JP7326730B2 - distance speed measuring device - Google Patents

Description

The present invention relates to a distance speed measuring device .

In recent years, research into automatic driving of automobiles and driving assistance systems has progressed, and in-vehicle radar as a sensing means has attracted attention. Among automotive radars, FMCW radar is widely used as a radar that can measure the distance to an object and the relative speed of the object, and as a heterodyne radar that can detect weak reflected waves. Developments such as directivity and miniaturization of antennas are progressing.

Under these circumstances, for example, like the radar device described in Patent Document 1, FMCW lidar research is also underway, aiming to improve directivity, reduce size, and reduce power consumption by replacing electromagnetic waves with laser light. .

FMCW Lidar obtains the distance to an object from the frequency difference between the outgoing wave and the reflected wave, which are frequency-modulated continuous waves. The FMCW lidar also measures the frequency difference between the transmitted wave and the reflected wave when the slope of the sweep is positive, and the frequency difference between the transmitted wave and the reflected wave when the slope of the sweep is negative, which is caused by the frequency shift caused by the Doppler effect. The relative velocity of the object is obtained from the difference between .

By the way, the frequency shift due to the Doppler effect decreases as the relative velocity of the object decreases. In general, it is considered that at least one cycle is required for waveform measurement, so the smaller the frequency shift, the longer the measurement time.
As a method of increasing the frequency shift, increasing the frequency of the transmitted wave is conceivable. However, for automotive FMCW radar, for example, millimeter waves of 24 GHz or 77 GHz are defined as standards. In addition, in FMCW Lidar, the operation speed of LD is currently about 2GHz. Therefore, there is a limit to increasing the frequency of the transmitted wave.

SUMMARY OF THE INVENTION An object of the present invention is to provide a distance/speed measuring device and a distance/speed measuring method capable of performing measurement in a short time.

In order to solve the above-described problems, the distance /velocity measuring apparatus of the present invention includes a repetitive wave generating circuit for generating a repetitive wave having a positive frequency sweep and a constant frequency of a first frequency; a constant frequency continuous wave generating circuit for generating a constant frequency continuous wave of a frequency of , a transmitting circuit for transmitting the repetitive wave, a receiving circuit for receiving a reflected wave of the repetitive wave from an object, and the frequency sweep period of the a first processing circuit for generating a first beat signal for calculating a distance to the object from the reflected wave and the repeated wave; a second processing circuit for generating a second beat signal for calculating the relative velocity of the object.

According to the present invention, it becomes possible to perform measurement in a short time.

1 is a block diagram showing an example of the configuration of a distance/speed measuring device according to a first embodiment; FIG. The figure which shows an example of a structure of general FMCW Lidar. A first diagram showing the relationship between the reference wave and the reflected wave and their frequency difference in a typical FMCW lidar (when the object is stationary). A second diagram showing the relationship between the reference wave and the reflected wave and their frequency difference in a typical FMCW lidar (when the object is moving). A first timing chart for explaining the operation of the distance/velocity measuring device of the first embodiment (when the relative velocity is 0 km/h). A second timing chart for explaining the operation of the distance/velocity measuring device of the first embodiment (when the relative velocity is not 0 km/h). 4 is a flowchart showing the operation procedure of the distance/speed measuring device of the first embodiment; The block diagram which shows an example of a structure of the distance-speed measuring apparatus of 2nd Embodiment. The block diagram which shows an example of a structure of the distance-speed measuring apparatus of 3rd Embodiment. FIG. 11 is a timing chart for explaining the operation of the distance/speed measuring device of the third embodiment; The block diagram which shows an example of a structure of the distance-speed measuring apparatus of 4th Embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
First, a first embodiment of the present invention will be described.
FIG. 1 is a block diagram showing an example of the configuration of a distance/speed measuring device according to this embodiment. In this embodiment, it is assumed that the distance/velocity measuring device of the present invention is implemented as an FMCW lidar using laser light. In addition to the FMCW lidar, the distance/velocity measuring device of the present invention can be implemented as various types of radar using continuous frequency modulated waves. Further, hereinafter, the distance to the object means the distance between the distance/speed measuring device and the object, and the relative speed of the object means the speed when the object is viewed from the distance/speed measuring device. It shall mean the relative velocity of an object with respect to some range velocity measuring device.

This distance/speed measuring device comprises a reference oscillator (Xtal: crystal oscillator) 101, a phase locked loop circuit (PLL1_RAMP) 102 with a frequency sweep function (ramp function), and a voltage controlled oscillator (VCO1) 104. It has a frequency modulated continuous wave generator circuit. This distance/velocity measuring device also has a second frequency-modulated continuous wave generator circuit composed of a reference oscillator 101, a phase locked loop circuit with frequency sweep function (PLL2_RAMP) 103, and a voltage controlled oscillator (VCO2) 105. .

The output of the first frequency modulated continuous wave generating circuit is applied to a laser diode (LD) 108 through a capacitor 106 together with a DC bias current from a constant current bias circuit (Bias) 107 to output a transmission wave a1. On the other hand, the output of the second frequency modulated continuous wave generating circuit is applied to the multiplier circuit (MIX) 111 as the reference wave a2.

Here, first, as a comparative example, with reference to FIGS. 2 to 5, the configuration of a general FMCW Lidar and the method by which the general FMCW Lidar measures distance and relative velocity will be described.
FIG. 2 is a diagram showing an example of the configuration of a general FMCW lidar.

The FMCW Lidar output light is a linear frequency-modulated continuous wave, generated by a reference oscillator (Xtal: crystal oscillator) 901, a phase locked loop circuit with frequency sweep function (PLL_RAMP) 902, and a voltage controlled oscillator (VCO) 903. be done. The generated linear frequency-modulated continuous wave is applied to a laser diode (LD) 906 as an output wave b1, converted into an optical signal and output to the outside, and applied to a multiplier circuit 909 as a reference wave b2. It is divided into those that can be

Of the optical signals transmitted to the outside, the optical signal that hits and is reflected by the object is received by an avalanche photodiode (APD) 912 as a reflected wave b3, converted into an electrical signal, and converted to a reference wave b2 by a multiplier circuit (MIX) 909. is multiplied with At this time, the reflected wave b3 has a time delay due to the distance from the object. Also, when the object is moving, a frequency shift occurs due to the Doppler effect. Therefore, the beat signal (multiplied signal of the reflected wave and the reference wave) obtained from the multiplier circuit 909 contains the frequency difference between the reference wave b2 and the reflected wave b3. Therefore, by performing frequency analysis and obtaining the frequency difference, the distance to the object and the relative speed of the object can be obtained.

3 and 4 are diagrams showing the relationship between the reference wave b2 and the reflected wave b3 and their frequency difference in a general FMCW lidar.
FIG. 3 shows the case where the object is stationary. As shown in FIG. 3A, the frequency of the reflected wave b3 is delayed with respect to the reference wave b2 by the time required for the round trip to the object. there is Since the slope of the frequency sweep is constant, the frequency difference c1 (reference wave-reflected wave) has a constant frequency, as shown in FIG. 3B, and the distance to the object can be obtained from this frequency difference.

On the other hand, FIG. 4 shows the case where the object is moving, and as indicated by symbol c2 in FIG. 4A, the frequency is shifted by the Doppler effect in addition to the delay due to the distance. Therefore, as shown in FIG. 4B, the frequency difference c1 differs depending on whether the slope of the sweep is positive or negative. .

By the way, the frequency shift due to the Doppler effect for relative velocity measurement as described above can be obtained by the following (Equation 1).
Frequency shift due to Doppler effect = 2 x relative velocity / wavelength … (Formula 1)
Also, the wavelength in (Equation 1) is obtained by the following (Equation 2).

Wavelength = Speed of light ÷ Frequency of reference wave (Formula 2)
Here, in (Formula 1) and (Formula 2), the frequency shift due to the Doppler effect is calculated assuming that the relative velocity is 1 km/h (0.28 m/s) and the frequency of the reference wave is 2 GHz.
Wavelength = (3 x 10 ⁸ ) ÷ (2 x 10 ⁹ ) = 0.15m
Frequency shift due to Doppler effect = 2 x 0.28 ÷ 0.15 ≒ 3.73 Hz
Thus, when the relative velocity is as slow as 1 km/h (0.28 m/s), the frequency obtained as a frequency shift due to the Doppler effect is low. And the slower the relative velocity, the smaller the frequency shift.

In general, waveform measurement requires at least one cycle, considering the offset error and waveform distortion of the signal. ) is required for measurement.
In order to shorten the measurement time, it is necessary to increase the frequency shift due to the Doppler effect. do. In the FMCW lidar assumed in this embodiment, the operating speed of the LD is currently about 2 GHz, and there is a limit to increasing the frequency of the reference wave.

Therefore, the distance/velocity measuring apparatus of this embodiment has a mechanism capable of measuring the relative velocity in a short period of time without being affected by the relative velocity of the object, such as when the relative velocity is slow. This point will be described in detail below.
Returning to FIG. 1, the description of the distance/speed measuring device of the present embodiment will be continued.

The phase synchronization circuit 102 with a frequency sweep function and the phase synchronization circuit 103 with a frequency sweep function can easily control the frequency sweep timing, slope frequency range, etc. by writing data. Further, by sharing the reference oscillator 101 between them, timing errors, temperature characteristics, aging errors, etc. are reduced. A laser diode (LD) 108 is used as a light emitting unit. The light receiving section uses an avalanche photodiode (APD) 114 and is composed of this avalanche photodiode 114 , a resistor 113 and a resistor 115 . A processing circuit for the received signal (reflected wave a3) transferred via the capacitor 112 is composed of a multiplier circuit 111 supplied with the reference wave a2 and the reflected wave a3, a low-pass filter (LPF) 110 and a variable gain amplifier (VGA) 109. are doing. The output from the received signal processing circuit is input to a signal processing unit 116 including an analog-digital conversion circuit (ADC), and processed in the signal processing unit 116 such as calculation of distance and relative velocity.

As the laser diode 108, an edge emitting laser, a vertical cavity surface emitting laser (VCSEL), or the like can be used. In particular, VCSELs are advantageous in that they can be easily miniaturized and highly integrated, and are more suitable for high-frequency driving than edge-emitting lasers.

5 and 6 are timing charts for explaining the operation of the distance/speed measuring device of this embodiment.
FIG. 5 shows the case where the transmitted wave frequency and the reflected wave frequency peak are the same, and the relative velocity is 0 km/h with no frequency shift due to the Doppler effect.
In FIG. 5A, symbol a1 denotes a transmission wave output from the first frequency-modulated continuous wave generating circuit, and symbol a2 denotes a reference wave output from the second frequency-modulated continuous wave generating circuit. In the configuration of the distance/velocity measuring apparatus of this embodiment, the frequency of the reference wave a2 of the multiplier circuit 111 is set to a frequency higher by a certain frequency (f _b0 ) than the frequency of the outgoing wave a1. Also, the reflected wave indicated by symbol a3 is time-delayed from the outgoing wave a1 according to the distance from the object. FIG. 5B shows the beat signal d1(f _b ) which is the difference frequency between the reference wave a2 and the reflected wave a3. Between the frequency (f _b1 ) of the beat signal d1 during the upward modulation period during which the frequency of the outgoing wave a1 increases and the frequency (f _b2 ) of the beat signal d1 during the downward modulation period during which the frequency of the outgoing wave a1 decreases, There are the following (Equation 3) and (Equation 4) relationships including the difference frequency _fb0 between the outgoing wave a1 and the reference wave a2.

_fb1 = _fb0 + _fr (Formula 3)
f _b2 = f _b0 - f _r (Formula 4)
Here, f _r is the frequency based on the delay time τ of the reflected wave.
In FIG. 5B, the intermediate value (broken line) between _fb1 and _fb2 indicates the difference frequency _fb0 between the outgoing wave a1 and the reference wave a2.

On the other hand, FIG. 6 shows the case where the relative speed is not 0 km/h. In this case, as shown in FIG. 6A, the frequency change due to the relative velocity is included, and in addition to the time delay that occurs according to the distance, the reflected wave a3 has a Doppler effect as indicated by symbol d2. A positive and negative frequency shift occurs. Then, the following (Equation 5) and (Equation 6) are established between the beat frequency _fb1 in the up-modulation period and the beat frequency _fb2 in the down-modulation period shown in FIG. 6(B).

_fb1 = _fb0 + _fr - _fd (equation 5)
f _b2 =f _b0 -f _r -f _d (Formula 6)
where _fd is the Doppler shift frequency.
In this example, due to the Doppler effect, a frequency shift occurs in the positive direction, and the peak of the frequency of the reflected wave a3 is higher than the peak of the frequency of the transmitted wave a1. Compared to the relative velocity of 0 in FIG. 5, the beat frequency is lower by the positive shift due to the Doppler effect.

Next, a method of calculating the distance R and the relative velocity v from the object to be measured in the distance/velocity measuring device of this embodiment will be described.
Assuming that the speed of light is c, the delay time τ of the reflected wave a3 is expressed by τ=2R/c. Further, if the repetition frequency of the transmitted wave a1 is f _m and the frequency displacement width of the transmitted wave a1 is Δf, then the frequency f _r is
f _r =τ·Δf·2f _m
f _r = 4R·Δf·f _m /c
is represented by

Therefore, since f _r =(f _b1 −f _b2 )/2 from (Equation 5) and (Equation 6), the distance R can be determined from the beat signal d1.
Further, if the center frequency of the transmitted wave a1 is f ₀ , the Doppler shift frequency is expressed by the following (Equation 7) and (Equation 8).
f _d =2v·f ₀ /c (Formula 7)
v=c·f _d /2f ₀ (Formula 8)
Since f _d =f _b0 -(f _b1 +f _b2 )/2 from (Equation 5) and (Equation 6), the relative velocity v can be determined from the beat signal d1.

As can be seen from the above, in the distance/velocity measuring apparatus of the present embodiment, even when the relative velocity is 0 or close to 0, by appropriately setting f _b0 , the frequency f _d can be measured in a practical time. can be Therefore, the relative velocity can be measured in a short time without the measurement time being affected by the relative distance to the object to be measured.

In this embodiment, it is preferable to set f _b0 so that the beat frequency (f _b ) does not become a negative value. In other words, it is preferable to set _fb0 so that aliasing does not occur at 0 Hz. Since the beat frequency depends on the distance to the object and the relative speed of the object, _fb0 may be changed according to the range to be measured.

Further, the frequency of the reference wave a2 may be shifted in the negative direction with respect to the frequency of the outgoing wave a1.
FIG. 7 is a flow chart showing the operation procedure of the distance/speed measuring device of this embodiment.
In the distance/velocity measuring apparatus of the present embodiment, a first frequency-modulated continuous wave (outgoing wave) is generated (step S1), and a second frequency-modulated continuous wave having a certain frequency difference with respect to the first frequency-modulated continuous wave is generated. is generated (step S2).

The distance/velocity measuring device transmits a first frequency-modulated continuous wave (step S3) and receives a reflected wave of the first frequency-modulated continuous wave from the object (step S4). Then, the distance/velocity measuring device multiplies the reflected wave by the second frequency-modulated continuous wave to generate a beat signal (step S5).

Thereafter, the distance/velocity measuring device frequency-analyzes the beat signal obtained by the procedure of steps S1 to S4 to calculate the frequency difference between the reflected wave and the second frequency-modulated continuous wave (step S6). The distance and relative velocity to the object are calculated from the frequency difference from the second frequency-modulated continuous wave (step S7).

As described above, in the distance/velocity measuring apparatus of the present embodiment, the frequency range obtained as the beat signal can be set by giving a certain frequency difference between the transmission wave and the reference wave. As a result, the distance/speed measuring device of this embodiment can measure the relative speed in a short period of time without being affected by the relative speed of the object.

(Second embodiment)
Next, a second embodiment of the invention will be described.
FIG. 8 is a block diagram showing an example of the configuration of the distance/speed measuring device according to this embodiment. As in the first embodiment, also in this embodiment, it is assumed that the distance/speed measuring device of the present invention is implemented as an FMCW lidar using laser light. Further, as described above, the distance/velocity measuring device of the present invention can be realized as various kinds of radars using continuous frequency modulation waves, not limited to FMCW lidar. Here, the same reference numerals are used for the same components as in the first embodiment, and overlapping descriptions thereof are omitted.

In the distance/speed measuring device of the present embodiment, a multiplication circuit (MIX) 203, a low-pass filter (LPF) 202 and a variable gain amplifier (VGA) are added to the configuration of the distance/speed measuring device of the first embodiment shown in FIG. ) 201 for processing the received signal is added (the portion surrounded by the dashed line). The output of the first frequency-modulated continuous wave generating circuit is applied to the multiplier circuit 203 as the reference wave a2-2.

In other words, the beat signal obtained by the multiplier circuit 203 is the same as the beat signal obtained by the general FMCW lidar described with reference to FIGS. 2 to 5. FIG. That is, in the distance/velocity measuring apparatus of the present embodiment, two types of beat signals, one obtained by the measuring method described in the first embodiment and the other beat signal obtained by the conventional measuring method, can be obtained. I have to. Specifically, the distance/speed measuring device of the present embodiment allows one of two types of beat signals to be selected according to the measurement state.

In the measurement method described in the first embodiment, the measurement result may include an error in the difference frequency between the phase synchronization circuit 102 with frequency sweep function and the phase synchronization circuit 103 with frequency sweep function. Therefore, the signal processing unit 116 in the distance/speed measuring device of the present embodiment selects the conventional measurement method (the On the other hand, when the relative speed is small, it is possible to select the measurement method described in the first embodiment (use the output of the multiplication circuit 111).

Further, the signal processing unit 116 in the distance/velocity measuring apparatus of the present embodiment selects the conventional measurement method (using the output of the multiplication circuit 203) in distance measurement, while in relative velocity measurement, the first It is also possible to select the measurement method described in the embodiment (using the output of the multiplication circuit 111).

As described above, in the distance/velocity measuring apparatus of the present embodiment, two beat signals having different reference wave frequencies can be obtained. You will be able to choose adaptively.
(Third embodiment)
Next, a third embodiment of the invention will be described.

FIG. 9 is a block diagram showing an example of the configuration of the distance/speed measuring device according to this embodiment. As in the first and second embodiments, also in this embodiment, it is assumed that the distance/speed measuring device of the present invention is realized as an FMCW lidar using laser light. Further, as described above, the distance/velocity measuring device of the present invention can be realized as various kinds of radars using continuous frequency modulation waves, not limited to FMCW lidar. Here, the same reference numerals are used for the same components as in the first embodiment and the second embodiment, and overlapping descriptions thereof are omitted.

In the distance/velocity measurement apparatus of the present embodiment, in place of the phase synchronization circuit 103 with frequency sweep function in the configuration of the distance/velocity measurement apparatus of the second embodiment shown in FIG. A change is made to place the circuit (PLL2) 301 . As described above, the phase synchronization circuit 103 with a frequency sweep function can easily control the frequency sweep timing, slope frequency range, etc. by writing data. may be used as the constant frequency continuous wave generator.

In the case of distance measurement, since the time delay until the transmitted wave a1 hits the object and is received as the reflected wave a3 is measured, it is necessary to sweep the frequency. On the other hand, in the case of relative velocity measurement, since frequency shift is measured by the Doppler effect, there is no need to use frequency sweep. Therefore, in the distance/velocity measuring apparatus of the present embodiment, the reference wave a2-3 for obtaining the acquired beat signal in addition to the beat signal obtained by the conventional measurement method can be controlled simply and frequency stability can be expected. A constant frequency continuous wave is assumed.

FIG. 10 is a timing chart for explaining the operation of the distance/speed measuring device of this embodiment having such a configuration.
In the distance/speed measuring apparatus of this embodiment, the reference wave a2-3 of the multiplier circuit 111 is set to a constant frequency higher than that of the reference wave a2-2 of the multiplier circuit 203, as shown in FIG. 10(A). Also, the reference wave a2-2 of the multiplier circuit 203 is a repetition of positive frequency sweep and constant frequency.

In the case of the distance/velocity measuring apparatus of the present embodiment, the reference wave (a2-2)-reflected wave (a3) of the multiplier circuit 203 indicated by symbol d1-2 in FIG. Measurement is performed (e1: distance measurement point). Also, in FIG. 10B2, the reference wave (a2-3)-reflected wave (a3) of the multiplier circuit 111 indicated by symbol d1-3 measures the relative velocity in a constant frequency period (e2: relative speed measurement point).

As described above, in the distance/velocity measuring apparatus of the present embodiment, it is possible to achieve both measurement accuracy and measurement speed by eliminating frequency sweep errors by performing control at a constant frequency during relative velocity measurement.
(Fourth embodiment)
Next, a fourth embodiment of the invention will be described.

FIG. 11 is a block diagram showing an example of the configuration of the distance/speed measuring device according to this embodiment. As in the first to third embodiments, also in this embodiment, it is assumed that the distance/speed measuring device of the present invention is realized as an FMCW lidar using laser light. Further, as described above, the distance/velocity measuring device of the present invention can be realized as various kinds of radars using continuous frequency modulation waves, not limited to FMCW lidar. Here, the same reference numerals are used for the same components as in the first to third embodiments, and overlapping descriptions thereof are omitted.

In the distance/speed measuring device of this embodiment, a multiplication circuit (MIX) 403, a low-pass filter (LPF) 402 and a variable gain amplifier (VGA) are added to the configuration of the distance/speed measuring device of the first embodiment shown in FIG. ) 401 for generating correction data is added (the portion surrounded by the dashed line). Multiplier circuit 403 receives the output (a1) of the first frequency-modulated continuous wave generator and the output (a2) of the second frequency-modulated continuous wave generator.

In other words, in the distance/speed measuring apparatus of this embodiment, the measurement data (data including the difference frequency between the reference wave a2 and the reflected wave a3) is generated by the measurement method described in the first embodiment, and the analog - Output to the digital conversion circuit (ADC1). Furthermore, the multiplication circuit 403 generates correction data including the frequency difference between the output (transmission wave) a1 of the first frequency-modulated continuous wave generating circuit and the output (reference wave) a2 of the second frequency-modulated continuous wave generating circuit. and output to the analog-digital conversion circuit (ADC2) of the signal processing unit. Based on the output from ADC1 and the output from ADC2, the signal processing unit 116 calculates the distance and relative velocity.

In the distance/velocity measuring apparatus of the present embodiment, since the correction data including the frequency difference between the transmission wave a1 and the reference wave a2 is input to the signal processing section 116, the measurement data is corrected based on this correction data. It can be performed. The voltage controlled oscillator 104 and the voltage controlled oscillator 105 are feedback-controlled by the phase locked loop circuit 102 with frequency sweep function and the phase locked loop circuit 103 with frequency sweep function. There is If fluctuation occurs, its frequency appears in the beat signal (beat frequency), so it is desirable to be able to correct this fluctuation.

In the distance/velocity measuring apparatus of the present embodiment, the frequency difference between the voltage-controlled oscillator 104 and the voltage-controlled oscillator 105 can be measured using the correction data output synchronously with the measurement data. can be corrected.
As described above, in the distance/velocity measuring apparatus of the present embodiment, by measuring the frequency difference regardless of the relative velocity and distance, it is possible to further reduce the effects of circuit errors and the like.

In this embodiment, the multiplication circuit 403 for multiplying the output of the voltage-controlled oscillator 104 and the output of the voltage-controlled oscillator 105 is added to the configuration of the distance/speed measuring device of the first embodiment. A multiplier circuit 403 for multiplying the output of the voltage controlled oscillator 104 and the output of the voltage controlled oscillator 105 is added to the configuration of the distance/speed measuring device of the embodiment or the configuration of the distance/speed measuring device of the third embodiment. can be Even in this case, it is possible to cancel the effects of circuit errors and the like.

As described above, in the distance/velocity measuring apparatus of some embodiments shown here, two continuous wave generating circuits are provided, and the respective outputs are selectively used for the sending wave and the reference wave. Also, these two continuous wave generating circuits are controlled in advance so that there is a constant frequency difference between the outgoing wave and the reference wave. As a result, even when the relative speed is 0 km/h and the distance is 0 m, there is a frequency difference between the outgoing wave and the reference wave, which are given to the beat signal in advance. Based on this frequency difference, the frequency changes depending on the relative speed and distance. It will be. As a result, it is possible to measure the relative velocity in a short time without being affected by the relative velocity of the object.

The above description of several embodiments is not intended to limit the scope of the invention, and various modifications and changes can be made without departing from the gist of the invention.

101... Reference oscillator 102, 103... Phase locked loop circuit with frequency sweep function 104, 105... Voltage controlled oscillator 106, 112... Capacitor 107... Constant current bias circuit 108... Laser diode 109, 201, 401... Variable Gain amplifier 110, 202, 402 Low-pass filter 111, 203, 403 Multiplication circuit 113, 115 Resistor 114 Avalanche photodiode 116 Signal processing section 301 Phase synchronization circuit.

JP 2015-129646 A

Claims (3)

a repetitive wave generating circuit that generates a repetitive wave with a positive frequency sweep and a constant frequency of the first frequency ;
a constant frequency continuous wave generating circuit for generating a constant frequency continuous wave having a second frequency higher than the repetitive wave ;
a sending circuit for sending the repetitive wave;
a receiving circuit for receiving a reflected wave of the repetitive wave from an object;
a first processing circuit for generating a first beat signal for calculating a distance to the object from the reflected wave and the repeated wave during the frequency sweep period;
a second processing circuit for generating a second beat signal for calculating the relative velocity of the object from the reflected wave in a constant frequency period and the constant frequency continuous wave;
A distance speed measuring device comprising: 2. The distance and speed measuring device according to claim 1 , wherein said constant frequency continuous wave generating circuit is a phase locked loop circuit with a frequency sweep function in which a frequency sweep timing and a slope frequency range are set so as to generate said constant frequency continuous wave. 3. The distance/velocity measurement according to claim 1 , further comprising a third processing circuit for generating data including a frequency difference between said repetitive wave and said constant frequency continuous wave from said repetitive wave and said constant frequency continuous wave. Device.

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