancel pulse generation circuit 22 that compares the outputs of the memory circuit 20 and a cancel pulse according to the comparison result, and a signal cancel circuit 26 that deletes the data corresponding to the cancel pulse from the received signal. There is.

Generally, a received signal handled by an apparatus having a structure as shown in FIG. 8 has a structure as shown in FIG. In FIG. 9, sweeps 1, 2, ...
N-1 and N correspond to one sweep of the pulse signal transmitted from the transmission / reception circuit 14, respectively.

In FIG. 8, the received signal is input to the threshold circuit 18 for each sweep, and it is determined whether or not it has exceeded a predetermined threshold level, for example, the level shown by the alternate long and short dash line in FIG. The memory circuit 20 is a circuit that stores the output of the threshold circuit 18 according to the range clock corresponding to the sampling timing, and is a circuit that stores the output of the threshold circuit 18 corresponding to one sweep of the received signal. . For example, the threshold circuit
In 18, if a binary value of "1" is output when the received signal exceeds the threshold level, and if it does not exceed the threshold level, a binary value of "0" is output to the memory circuit 20. These "1" which are the outputs of the circuit 18,
The binary value "0" is stored. Further, in the memory circuit 20, at the same time, the data of the same sampling timing in the previous sweep is read out to the cancel pulse generating circuit 22. For example, data written in the memory circuit 20, when the sampling timing t ₀ is the data D _1, the data D ₂ in accordance with the sweep 2 when reaching the same sampling timing t ₀ in the next sweep Is written in the memory circuit 20, and at the same time, the data D ₁ related to the previous sweep is the cancel pulse generation circuit.
Read on 22.

In the cancel pulse generation circuit 22, the outputs of the threshold circuit 18 and the memory circuit 20 are compared. That is, the binary value output from the threshold circuit 18 is the binary value relating to the sweep currently handled by the threshold circuit 18, and the binary value output from the memory circuit 20.
The decimal value is a binary value related to the previous sweep. Therefore, in the cancel pulse generation circuit 22, whether the outputs of the threshold circuit 18 and the memory circuit 20 have the same value, that is, when the received signal at the present time exceeds the predetermined threshold level, Whether the received signal at the same sampling timing in the previous sweep still exceeded the threshold level, and if the received signal at the present time does not exceed the threshold level, the received signal at the same sampling timing in the previous sweep still remains at the threshold level. It is judged whether or not the hold level is exceeded.

On the other hand, the received signal is supplied to the signal cancel circuit 26. The signal cancel circuit 26 cancels the data of the sampling timing from the received signal in response to the cancel pulse supplied from the cancel pulse generation circuit 22. That is, in the cancel pulse generation circuit 22, for example, as shown in sweep 1 and sweep 2 in FIG. 9, when the reception signal rising 104 suddenly occurs in this sweep, a cancel pulse is generated, In the signal cancel circuit 26, such a rising 10
4 is canceled according to the cancel pulse generated from the cancel pulse generating circuit 22.

Therefore, in the conventional radar signal processing device, when a sudden change in the received signal as shown by the rising edge 104 in FIG. 9 occurs, it is possible to remove this sudden change and output good data. is there.

[Problems to be Solved by the Invention] However, in the related art, when the true reflection pulse and noise in the received signal happen to occur at the same timing in successive sweeps, the latter, that is, noise cannot be removed. There was a problem.

For example, the received signal 1 as shown by 104 in FIG.
When the sudden change of 02 occurs, the cancel operation by the signal cancel circuit 26 can be accurately performed if there is no received signal exceeding the threshold level at the same sampling timing of the previous sweep. However, if the true reflection pulse 106 from the target 10 exists here, the sudden change 104 is not recognized as noise, and therefore the signal cancellation circuit 26 does not cancel it. The sudden change 104 as shown in this figure can generally occur frequently due to intrusion of transmission waves of other radars, so-called radar interference.

The output data failure due to such radar interference causes radial noise 108 on the screen of the indicator 16 as shown in FIG. 10, and as a result, the indicator 16
The screen of was difficult to see.

In addition, the reflection from the target generally includes fluctuations called fractuation.

Therefore, for example, consider the case where there is a fluctuation in the sweep in which the reflection signal from the target is continuous, and one sweep exceeds the threshold level and the other does not, in one sweep and the next sweep. Therefore, there is a problem in that a cancel pulse is generated even though it is a signal, which may result in a decrease in detection probability of the signal.

The present invention has been made to solve such a problem, and eliminates determination by one threshold level to reduce erroneous recognition due to radar interference, for example, to display an indicator screen. An object of the present invention is to provide a radar signal processing method and device capable of providing a high quality screen.

[Means for Solving the Problems] In order to achieve the above-mentioned object, the concatenation determination method of the present invention uses data obtained by sampling a reflection signal from a target by a pulse signal repeatedly transmitted by a predetermined number of sweeps. , Amplitude division of the data sampled at the same sampling timing in each sweep, and as a result of the amplitude division, it is determined whether or not the data of the same sampling timing that crosses the maximum amplitude division exists in a predetermined number and a continuous number or more. However, if it is determined that the number and the number of consecutive numbers are not equal to or greater than the predetermined number and the number of consecutive consecutive numbers, the data that crosses the amplitude division region related to this number and the number of consecutive determinations is simulated if it crosses the next amplitude division region. Then, repeat the same number and continuous number judgment for the data that crosses the next amplitude division area, If the result of the number and continuity determination is that the number and the number of continuations are greater than or equal to the predetermined number, it is considered that the amplitude division area related to this number and the number of continuity determinations is linked or high, and the number and the number of consecutives It is characterized in that the data related to the above-mentioned dummy is excluded from the data simulated to cross or cross the amplitude division area related to the determination, and then the data is used for extraction of information such as the position and shape of the target.

Further, the radar signal processing method of the present invention transmits a pulse signal by repeating a predetermined number of sweeps, receives a reflection signal from a target due to the pulse signal, samples the received reflection signal, and obtains data obtained as a result of sampling. In the radar signal processing method for extracting the information such as the position and shape of the target from the data of the data sampled at the same sampling timing in each sweep, the method of the present invention determines the concatenation and excludes the data related to imitation. The above information is extracted based on the obtained data.

Further, in the radar signal processing device according to the present invention, the transmission / reception circuit determines the concatenation of the data sampled at the same sampling timing from the reflection signal corresponding to each sweep of the pulse signal by the method of the present invention. It is characterized by including a judgment circuit and a data selector for selecting data to be supplied to the indicator from the data excluding the data related to the imitation based on the result of the judgment in the judgment circuit.

Further, the transmission / reception circuit further includes a storage unit that stores the sampled data for each sweep and supplies the determination circuit and the data selector with the data of the same sampling timing according to the range clock.

[Operation] In the concatenation determination method according to the first aspect, the concatenation of data sampled at the same sampling timing in each sweep is determined. The determination of this linkage is based on the amplitude division of the sampled data,
And the number and continuous number determination based on this amplitude classification. The number and continuous number determination is a determination regarding the number and continuous number of data of the same sampling timing that crosses the amplitude division region, and is performed so as to sequentially shift from the maximum amplitude region to a lower amplitude division region.

More specifically, first, data sampled at the same sampling timing in each sweep is amplitude-divided. As a result of this amplitude division, it is determined whether or not the data of the same sampling timing that crosses the maximum amplitude division area exists in a predetermined number and a predetermined continuous number or more. As a result of this number and continuous number judgment, when it is determined that it is not more than the predetermined number and the predetermined continuous number, the data of the amplitude division area related to the number and continuous number judgment is the same sampling timing across the next amplitude division area. Together with the data, it is used for the same number and continuous number judgment. That is,
The determination of the number and the number of consecutive numbers is repeated while the amplitude division area that is the target of the determination of the number and the number of consecutive numbers is sequentially expanded.
As a result of the number of times and the number of consecutive times being repeatedly executed as described above, when it is determined that the number is equal to or more than the predetermined number and the number of consecutive times, the amplitude division area related to the number and the number of consecutive times has a linkage or a high degree. Is considered.

As described above, in the concatenation determination method of the present invention, since the concatenation is determined by the amplitude division of data and the number and continuous number determination based on this, information such as the position and shape of the target is sampled. It becomes possible to extract from the obtained data. At that time, by excluding the data that is simulated if it crosses the amplitude division area in order to expand the target of the number and continuous number determination, the information such as the position and shape of the target is extracted only by the data with a certain degree of concatenation. Therefore, noise due to radar interference and the like and one threshold level determination are excluded, and more accurate data is output.

Further, in the radar signal processing method according to claim (2), the chaining is determined by the method according to claim (1) for the data sampled at the same sampling timing in each sweep. Furthermore, the data that has been subjected to the imitation in this determination is excluded from the target of the information extraction processing such as the position and shape of the target. Therefore, as described above, noise removal due to radar interference,
Elimination of one threshold level judgment and highly accurate data output are realized.

Further, in the data signal processing device according to claim (3), the determination circuit determines the concatenation of the data sampled at the same sampling timing from the reflection signal corresponding to each sweep of the pulse signal. Further, the data selector excludes the data related to the imitation and selects the data to be supplied to the indicator from the other data. Therefore, the information such as the position and shape of the target displayed on the screen by the indicator is the information from which the noise of radar interference is removed.

In the radar signal processing device according to the fourth aspect, data of the same sampling timing is supplied from the storage unit to the determination circuit and the data selector.

[Embodiment] A preferred embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the configuration of a radar signal processing apparatus according to an embodiment of the present invention. The apparatus shown in this figure fetches a received signal according to a range clock,
N FIs that store data related to received signals for sweeps
FO memories 28-1 to 28-N, a decision circuit 30 for fetching data output from the FIFO memories 28-1 to 28-N, and performing a chainness determination according to a feature of the present invention, and a chainability determination in the determination circuit 30. A data selector 32 that selects data according to the result and outputs the selected data.

Next, this operation will be described with respect to the embodiment shown in FIG.

FIG. 2 shows the flow of the chaining determination operation in this embodiment.

First, immediately after the start of operation 200, a map is created for the data of each sweep related to the same sampling timing (202).

In the device shown in FIG. 1, each FIFO memory 28 stores data for one sweep of the received signal, and the data of the same sampling timing is sequentially output according to the range clock, and the FIFO of the next stage is output. It is stored in the memory 28. At the same time, the output of the FIFO memory 28 is supplied to the decision circuit 30 and the data selector 32. Judgment circuit 30
, The data supplied from the N FIFO memories 28, that is, the data as shown in FIG.
A map is created as shown in the figure.

That is, the data supplied from the FIFO memory 28 to the determination circuit 30 is divided into M + 1 amplitude divisions as shown in FIG. 3, and the number of data and the maximum continuous data number that cross each amplitude division are It is tabulated like the right edge of the map shown in FIG.

Next, based on the map created in step 202, the linkage determination is performed for the maximum amplitude segment (amplitude segment M) (204).

FIG. 5 shows an example in which the number M relating to the amplitude division is 3 and the number N of sweeps is 5. In step 204, the maximum number of amplitudes, for example, the number of data that crosses the third amplitude segment in FIG.
And the maximum continuous number of data is a predetermined continuous number, for example, 3
It is determined whether or not

In the determination 204, if the condition is satisfied, that is, the number of data that crosses the maximum amplitude section is a predetermined number or more, and the maximum continuous number of data is a predetermined continuous number or more, the central sweep is performed. Such data is selected and output (206). Here, the center sweep is a sweep with an intermediate number among a plurality of sweeps, and when N is an even number, the sweep immediately before or after N / 2 is selected. That is, the data related to the central sweep is adopted as the data supplied to the indicator 16, for example.

If it is determined in the determination 204 that the condition is not satisfied, the process proceeds to the next step 208, and the chaining determination 210 including the next amplitude section is performed.

For example, in the data shown in FIG. 5A, the number of data that crosses the third amplitude segment is two, the maximum number of consecutive data is one, and the number of data that crosses the second amplitude segment is three. The number and the maximum continuous number are one. Therefore, in the above-described determination 204, since the number of data that crosses the maximum amplitude section (third amplitude section) is 2, the predetermined number (4)
Not only is it determined not to cross this amplitude segment, but the maximum continuous number is 1 and the predetermined continuous number (3) is not satisfied either. Therefore, the process proceeds to step 208, and the maximum amplitude segment (third amplitude segment) is set. ) Is simulated as data that crosses only the next amplitude section (second amplitude section).
Then, as shown in FIG. 5B, the number of pieces of data that crosses the second amplitude section or is regarded as crossing the second amplitude section is 3
Since there are two and the maximum consecutive number is two, the determination 210
In, it is determined that the conditions are not met.

If it is determined in decision 210 that the condition is satisfied, the approximate center sweep is selected (212). Here, the approximate center sweep is a judgment circuit from the FIFO memory 28.
Of the data supplied to 30, it is the sweep closest to the central sweep obtained by removing the data related to the imitation in step 208 and obtaining the remaining sweeps. (If the approximate center sweep candidates before and after the center sweep there are two. Keep decide in advance choose which side) That is, the data crosses the large amplitude indicator, is considered a low-linked data, which The data to be supplied to the indicator 16, for example, from the data except for is selected by a command to the data selector.

When it is determined in the determination 210 that the conditions are not satisfied, for example, as shown in FIG. 5 (b),
Returning to step 208 again, the chaining determination 210 is performed until the condition is satisfied.
Is repeated. For example, in FIG. 5, the range is reduced from FIG. 5 (b) to FIG. 5 (c), that is, the imitation is performed again and the chainness determination is performed, but in this case,
The number of data items belonging to the first amplitude division is 5, which exceeds the predetermined number (4), and the maximum continuous number is 5, which exceeds the predetermined continuous number (3). At this point, it is determined that the conditions are satisfied, and the process moves to step 212.

For example, when the data shown in FIG. 5 (d) is input to the judgment circuit 30 from the FIFO memory 28 instead of the data shown in FIG. 5 (a), the step input 08 is set to 2
After being executed once, as shown in FIG. 5 (e), the first
There are four pieces of data that are simulated if the amplitude categories of or are crossed. In this case, the predetermined number of 4 is satisfied, but the maximum continuous number is an input and does not satisfy the predetermined maximum continuous number of 3. Therefore, in the determination 210, the flow returns to step 208 again, and FIG.

In FIG. 5 (f), there are 5 pieces of data that are crossed or are simulated when the 0th amplitude section is crossed, and the maximum number of consecutive pieces is also 5.
Since it is the number, the determination 210 determines that the condition is satisfied at this time point, and the process proceeds to step 212.

As described above, according to the present embodiment, since one threshold level determination is excluded in the information extraction from the reflected signal and the chaining determination is performed on the data of the same sampling timing, it is caused by, for example, radar interference. Low level noise is removed, preventing radial noise 108, as shown for example in FIG.

In the present embodiment, the signal is divided into M + 1 amplitude divisions, but the amplitude divisions do not necessarily have to be at equal intervals, and the type of receiver used (logarithmic, linear, etc.) and the signal level. According to the above, it is possible to arbitrarily select, for example, to make the vicinity of the signal level of interest dense.

In addition, the number of sweeps N related to the condition in the linkage determination is
It is preferable that the number of antenna hits is about the same as the number of antenna hits shown in the description of FIG.

Further, the predetermined number of data and the predetermined maximum continuous number of data across each amplitude range are arbitrary under the condition that N ≧ predetermined number ≧ predetermined maximum continuous number, but the detection probability of the target and unnecessary noise such as interference It is preferable to set so as to satisfy both the removal performance.

[Effects of the Invention] As described above, according to the radar signal processing method and apparatus of the present invention, low-level noise such as radar interference is removed, and the position, shape, etc. of a target obtained by reflection of a pulse signal are detected. Information can be extracted more accurately, and unnecessary noise on the indicator screen can be removed to obtain a good screen.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing the configuration of a radar signal processing apparatus according to an embodiment of the present invention, and FIG. 2 is a feature of the present invention and is shown in FIG. FIG. 3 is a flow chart showing the flow of operation of the decision circuit in the example, FIG. 3 is a data distribution diagram showing an example of data distribution, and FIG. 4 is a map created from the data distribution shown in FIG. 3 in this embodiment. 5 and 5 are diagrams showing an example of the chaining determination operation in this embodiment. FIG. 5 (a) is an amplitude division diagram of initial data, and FIG. 5 (b) is the next stage. Fig. 5 (c) is an amplitude sectional view showing the pseudo-control of the next stage, Fig. 5 (d) is a second initial data amplitude sectional view, FIG. 5 (e) is FIG. 5 (d).
Fig. 5 (f) is an amplitude division diagram depicting the second pseudo-control based on the initial data shown in Fig. 5, Fig. 5 (f) is an amplitude division diagram depicting the third pseudo-control, and Fig. 6 is a system configuration of a general radar signal processing device. FIG. 7 is a principle diagram showing the operation principle of a pulse radar, FIG. 8 is a block diagram showing the configuration of a conventional radar signal processing device, and FIG. 9 is a waveform showing the configuration of a received signal. FIG. 10 is a screen diagram when radar interference occurs by the conventional radar signal processing method and apparatus. 10 ... Target 14 ... Transceiver circuit 16 ... Indicator 28 ... FIFO memory 30 ... Judgment circuit 32 ... Data selector 100 ... Pulse signal 102 ... Reflected signal 104 ... Sudden change 106 ... Reflected pulse D ₁ , D ₂ , ..., _DN ... data N ... number of sweeps t 0 _... sampling timing M ... amplitude number of divisions

Claims (4)

[Claims] 1. Amplitude division of data sampled at the same sampling timing in each sweep from data obtained by sampling a reflection signal from a target by a pulse signal repeatedly transmitted by a predetermined number of sweeps, As a result, it is determined whether or not the data of the same sampling timing that crosses the maximum amplitude divisional region is present in a predetermined number and a predetermined continuous number or more. If this is the case, it is assumed that the data that crosses the amplitude division area related to this number and continuous number judgment crosses the next amplitude division area, and then the same number and continuous number for the data that crosses the next amplitude division area. The judgment was repeated, and as a result of the judgment of the number of pieces and the number of consecutive pieces, it was determined that the number of pieces was equal to or more than the predetermined number In this case, it is considered that the amplitude division areas related to this number and continuous number judgment are concatenated or high, and if the amplitude division areas related to this number and continuous number judgment are crossed or crossed, the above pseudo assumption A method for determining linkage, wherein data is excluded, and then the data is used for extraction of information such as the position and shape of the target. 2. A pulse signal is repeatedly transmitted for a predetermined number of sweeps, a reflection signal from a target due to the pulse signal is received, the received reflection signal is sampled, and the position of the target is determined from the data obtained as a result of sampling.
A radar signal processing method for extracting information such as a shape, wherein data sampled at the same sampling timing in each sweep is used.
A radar signal processing method, characterized in that the chainness is determined by the method described, and the information is extracted based on data excluding data related to imitation. 3. A transmission / reception circuit for repeatedly transmitting a pulse signal for a predetermined number of sweeps, receiving a reflection signal from a target, and sampling the received reflection signal, and based on data obtained as a result of sampling by the transmission / reception circuit, An indicator for displaying information such as the position and shape of the target on the screen, and a radar signal processing device including: In the radar signal processing device, from the reflection signal corresponding to each sweep of the pulse signal,
Among the data sampled at the same sampling timing, from the judgment circuit for judging the chainness by the method according to claim (1), and the data excluding the data related to imitation based on the judgment result in the judgment circuit. And a data selector that selects data to be supplied to the indicator, the radar signal processing device. 4. The radar signal processing device according to claim 3, wherein the transmission / reception circuit stores sampled data for each sweep, and the decision circuit and the decision circuit store data of the same sampling timing according to a range clock. A radar signal processing device comprising a storage unit for supplying to a data selector.