JP5677275B2 - Radar device and vehicle - Google Patents

Description

  Embodiments described herein relate generally to a radar apparatus and a vehicle that are installed in a vehicle or a structure and observe a fixed object such as another vehicle or a road surface.

  In the case of an on-vehicle radar device, it is common to use a high-frequency millimeter wave, and in order to obtain a high gain at low cost, the antenna configuration and transmitter / receiver are simplified, and a single or multiple transmit / receive beams are used in the horizontal direction In order to observe a vehicle that moves in a horizontal direction, a coverage surface is set on a horizontal plane.

  Here, as an example of mounting the radar device on the vehicle, consider the case where the radar device is installed at a high position from the road surface, for example, inside the windshield. In this case, if the coverage plane is set to be horizontal, the beam width of the vertical plane is generally narrow in the case of a high gain antenna. May not be detected. Further, when the coverage surface is directed downward in order to detect the own speed by observing the road surface, speed measurement may be difficult if reflection on the road surface becomes small due to the influence of snowfall or the like.

  Further, when observing a target having a width of a reflection point in the height direction in the cross range direction, if the coverage surface is leveled, a point with a large reflection cannot be observed and may not be detected. In addition, if the radar device is fixed and installed on a structure having a high height, it is not possible to observe the vicinity immediately below, and the structure having a limited installation location is restricted. If the coverage plane is vertical for this measure, only a narrow area in the lane can be observed. Furthermore, if the coverage plane is horizontal, the target height cannot be observed, and for example, vehicle type identification or the like cannot be performed.

JP 2010-271115 A JP2011-149898A

As described above, the conventional radar apparatus has the following problems. That is,
(1) When the installation position of the radar apparatus is high, it is difficult to observe the vicinity near the short distance.

(2) When observing the road surface (near directly below) for speed detection or the like, simultaneous observation of high positions in different directions becomes difficult.

(3) When observing a target with a reflection point width in the height direction in the cross-range direction, if the coverage surface is leveled, a point with a large reflection cannot be observed. Then, only the moment of crossing in the cross range direction can be observed, and there may be no detection.

(4) If the radar device is fixed at a high place, it cannot be observed near the bottom, and if the coverage plane is vertical, only a narrow range in the lane can be observed.

(5) When the coverage surface is horizontal, there is a problem that the target height cannot be observed and the vehicle type cannot be identified.

  The problem to be solved by the present invention is to provide a radar apparatus and a vehicle that can detect and track a required target in a required observation range even when the installation position is high.

  The radar apparatus according to the embodiment has a wide-angle coverage surface by a single or a plurality of transmission / reception beams and a narrow-angle coverage surface orthogonal to the coverage surface, and includes a transceiver and a signal processor. The transceiver transmits the wide-angle coverage surface at least in the roll direction. The signal processor processes a signal received by the transceiver in response to transmission from the transceiver, thereby observing the road surface on the side where the wide-angle coverage surface contacts by forward and rotation. The signal processor converts polar coordinate signals obtained by distance measurement and angle measurement in a wide-angle coverage plane into rectangular coordinate signals based on signals received by the transceiver in response to transmission from the transceiver. A coordinate conversion unit; and a coordinate correction unit that corrects the orthogonal coordinate signal obtained by the coordinate conversion unit according to the rotation in the roll direction.

It is a figure for demonstrating an example of the mounting position of a radar apparatus. It is a block diagram which shows the structure of the radar apparatus by which the general ranging and speed-measuring system was employ | adopted. It is a flowchart which shows operation | movement of the radar apparatus shown in FIG. It is a figure which shows an example of the transmission / reception sweep signal in the radar apparatus shown in FIG. It is a figure which shows the change of the sweep signal of transmission / reception in the radar apparatus shown in FIG. It is a figure for demonstrating a mode that the frequency which an amplitude has a peak value in the radar apparatus shown in FIG. 2 is extracted. It is a figure for demonstrating the phase monopulse system used in the angle measurement of the radar apparatus shown in FIG. It is a figure for demonstrating the correlation tracking performed with the radar apparatus shown in FIG. It is a figure for demonstrating rotation of the coordinate system performed with the radar apparatus shown in FIG. FIG. 3 is a diagram illustrating a state in which the radar apparatus illustrated in FIG. 2 observes two lanes, a short distance below the same lane and an adjacent lane. It is a block diagram which shows the structure of the radar apparatus which concerns on 1st Embodiment. It is a flowchart which shows operation | movement of the radar apparatus which concerns on 1st Embodiment. It is a figure for demonstrating the state which observes a road surface with a common radar apparatus. It is a figure which shows the state which rolled the coverage surface in the radar apparatus which concerns on 2nd Embodiment, and turned to the road surface which observes one, and turned the other to the fixed structure of a high place. It is a block diagram which shows the structure of the radar apparatus which concerns on 2nd Embodiment. It is a figure which shows the state which observes the target which has the width | variety of a reflective point in a height direction with a common radar apparatus in a cross range direction. It is a figure which shows the state which observes the target which makes a coverage surface perpendicular | vertical with a common radar apparatus, and crosses in a cross range direction. It is a figure which shows the state which angle-measures the target which moves to a cross-range direction with the roll angle of a coverage surface with the radar apparatus which concerns on 3rd Embodiment. It is a figure which shows the state which installs a common radar apparatus in a high place and observes a target. It is a figure which shows the state which observes a range-cross range with the radar apparatus which concerns on 4th Embodiment. It is a figure which shows the state which measures the angle in a coverage surface with the radar apparatus which concerns on 5th Embodiment, and calculates the target height by a distance value (range) and an angle value. It is a figure which shows the special example which sets a coverage surface diagonally with the radar apparatus which concerns on 1st Embodiment-5th Embodiment. It is a figure which shows the other example which sets a coverage surface diagonally with the radar apparatus which concerns on 1st Embodiment-5th Embodiment. It is a figure which shows the application example in the case of crossing a coverage surface diagonally with the radar apparatus which concerns on 3rd Embodiment.

  Embodiments of a radar apparatus and a vehicle according to the present invention will be described below in detail with reference to the drawings.

(First embodiment)
In order to facilitate understanding of the first embodiment described below, first, consider a case where the radar apparatus 1 is mounted at a high position from the road surface such as the inside of a windshield of a vehicle. In this case, as shown in FIG. 1, if the wide-angle coverage plane 2 formed by a single or a plurality of transmission / reception beams is horizontal, the high-gain antenna generally has a vertical plane (a narrow angle orthogonal to the wide-angle coverage plane). The beam width of the coverage surface 2a) is narrow. For this reason, the amplitude of a reflection point of a target such as another vehicle existing in a non-detection region nd or a short-distance wide-angle (left and right of the radar device 1) formed below a short distance becomes small and is not detected. There is. 1A is a three-dimensional view, FIG. 1B is a top view, and FIG. 1C is a side view.

  As a countermeasure for this, each method of ranging, speed measurement, and angle measurement is not particularly limited as long as it can be observed on the wide-angle coverage surface 2, but it is effective for a large number of reflection points on the coverage surface 2. As a method, for example, there are techniques disclosed in Patent Document 1 and Patent Document 2 (MRAV: Measurement Range after Measurement Velocity).

  Here, first, a general distance measurement and speed measurement method will be described with reference to the drawings. The ranging and speed measurement methods are described in, for example, “Supervised by Takashi Yoshida,“ Revised Radar Technology ”, The Institute of Electronics, Information and Communication Engineers, pp.274-275 (1996)”.

  FIG. 2 is a block diagram showing a configuration of a radar apparatus employing a general distance measurement and speed measurement method, and FIG. 3 is a flowchart showing its operation. The radar apparatus includes an antenna 10, a transceiver 20 and a signal processor 30.

  The antenna 10 includes an antenna transmitting element 11 and a plurality of antenna receiving elements 12. The antenna transmission element 11 converts a transmission signal sent as an electrical signal from the transceiver 20 into a radio wave and sends it out. The plurality of antenna receiving elements 12 receive external radio waves, convert them into electrical signals, and send them to the transceiver 20 as received signals.

  The transceiver 20 includes a transmitter 21 and a plurality of mixers 22, and the plurality of mixers 22 are provided corresponding to the plurality of antenna receiving elements 12, respectively. The transmitter 21 generates a transmission signal in accordance with the transmission control signal sent from the signal processor 30 and sends it to the antenna transmission element 11 and the plurality of mixers 22. The plurality of mixers 22 frequency-convert the received signals received from the plurality of antenna receiving elements 12 in accordance with the signals from the transmitter 21 and send the signals to the signal processor 30.

  The signal processor 30 includes an AD converter 31, an up sequence down sequence extraction unit 32, an FFT (Fast Fourier Transform) unit 33, a DBF (Digital Beam Forming) unit 34, a pairing unit 35, A distance measurement / speed measurement unit 36, an angle measurement unit 37, a coordinate conversion unit 38, and a correlation tracking unit 39 are provided.

  The AD converter 31 converts the analog signal sent from the transceiver 20 into a digital signal and sends it as an element signal to the up sequence down sequence extraction unit 32. The up-sequence / down-sequence extraction unit 32 extracts an up-chirp sequence signal and a down-chirp sequence signal from the element signal transmitted from the AD converter 31, and sends the extracted signal to the FFT unit 33.

  The FFT unit 33 converts the signal sent from the up sequence down sequence extraction unit 32 into a signal on the frequency axis by fast Fourier transform, and sends the signal to the DBF unit 34. The DBF unit 34 uses the signals on the frequency axis sent from the FFT unit 33 to form a Σ beam and a Δ beam. The Σ beam (up sequence and down sequence) formed by the DBF unit 34 is sent to the pairing unit 35, and the Δ beam is sent to the angle measuring unit 37.

  The pairing unit 35 extracts a frequency having a peak in amplitude from the up-chirp sequence signal and the down-chirp sequence signal of the Σ0 beam sent from the DBF unit 34, and creates a frequency pair. A signal indicating the frequency pair created by the pairing unit 35 is sent to the distance measurement / speed measurement unit 36. The distance measurement / speed measurement unit 36 performs distance measurement and speed measurement based on the signal (Σ beam) sent from the pairing unit 35, and outputs a signal indicating the distance and speed obtained thereby to the angle measurement unit 37 and the coordinates. The data is sent to the conversion unit 38.

  The angle measurement unit 37 performs angle measurement based on the signal (Σ beam) sent from the distance measurement / speed measurement unit 36 and the Δ beam sent from the DBF unit 34. A signal indicating the angle obtained by the angle measurement in the angle measurement unit 37 is sent to the coordinate conversion unit 38.

  The coordinate conversion unit 38 is a coordinate for converting a polar coordinate signal indicating the distance and speed sent from the distance measurement / speed measurement unit 36 and a polar coordinate signal indicating the angle sent from the angle measurement unit 37 into a rectangular coordinate signal. The conversion is performed and sent to the correlation tracking unit 39. The correlation tracking unit 39 performs a correlation tracking process to calculate the target position and speed and outputs the target position and speed to the outside.

  Next, the schematic operation of the radar apparatus configured as described above will be described with reference to the flowchart shown in FIG.

  When the radar apparatus is activated, first, transmission / reception data is input (step S11). As a result, the signal swept by the transmitter 21 inside the transceiver 20 is transmitted from the antenna transmission element 11. On the other hand, the signals received by the plurality of antenna receiving elements 12 are frequency-converted by the plurality of mixers 22 and sent to the signal processor 30. 4 and 5 show examples of transmission / reception sweep signals. In the signal processor 30, the signal sent from the transmitter / receiver 20 is converted into a digital signal by the AD converter 31, and sent to the up sequence down sequence extraction unit 32 as an element signal.

  Next, the up-chirp sequence and the down-chirp sequence are separated (step S12). That is, the up-sequence down-sequence extraction unit 32 separates the up-chirp signal and the down-chirp signal from the element signal (digital signal) transmitted from the AD converter 31, and sends it to the FFT unit 33.

  Next, up series / down series FFT and DBF are performed (step S13). That is, the FFT unit 33 converts the up-chirp signal and the down-chirp signal sent from the up-sequence down-sequence extraction unit 32 into a signal on the frequency axis by fast Fourier transform, and sends the signal to the DBF unit 34. The DBF unit 34 forms a Σ beam (up sequence and down sequence) and a Δ beam for each frequency using the signal on the frequency axis sent from the FFT unit 33. The Σ beam formed by the DBF unit 34 is sent to the pairing unit 35, and the Δ beam is sent to the angle measuring unit 37.

  Next, up series / down series frequency peaks are extracted (step S14). That is, the pairing unit 35 extracts a frequency having a peak value in amplitude as shown in FIG. 6 from the up-sequence and down-sequence signals of the Σ beam sent from the DBF unit 34.

  Next, up-sequence / down-sequence pairing is performed (step S15). That is, since the peak frequencies of the down chirp sequence and the up chirp sequence are different, the pairing unit 35 associates the frequencies extracted in step S14 and generates a frequency pair. A signal indicating the frequency pair generated by the pairing unit 35 is sent to the distance measurement / speed measurement unit 36.

  Next, the distance and speed are calculated (step S16). That is, the distance measurement / speed measurement unit 36 performs distance measurement and speed measurement based on the signal (Σ beam) sent from the pairing unit 35, and sends a signal indicating the distance and speed obtained thereby to the angle measurement unit 37. And to the coordinate conversion unit 38.

Here, the relational expression from the frequency peak extraction of the up series / down series (step S14) to the calculation of the distance and speed (step S16) is shown below.

here,
Δf1; Observation frequency of down-chirp signal Δf2; Observation frequency of up-chirp signal fd; Doppler frequency fr;

On the other hand, the frequency fr depending on the distance and the Doppler frequency fd depending on the target speed are as follows.

here,
B: Frequency band R; Target distance T; Sweep time c; Light speed V; Target speed λ; Wavelength When the formula (3) is developed with the distance R and the speed V, and the formula (2) is substituted, the following formula is obtained. Thereby, the distance R and the speed V can be calculated.

  Next, an angle is calculated (step S17). That is, the angle measuring unit 37 performs angle measurement based on the Σ beam signal sent from the distance measuring / speed measuring unit 36 and the Δ beam signal sent from the DBF unit 34. For this angle measurement, for example, a phase monopulse method can be used. The phase monopulse system is described in, for example, “Supervised by Takashi Yoshida,“ Revised Radar Technology ”, The Institute of Electronics, Information and Communication Engineers, pp.262-264 (1996)”.

In this phase monopulse method, as shown in FIG. 7A, an error voltage represented by the following equation is observed using a Σ beam signal and a Δ beam signal.

here,
Σ; sum beam Δ; difference beam *; complex conjugate Re; real part And, as shown in FIG. 7B, a table of error voltage represented by equation (5) and angle-error voltage stored in advance is shown. Use to calculate the angle. A signal indicating the calculated angle is sent to the coordinate conversion unit 38. The distance, speed, and angle of the coverage surface are calculated by the distance measurement, speed measurement, and angle measurement methods described above.

Next, coordinate conversion is performed (step S18). That is, the coordinate conversion unit 38 performs coordinate conversion on the signal indicating the distance and speed sent from the distance measuring / speed measuring unit 36 and the signal showing the angle sent from the angle measuring unit 37, and the correlation tracking unit Send to 39. More specifically, the coordinate conversion unit 38 performs polar coordinate-orthogonal coordinate conversion of the following equation in order to convert the cross range to the (X, Y) axis, and sends the conversion result to the correlation tracking unit 39.

here,
R: Distance measurement value V: Speed measurement value (radial direction)
Θ: Angle measurement value (0 degree in front of radar)
(X, Y): Cross range, range position (Vx, Vy): Cross range, range speed The correlation tracking unit 39 calculates a smooth position and a smooth speed by correlation tracking processing. FIG. 8 is a diagram for explaining general correlation tracking (NN correlation, α-β tracking method). The correlation tracking is described in, for example, “Supervised by Takashi Yoshida,“ Revised Radar Technology ”, The Institute of Electronics, Information and Communication Engineers, pp.264-267 (1996)”.

Here, in order to simplify the description, it is expressed in one dimension (X-axis or Y-axis only). The observation (position) vector is y, the smooth vector is xs, the prediction vector is xp,

Then, the smooth position and smoothing speed can be expressed by the following equations.

とする。 here,
yr (k, j); observation kth, observation (position) vector jth residual vector y (k, j); observation kth jth observation (position) vector yr (k); observation k Residual vector xs (k) that minimizes the second square error; k-th smoothing vector xp (k); k-th predicted vector (using data up to k−1)
H: Observation matrix
H = [1 0]

And

  The method for obtaining a smooth value by correlation tracking as a general observation value has been described above. However, for smooth values, multiple observations in the vicinity of the same reflection point in a cycle can be performed without performing correlation tracking between cycles. It can also be obtained by a process of taking the average of the values.

  When the process of step S18 is completed, it is next checked whether or not the cycle is completed (step S20). If it is determined in step S20 that the cycle has not ended, a process for moving to the process of the next cycle is performed (step S21). Then, it returns to step S11 and the process mentioned above is repeated. On the other hand, if it is determined in step S20 that the cycle has ended, the processing of this radar apparatus ends.

  Next, the radar apparatus according to the first embodiment will be described in detail. In the case of an in-vehicle radar device or the like, since the installation position of the radar device is relatively high, as already described with reference to FIG. 1, when the coverage surface 2 is leveled, it becomes difficult to detect a target below a short distance. As a countermeasure, the coverage surface 2 is rotated in the roll direction as shown in FIG. The rotation of the coverage plane 2 is performed by controlling a transmission / reception beam transmitted from the transceiver 20 via the antenna 10.

  The rotation angle is set according to the observation range. For example, in order to observe the same lane and the adjacent lane, the coverage surface 2 faces the vicinity of the adjacent lane (one end portion of the coverage surface 2 is in contact with the adjacent lane). ) Is set as follows. Thereby, as shown in FIG. 10, it is possible to observe two lanes, a short distance below the same lane and an adjacent lane. 10A is a three-dimensional view, and FIG. 10B is a top view.

In order to formulate this, the rotation of the coordinate system will be described with reference to FIG. The coordinates (X ′, Y ′, Z ′) after conversion when the coordinates are (X, Y, Z) and rotated by an angle α around the X axis are as follows:

here,
(X, Y, Z): Original coordinates (X ′, Y ′, Z ′): Coordinates after conversion α: Pitch angle.

Also, when rotated by an angle β around the Y axis,
It becomes. If the angle β is rotated around the Y axis,

here,
(X, Y, Z): Original coordinates (X ′, Y ′, Z ′): Coordinates after conversion β: Roll angle.

Also, when rotated by an angle γ around the Z axis,

here,
(X, Y, Z): Original coordinates (X ′, Y ′, Z ′): Coordinates after conversion γ: Yaw angle.

Therefore, if the coordinates after sequentially combining the angles α, β, and γ as coordinate rotation are (X ′, Y ′, Z ′),

It becomes.

From this, using the inverse matrix

When the inverse matrix is converted, the following equation is obtained.

here,
(X, Y, Z): Original coordinates (X ′, Y ′, Z ′): Coordinates after conversion α, β, γ: Pitch, roll, yaw angle By the above equations (11) to (13) The observed values (X ′, Y ′, Z ′) can be converted into the original coordinates (X, Y, Z).

  Based on the above points, for example, when only the roll angle β is rotated (α = γ = 0), the coverage surface is tilted by the roll angle, so the coordinates in the real space (horizontal plane) are the observed values (X ′, Based on Y ′, Z ′), correction is performed using the following equation in the coordinate correction processing described later.

From the inverse matrix operation of equation (9),

If we ignore the height Z

here,
(X ′, Y ′, Z ′): Coordinates on observation coverage plane (X, Y, Z): Coordinates in real space β: Formulated as roll angle of coverage plane. When other rotations are added, equation (13) can be used.

  FIG. 11 is a block diagram showing the configuration of the radar apparatus according to the first embodiment. This radar apparatus is configured by adding a coordinate correction unit 40 to the signal processor 30 of the radar apparatus shown in FIG. The coordinate correction unit 40 performs the above-described coordinate correction processing on the signal indicating the orthogonal coordinates sent from the coordinate conversion unit 38 and sends the signal to the correlation tracking unit 39.

  Next, the schematic operation of the radar apparatus according to the first embodiment configured as described above will be described with reference to the flowchart shown in FIG. This flowchart is configured by adding step S19 for performing coordinate correction processing to the flowchart shown in FIG. That is, in step S <b> 19, the coordinate correction unit 40 performs the above-described correction on the signal indicating the coordinates sent from the coordinate conversion unit 38 and sends the signal to the correlation tracking unit 39.

  That is, the signal processor 30 processes the signal received by the transceiver 20 in response to the transmission from the transceiver 20. Thereby, the road surface on the side where the wide-angle coverage surface 2 is in contact with the front and the rotation can be observed.

  As described above, according to the radar device according to the first embodiment, by rotating the coverage surface 2 in the roll direction, even when the height of the radar device is high, a wide-angle reflection point on the horizontal plane. It is possible to observe the same lane and adjacent lanes while suppressing the effects of fading.

(Second Embodiment)
The radar apparatus according to the second embodiment observes the speed of the vehicle by observing the road surface of the vehicle in an automobile, a railway vehicle, or the like. When observing the road surface (near directly below), the coverage surface 2 is directed downward as shown in FIG. 13, so the road surface may not be observed due to the influence of snowfall or the like, and the speed may not be detected.

  Even if the road surface can be observed, the area where the transmitted and received beams irradiate the road surface is small, and the time for observing the same reflection point (road surface reflection point) is shortened. In some cases, the speed cannot be observed accurately. 13A is a three-dimensional view, FIG. 13B is a top view, and FIG. 13C is a side view.

  As a countermeasure against this, the radar apparatus according to the second embodiment has a fixed structure in which one of the coverage surfaces 2 is directed to the road surface to be observed by the roll angle of the coverage surface 2 as shown in FIG. Turn to. 14A is a three-dimensional view, FIG. 14B is a top view, FIG. 14C is a front view, and FIG. 14D is a side view. By measuring the angle with the coverage surface 2, it is possible to determine whether it is on the road surface side or on the structure side. Therefore, it is possible to calculate the own speed by detecting each reflection point and tracking the correlation as necessary. . In this case, since the speed based on different places can be calculated, even if one is not detected due to the influence of snowfall or the like, the other can be detected, and the speed can be stably obtained by such redundancy. In addition, since the time during which the road surface can be irradiated is long with respect to the traveling direction, the same reflection point (road surface reflection point) can be observed for a long time, it is difficult to detect non-detection, and the correlation tracking is also simplified.

The formulation is as follows. When the observed value on the observation coverage plane is (X ′, Y ′, Z ′), the coordinates in the real space including the height are as follows.

here,
(X ′, Y ′, Z ′): coordinates in the observation coverage plane (X, Y, Z): coordinates in the real space β: roll angle of the coverage plane In the observation coverage plane, Z ′ = 0

It becomes.

  FIG. 15 is a block diagram illustrating a configuration of a radar apparatus according to the second embodiment. This radar apparatus is configured by adding a height determination unit 41 to the radar apparatus according to the first embodiment. The height determining unit 41 uses the thresholds Zth1 and Zth2 for extracting the road surface and the height structure, and determines that the road surface is Zth1 or less, and determines the height structure if Zth2 or more. The velocity in the real space (X, Y) axis can be extracted from the extracted road surface and the reflection point of the height structure by using equation (4).

  Thereby, the speed of the reflection point of at least one of the road surface or the height structure can be calculated, and the vehicle speed of the opposite sign to the calculated speed can be calculated. Further, in order to calculate the smoothing speed, the position (X, Y) of the reflection point is used to correlate with (X, Y) in the next cycle, and the tracking process may be performed based on the observed value. As the correlation tracking process, the above-described correlation tracking (NN correlation, α-β tracking method) can be used, thereby improving the speed accuracy.

  As described above, according to the radar apparatus according to the second embodiment, by extracting the lower and upper reflection points detected on the coverage surface, the influence of other reflection points is suppressed, and then the road surface Since the reflection point and the reflection point of the structure at a high place can be extracted, the vehicle speed can be detected with high accuracy. Further, even if one of the lower or upper reflection points cannot be detected due to the influence of snowfall or the like, interpolation can be performed on the other, so that stable speed extraction can be performed.

(Third embodiment)
As shown in FIG. 16, when observing a target (target vehicle 4 or target person 5) having a reflection point width in the height direction in the cross range direction, if the coverage surface 2 is leveled, a point having a large reflection is obtained. It may not be observable and may not be detected. 16A is a three-dimensional view, and FIGS. 16B and 16C are side views. In order to avoid this, there is a method of observing a target crossing in the cross range direction with the coverage surface 2 vertical as shown in FIG. 17, but there are cases where the detection time is not detected because the observation time is shortened. 17A is a three-dimensional view, FIG. 17B is a side view, and FIG. 17C is a top view.

As a countermeasure, the radar apparatus according to the third embodiment crosses the coverage surface 2 from a low part to a high part of the target moving in the cross range direction according to the roll angle of the coverage surface 2 as shown in FIG. Thus, the angle is measured on the coverage plane 2. 18A is a three-dimensional view, and FIGS. 18B and 18C are side views. Using this angle measurement value, roll angle, and range value, the cross range position can be calculated by the following equation. The calculation of the cross range position can be performed by the correlation tracking unit 39, for example.

Ignoring the height Z

here,
(X ′, Y ′, Z ′): Coordinates in the observation coverage plane (X, Y, Z): Coordinates in the real space β: Roll angle of the coverage plane By the above, detection of the target position in the cross-range direction and its position The correlation tracking used can be performed.

  As described above, according to the radar apparatus according to the third embodiment, when detecting a target having a height that moves in the cross-range direction, not only a reflection point having a certain height but also the entire height. Therefore, stable tracking can be achieved.

(Fourth embodiment)
When the radar apparatus 1 is installed at a high place, as shown in the side view of FIG. 19A, the area directly below the radar apparatus 1 cannot be observed, and when the coverage surface 2 is vertical, the top view of FIG. As can be seen, only a narrow range in the lane can be observed.

As a countermeasure, the radar apparatus according to the fourth embodiment sets the coverage surface 2 to be vertical as shown in FIG. 20 and further sets an angle in the azimuth direction, so that an observation range of a predetermined range-cross range is set. Observe the range-cross range diagonally on the diagonal of 5. 20A is a side view and FIG. 20B is a top view. Considering that the coverage surface 2 is directed downward, generally, all the rotations of the pitch angle α, the roll angle β, and the yaw angle γ are involved.

here,
(X, Y, Z): Original coordinates (X ′, Y ′, Z ′): Coordinates after conversion α: Pitch angle β: Roll angle (90 degrees)
γ: Yaw angle The pitch angle α is set downward to cover the observation width. The roll angle β is basically 90 degrees. The yaw angle γ is set so as to cover one lane. The observed value Z ′ is generally 0, and Z = Z ′ = 0 when the height information is not used even after conversion. Thereby, detection of the target position in the cross range direction and correlation tracking using the position can be performed.

  As described above, according to the radar apparatus of the fourth embodiment, by setting the coverage plane on the diagonal line of the observation range 5 of the predetermined range-cross range, a vehicle having a predetermined width or more is observed. In range 5, both the range and the cross range can be observed up to near the short distance.

(Fifth embodiment)
If the coverage plane is horizontal, the target height cannot be observed, and the vehicle type cannot be identified. As a countermeasure, the radar apparatus according to the fifth embodiment measures the angle on the coverage plane 2 as shown in the side view of FIG. 21A and the top view of FIG. ) And the measured angle value, the target height Z ′ is calculated by the following equation.

here,
(X, Y, Z): Original coordinates (X ′, Y ′, Z ′): Coordinates after conversion α: Pitch angle β: Roll angle (90 degrees)
γ: Yaw angle The pitch angle α is set downward to cover the observation width. The roll angle β is basically 90 degrees. The yaw angle γ is set so as to cover one lane. The observed value Z ′ is generally zero. Using the converted height information Z ′, comparison is made with a predetermined threshold Zth (n) (n = 1 to N, N is the type of vehicle to be identified) corresponding to the height of each of a normal vehicle or a large vehicle, etc. By doing so, the target is identified.

  As described above, according to the radar apparatus according to the fifth embodiment, in addition to the radar apparatus according to the fourth embodiment, target conversion is performed by coordinate conversion based on the range-cross range value of the coverage surface. A small car or a large car can be identified by extracting the height and comparing it with a predetermined threshold.

  As described above, according to the radar apparatus according to the first to fifth embodiments, the radar apparatus is relatively high in position by the set angles of the three axes (roll / pitch / yaw) of the wide-angle coverage surface. Even in the case of being installed in the vehicle, it is possible to improve the detection / tracking ability of a target in a predetermined range from a short distance to a long distance. In addition, by setting the coverage surface obliquely with respect to the direction of travel of the target, it is possible to observe even if the unnecessary reflection points in the coverage are suppressed and the required reflection points have a three-dimensional width. By increasing the length, detection / tracking capability can be increased.

  As a special example of setting the coverage surface 2 obliquely, as shown in FIG. 22, there is a case where the coverage surface 2 is made vertical by an in-vehicle radar device, which is included in the contents of the first embodiment. It is. 22A is a top view, FIG. 22B is a front view, and FIG. 22C is a side view. In the first embodiment, as shown in the side view of FIG. 23 (a) and the top view of FIG. 23 (b), the radar apparatus 1 may be fixed at the height of the structure to observe the lane. is there.

  Further, as an application example in the case where the coverage surface 2 described in the third embodiment is crossed obliquely, as shown in FIG. The detection time can be increased by extending the observation time. 24A is a three-dimensional view, FIG. 24B is a side view, and FIG. 24C is a top view.

  As mentioned above, although several embodiment of this invention was described, these embodiment is shown as an example and is not intending limiting the range of invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 10 Antenna 11 Antenna transmission element 12 Antenna receiving element 20 Transmitter / receiver 21 Transmitter 22 Mixer 30 Signal processor 31 AD converter 32 Up series down series extraction part 33 FFT part 34 DBF part 35 Pairing part 36 Ranging and speed measurement part 37 Angle measurement unit 38 Coordinate conversion unit 39 Correlation tracking unit 40 Coordinate correction unit 41 Height determination unit

Claims (6)

In a radar apparatus having a wide-angle coverage surface by a single transmission / reception beam or a narrow-angle coverage surface orthogonal to the coverage surface,
A transmitter / receiver that rotates and transmits at least the wide-angle coverage surface in the roll direction;
A signal processor for observing the road surface in front of and in contact with the wide-angle coverage surface by the rotation by processing a signal received by the transceiver in response to transmission from the transceiver;
With
The signal processor is
A coordinate converter that converts a polar coordinate signal obtained by distance measurement and angle measurement on a wide-angle coverage surface based on a signal received by the transceiver in response to transmission from the transmitter / receiver into an orthogonal coordinate signal; ,
A coordinate correction unit that corrects a signal of orthogonal coordinates obtained in the coordinate conversion unit according to the rotation in the roll direction;
A radar apparatus comprising: The signal processor is
A height for judging whether the reflection point is a road surface or a high place by calculating the height of the reflection point of the transmission / reception beam from the road surface based on the signal corrected by the coordinate correction unit and comparing it with a predetermined threshold. The radar apparatus according to claim 1, further comprising a height determination unit, and calculating a self-speed from the speed of the reflection point based on an output of the height determination unit. The signal processor is
The correlation tracking part which calculates a cross-range direction based on the signal correct | amended by the said coordinate correction | amendment part, detects the target of the calculated cross-range direction, and performs a correlation tracking is provided, The correlation tracking part characterized by the above-mentioned. The radar apparatus described. The signal processor is
4. The range-cross range is observed by setting a wide-angle coverage plane diagonally on a diagonal line of a predetermined range-cross range observation range. 5. The radar apparatus described. The signal processor is
5. The radar apparatus according to claim 4, wherein a target height is extracted based on the signal corrected by the coordinate correction unit, and the extracted target is identified. Vehicle coverage surface, characterized in that the radar apparatus according to any one of claims 1 to 5 so as to be horizontal and non-parallel in the traveling state are installed.

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