JPH11271430A - Radar equipment for automobile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the measuring accuracy and reliability of radar equipment for an automobile under such a condition that a plurality of targets, etc., exist. SOLUTION: Reflected waves from a target are received by two reception antennas 16a and 16b for left- and right channels. A signal processor 20 performs frequency analysis on the received waves of the left and right channels. An azimuth computing section 26 decides the azimuth to the target by a phase monopulse method by using a pair of peaks at which the frequencies are coincident with each other in the left and right channels. A pairing section 28 pairs the peaks in the rise and fall phase periods of the FMCW method with each other. The pairing section 28 constitutes a peak pair by selecting the peaks to which the same azimuth is given by means of the azimuth computing section 26 out of many existing peaks. A distance and speed computing section 30 decides the distance to and speed of the target based on the FMCW method by using the peak pair decided by means of the pairing section 28.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tracking radar device for detecting a relative speed and a relative distance to a target from a pair of echoes in an up phase period and a down phase period in FM modulation, and monitoring the behavior of the target by a tracking filter. About.

[0002]

2. Description of the Related Art Conventionally, in an automobile, various radars have been used to detect the position and speed of a target such as a preceding vehicle with respect to the own vehicle. For example, FMC that detects the distance to the target and the relative speed
2. Description of the Related Art A W (frequency modulated continuous wave) type radar device and a phase monopulse type radar device which detects a direction of a target based on a phase difference between signals from a plurality of receiving antennas are known.

[Phase monopulse radar] In a phase monopulse radar, reflected waves from a target obtained by radiating radio waves from one transmitting antenna are received by a plurality of receiving antennas. Since the plurality of receiving antennas are spatially different in position, the phases of the reflected waves from the same target differ between the receiving antennas. The azimuth of the target can be detected by detecting this phase shift. This phase monopulse radar has an advantage that basically there is no need to mechanically move a transmitting antenna and a receiving antenna for azimuth detection.

Referring to FIG. 1, the distance to the target is R0, the interval between the two receiving antennas is L, and the azimuth of the target is θ. The distances R1 and R2 from the antennas 1 and 2 to the target are:

R1 = R0 + (L / 2) sin θ R2 = R0− (L / 2) sin θ The phase difference Δφ between the received signals (wavelength: λ) of the two receiving antennas is

Δφ = (L / λ) sin θ Therefore, the azimuth θ of the target is

## EQU3 ## θ = sin ⁻¹ {Δφ (λ / L)}. In this way, the azimuth of the target can be obtained from the phase difference of the received signal.

[FMCW radar] The FMCW radar detects the distance and velocity of a target using continuous waves. By combining the FMCW radar and the phase monopulse radar, it is possible to determine the distance, speed, and azimuth of the target.

[0006] The FMCW radar applies FW to a continuous wave transmission signal.
M modulation is performed. FIG. 2 shows the principle of relative distance and relative speed detection by the FMCW radar. For example, a transmission wave is frequency-modulated by a triangular wave. by this,
The frequency of the transmission wave repeatedly increases and decreases sequentially. When this transmission wave is radiated from the radar and reflected by the target and received, the frequencies of the transmission wave and the reception wave have a relationship as shown in FIG. However, this is a case where the relative speed of the target is zero. Then, by detecting the received wave with the reference wave (transmitted wave), a beat signal (FIG. 2 (lower)) having a frequency component of a difference between the transmitted frequency and the received frequency is obtained.

[0007] The propagation delay time τ is a time until a transmission wave is received. Assuming that the relative distance to the target is R and the speed of light is c, τ = 2R / c. Further, the repetition frequency of FM (the frequency of the triangular wave in FIG. 2) is fm, F
If the frequency shift width of M (the change width of the frequency of the reference wave) is Δf, the beat frequency fr is

## EQU4 ## fr = 4R · fm · Δf / c Therefore, from the beat signal, the beat frequency fr
Is determined, the relative distance R is determined.

FIG. 3 (upper) shows that the relative speed of the target is zero.
3 shows the relationship between the frequency of the transmission wave and the frequency of the reception wave in a case other than the above. When the target has a relative speed to the radar, the frequency of the received wave shifts up or down by the Doppler frequency fd. FIG. 3 (lower) shows a beat signal. This beat signal is obtained by adding the Doppler frequency fd to the beat frequency fr of the target having a relative speed of 0 during the up phase period in which the frequency of the transmission wave is increasing. On the other hand, in the down phase period in which the frequency of the transmission wave is decreasing, the beat signal is obtained by subtracting the Doppler frequency fd from the beat frequency fr. Therefore, the Doppler shift is determined from the frequency of the up phase period and the down phase period of the beat signal, and the relative speed of the target is determined from this.

That is, the frequency fbu, fbd of the beat signal in the up phase period and the down phase period
Is

Fbu = fr + fd fbd = fr-fd Therefore, the frequency fbu, fbd
Are obtained individually, a beat frequency fr representing a relative distance,
A Doppler frequency fd representing the relative speed is obtained.

[0010]

In an extremely ideal environment in which only a single target exists, the phase monopulse type radar apparatus can accurately detect the azimuth of the target, and the FMCW. The radar system of the type can accurately detect the distance and the speed of the target. Therefore, in such a simple environment, the azimuth, the distance, and the speed can be accurately determined by using both methods in combination.

However, in an environment where an automobile radar device is used, reflected waves from various objects (for example, a plurality of preceding vehicles as targets, other trees and guardrails other than the target, etc.) are received in an overlapping manner. FMC
In the W method, as described above, for a target having a relative speed, the peak of the received signal spectrum is split into two, and unless the peaks are correctly combined, the correct distance and speed cannot be detected. It is difficult to correctly determine such a combination (pairing) in an environment where there are many peaks in the received signal spectrum due to reflected waves from various objects. Also in the phase monopulse method, when the distance or speed of a plurality of targets is different, if the above-mentioned pairing can be performed well, the azimuth of the target can be detected.However, when there are a plurality of targets having substantially the same distance and speed, For example, when a plurality of vehicles are running in parallel on a road having a plurality of lanes, it is basically difficult to detect the bearing. Therefore, it is also difficult to accurately determine the azimuth, the distance, and the speed simply by combining these two methods.

The present invention has been made in view of the above problems, and has as its object to provide a highly reliable azimuth, even in a radar use environment where reflected waves of a plurality of targets and objects other than the targets are synthesized and received. An object of the present invention is to provide an automobile radar device capable of measuring a relative distance and a relative speed.

[0013]

To achieve the above object, a first aspect of the present invention is to transmit an FM-modulated transmission wave having an upstream phase period in which the frequency increases and a downstream phase period in which the frequency decreases. A transmitting unit, a receiving unit of a plurality of channels for receiving the reflected wave, an analyzing unit for performing frequency analysis of the received wave of each channel to obtain a peak of an echo corresponding to a target and phase information of the echo, An azimuth calculation unit for obtaining a set of peaks whose frequencies correspond to each other between channels and obtaining an azimuth based on a phase difference between the peaks forming the set, and the uplink phase period based on the azimuth obtained by the azimuth calculation unit A distance / speed calculation unit for determining a pair of peaks between the peak phase and the down phase period, and calculating a relative speed and a relative distance of the target based on the frequency of the paired peak. Characterized in that it has a.

According to the present invention, in order to perform azimuth detection by the phase monopulse method, a plurality of channel receiving units are provided, and received waves at different positions are received. The difference in the amount of Doppler shift due to the difference in the reception position is slight because the distance to the target is larger than the interval between the reception positions. Therefore, the position of the peak of the reflected wave appearing in the received signal spectrum obtained by analyzing the received signal, that is, the frequency, has almost no difference between the plurality of channels. That is, for a certain target, even if the phase of the received signal is different between a plurality of channels, the peak frequency corresponding thereto can be basically regarded as the same. The azimuth calculation unit is
Basically, a set of peaks having frequencies that can be regarded as the same in each of the plurality of channels is obtained, and it is determined that the peaks belonging to the set are caused by the same target. Then, from the phase difference between the echoes corresponding to the peaks belonging to the set, the azimuth of the target that has generated the set of peaks is obtained based on the phase monopulse method. When the target has a relative speed with respect to the present apparatus, the position of the peak for the same target differs between the up phase period and the down phase period. For example, when there are a plurality of targets, and a plurality of echo peaks occur in each of the up phase period and the down phase period, the distance / speed calculation unit obtains the azimuth calculation unit in the up phase period and the down phase period. A pair of peaks having the same orientation is found, and it is determined that the peaks forming the pair are caused by the same target. Then, based on each frequency of the paired peaks, the relative speed and relative distance of the target that generated the paired peaks are obtained based on the FMCW method. In the present invention, first, the azimuth of the target is determined based on the phase monopulse method, and the peak pair of the up phase period and the down phase period is determined based on the equal azimuth. In this case, a set of peaks used in the processing of the FMCW method can be correctly selected, and the azimuth, relative speed and relative distance can be detected with high reliability.

According to a second aspect of the present invention, there is provided an integrated processing unit for obtaining tracking information including an azimuth, a relative speed, and a relative distance from the azimuth calculating unit and the distance / speed calculating unit. The transmission unit switches and transmits directional beams in different directions, and the integrated processing unit, when the tracking information for each of the different directional beams matches within a predetermined range, for the plurality of tracking information A predetermined averaging process to determine tracking information of one target.

According to the present invention, the transmitting section switches the beam direction and transmits a directional beam. As a result, the exploration can be performed by dividing the space of the wide target area. The phase monopulse calculation unit and the distance / velocity calculation unit respectively perform the same processing as that of the first invention for the directional beams in each direction. Thus, the azimuth, relative speed, and relative distance of the target located within the range of each beam are obtained. Here, these azimuth, relative speed, and relative distance are collectively referred to as tracking information. Since directional beams generally have overlapping portions, the same target may be detected with multiple directional beams. The integration processing unit compares the tracking information obtained for each directional beam, and searches for those which can be regarded as basically matching between the directional beams. Then, a predetermined averaging process is performed on tracking information that can be regarded as matching. The averaging process includes, for example, a simple average and an average in which each tracking information is weighted based on a predetermined method.
As a special case of weighted averaging, there is a method of selecting the most accurate one of a plurality of pieces of tracking information. Thereby, the accuracy of the tracking information of the target detected by the plurality of beams can be improved.

In a preferred aspect of the present invention, the averaging process includes
The weighted average is based on the degree of coincidence between the direction of the directional beam and the azimuth detected by the azimuth calculation unit for the beam. In general, the closer the direction of the target is to the direction of the directional beam, the higher the intensity of the echo, and the lower the tracking information error based on it. Therefore,
According to this aspect, weighting is performed according to the echo intensity, and a large value is given to a value with a small error.
The accuracy of tracking information is improved satisfactorily.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [Embodiment 1] Hereinafter, a preferred embodiment of the present invention (hereinafter, referred to as an embodiment) will be described.
This will be described with reference to the drawings.

FIG. 4 shows the configuration of an automotive radar device according to an embodiment of the present invention. The vehicle radar device is mounted on a vehicle, and information provided by the vehicle radar device is used for traveling control or the like for securing a safe inter-vehicle distance with a preceding vehicle or the like. This apparatus transmits an FMCW-modulated transmission wave, and receives reflected waves from a target in left and right channels. Then, according to the principle of the phase monopulse method, the azimuth of the target is obtained from the received waves of the left and right channels. In addition, according to the principle of the FMCW method, the distance and speed of the target are obtained from the reception waves in the up phase and the down phase.

The voltage controlled oscillator (VCO) 10 functions as a frequency modulator. A triangular wave whose voltage increases or decreases with time is supplied to the VCO 10 from a control unit (not shown). The VCO 10 generates a high frequency frequency-modulated by the triangular wave. This high frequency is distributed by the distributor 12, one of which is sent to the transmitting antenna 14. In this way, the high frequency modulated by the triangular wave is radiated to the outside as a radio wave.

The radio wave radiated from the transmitting antenna 14 is reflected by the target. In the figure, two preceding vehicles are shown as targets 1 and 2. The reflected signal is 2
It is received by two receiving antennas 16a and 16b. This 2
The two receiving antennas 16a and 16b are spatially spaced apart by a predetermined distance L. Detectors 18a and 18b are connected to the receiving antennas 16a and 16b, respectively. To the detectors 18a and 18b, a high frequency (transmission signal) frequency-modulated by a triangular wave is supplied from the distributor 12 as a reference wave. Detector 18a, 1
8b detects the received wave based on the reference wave, whereby a beat signal having a frequency component of a difference between the transmission frequency and the reception frequency is obtained and supplied to the signal processing device 20.

In the signal processing device 20, the frequency analyzers 22a and 22b and the peak detectors 24a and 24b
It functions as the analysis unit of the present invention. Frequency analysis unit 22a,
Reference numeral 22b performs frequency analysis on beat signals obtained from the left channel and right channel received signals, respectively, to obtain a frequency spectrum of the signal. Here, the complex F
FT (Fast Fourier Transform) is performed, and a complex amplitude (voltage) for each appropriate frequency interval (frequency bin) is obtained. In the subsequent processing in the signal processing device 20,
The bin number is used as an index corresponding to the frequency. The peak detectors 24a and 24b detect peaks (the number of the frequency bin at which the peak appears and the complex amplitude value of the frequency bin) in each of the left and right channels of the phase monopulse based on the frequency analysis result.

FIGS. 5A and 5B show examples of frequency analysis results of the left channel and the right channel, respectively. In the left channel, peaks UL1 and DL1 with large amplitudes
Are the peaks of the up phase and the down phase of the target 1, respectively. The fact that the peak frequency of the downstream phase is higher than the upstream phase indicates that the target 1 is relatively slower (approaching) than the own vehicle.
The peaks UL2 and DL2 having small amplitudes are the peaks of the up phase and the down phase of the target 2, respectively. The fact that the peak frequency of the down phase is lower than the up phase indicates that the target 2 is relatively faster (away) from the own vehicle. Similarly, in the right channel, the peaks UR1 and DR1 are the peaks of the up phase and the down phase of the target 1, respectively. The peaks UR2 and DR2 are the peaks of the up phase and the down phase of the target 2, respectively.

However, in this embodiment, a plurality of targets (preceding vehicles) are used in an environment where the apparatus is used, such as a road.
And objects other than the target, such as trees and guardrails. Reflected waves from various objects are combined and received by the radar. Therefore, actually, there are many more peaks in addition to the peaks shown in FIG. From such a large number of peaks, the left and right channel peaks of the same target are selected as follows.

Returning to FIG. 4, the receiving antennas 16a and 16b
Is smaller than the distance to the target, the azimuth facing the target from each receiving antenna is almost the same, and the relative speed of the target to each receiving antenna is almost the same. Therefore, even if the channels are different, the frequency of the peak corresponding to the same target is
Same or very close. Therefore, in the azimuth calculation unit 26, a peak having a close frequency bin is selected from the left and right channels, and the selected two peaks are used as a peak pair. Here, a peak pair in which the difference in frequency bin between the left and right channels is equal to or smaller than a predetermined threshold frequency difference is selected. here,
Assuming that the peaks A and B form a pair as <A, B>, the peak pair <UL1, UR1>, <UL
2, UR2>, and <DL1, DR1> and <DL2, DR2> are detected for the down phase period.

The azimuth calculation unit 26 includes a frequency analysis unit 22a,
22b, based on the phase information obtained in the complex FFT processing, the phase difference Δφ between each peak constituting each peak pair.
And the target orientation θ corresponding to the peak pair
Ask for. That is, as described with reference to FIG. 1, the phase difference between the reception waves at the two reception antennas 16a and 16b is Δ
If φ, the distance between the two receiving antennas is L, and the wavelength of the radio wave is λ, the azimuth θ can be obtained by the following equation.

[0027]

Θ = sin ⁻¹ {Δφ (λ / L)} The pairing unit 28 performs peak pairing between the up phase period and the down phase period. That is, the pairing unit 28 associates a peak obtained in the up phase period with a peak obtained in the down phase period, and determines a pair of peaks used for distance / speed calculation.

Here, the pairing section 28 may regard the azimuth θ as the same for the left and right channel peak pairs obtained for the up phase period and the left and right channel peak pairs obtained for the down phase period. Ask for a pair of things you can do. For example, a peak (pair) in which the difference between the directions during the up phase and the down phase is equal to or less than a predetermined threshold.
Is selected. By this processing, for the example shown in FIG. 5, the peak pair <UL1, U
R1> and <DL1, DR1> (or UL1 and DL1, or peaks UR1 and DR1), and the peak pair <UL2, UR2> and <DL2, D generated by the target 2
R2> (or UL2 and DL2 or peak UR2 and DR2) is selected.

In this processing, the amplitude of the peak can be taken into consideration. That is, based on the fact that the intensities of the echoes from the same target do not greatly differ between the up phase period and the down phase period, the amplitude difference is also predetermined along with the condition that the difference in the azimuth angle θ is equal to or less than a predetermined threshold. The condition of being equal to or less than the threshold value may be imposed, and the pair of peaks may be obtained here. According to such a configuration, there are many targets,
Even in the case where peaks from a plurality of targets are included in a narrow azimuth angle range, the targets can be discriminated based on the difference in their amplitudes, and the peaks in each of the upward and downward phase periods can be correctly combined.

The distance / speed calculation unit 30 includes a pairing unit 2
The relative distance and the relative speed of the target are obtained based on the pair of peaks determined in Step 8. That is, as described with reference to FIGS. 2 and 3, the beat signal includes a component based on the delay of the received wave according to the distance to the target and a component based on the Doppler shift according to the speed of the target. The beat signal frequencies fbu and fbd in the up phase period and the down phase period are represented by fr representing the beat frequency representing the relative distance and fpp representing the relative speed.
If d

Fbu = fr + fd fbd = fr-fd Therefore, the beat frequency fr and the Doppler frequency fd are obtained from the frequencies fbu and fbd, and the relative distance and the relative speed are obtained. In the present embodiment, the distance and the speed are obtained based on the bin numbers of the corresponding peaks of the up and down phases of the pair determined by the pairing unit 28. This bin number corresponds to the frequency of the peak. Further, the distance and the speed can be obtained independently based on the received waves of the left and right channels, and a more accurate detection result can be obtained by using both the detected values.

The radar device according to the present embodiment has been described above. As described above, in the present embodiment, the azimuths of a plurality of targets are obtained first, and the pairing of the peaks in the up phase period and the down phase period is performed with reference to the azimuths. Therefore, it is possible to correctly pair a plurality of peaks respectively in the up phase and the down phase phase, and to detect the azimuth, the relative speed and the relative distance with high reliability.

In this embodiment, the threshold value of the frequency difference and the threshold value of the determination that the azimuth is considered to be the same are respectively set to appropriate values in advance. It is preferable that the threshold value of the frequency difference is set based on the magnitude of variation in the frequency of the peak obtained from the reflected wave of the same target. Similarly,
The threshold value of the azimuth determination can be determined by assuming the magnitude of the azimuth angle that can be changed by the relative movement between the target and the device between the up phase period and the down phase period. Further, for example, both thresholds can be set to a standard value of the variation, or set to the maximum value of the variation. Each threshold may be set based on experimental results or experience.

[Embodiment 2] Next, a second embodiment of the present invention will be described. FIG. 6 shows the configuration of the vehicle radar device according to the embodiment of the present invention. Among the components of the present embodiment, the same components as those of the first embodiment shown in FIG. 4 are denoted by the same reference numerals, and the description thereof will be appropriately omitted. The second embodiment differs from the first embodiment in the transmitting unit.
In other words, the present apparatus includes a plurality of transmitting antennas 44-1 and 44
,..., 44-n, and a switch 46 for switching the supply of transmission waves from the VCO 10 to these transmission antennas 44 in a time-division manner. In addition, the signal processing device 50 has an integrated processing unit 48 after the distance / speed calculation unit 30 that finally summarizes the calculation results for the plurality of directional beams transmitted from the plurality of transmission antennas 44.

The transmission wave from the VCO 10 is sequentially supplied to each of the transmission antennas 44 via the switch 46 in a time-division manner. Each transmitting antenna 44 is configured such that the directions of the transmitting beams are different, thereby dividing the detection area and transmitting and receiving radio waves for each area. Note that the same division of the detection area can be realized by, for example, a configuration in which a plurality of receiving antennas 16 having different directivities are arranged to switch between them, or a configuration in which switching is performed for both transmission and reception.

The processing of the received signal for each detection area switched by time division is the same as in the above embodiment, and the obtained beat signal is passed to the signal processing device 50. The processing from the frequency analysis processing in the signal processing device 50 to the processing in the distance / speed calculation unit 30 is the same as in the first embodiment. Therefore,
For each detection area, tracking information (azimuth, distance, and speed) of a target in that area is detected.

The tracking information of the targets obtained in the respective detection areas by the switching as described above is input to the integration processing section 48. The detection area of each directional beam is
It is configured such that adjacent ones overlap. Therefore, the same target may be detected in a plurality of detection areas. The integration processing unit 48 compares the tracking information of the target between the adjacent detection regions, and searches for tracking information that matches each other with a predetermined accuracy. If a match is found, it is determined that the tracking information corresponds to the same target.

The determination of the coincidence can be made, for example, based on the fact that the difference between the respective values of the azimuth, the distance and the speed constituting the tracking information between the adjacent detection areas is equal to or smaller than a predetermined allowable range. Also, a criterion such that the sum of squares of the difference between the azimuth, the distance, and the speed is equal to or smaller than a predetermined threshold value can be used.

A plurality of pieces of tracking information determined to correspond to the same target are integrated into one piece of tracking information by a predetermined averaging process. As the predetermined averaging process, for example, there is a simple averaging that simply averages tracking information detected by each beam with equal weight. Further, as another method, there is an average (weighted average) in which weighting is performed based on the likelihood of each tracking information detected by each beam. Here, weighted averaging is performed using the degree of coincidence between the direction of the axis of the directional beam and the azimuth detected by the azimuth calculation unit as a weight coefficient. This is because, in general, the closer the direction is to the beam axis, the greater the echo intensity and the smaller the error. For the same reason, it is also possible to use, for example, the intensity of the beam in the detected direction as the weight coefficient. Further, the integration processing section 48 may select the tracking information having the highest accuracy or precision from the tracking information detected by each beam. This is a special case of weighted averaging, and corresponds to a case where the weight coefficient of the tracking information with the highest accuracy or precision is set to 1 and the weight coefficient of the other tracking information is set to 0.

According to the present apparatus, even when there are a plurality of targets having similar distances and velocities, an area for transmitting and receiving radio waves is divided to detect the plurality of targets by separating them with different beams. be able to. When the same target is detected by a plurality of beams, the obtained plurality of pieces of tracking information are averaged in some form and integrated to obtain accurate tracking information.

Third Embodiment Next, a third embodiment of the present invention will be described. FIG. 7 shows the configuration of the vehicle radar device according to the embodiment of the present invention. Among the components of the present embodiment, the first and second embodiments shown in FIGS.
The same reference numerals are given to the same components as
The description is omitted as appropriate. The configuration of the third embodiment differs from the first embodiment in that the signal processing device 70 includes a tracking filter processing unit 72. Tracking filter processing unit 72
Is provided between the distance / speed calculation unit 30 and the integration processing unit 48.

As in the second embodiment, this apparatus also has a plurality of transmission antennas 44, measures each detection area in a time-division manner, and obtains tracking information of a target existing in each area. That is, the present apparatus and the apparatus of the second embodiment are different from each other in the distance / speed calculating unit 3.
The operation and processing up to 0 are the same.

In the present apparatus, the tracking filter processing section 72
A tracking filter process is performed on the tracking information of each area obtained by the distance / speed calculation unit 30. Tracking filter processing unit 7
The tracking filter processing performed by 2 is prediction filter processing such as Kalman filter processing or α-β filter processing performed on the azimuth, distance, and speed obtained up to the distance / speed calculation unit 30. With this prediction filter processing, the true azimuth, distance, and speed of the target are estimated based on past tracking information. This makes it possible to avoid an erroneous detection state caused by the presence of a plurality of targets and objects other than the target, such as a tree or a guardrail, and an undesired effect of the non-detection state.

The integration processing unit 48 determines that the estimated values of the tracking information correspond to the same target, for example, when the estimated values of the tracking information of the targets obtained in the plurality of divided areas are equal to or smaller than a predetermined difference. I do. In addition, the integrated processing unit 4
8, for example, a trajectory of the estimated value of the tracking information from the past to the present is obtained for each divided region of the beam, and when the distance between the trajectories is equal to or smaller than a predetermined value, the targets corresponding to the trajectories are the same. It is also possible to determine that

The integration processing unit 48 determines the identity of the target based on the estimated value or the trajectory of the estimated value as described above.
The respective estimated values of the tracking information obtained for a plurality of regions for the same target are averaged by the same method as in the second embodiment and integrated into one tracking information.

As described above, in the present apparatus, the tracking information obtained by the FMCW method and the phase monopulse method is
By performing a prediction filter process and further performing a process of integrating tracking information obtained in a plurality of regions by beam switching, a plurality of targets whose distances and velocities are substantially the same at a certain time or period are identified by tracking information. Discrimination can be based on time series. Further, in an actual use environment in which an object such as a tree or a guardrail other than a plurality of targets or targets exists, highly accurate distance, speed, and azimuth detection can be performed.

In this apparatus, the tracking filter processing section 7
Although 2 is provided before the integration processing section 48, a configuration in which the tracking filter processing section 72 is provided after the integration processing section 48 is also possible.

Incidentally, the tracking filter processing section 72 can be employed irrespective of the division of the detection area by the beam, and can be used also in the apparatus of the first embodiment, for example.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating the principle of a phase monopulse radar.

FIG. 2 is a diagram illustrating the principle of an FMCW radar.

FIG. 3 is a diagram illustrating the principle of an FMCW radar.

FIG. 4 is a diagram illustrating a configuration of a first exemplary embodiment of the present invention.

FIG. 5 is a diagram illustrating a frequency analysis result of received signals of a left channel and a right channel of the apparatus of FIG. 4;

FIG. 6 is a diagram showing a configuration of a second exemplary embodiment of the present invention.

FIG. 7 is a diagram showing a configuration of a third embodiment of the present invention.

[Explanation of symbols]

10. Voltage Controlled Oscillator (VCO), 14, 44-1, 44
-2, 44-n transmitting antenna, 16a, 16b receiving antenna, 18a, 18b detector, 20, 50, 70 signal processing device, 22a, 22b frequency analyzing unit, 24a,
24b Peak detection unit, 26 azimuth calculation unit, 28 pairing unit, 30 distance / speed calculation unit, 48 integrated processing unit, 72 tracking filter processing unit.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Tomo Harada 41-Cho, Yokomichi, Nagakute-cho, Aichi-gun, Aichi Prefecture Inside Toyota Central Research Laboratory Co., Ltd. 41, Yokomichi, Toyota Central Research Institute, Inc.

Claims (3)

[Claims] A transmitter for transmitting an FM-modulated transmission wave having an up phase period in which the frequency increases and a down phase period in which the frequency decreases; a plurality of channels for receiving reflected waves; An analysis unit that performs frequency analysis of a received wave of a channel and obtains a peak of an echo corresponding to a target and phase information of the echo, and obtains a set of peaks whose frequencies correspond to each other among the plurality of channels, and forms the set. An azimuth calculation unit that obtains an azimuth based on a phase difference between peaks, Based on the azimuth obtained by the azimuth calculation unit, obtains a pair of peaks in the up phase period and the down phase period, and obtains the pair. And a distance / speed calculating unit for calculating a relative speed and a relative distance of the target based on a peak frequency to be formed. 2. An integrated processing unit for obtaining tracking information including an azimuth, a relative speed, and a relative distance from the azimuth calculating unit and the distance / speed calculating unit, wherein the transmitting unit includes a directional beam in directions different from each other. When the tracking information for each of the different directional beams matches within a predetermined range, the integrated processing unit performs a predetermined averaging process on the plurality of pieces of tracking information to generate one target. 2. The vehicle radar device according to claim 1, wherein the tracking information is determined. 3. The averaging process is a weighted averaging based on a degree of coincidence between the direction of the directional beam and the azimuth detected by the phase monopulse calculation unit for the beam. 3. The vehicle radar device according to claim 2, wherein: