JP2017062398A - Rotation angle detector and laser radar device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately detect an angle of a rotor.SOLUTION: When a polygon mirror is rotationally being driven by a polygon mirror motor, a rotation angle counter 54 counts up at every constant cycle and holds a value indicating a rotation angle over one rotation cycle from an origin of the polygon mirror. Based of position signals indicating that a plurality of angles to be specified of the polygon mirror have reached the specified angles, corrected value registers #1-#9 correct values of the rotation angle counter 54 to values indicating the specified angles.SELECTED DRAWING: Figure 8

Description

  The present invention relates to a rotation angle detection device and a laser radar device, and more particularly to a rotation angle detection device for detecting the angle of a rotating body and a laser radar device that emits laser light.

  FIG. 1 shows scanning of the laser beam irradiation direction by a polygon mirror.

  As the polygon mirror rotates, the angle (incident angle) of the mirror surface that reflects the laser light changes, so that the direction of the emitted laser light can be changed.

  Patent Document 1 shows an example in which alignment is performed using only an origin signal instead of a position signal using an 8-sided polygon.

JP 2000-162533 A

  However, in the technique described in Patent Document 1, when there is rotation unevenness in the rotation of the polygon mirror, if the irradiation timing of the laser light is determined only by the time from the origin signal, the irradiation azimuth varies, particularly at a far distance. It causes the lateral position accuracy to deteriorate.

  It is an object of the present invention to provide a rotation angle detection device and a laser radar device that can accurately detect the angle of a rotating body.

  In order to achieve the above object, a rotation angle detection device according to the present invention is a counter that holds a value indicating a rotation angle over one rotation from the origin of a rotating body that is driven to rotate by a drive unit, and counts up at regular intervals. And a correction for correcting the value of the counter to a value indicating the specified angle based on a signal indicating that the rotating body has reached the specified angle for each of a plurality of specified angles of the rotating body Part.

  According to the present invention, when the rotator is rotationally driven by the drive unit, the counter counts up at regular intervals and holds a value indicating the rotation angle over one rotation from the origin of the rotator. Then, the correction unit corrects the value of the counter to a value indicating the specified angle based on a signal indicating that the rotating body has reached the specified angle for each of the plurality of specified angles of the rotating body. To do.

  Thus, for each of a plurality of specified angles of the rotating body, the counter value is corrected to a value indicating the specified angle based on the signal indicating that the rotating body has reached the specified angle. The angle can be detected with high accuracy.

  The rotating body according to the present invention is a polygon mirror having a plurality of mirror surfaces, and at least one rotation angle can be set as the specified angle for each mirror surface. Further, at least two rotation angles can be set as the designated angle for each mirror surface.

  Further, the rotating body according to the present invention can be a polygon mirror having a plurality of mirror surfaces with different normal angles with respect to the rotation axis.

  Further, the rotation angle detection device according to the present invention sets the count-up cycle of the counter based on a difference between a value of the counter when the rotating body reaches the specified angle and a value indicating the specified angle. A period correction unit for correction may be further included.

  A laser radar device according to the present invention includes the above rotation angle detection device, a laser diode that emits laser light, and laser light emitted from the laser diode, scanned by the rotating body, and a target object. A light receiving unit that receives the reflected laser light and outputs a signal corresponding to reception of the light including the laser light, and a flight time of the laser light to the object based on the signal output from the light receiving unit And an arithmetic unit for obtaining the above.

  As described above, according to the rotation angle detection device and the laser radar device of the present invention, for each of a plurality of specified angles of the rotating body, based on the signal indicating that the rotating body has reached the specified angle, By correcting the value to a value indicating the specified angle, the angle of the rotating body can be detected with high accuracy.

It is a top view which shows a polygon mirror. 1 is a side view showing a schematic configuration of a laser radar apparatus according to a first embodiment of the present invention. It is a figure which shows an example of measurement data. It is a block diagram which shows the functional structure of the control apparatus which concerns on the 1st Embodiment of this invention. It is a figure which shows the timing chart which illustrates operation | movement of the control apparatus which concerns on the 1st Embodiment of this invention. It is a figure which shows the timing chart which illustrates operation | movement of the control apparatus which concerns on the 1st Embodiment of this invention. 1 is a block diagram showing a functional configuration of a timing control circuit according to a first embodiment of the present invention. It is a block diagram which shows the functional structure of the rotation angle correction circuit which concerns on the 1st Embodiment of this invention. FIG. 2 is a block diagram showing a functional configuration of a scanning range signal generation circuit according to the first embodiment of the present invention. It is a block diagram which shows the functional structure of the rotation angle correction circuit which concerns on the 2nd Embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the drawings. In the drawings, substantially the same or equivalent components or parts are denoted by the same reference numerals.

<First Embodiment>
A laser radar device according to a first embodiment of the present invention will be described. As shown in FIG. 2, the laser radar device 100 according to the first embodiment of the present invention includes a light receiving element 10, a polygon mirror 12, a laser diode 14 that emits laser light, and a perforated mirror 16. I have. The polygon mirror 12 is an example of a rotating body.

  The light receiving element 10 receives the laser light emitted by the laser diode 14 and scanned by the polygon mirror 12 and reflected by the object. The light receiving element 10 outputs electric pulses to the control device 22 described later in response to light.

  The polygon mirror 12 is a mechanism for reflecting the laser light emitted from the laser diode 14 and irradiating it forward, and for scanning the laser light, and has a plurality of mirror surfaces each having a different normal depression angle. .

  The perforated mirror 16 is a laser beam reflected and returned from the object, and reflects the light reflected by the polygon mirror 12 so as to be focused on the light receiving element 10 and enter the light receiving element 10. Mechanism.

  Here, the operation principle of the laser radar device 100 will be described.

  The laser radar device 100 is a sensor that is mounted on a vehicle and detects a vehicle or a pedestrian around the vehicle. The flight time of the light from the irradiation of the laser beam to the reflection of the object and the return is measured and converted to the distance to the object. Since a collimated laser beam is used, a scanning mechanism using a polygon mirror 12 is provided. The laser light emitted from the laser diode 14 is once reflected by the polygon mirror 12 and irradiated forward. At this time, the irradiation direction of the laser light is determined by the rotation angle of the polygon mirror 12. The laser beam reflected and returned by the object is reflected again by the polygon mirror 12, is reflected by the perforated mirror 16 so as to be condensed on the light receiving element 10, and enters the light receiving element 10. The light receiving element 10 divides and receives 16 pixels in the vertical direction. For this reason, the distance of 16 points | pieces can be measured simultaneously by the irradiation of a laser beam once. By irradiating the laser beam in accordance with the rotation of the polygon mirror 12, scanning in the horizontal direction becomes possible. Measurement of 16 × 320 points is realized by a combination of divided light reception by the light receiving element 10 and horizontal scanning by the polygon mirror 12. Further, the vertical scanning is realized by changing the normal depression angle of each mirror surface using the five polygon mirrors 12, and the vertical mirror 16 points × 5 surfaces = while the polygon mirror 12 rotates once. Get 80 points of data. Therefore, the measurement of 80 × 320 points is realized by one rotation of the polygon mirror 12 in a combination of vertical and horizontal directions (see FIG. 3).

  As shown in FIG. 4, the laser radar device 100 includes a polygon mirror motor 18, a position detection sensor 20, and a control device 22. The polygon mirror motor 18 is an example of a drive unit.

  The polygon mirror motor 18 is a motor for rotating the polygon mirror 12 at a constant speed, and is, for example, a DC brushless motor.

  The position detection sensor 20 outputs to the control device 22 an origin signal that outputs a pulse when the rotation of the mirror is at the origin (position of 0 degree) and a position signal that outputs a pulse every 36 degrees.

  The control device 22 controls the driving of the polygon mirror motor 18 and controls the light emission timing of the laser diode 14 based on the signal from the position detection sensor 20, and the object to the object based on the light reception signal from the light receiving element 10. Is measured and output to the host device.

  The control device 22 includes a timing control circuit 30, a time-of-flight measurement circuit 32, a measurement data processing circuit 34, and a host interface 36. The flight time measurement circuit 32 is an example of a calculation unit.

  The timing control circuit 30 outputs a control signal for controlling the driving of the polygon mirror motor 18 and controls the light emission timing of the laser diode 14 based on the origin signal and the position signal from the position detection sensor 20. The light emission signal is output to the laser diode 14 and the time-of-flight measurement circuit 32. Further, the timing control circuit 30 generates coordinate data representing the irradiation direction of the laser beam from the polygon mirror 12 based on the origin signal and the position signal from the position detection sensor 20 and outputs the coordinate data to the measurement data processing circuit 34.

  The flight time measurement circuit 32 measures the flight time of the laser light to the object based on the light emission signal and the light reception signal from the light receiving element 10.

  The measurement data processing circuit 34 is based on the flight time of the laser light obtained from the time-of-flight measurement circuit 32 and the coordinate data obtained from the timing control circuit 30, and 80 × 320 points obtained by one rotation of the polygon mirror. The measurement data representing the measurement result is generated and output to the host device via the host interface 36.

  Next, the operation principle of the control device 22 will be described. The polygon mirror 12 is rotated at a constant speed by a polygon mirror motor 18. The control signal for the polygon mirror motor 18 output from the timing control circuit 30 is only a start / stop instruction. A position detection sensor 20 is added to the polygon mirror 12. The position detection sensor 20 outputs an origin signal that outputs a pulse when the rotation of the polygon mirror 12 is at the origin (position of 0 degree), and every 36 degrees. And a position signal for outputting a pulse. For example, the position signal outputs pulses at 10 positions of 0 degree, 36 degrees, 72 degrees, 108 degrees, 144 degrees, 180 degrees, 216 degrees, 252 degrees, 288 degrees, and 324 degrees. In addition, 0 degrees, 72 degrees, 144 degrees, 216 degrees, and 288 degrees are the rotation angles corresponding to the end points of the mirror surface, and 36 degrees, 108 degrees, 180 degrees, 252 degrees, and 324 degrees are the end points of the mirror surface. It is a rotation angle corresponding to other than.

  The timing control circuit 30 determines the rotation angle of the polygon mirror 12 based on the origin signal and the position signal from the position detection sensor 20, and when the rotation angle is at a predetermined rotation angle, In response to this, a light emission signal is transmitted to instruct light emission. A part of the laser light emitted and emitted from the laser diode 14 is reflected by the object and finally received by the light receiving element 10. The time from the light emission signal output from the timing control circuit 30 to the light reception signal output from the light receiving element 10 is measured by the flight time measurement circuit 32 and used as flight time data. The measurement data processing circuit 34 converts the flight time data into distance data and sends it to the host interface 36 in combination with the coordinate data from the timing control circuit 30. The host interface 36 sends measurement results to a host device that uses the output of the laser radar device 100.

  The coordinate data output from the timing control circuit 30 must be coordinate data reflecting the rotation angle of the polygon mirror 12 at the time of laser light irradiation with high accuracy. However, since the rotation angle of the polygon mirror 12 cannot be measured with high precision at the timing of laser light irradiation, interpolation between the position signal and the position signal is performed based on the position signal output at 10 positions per rotation. Then, the rotation angle of the polygon mirror 12 at the timing of laser beam irradiation is obtained. This will be described with reference to FIG. In the present embodiment, the timing control circuit 30 includes a rotation angle counter 54 that holds a value corresponding to the rotation angle of the polygon mirror 12 as will be described later. The rotation angle counter 54 is reset by the origin signal and counts up one rotation up to the next origin signal at a constant cycle. Since the polygon mirror 12 rotates 10 times per second, if it is counted up (+1) every 277.8 microseconds, it becomes 360 counts in 100 milliseconds, and 1 count corresponds to 1 degree. When the position signal of 36 degrees is output, the value held by the rotation angle counter 54 is corrected to 36. In an ideal state where there is no rotation unevenness, the value counted up is also 36 at that time.

  After that, every time the position signal is output, the value held by the rotation angle counter 54 is updated to the corresponding rotation angle.

  FIG. 6 shows a state where there is rotation unevenness. When the rotation of the polygon mirror 12 is delayed, the value held by the rotation angle counter 54 at the time when the position signal of 36 degrees is output has already exceeded 36, and it is 39 if there is no correction. The value held by the rotation angle counter 54 is corrected to 36 by the position signal, and the count up is continued every 277.8 microseconds until the next 72 degree position signal is output. In the vicinity of 108 degrees, an example is shown in which the rotation of the polygon mirror 12 is progressing, and the value held by the rotation angle counter 54 immediately before the position signal is output indicates 106. Since the position signal is output there, the value held by the rotation angle counter 54 is corrected to 108 by skipping 107. The rotation angle counter 54 continues to count up every 277.8 microseconds until the next position signal of 144 degrees is output. Similarly, the value held by the rotation angle counter 54 is rewritten to a value corresponding to the rotation angle every time a position signal is output, but otherwise counts up at regular intervals.

  In order to realize the above operation principle, the timing control circuit 30 rotates the polygon mirror 12 based on the mirror control circuit 42 that outputs a control signal to the polygon mirror motor 18 and the origin signal, as shown in FIG. The angle is detected, and based on the position signal, the rotation angle correction circuit 44 that corrects the rotation angle of the polygon mirror 12 and the distance measurement based on the rotation angle of the polygon mirror 12 detected by the rotation angle correction circuit 44 are performed. Based on the rotation angle of the polygon mirror 12 detected by the rotation angle correction circuit 44 and the scanning range signal generation circuit 46 that generates a scanning range signal representing the range, the light emission signal is output and detected by the rotation angle correction circuit 44 Control for outputting coordinate data representing the rotation angle of the polygon mirror 12 based on the rotation angle of the polygon mirror 12 and the scanning range signal. It includes a road 48, a. The rotation angle correction circuit 44 is an example of a rotation angle detection device.

  FIG. 8 shows a block diagram of the rotation angle correction circuit 44. The rotation angle correction circuit 44 includes a position signal counter 50, correction value registers # 1 to # 9, and a rotation angle counter 54.

  The rotation angle counter 54 is a counter representing the rotation angle of the polygon mirror 12 and expresses from 0 degrees to 360 degrees. One count is a rotation angle of 1 degree, and the entire counter is 9 bits (0 to 511). Normally, the count-up (+1) operation is repeated every 277.8 microseconds. The value held by the rotation angle counter 54 with the origin signal “1” is reset (0 is loaded to the count value), and the correction value is loaded into the rotation angle counter 54 with the position signal “1”. When the position signal is "0", the count-up operation is repeated every 277.8 microseconds. The correction value loaded into the rotation angle counter 54 is provided from one of the correction value registers # 1 to # 9. When the position signal is at the position of 36 degrees, the correction value 36 is provided, and the position signal counter 50 selects one of the correction value registers # 1 to # 9 so that the correction value corresponding to each position signal can be provided. It is configured as follows. The position signal counter 50 is a counter that is reset by the origin signal and counts up (+1) every time the position signal is received, and is a 4-bit counter that holds a value of 0 to 9. When the value held by the position signal counter 50 is 0 and the position signal becomes “1”, the correction value register # 1 is selected, and when the value held by the position signal counter 50 is 1, the correction is made. The value register # 2 is selected. Similarly, when the value held by the position signal counter 50 is 8, the correction value register # 9 is selected. An appropriate value may be written in advance in the correction value registers # 1 to # 9.

  FIG. 9 shows a block diagram of the scanning range signal generation circuit 46. The rotation angle correction circuit 44 includes scanning start point registers # 1 to # 5, scanning end point registers # 1 to # 5, comparison units 60 and 62, and a signal generation circuit 64.

  Here, the range in which the distance is measured by irradiating the laser beam is the scanning range. The mirror surface rotates 72 degrees, but the measurement is performed in the range of 40 degrees. The angle range of the mirror surface <1> is 16 degrees to 56 degrees, and the mirror surface <2> is 88 degrees to 128 degrees. Therefore, the comparison unit 60 detects that the corrected rotation angle obtained by the rotation angle correction circuit 44 coincides with the scanning start point 16 degrees of the mirror surface <1>, and the signal generation circuit 64 detects the comparison unit 60. The scanning range signal is turned on based on the detection result by. Further, the comparison unit 62 detects that the corrected rotation angle coincides with the scanning end point 56 degrees of the mirror surface <1>, and the signal generation circuit 64 detects the scanning range based on the detection result by the comparison unit 62. Turn off the signal. Since the scanning start point and the scanning end point have different values for each mirror surface, the scanning start point register and the scanning end point register are used by appropriately switching between five sets.

  Furthermore, it is necessary to generate timing signals necessary for each part, such as the timing of laser light emission. However, as with the scanning range signal, it may be generated based on the corrected rotation angle, or based on the scanning range signal. May be generated.

<Operation of Laser Radar Device 100>
Next, the operation of the laser radar device 100 will be described.

  First, based on a control signal from the timing control circuit 30, the polygon mirror motor 18 is driven to rotate the polygon mirror 12 at a constant speed. The position detection sensor 20 outputs an origin signal and a position signal according to the rotation angle of the polygon mirror 12.

  In the timing control circuit 30, when the origin signal is input, the value held by the rotation angle counter 54 is reset, and when the position signal is input, the position signal counter 50 and the correction value registers # 1 to # 9 rotate. The value held by the angle counter 54 is corrected to a value corresponding to the position signal.

  The timing control circuit 30 sends a light emission signal to the laser diode 14 to instruct light emission when the rotation angle of the polygon mirror 12 is a predetermined rotation angle. When the laser light emitted and emitted from the laser diode 14 is reflected by the object and finally received by the light receiving element 10, the time-of-flight measuring circuit 32 uses the light emission signal output from the timing control circuit 30. The time until the light receiving signal output from the light receiving element 10 is measured and used as flight time data. The measurement data processing circuit 34 converts the flight time data into distance data and sends it to the host interface 36 in combination with the coordinate data from the timing control circuit 30. The host interface 36 sends measurement results to a host device that uses the output of the laser radar device 100.

  As described above, according to the laser radar device according to the first embodiment, the polygon mirror becomes the specified angle for each of the end points of the mirror surfaces of the polygon mirror and the specified angles other than the end points. By correcting the counter value to a value indicating the specified angle based on the position signal shown, the angle of the polygon mirror can be accurately detected even when the rotation of the polygon mirror is uneven. . In particular, even if the normal depression angle of each mirror surface of the polygon mirror is different and there is uneven rotation, the angle of the polygon mirror can be detected with high accuracy.

  Further, the value of the rotation angle counter managed by the timing control circuit is corrected based on the position signal from the position detection sensor for detecting the rotation angle added to the polygon mirror. At that time, by correcting the rotation angle counter at rotation angles other than the end points of the mirror surface, a rotation angle counter that can follow the rotation unevenness of the polygon mirror with higher accuracy can be realized.

  In addition, when a polygon mirror is used as the scanning mechanism of the laser radar, if the polygon mirror rotates unevenly, the accuracy of the laser irradiation azimuth decreases, and as a result, the azimuth accuracy of the object decreases. Since the rotation angle can be corrected even if the rotation of the polygon mirror is uneven, it is possible to avoid a decrease in azimuth accuracy.

  In the above-described embodiment, priority is given to the ease of explanation, and the count 1 of the rotation angle counter is described as corresponding to the rotation angle of 1 degree. However, the count-up cycle is set so as to satisfy the required accuracy. Can be determined. For example, even counting up every 1 microsecond can be easily realized. Further, the position signal is described as being divided into 360 degrees by 10 and outputting “1” every 36 degrees, but the number of divisions is not limited to this, and the division method may not be equally divided.

  Furthermore, the correction value register and the scan start point register / scan end point register may be modified in various ways, for example, by generating each time instead of arranging the illustrated number.

<Second Embodiment>
Next, a second embodiment will be described. In addition, about the part which becomes the structure similar to 1st Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  In the first embodiment described above, the rotation angle counter is counted up every 277.8 microseconds and the count value is corrected at the timing when the position signal is “1”. However, in the present embodiment, The point that the rotational speed is corrected together with the rotational angle is different from the first embodiment.

  A laser radar apparatus according to the second embodiment of the present invention will be described. As shown in FIG. 10, the rotation angle correction circuit 44 of the laser radar apparatus according to the second embodiment of the present invention includes a position signal counter 50, correction value registers # 1 to # 9, a rotation angle counter 54, a frequency division. A circuit 256 and a frequency division ratio calculation circuit 258 are provided. The frequency division ratio calculation circuit 258 is an example of a period correction unit.

  When a delay (advance) is detected in the rotation of the polygon mirror 12, the count-up cycle of the rotation angle counter 54 may be lengthened (shortened). Therefore, the clock is set to 2.778 microseconds which is 100 times faster so that the count-up cycle 277.8 microseconds of the rotation angle counter 54 can be adjusted, and the clock is divided by 100 by the frequency dividing circuit 256 to 277.8. Create microseconds. The frequency division ratio calculation circuit 258 adjusts the count-up cycle by controlling the frequency division ratio. If the division ratio is 101, the count-up cycle is 280.6 microseconds, and if the division ratio is 99, the speed is 275.0 microseconds, and speed adjustment with 1% accuracy is possible. When performing the correction when the position signal is “1”, the frequency division ratio calculation circuit 258 calculates the difference between the rotation angle counters 54 before and after the correction as a correction difference, and calculates a new frequency division from the correction difference and the current frequency division ratio. The ratio is calculated and held until the correction timing at which the next position signal becomes “1”. For example, if the value of the rotation angle counter 54 before correction is larger than the value of the rotation angle counter 54 after correction, a delay is detected in the rotation of the polygon mirror 12, so that the frequency division ratio calculation circuit 258 Increase the circumference ratio by one. In addition, when the value of the rotation angle counter 54 before correction is smaller than the value of the rotation angle counter 54 after correction, the progress of the rotation of the polygon mirror 12 is detected. Shorten the circumference ratio by one.

  The rotational speed adjustment requires different adjustment accuracy depending on the characteristics of the motor. Therefore, if a finer adjustment is required, the frequency division ratio may be set high.

  Further, since the other configuration and operation of the laser radar apparatus according to the second embodiment are the same as those of the first embodiment, description thereof is omitted.

  As described above, according to the laser radar device of the second embodiment, the difference between the rotation angle counter 54 before and after correction is calculated as a correction difference, and a new division is calculated from the correction difference and the current frequency division ratio. By calculating the circumference ratio and correcting the count-up cycle of the rotation angle counter, the angle of the polygon mirror can be accurately detected even when the rotation of the polygon mirror is uneven.

  Note that the present invention is not limited to the above-described embodiment, and various modifications and applications are possible without departing from the gist of the present invention.

  For example, in the above-described embodiment, the case where the method for correcting the rotation angle of the rotating body of the present invention is used in a laser radar device has been described. However, the present invention is not limited to this.

  Moreover, although the case where the rotation angle of a polygon mirror having a plurality of mirror surfaces with different normal depression angles is corrected has been described as an example, the present invention is not limited to this, and a polygon having a plurality of mirror surfaces with the same normal depression angle For the mirror, the rotation angle of the polygon mirror may be detected to correct the rotation angle. Further, for a rotating body other than the polygon mirror, the rotation angle of the rotating body may be detected and the rotation angle may be corrected.

DESCRIPTION OF SYMBOLS 10 Light receiving element 12 Polygon mirror 14 Laser diode 16 Perforated mirror 18 Polygon mirror motor 20 Position detection sensor 22 Control device 30 Timing control circuit 32 Flight time measurement circuit 34 Measurement data processing circuit 36 Host interface 42 Mirror control circuit 44 Rotation angle correction circuit 46 Scanning range signal generation circuit 48 Light emission control circuit 50 Position signal counter 54 Rotation angle counter 60 Comparison unit 62 Comparison unit 64 Signal generation circuit 100 Laser radar device 256 Frequency division circuit 258 Frequency division ratio calculation circuit

Claims (6)

A counter that holds a value indicating a rotation angle over one rotation from the origin of a rotating body that is rotationally driven by a driving unit, and that counts up at regular intervals;
For each of a plurality of specified angles of the rotating body, based on a signal indicating that the rotating body has reached the specified angle, a correction unit that corrects the value of the counter to a value indicating the specified angle;
Rotation angle detection device. The rotating body is a polygon mirror having a plurality of mirror surfaces;
The rotation angle detection device according to claim 1, wherein at least one rotation angle is set as the specified angle for each mirror surface.   The rotation angle detection device according to claim 2, wherein at least two rotation angles are set as the designated angles for each mirror surface.   4. The rotation angle detection device according to claim 1, wherein the rotating body is a polygon mirror having a plurality of mirror surfaces having different normal angles with respect to a rotation axis. 5.   The period correction | amendment part which correct | amends the count-up period of the said counter based on the difference of the value of the said counter when the said rotary body becomes the said specified angle, and the value which shows the said specified angle is further included. The rotation angle detection device according to claim 4. The rotation angle detection device according to any one of claims 1 to 5,
A laser diode that emits laser light;
A laser beam emitted from the laser diode, which receives the laser beam scanned by the rotating body and reflected by the object, and outputs a signal corresponding to the reception of the light including the laser beam. And
Based on the signal output from the light receiving unit, a calculation unit for obtaining the flight time of the laser light to the object;
A laser radar apparatus including: