JP2010181272A - Radar signal processing apparatus and target determination method of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To identify targets and to specify the distance to and speed of the targets even under a low S/N environment. <P>SOLUTION: Reflected waves from targets 11 are captured by an antenna 1 and received by a receiver 2. Received signals are converted into digital signals at an A/D converter 3 and signal-processed at a target detector 4 to determine temporary data of target tracks. The target detector 4 performs Fourier transform on signals converted into digital signals, captures them of the amount of a plurality of times, extracts tracks estimated as of targets by a method such as the Hough transform and a TBD algorithm, and takes them as target track temporary data. The target track temporary data is a distance data string and a speed data string for each observation and transmitted to a target determination processor 5. The target determination processor 5 determines tracks of targets on the basis of the target track temporary data obtained for each observation, and when a single target is determined, the tracks of targets are taken as track information of the target to obtain true target track data. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a flying object mounted radar signal processing apparatus for obtaining a target distance and direction and a target determination method thereof.

  In the radar signal processing device, as a target detection method, the received signal is Fourier-transformed and a signal exceeding a preset threshold value is determined as a target, and a sum signal is obtained from the received signal determined as the target. Generally, a method of obtaining a difference signal and obtaining a target direction by monopulse angle measurement processing.

  However, in a radar signal processing apparatus mounted on a flying object, a target component often does not exceed a threshold value in a low S / N environment during flight, so that it becomes extremely difficult to detect a target. If the threshold value itself is lowered, false detections other than the target increase. In the case of a terrestrial radar, the S / N can be improved by extending the observation time if it is a stationary target. However, in the case of a radar mounted on a flying object, a change in distance from the target occurs, so that the effect cannot be obtained.

  As means for solving this problem, observation is repeated a plurality of times, and changes in distance and speed are performed using a Hough transform (see, for example, Patent Document 1) or a TBD (Track Before Detect) algorithm (see, for example, Non-Patent Document 1). Corresponding methods have been proposed. By these methods, the target can be detected and the distance can be obtained with almost the same hardware scale as that of the prior art.

  However, even with these methods, there are cases in which a plurality of wakes are detected or a plurality of target candidate points are raised at the same time, so that the detection result does not converge and the target cannot be specified. In addition, these methods only know that the target is in the vicinity of the beam scanning direction of the antenna, and the accuracy is insufficient as angle information for following the target.

JP 2004-340691 A

Y. Boers, “Multitarget particle filter track before detect application”, IEE proc.- Radar Sonar Navig., Vol. 151, No. 6, Dec. 2004.

  As described above, in the conventional radar signal processing apparatus mounted on a flying object, target detection is difficult because the target component does not exceed the threshold value in a low S / N environment.

  The object of the present invention is to solve the above-mentioned problems, identify a target even in a low S / N environment, specify a distance and a speed, and increase the error in direction (angle) due to the low S / N environment. It is an object of the present invention to provide a radar signal processing apparatus and a target determination method thereof that can suppress the noise and can accurately obtain the target direction and improve the tracking performance of the flying object.

  In order to achieve the above object, the present invention provides a radar signal processing apparatus for target detection mounted on a flying object, an antenna for receiving a radar reflected wave reflected by the target, and a receiving unit for detecting the reflected wave. The target detection unit that performs provisional detection of the target a plurality of times from the detection signal of the reception unit and obtains each track, and compares the plurality of track results of the temporarily detected target to determine the true target A target determination unit and an angle measurement processing unit that determines a target direction from the detection output of the reception unit for the true target determined by the target determination unit are provided.

  Further, the present invention is used in a radar signal processing apparatus for target detection mounted on a flying object, receives a radar reflected wave reflected by the target, detects the reflected wave, and detects the target from the detected signal. In the target determination method for determining a true target by performing a plurality of tentative detections of each time to obtain respective wakes and comparing a plurality of wake results of the tentatively detected targets, each tentatively detected target track result Is divided into distance component and speed component, and the difference between the maximum value and minimum value is counted less than the distance width and speed width, and when the number of count exceeds a certain number, it is judged as a single target track. The wake target is determined to be a true target.

  With the above configuration, according to the present invention, it is possible to identify a target and specify a distance and speed even in a low S / N environment, and the direction (angle) is also increased in a low S / N environment. Therefore, it is possible to provide a radar signal processing apparatus and a target determination method that can suppress the error and can accurately obtain the target direction and improve the tracking performance of the flying object.

The block diagram which shows the structure of the radar signal processing apparatus mounted in a flying body as one Embodiment of this invention. The flowchart which shows the flow of a more concrete process of the target determination processor shown in FIG. The figure which shows the example of distribution of the target track temporary data for demonstrating the process sequence shown in FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a block diagram showing a configuration of a radar signal processing apparatus mounted on a flying object as one embodiment of the present invention. This radar signal processing apparatus includes an antenna 1 that receives a radio wave from a target 11 (a reflected wave of a transmission pulse transmitted from a transmission system (not shown)), a receiver 2 that detects the reflected wave, and a detection signal as a digital signal. An A / D (analog / digital) converter 3 for conversion, a target detector 4 for detecting a target by detecting a target from a detection signal, a target determination processor 5 for determining a target from the target detection result, a target An angle measuring processor 6 for obtaining a direction is used.

  As the processing of the target detection unit 4, for example, a TBD algorithm can be used. Further, the angle measurement processor 6 performs processing for obtaining a target direction by taking in a digital signal necessary for angle measurement from the result of the target determination processor 5 from the A / D converter 3.

  That is, in the radar signal processing device having the above configuration, the reflected wave from the target 11 is taken in from the antenna 1 and received by the receiver 2. The received signal is converted into a digital signal by the A / D converter 3 and then subjected to signal processing by the target detector 4 to obtain temporary data of the target track.

  Specifically, the target detector 4 performs Fourier transform on the signal converted into a digital signal, takes in a plurality of times, and extracts a wake that seems to be a target by a method such as a Hough transform or a TBD (Track Before Detect) algorithm. This is used as the target track temporary data. This temporary target track data is a distance data string and a speed data string for each observation, and is sent to the target determination processor 5.

  The target determination processor 5 determines the target track from the target track temporary data obtained for each observation, and when the target track is determined to be a single target, the target track data is obtained as true target track data. Ask for.

  FIG. 2 is a flowchart showing a more specific processing flow of the target determination processor 5, and FIG. 3 is a diagram showing an example of distribution of target track provisional data for explaining the processing. In FIG. 2, target wake temporary data is captured in step S1. As shown in FIG. 3, there are a plurality of target wake temporary data, and the number thereof is X. Each target track tentative data is a data string obtained by observing a plurality of times (here, T times), and the number of data is T.

In the target tentative temporary data, when the distance is R ′, it can be expressed as follows. The value of the data r ′ indicates the distance.
R ₁ '= {r' (1,1), r '(1,2), ..., r' (1, T)}
R ₂ '= {r' (2,1), r '(2,2), ..., r' (2, T)}
::
R _X '= {r' (X, 1), r '(X, 2), ..., r' (X, T)}
Next, in step S2, removed most recent A batch of data from the T-th observation, the distance comparison data D _R. In this case, the distance comparison data can be expressed as follows.
D _R1 = {r ′ (1, T), r ′ (2, T),..., R ′ (X, T)}
D _R2 = {r ′ (1, T−1), r ′ (2, T−1),..., R ′ (X, T−1)}
::
D _RA = {r ′ (1, T− (A−1)), r ′ (2, T− (A−1)),..., R ′ (X, T− (A−1))}
Subsequently, in step S3, the maximum value and the minimum value of the elements are obtained for each of the comparison data D _{R1 to} D _RA . Next, in step S4, determines the difference between the maximum value and the minimum value, it is determined whether it is the distance the width B or _R smaller. If it is smaller, the match is made at that time, and the number of matches is counted in step S5. In step S6, this is all performed for D _{1 to} D _A.

Similar processing is performed for speed. That is, in the target track temporary data, when the speed is V ′, it can be expressed as follows. The value of data v ′ indicates speed.
V ₁ '= {v' (1,1), v '(1,2), ..., v' (1, T)}
V ₂ '= {v' (2,1), r '(2,2), ..., v' (2, T)}
::
V _X '= {v' (X, 1), v '(X, 2), ..., v' (X, T)}
Next, in step S12, it retrieves the most recent A batch of data from the T-th observation, and the speed comparison data D _V. In this case, the speed comparison data can be written as follows.
D _V1 = {v ′ (1, T), v ′ (2, T),..., V ′ (X, T)}
D _V2 = {v ′ (1, T−1), v ′ (2, T−1),..., V ′ (X, T−1)}
::
D _VA = {v ′ (1, T- (A-1)), v ′ (2, T- (A-1)),..., V ′ (X, T- (A-1))}
Subsequently, in step S13, the maximum value and the minimum value of the elements are obtained for each of the speed comparison data D _{V1 to} D _VA , and in step S14, the difference between the maximum value and the minimum value is obtained, which is the distance width B _V If it is smaller, the match is made at that time, and the number of matches is counted in step S15. In step S16, this is all performed for D _{V1 to} D _VA .

At step _S7, D R1 if _~D match count of the matching count is _{C R} or more times and _D V1 _{~D VA} of _RA is equal to or greater than _{C V} times at step S8, X number of target track temporary data Single It is determined that there is one track, and the target track data is obtained from these.

In the target track data, if the distance is R and the speed is V, it can be written as follows. The value of data r indicates distance, and the value of v indicates speed.
R = {r (1), r (2), ..., r (T)}
V = {v (1), v (2), ..., v (T)}
r is obtained by the following equation.
r (1) = Σr ′ (x, 1) / X
r (2) = Σr '(x, 2) / X
:
r (T) = Σr ′ (x, T) / X
v is obtained by the following equation.

v (1) = Σv '(x, 1) / X
v (2) = Σv '(x, 2) / X
:
v (T) = Σv ′ (x, T) / X
The angle measurement processor 6 extracts the digital signal of the portion including the reflected wave from the target from the target track data from the A / D converter 3 and performs angle measurement processing.

  The angle measuring processor 6 performs the following processing. First, every time a digital signal is observed a plurality of times, a sum signal and a difference signal are obtained, and a target direction is obtained by monopulse angle measurement processing. Next, smoothing processing is performed from the angle measurement result for each observation, and the result is used as the target direction result.

  As the smoothing process, for example, the least square method or Kalman filter can be used, and when it can be assumed that the direction of the target does not change greatly between multiple observations, the average of the angle measurement results for each observation is calculated. It is possible to replace it by seeking.

  According to the radar signal processing apparatus having the above-described configuration, a target can be identified and a distance and a speed can be specified in a low S / N environment, and errors (directions) increased due to the low S / N environment can be suppressed with high accuracy. The target direction can be obtained, and thereby the follow-up performance of the flying object can be improved.

In the above embodiment, "the number of matches of _D R1 _{to D RA} match count of _{C R} times or more and _D V1 _{to D VA} is _C or _V times" Step S7, in FIG. 2 was set to determine if the but the distance, since it may be one of speed, so as to determine the case of the _"D R1 _{to D} matches the number of _RA is more than _{C R} times or _D V1 _{to D VA} match count is more than _{C V} times" May be.

  In addition, the embodiments may be appropriately combined as much as possible, and in that case, the combined effect can be obtained. Further, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. For example, even if some constituent requirements are deleted from all the constituent requirements shown in the embodiment, the problem described in the column of the problem to be solved by the invention can be solved, and the effect described in the column of the effect of the invention Can be obtained as an invention.

  DESCRIPTION OF SYMBOLS 1 ... Antenna, 2 ... Receiver, 3 ... A / D converter, 4 ... Target detection part, 5 ... Target determination processor, 6 ... Angular measurement processor.

Claims (4)

In a radar signal processing device for target detection mounted on a flying object,
An antenna for receiving a radar reflected wave reflected by the target;
A receiver for detecting reflected waves;
A target detection unit for obtaining each wake by performing provisional detection of the target multiple times from the detection signal of the reception unit;
A target determination unit that compares a plurality of wake results of the temporarily detected target to determine a true target;
A radar signal processing apparatus, comprising: an angle measurement processing unit that obtains a target direction from a detection output of the reception unit for a true target obtained by the target determination unit. 2. The radar according to claim 1, wherein the target detection unit acquires the detection signal of the reception unit a plurality of times and obtains the temporary detection of the target and each track by a Hough transform or a TBD (Track Before Detect) algorithm. Signal processing device. The target determination unit divides each target track result temporarily detected by the target detection unit into a distance component and a speed component, and counts the number of times that the difference between the maximum value and the minimum value is smaller than the distance width and the speed width. 2. When the number of counts of at least one of the distance component and the speed component exceeds a certain number, it is determined as a single target track, and the target of the track is determined as a true target. The radar signal processing apparatus described. Used in radar signal processing equipment for target detection mounted on flying objects,
The radar reflected wave reflected by the target is received, the reflected wave is detected, the target is detected a plurality of times from the detected signal to obtain each track, and a plurality of tracks of the temporarily detected target are detected. In the target determination method that determines the true target by comparing the results,
Dividing into a distance component and a speed component for each temporarily detected target track result,
Count the number of times the difference between the maximum and minimum values is smaller than the distance width and speed width,
A radar signal processing device, wherein when at least one of the distance component and the speed component is counted more than a certain number, it is determined as a single target track, and the target of the track is determined as a true target. Target judgment method.

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