JP4001611B2 - Ranging radar equipment - Google Patents

Description

  The present invention relates to an angle measuring radar apparatus that radiates a transmission beam, receives reflected beams reflected by a detection object by two antennas having different directivity angles, and calculates an angle in the direction of the detection object from the intensity of the reception beam. .

  Travel management that uses various sensors and communications to support vehicle travel, notifies drivers and managers of road condition information, or allows toll collection to be performed while the vehicle is traveling Is being promoted. One of the technologies required among them is the detection of the position of a detection object such as a traveling vehicle or an obstacle, and a radar device has been used as means for achieving it.

  Conventionally, as such a radar apparatus, there has been one disclosed in Patent Document 1. FIG. 1 is a conceptual diagram showing a situation in which the radar apparatus of the above document is used. A vehicle 1 and a vehicle 2 are traveling on the road, and the FM-CW radar device 3 mounted on the vehicle 1 emits a transmission beam to the road ahead and receives radio waves from different monitoring areas B1 and B2. 2 shows a state in which the reflected beam from the other vehicle 2 traveling in the monitoring area is received and the other vehicle 2 is detected using the two receiving antennas.

  FIG. 6 is a block diagram showing a configuration of a conventional FM-CW radar apparatus 3. The FM-CW radar apparatus 3 includes a transmission antenna 4 that radiates a transmission beam forward of the vehicle, and a first reception antenna 5a that receives radio waves from a monitoring region B1 whose center direction is inclined to the left with respect to the center direction of the transmission beam. The second receiving antenna 5b that receives radio waves from the monitoring region B2 whose center direction is tilted to the right with respect to the center direction of the transmission beam, one of the first receiving antenna 5a and the second receiving antenna 5b A receiving antenna changeover switch 6 that is enabled alternately every predetermined time, an FM-CW transmission / reception device 7 that always generates an FM-CW transmission wave as a transmission beam, and converts the reception beam into a frequency that can be processed by a signal processing device; The A / D converter 8 that digitally converts the received beam intensity output from the FM-CW transceiver 7 and the received beam intensity output from the A / D converter 8 are in the monitoring region. The signal processing device 9 for obtaining the (relative) distance, (relative) velocity of the object to be detected, and the intensity of the reflected beam component from the object to be detected in the received beam, and the error generated when detecting the moving object to be detected The correction device 10 to be corrected, the storage device 11, and the direction of the detection object, that is, the direction of the detection object based on the vehicle front direction using the difference in the intensity of the reflected beam received by the two receiving antennas 5a and 5b. It is comprised from the angle measuring device 12 which calculates the angle of.

  In the conventional FM-CW radar apparatus 3 having the above configuration, the signal processing apparatus 9 first performs frequency analysis on the reflected beam signal input from the A / D converter 8 using means such as FFT (Fast Fourier Transform). And calculate the beam intensity at each frequency. Next, a threshold setting means such as CFAR (Constant False Alarm Rate) is used to obtain a frequency at which the beam intensity is equal to or higher than a predetermined threshold, and this frequency is set as the frequency of the reflected beam component from the detection target. The beat frequency is calculated by calculating the difference between the frequency of the reflected beam component from the detected object to be detected and the frequency of the transmission beam, and the (relative) distance and (relative) speed of the object to be detected are calculated from this beat frequency. Is calculated and output. Further, the signal processing unit 9 outputs the beam intensity, which is equal to or higher than a predetermined threshold by the threshold setting unit, to the angle measuring device 12 as the intensity of the reflected beam component from the detection target. Then, the angle measuring device 12 calculates the angle of the detection object direction based on the input intensity.

  Here, the calculation of the direction of the detection target performed by the angle measuring device 12 will be described in detail. FIG. 7 is a diagram illustrating the radiation area A of the transmission beam, the monitoring areas B1 and B2, and the detection object 2 when the radar apparatus 3 detects the detection object in the monitoring area. As shown in FIG. 7, the monitoring areas B1 and B2 are directed in directions shifted by an angle θ to the left and right with respect to the center direction of the radiation area A of the transmission beam. Are the curves S and T in FIG. FIG. 8B shows the sum (Σ), difference (Δ), and ratio (Δ / Σ) of the sum and difference of the reception strengths A and B of the two antennas 5a and 5b. The ratio (Δ / Σ) is substantially a straight line in the section between direction 1 and direction 2. The angle measuring device 12 uses this characteristic to obtain the intensity ratio (Δ / Σ) of the reflected beam component from the detection target inputted from the signal processing unit 9 and calculates the angle in the direction of the detection target.

JP 2000-241537 A

  However, in the radar device 3 as described above, since the gain varies for each receiving antenna, the gain differs between the first receiving antenna 5a and the second receiving antenna 5b. As shown in FIG. The receiving beam intensities of the second receiving antennas 5a and 5b are shifted from each other in gain difference. This shift appears as a variation in received beam intensity when the receiving antennas 5a and 5b are switched. In addition, the received beam intensity includes not only the reflected beam component from the other vehicle 2 that is the detection target, but also the noise component from the periphery of the detection target. Therefore, when the angle measuring device calculates the angle in the direction of the detection target, the angle includes the above-described deviation of the received beam intensity and the error due to the noise component, and the angle in the direction of the detection target cannot be accurately calculated. There was a problem.

  The present invention is for solving such a problem, and in an angle measuring radar device that calculates an angle of a detection target direction based on two antenna reception strengths, the angle of the detection target direction is accurately obtained. It is aimed.

A first aspect of the present invention is an angle measuring radar device that radiates a transmission beam, receives reflected beams reflected by a detection object with two antennas, and calculates an angle in the direction of the detection object from the intensity of the received beams. and receiving the reference signal memory unit for holding data of the gain difference between the two antennas, an output signal obtained by frequency converting the received beam, the a / D converter for digitally converting, output from the a / D converter An antenna gain difference correction unit that corrects a received beam intensity based on the antenna gain difference data and corrects a deviation in received beam intensity between the two antennas due to the antenna gain difference between the two antennas. .

  According to a second aspect of the present invention, there is provided an angle radar device that radiates a transmission beam, receives reflected beams reflected by a detection object with two antennas, and calculates an angle in the direction of the detection object from the intensity of the reception beams. A reception reference signal memory unit that holds gain difference data of two antennas, and an antenna gain difference correction unit that corrects a deviation in received beam intensity between the two antennas based on the antenna gain difference data. is there.

  According to a third aspect of the invention, the radar apparatus calculates a control gain based on the intensity of the received beam and performs automatic gain control for amplifying the received beam in order to prevent the target signal from being buried in noise. The antenna gain difference data held by the memory unit is data corresponding to the value of the control gain. Based on the calculated control gain, the corresponding antenna gain difference is selected, and the received beam intensity that varies depending on the control gain is obtained. This is to correct the deviation.

  According to a fourth aspect of the present invention, a difference between the intensity of the reflected beam from the standard reflector received by one antenna and the intensity of the reflected beam from the standard reflector received by the other antenna is used as the antenna gain difference to receive the received reference signal. Gain difference writing means for writing to the memory unit is provided.

  In a fifth aspect of the invention, a transmission beam is radiated, a reflected beam reflected by a detection object is received by two antennas, a frequency analysis is performed on the received reflected beam to calculate a beam intensity for each frequency, and a predetermined threshold value or more is calculated. An angle measurement radar device that extracts a beam intensity as a reflected beam component intensity from a detection object and calculates an angle of the detection object direction from the extracted beam intensity, wherein the extraction is performed from the extracted beam intensity. A peripheral noise correction unit that subtracts the beam intensity in the vicinity of the frequency of the beam intensity, and calculates the direction of the detection object based on the beam intensity subtracted by the peripheral noise correction unit.

  In a sixth aspect of the invention, the ambient noise correction unit subtracts, from the extracted beam intensity, the smaller one of the beam intensity at a higher frequency and the beam intensity at a lower frequency than the frequency of the extracted beam intensity. It is.

  According to the first invention, based on the gain difference data of the two antennas held in the received reference signal memory unit, the antenna gain difference correction unit corrects the received beam intensity of the antenna based on the antenna gain difference data. Since the shift of the received beam intensity of the two antennas due to the antenna gain difference between the two antennas is corrected, the angle in the direction of the detection object calculated from the received beams of the two antennas can be accurately measured.

  According to the second invention, since the antenna gain difference correction unit corrects the deviation of the received beam intensity of the two antennas based on the gain difference data of the two antennas held in the reception reference signal memory unit, the two antennas The angle in the direction of the detection object calculated from the received beam can be accurately measured.

  According to the third aspect, since the antenna gain difference data corresponding to the control gain of the automatic gain control is selected, it is possible to accurately correct the deviation of the received beam intensity that changes depending on the control gain.

  According to the fourth aspect of the present invention, the difference between the intensity of the reflected beam from the standard reflector received by one antenna and the intensity of the reflected beam from the standard reflector received by the other antenna is used as an antenna gain difference. Since the gain difference writing means for writing to the signal memory unit is provided, the antenna gain difference can be set easily.

  According to the fifth invention, since the ambient noise correction unit subtracts the beam intensity in the vicinity of the frequency of the extracted beam intensity from the extracted beam intensity, the detection target object calculated from the subtracted beam intensity is subtracted. The direction angle does not include an error due to noise, and therefore the angle in the direction of the detection target can be accurately measured.

  According to the sixth invention, the ambient noise correction unit subtracts, from the extracted beam intensity, the smaller one of the beam intensity at a higher frequency and the beam intensity at a lower frequency than the frequency of the extracted beam intensity. Therefore, even when there is a large component near the frequency of the extracted beam intensity, a noise intensity that does not include the component can be selected, and the angle in the direction of the detection target can be accurately measured.

  An embodiment of the angle measuring radar apparatus of the present invention will be described below. In the following description, an FM-CW radar device will be described. However, the present invention is not limited to this, and the angle in the direction of the object to be detected can be obtained from the intensity of the received beams of the two receiving antennas. For example, other types of radar devices such as a pulse radar may be used.

Embodiment 1 FIG.
FIG. 1 is a conceptual diagram illustrating a situation in which the angle radar device according to the first embodiment is used. A vehicle 1 and a vehicle 2 are traveling on the road, and the FM-CW radar device 13 mounted on the vehicle 1 emits a transmission beam to the road ahead and receives radio waves from the monitoring areas B1 and B2. A state in which a reflected beam from another vehicle 2 traveling in the monitoring area is received and the other vehicle 2 is detected using two receiving antennas is shown.

  FIG. 2 is a block diagram showing a configuration of the FM-CW radar apparatus 13 according to the first embodiment. The FM-CW radar apparatus 13 includes a transmission antenna 4 that radiates a transmission beam forward of the vehicle, and a first reception antenna 5a that receives radio waves from a monitoring region B1 whose center direction is inclined to the left with respect to the center direction of the transmission beam. The second receiving antenna 5b that receives radio waves from the monitoring region B2 whose center direction is tilted to the right with respect to the center direction of the transmission beam, either one of the first receiving antenna and the second receiving antenna is kept for a certain period of time. Receiving antenna changeover switch 6 that is enabled alternately every time, FM-CW transmission waves that always generate FM-CW transmission waves as transmission beams, and output signals of FM-CW transmission / reception devices 7 and FM-CW transmission / reception devices 7 that convert the frequency of reception beams The A / D converter 8 for digital conversion, the frequency and intensity of the received beam output from the A / D converter 8, and the relative distance, relative speed, and A signal processing device 14 for obtaining the intensity of a reflected beam component from a detection object in the reception beam, a correction device 10 for correcting an error that occurs when detecting a moving detection object, a storage device 11, and two reception antennas 5a , 5b, the control / angle measuring device 15 calculates the angle of the direction of the detection object based on the direction of the detection object, that is, the direction ahead of the vehicle, based on the intensity of the reflected beam.

  The signal processing device 14 includes a reception fixed gain determination unit 16, a reception reference signal memory unit 17, an antenna gain difference correction unit 18, an FFT processing unit 19, a CFAR processing unit 20, and an ambient noise correction unit 21.

  In the present embodiment, the FM-CW transmission / reception device 7 is generally used inside, so that the target signal from the detection target is not buried in the noise generated in the FM-CW transmission / reception device 7. Automatic gain control, which is a means, is performed. That is, the control / angle measuring device 15 samples the intensity of the received beam output from the A / D converter 8 at a fixed period, and outputs the received beam intensity having the maximum absolute value to the reception fixed gain determining unit 16. . The reception fixed gain determination unit 16 calculates a control gain for automatic gain control from the maximum value of the received beam intensity, sends it to the FM-CW transceiver 7, and receives the received beam with the control gain input by the FM-CW transceiver 7. Amplifying processing is performed.

  Further, in the angle measurement radar device 13 of the present embodiment, as a first characteristic matter, a process of correcting a shift in received beam intensity due to an antenna gain difference between the two receiving antennas 5a and 5b is performed. The process will be described.

  The reception fixed gain determination unit 16 calculates a control gain for automatic gain control and sends it to the FM-CW transmission / reception device 7, and simultaneously sends an address signal corresponding to the control gain to the reception reference signal memory unit 17. As shown in FIG. 3, the reception reference signal memory unit 17 includes a memory corresponding to each of the two reception antennas 5a and 5b, and is currently used based on the reception antenna switching signal input from the control / angle measuring device 15. The memory corresponding to the receiving antenna is selected. On each memory, correction data corresponding to the control gain is stored for each fixed address interval. Then, the correction data stored in the address designated by the address signal input from the reception fixed gain determination unit 16 is read and output to the antenna gain difference correction unit 18.

Next, the antenna gain difference correction unit 18 performs a calculation of a correction value n = ₁₀ Log ₁₀ (X) (unit: dB) based on the input correction data X, and the correction value n is converted into an A / D converter 8. Is added to the received beam intensity (unit: dB). By such processing, the shift in received intensity due to the antenna gain difference is corrected with the correction data corresponding to the control gain of the automatic gain control. The data stored in the memory corresponding to one receiving antenna 5a of the receiving reference signal memory unit 17 is all 1, and the data stored in the memory corresponding to the other receiving antenna 5b is stored in the receiving antennas 5a and 5b. The gain difference, that is, the value of (gain of receiving antenna 5a / gain of receiving antenna 5b) is stored. Therefore, when the received beam intensity of the receiving antenna 5a is corrected, the gain difference data is always 1, so that n = 0, and the received beam signal is not corrected. Further, in the case of correcting the received beam intensity of the received antenna 5b, since n = 10Log ₁₀ {(the gain of the gain / receiving antenna 5 b of the receiving antenna 5 a)} is added to the received beam intensity, receiving antennas 5a It is possible to obtain a received beam intensity equivalent to that when using.

  As described above, in the present embodiment, the received reference signal memory unit 17 holds the data of the gain difference between the two receiving antennas 5a and 5b in advance, and the antenna gain difference correcting unit 18 receives the received reference signal memory unit. 17 is based on the gain difference data stored in 17, and corrects the deviation of the received beam intensity of the two antennas 5a and 5b. By performing this processing, it is possible to correct the fluctuation in the reception intensity caused by the antenna gain difference generated by switching the reception antennas 5a and 5b, and as a result, the detection calculated by the control / angle measuring device 15 is performed. The angle in the direction of the object does not include an error due to a difference in reception intensity, and has an effect that can be obtained with high accuracy. Further, since the automatic gain control is performed by the FM-CW transceiver 13, when the control gain of the automatic gain control changes, the fluctuation range of the received beam intensity due to the gain difference between the receiving antennas 5 a and 5 b changes. However, since the gain difference data of the receiving antennas 5a and 5b is selected based on the control gain, such a problem does not occur.

  In the angle measurement radar device 13 of the present embodiment, as a second characteristic matter, the peripheral noise correction unit 21 performs a process of subtracting the beam intensity of the noise component from the intensity of the detection target component of the received beam. Is going. This process will be described.

  The reception beam corrected by the antenna gain difference correction unit 18 is frequency-analyzed by the FFT processing unit 19 and then output to the CFAR processing unit 20, where the beam intensity at each frequency is compared with a predetermined threshold value, and is equal to or higher than the predetermined threshold value. The obtained beam intensity is extracted as the intensity of the reflected beam component from the detection target. The extracted beam intensity is output to the ambient noise correction unit 21. At the same time, the beam intensity in the vicinity of the extracted beam intensity is sampled at predetermined frequency intervals and output to the ambient noise correction unit 21. The ambient noise correction unit 21 calculates an average value of the sampled beam intensities. Then, the average value of the beam intensity is subtracted from the extracted beam intensity. This process is based on the assumption that the received beam includes white noise having almost the same intensity at each frequency.

  By performing this processing, it is possible to remove ambient noise from the beam intensity of the reflected beam component from the extracted detection target. As a result, the angle in the direction of the detection target calculated by the control / angle measuring device 15 does not include an error due to surrounding noise components, and the angle in the direction of the detection target can be obtained with high accuracy.

  Next, the flow of processing for one cycle of measurement from when the radar apparatus 13 according to the present embodiment starts measurement by the receiving antenna 5a to when the measurement by the receiving antenna 5b is completed will be described.

  First, the control / angle measuring device 15 outputs a reception antenna switching signal to the antenna switching switch 6, and switches the reception antenna to be used from the reception antenna 5b to the reception antenna 5a. At the same time, the control / angle measuring device 15 causes the reception fixed gain determination unit 16 to receive the maximum value of the reception beam intensity of the A / D converter output sampled at a constant period during the previous cycle, that is, reception before frequency analysis. The maximum beam value, timing signal, and measurement status signal are output. In addition, a reception antenna switching signal is output to the reception reference signal memory unit 17.

  The reception fixed gain determination unit recognizes that the measurement cycle has changed by inputting the measurement status signal, and when the timing signal is input, calculates the control gain of automatic gain control from the maximum value of the input received beam intensity And output to the FM-CW transceiver 7. Further, an address corresponding to the calculated control gain is obtained, and an address signal is output to the reception reference signal memory unit 17.

The reception reference signal memory unit 17 recognizes that the reception antenna 5a is currently used from the reception antenna switching signal input from the control / angle measuring device 15, and selects a memory corresponding to the reception antenna 5a. Then, the correction data X (= 1) stored at the address of the address signal input from the reception fixed gain determination unit 16 is read and output to the antenna gain difference correction unit 18. The antenna gain difference correction unit 18 calculates an added value n (= ₁₀ Log ₁₀ (X) = 0) based on the input correction data, and receives the added value n from the A / D converter 8. Add to.

  Thereafter, the received beam intensity is processed by the FFT processing unit 19 and the CFAR processing unit 20, and components from the detection target in the received beam are extracted. Then, it is input to the ambient noise correction unit 21 and correction for removing the ambient noise is performed. The reception intensity from which the ambient noise component has been removed is output to the correction device 10 and correction described in Japanese Patent Laid-Open No. 2000-241537 is performed. Then, after being received by the receiving antenna 5a, the control / angle measuring device 15 stores the data subjected to the correction of the antenna gain difference and the correction for removing the peripheral noise. With the processing so far, the measurement by the receiving antenna 5a is completed.

  Next, measurement is performed by the antenna 5b. First, the control / angle measuring device 15 outputs a reception antenna switching signal to the reception antenna switching switch 6, and switches the reception antenna to be used from the reception antenna 5a to the reception antenna 5b. At the same time, a timing signal is output to the reception fixed gain determination unit 16 and a reception antenna switching signal is output to the reception reference signal memory unit 17.

  When receiving the timing signal, the reception fixed gain determination unit 16 calculates a control gain from the maximum value of the reception beam intensity of the previous cycle that has already been input, and outputs the control gain to the FM-CW transceiver 7. At this time, since the calculation is performed with the maximum value of the received beam intensity that has already been input, the calculated control gain is the same as that during measurement by the receiving antenna 5a. In addition, an address signal corresponding to the calculated control gain is transmitted to the reception reference signal memory unit 17. The address signal is the same as that measured by the receiving antenna 5a.

  The reception reference signal memory unit 17 selects a memory corresponding to the reception antenna 5 b based on the reception antenna switching signal input from the control / angle measuring device 15. Then, the correction data at the address specified by the address signal input from the reception fixed gain determination unit 16 is read out. The read correction data is output to the antenna gain difference correction unit 18.

The antenna gain difference correction unit 18 adds the added value n = ₁₀ Log ₁₀ {(gain of receiving antenna 5a / gain of receiving antenna 5b)} to the received beam intensity (unit dB) received by the receiving antenna 5b.

  Thereafter, the received beam intensity is processed in the same manner as when measured by the receiving antenna 5 a and is input to the control / angle measuring device 15. Then, the control / angle measuring device 15 receives the received beam intensity from the detection object corrected after being received by the receiving antenna 5a and the received beam intensity from the detection object corrected after being received by the receiving antenna 5b. From this, the angle in the direction of the detection object is calculated. With the above processing, one cycle of measurement is completed and the process proceeds to the next cycle.

Embodiment 2. FIG.
Next, the radar apparatus 13 according to Embodiment 2 of the present invention will be described.

  The radar apparatus 13 according to the second embodiment is different from the first embodiment only in the processing of the peripheral noise correction unit 21. Similar to the first embodiment, the ambient noise correction unit 21 compares the beam intensity at each frequency with a predetermined threshold value in the CFAR processing unit 20, and the beam intensity exceeding the predetermined threshold value is a reflected beam component from the detection target. Is extracted as the intensity. The extracted beam intensity is output to the ambient noise correction unit 21. At the same time, as shown in FIG. 4, the beam intensity in the vicinity of the extracted beam intensity is sampled at predetermined frequency intervals and output to the peripheral noise correction unit 21. The ambient noise correcting unit 23 calculates an average value of the beam intensities having a frequency higher than the extracted beam intensity frequency among the sampled beam intensities, and an average value of the beam intensities having a frequency lower than the extracted beam intensity frequency. Is calculated. Then, the average value of the smaller beam intensity is subtracted from the extracted beam intensity.

  As a result of the above processing, the beam intensity having a frequency higher than the extracted beam intensity frequency or the beam intensity having a lower frequency, whichever is smaller, is subtracted from the extracted beam intensity. Even when there is a large noise in the vicinity of the intensity frequency, there is an effect that the peripheral noise can be removed without being affected by such a large noise.

Embodiment 3 FIG.
Next, a radar apparatus according to Embodiment 3 of the present invention will be described.

  FIG. 5 is a block diagram showing a configuration of the radar apparatus 23 according to the third embodiment. In the third embodiment, correction data for correcting the gain difference stored in the reception reference signal memory unit 17 can be easily set and stored. The process will be described.

  First, a radio wave absorber is disposed in front of the transmission antenna 4 and the two reception antennas 5a and 5b. Then, a receiving antenna switching signal is sent from the control / angle measuring device 22 to enable the receiving antenna 5a, and an arbitrary received beam intensity maximum value and timing signal are sent to the receiving fixed gain determining unit 16, and the FM-CW transceiver 7 Set the control gain for automatic gain control. Then, radio waves are transmitted from the transmission antenna 4. The gain difference writing unit 24 of the control / angle measuring device 22 samples the intensity of the received beam directly input from the A / D converter 8 for a predetermined time, and obtains an average value of the intensity. Next, a receiving antenna switching signal is sent to enable the receiving antenna 5b. Similarly, the gain difference writing unit 24 samples the intensity of the received beam directly input from the A / D converter 8 for a predetermined time, and obtains an average value of the intensity. From the average value of the received beams by the two receiving antennas 5a and 5b obtained by the above processing, the average value of the received beam by the receiving antenna 5a / the average value of the received beam by the receiving antenna 5b is calculated. Is written to an address corresponding to the set control gain on the memory corresponding to the reception antenna 5b provided in the reception reference signal memory unit 17. Incidentally, “1” is written in the memory corresponding to the receiving antenna 5a at the time of manufacture.

  As described above, in the radar apparatus 23 of the present embodiment, the difference between the intensity of the received beam output from one antenna 5a and the intensity of the received beam output from the other antenna 5b is used as a gain difference. Since the gain difference writing unit for writing to the reception reference signal memory unit 17 is provided, the gain difference between the antennas 5a and 5b stored in the reception reference signal memory unit 17 can be easily set, and the antenna before product shipment can be easily set. Since the tests 5a and 5b can be performed, there is an effect that the price of the product can be suppressed.

It is the schematic which shows the condition where an angle radar apparatus is used. 1 is a block diagram illustrating a configuration of an angle radar device according to a first embodiment. 3 is an explanatory diagram illustrating a reception reference signal memory unit according to the first embodiment. FIG. FIG. 10 is an explanatory diagram for explaining a calculation process of the angle measurement radar device according to the second embodiment. FIG. 6 is a block diagram illustrating a configuration of an angle radar device according to a third embodiment. It is a block diagram which shows the structure of the angle measuring radar apparatus of a prior art. It is explanatory drawing which shows the radiation | emission area | region A of transmission beam, monitoring area | region B1, B2, and the detection target object 2. FIG. It is a graph of the receiving intensity of the receiving antenna with respect to the detection direction, and the sum, difference, and difference / sum. It is explanatory drawing for demonstrating the fluctuation | variation between receiving antennas and ambient noise.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Transmission antenna, 5a, 5b Reception antenna, 6 Reception antenna changeover switch, 7 FM-CW transmission / reception apparatus, 8 A / D converter, 10 correction apparatus, 11 Memory | storage device, 13 FM-CW radar apparatus, 14 Signal processing apparatus, DESCRIPTION OF SYMBOLS 15 Control and angle measuring device, 16 Reception fixed gain determination part, 17 Reception reference signal memory part, 18 Antenna gain difference correction part, 19 FFT process part, 20 CFAR process part, 21 Ambient noise correction part

Claims (4)

In an angle measuring radar device that radiates a transmission beam, receives a reflected beam reflected by a detection object with two antennas, and calculates an angle in the direction of the detection object from the intensity of the reception beam,
And receiving the reference signal memory unit for holding data of the gain difference between the two antennas,
An A / D converter that digitally converts an output signal obtained by frequency-converting the reception beam;
Antenna gain for correcting the deviation of the received beam intensity of the two antennas due to the antenna gain difference between the two antennas by correcting the received beam intensity output from the A / D converter based on the antenna gain difference data A difference correction unit;
An angle-measuring radar device comprising: The angle radar device calculates the control gain based on the intensity of the received beam, performs automatic gain control to amplify the received beam,
  The received reference signal memory unit holds gain difference data corresponding to the control gain value,
  The antenna gain difference correction unit shifts the received beam intensity of the two antennas due to the antenna gain difference between the two antennas based on the gain difference data corresponding to the control gain held in the reception reference signal memory unit. The angle-measuring radar device according to claim 1, wherein: An FFT processing unit that performs frequency analysis on the reception beam corrected by the antenna gain difference correction unit;
The angle measuring radar device according to claim 1, wherein the angle measuring radar device is provided. A CFAR processing unit that compares the beam intensity at each frequency with a predetermined threshold after frequency analysis by the FFT processing unit;
The angle measuring radar device according to claim 3, further comprising:

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