Optical interference measurement device, and program to be used in optical interference measurement device

Abstract

To identify a magnitude relation between reference light and reflection light to properly calculate a positional behavior of a target by means of a method different from a method using a different second wavelength in an FMCW method technology of using light.SOLUTION: A processing circuit is configured to extract two pieces of combinations of a magnitude relation between a frequency of reference light Lr and frequency of reflection light Ltr in an up-chiro area and a down-chirp area at each point of time n. Then, the processing circuit is configured to calculate provisional distances Dc1(n) and Dc2(n) of a target TR at the point of time n by a calculation method supposing the plurality of pieces of these combinations. Thus, the processing circuit is configured to select one of the provisional distances Dc1(n) and Dc2(n) on the basis of a determined distance Dis(n-1) and a determined velocity V(n-1) at a point of time n-1, and let the selected one be a determined distance Dis(n).SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to an optical interference measuring device and a program for use in the optical interference measuring device. [Background technology]

[0002] Conventionally, an optical interference measurement device that realizes the FMCW method using light emits an output light including an up-chirp region and a down-chirp region, causes reflected light generated by the output light being reflected by a target to interfere with a reference light based on the output light, and receives the obtained interference light. The optical interference measurement device then calculates the positional behavior (e.g., distance, speed, etc.) of the target based on a beat signal corresponding to this interference light. Specifically, the beat frequency corresponding to the frequency of the beat signal is determined by the phase difference generated between the reference light and the reflected light depending on the distance to the target, and the Doppler shift generated between the reference light and the reflected light depending on the relative speed of the target. Therefore, the position, speed, etc. of the target are determined by identifying the beat frequencies of the up-chirp region and the down-chirp region.

[0003] However, since the beat frequency is observed as the absolute value of the frequency difference between the reference light and the reflected light, it is not possible to determine from the beat frequency which of the reference light and the reflected light is larger in the beat signal. Normally, the reflected light has a lower frequency than the reference light in the up-chirp region, and the reflected light has a higher frequency than the reference light in the down-chirp region, so the position, speed, etc. of the target are calculated from the beat frequency using a formula based on this premise.

[0004] However, the above-mentioned frequency magnitude relationship may be reversed in the up-chirp region or the down-chirp region. In such a case, i.e., when a negative frequency or frequency aliasing occurs, the above-mentioned calculation method cannot properly calculate the target position, velocity, etc.

[0005] To address this problem, Patent Document 1 describes a technology that uses a two-wavelength light source to detect distance and speed based on the phase difference of a beat signal, making it possible to distinguish the magnitude relationship between the reference light and the reflected light in the beat signal. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2008-309582 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, the above-mentioned technology has a problem in that the number of light sources increases because two different wavelengths are used for measurement. In view of the above, the present invention aims to identify the magnitude relationship between the reference light and the reflected light in the beat signal and appropriately calculate the positional behavior of the target using a method other than the method using two different wavelengths in the FMCW type technology using light. [Means for solving the problem]

[0008] The invention described in claim 1 to achieve the above object is: A light source (1) that emits output light (Lp) including an up-chirp region in which the frequency increases over time and a down-chirp region in which the frequency decreases over time; an optical system (2, 3, 4, 5) that generates interference light (Lb) by combining reflected light (Ltr) generated by reflecting the emitted light on a target (TG) with a reference light (Lr) branched from the emitted light; a photodetector (6) that outputs a beat signal corresponding to the interference light; a processing circuit (7) for repeatedly measuring the position and velocity of the target based on the beat signal; The processing circuitry includes: extracting a plurality of combinations of a magnitude relationship between the frequency of the reference light and the frequency of the reflected light in an up-chirp region of the beat signal and a magnitude relationship between the frequency of the reference light and the frequency of the reflected light in a down-chirp region of the beat signal at a certain time point (n), and calculating a plurality of provisional positional behaviors (Dc1(n), Dc2(n)) of the target at the time point which are premised on the plurality of combinations, respectively; An optical interference measuring device that determines one of the plurality of tentative positional behaviors as the definitive positional behavior (Dis(n)) of the target based on the positional behavior (Dis(n-1), Dis(n-2), V(n-1), V(n-2)) of the target prior to the time point.

[0009] In this way, the optical interference measuring device selects an appropriate relationship between the frequencies of the reference light and the reflected light at the current time point based on the positional behavior of the target at the past time point. In this way, the positional behavior at the current time point can be appropriately determined using a method other than the method using two different wavelengths.

[0010] Note that the reference symbols in parentheses attached to each component indicate an example of the correspondence between the component and specific components described in the embodiments described below. [Brief description of the drawings]

[0011] [Figure 1] 1 is a configuration diagram of an optical interference measurement device according to a first embodiment. [Diagram 2] 1 is a diagram illustrating an example of a range of output light emitted from an optical interference measurement device; [Diagram 3] 1 is a diagram illustrating an example of a range of output light emitted from an optical interference measurement device; [Figure 4] 4 is a flowchart of a process executed by a processing circuit. [Diagram 5] 13 is a flowchart of a process for calculating a provisional distance. [Figure 6]1 is a graph showing an example of the magnitude relationship between the frequencies of a reference light and a reflected light in a beat signal. [Figure 7] 1 is a graph showing an example of the magnitude relationship between the frequencies of a reference light and a reflected light in a beat signal. [Figure 8] 11 is a table showing examples of the determined distance and determined speed in the previous calculation cycle, and the estimated distance and provisional distance in the current calculation cycle in each direction. [Figure 9] 10 is a flowchart of a process executed by a processing circuit in the second embodiment. [Figure 10] 11 is a table illustrating the determined distance and determined speed in the previous calculation cycle, and the estimated distance, provisional distance, and acceleration in the current calculation cycle in each direction. [Figure 11] 13 is a flowchart of a process executed by a processing circuit in the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] An embodiment of the present invention will be described below. An optical interference measurement device 10 according to this embodiment is mounted on a vehicle and detects objects around the vehicle using an FMCW-LiDAR method. As shown in FIG. 1, the optical interference measurement device 10 has a light source 1, a branching coupler 2, a circulator 3, a beam scanner 4, a combining coupler 5, a photodetector 6, and a processing circuit 7. The coupler 2, the circulator 3, the beam scanner 4, and the coupler 5 constitute an optical system. The optical path between the light source 1, the coupler 2, the circulator 3, and the coupler 5 is formed by, for example, an optical fiber.

[0013] The light source 1 includes a laser oscillator, a modulator, etc. The oscillator generates and outputs a laser beam of a predetermined reference frequency (for example, 1550 nm, 1300 nm). For the laser oscillator, for example, a laser diode is used, but other devices may also be used.

[0014] The modulator 12 performs frequency modulation with a predetermined modulation amplitude (e.g., 0.001 nm width, e.g., 0.005 nm width) on the laser light of the reference frequency output by the laser oscillator 11, and outputs output light Lp, which is laser light whose frequency increases and decreases, to the coupler 2. The change in frequency is, for example, triangular in shape, in which the frequency increases at a predetermined chirp rate in the up-chirp region and then decreases at a predetermined chirp rate in the down-chirp region.

[0015] The coupler 2 is an optical component that outputs a part of the output light Lp emitted from the light source 1 to the circulator 3, and branches another part of the output light Lp to output it to the coupler 5 as reference light Lr.

[0016] The circulator 3 is an optical component having three ports. The circulator 3 outputs the emitted light Lp input from the coupler 2 to the first port to the beam scanner 4 from the second port, and outputs the reflected light Ltr input from the beam scanner 4 to the second port to the coupler 5 from the third port.

[0017] The beam scanner 4 is a scanning device capable of beam scanning a detection range including the target TG according to a predetermined scanning pattern by manipulating the direction of the emitted light Lp output from the circulator 3. The beam scanner 4 also changes the direction of reflected light Ltr generated when the emitted light Lp is reflected by the target TG, and guides the reflected light Ltr to the circulator 3. The target TG may be, for example, a preceding vehicle traveling in front of the vehicle, a following vehicle traveling behind the vehicle, people and obstacles around the vehicle, etc.

[0018] For example, the beam scanner 4 is a scanning mirror that can reflect the output light Lp from the circulator 3 and manipulate the direction of the reflected output light Lp to perform beam scanning on a detection range including the target TG. In this case, the beam scanner 4 reflects reflected light Ltr generated when the output light Lp is reflected by the target TG and guides it to the circulator 3. The beam scanner 4 may be rotatable by, for example, one or more galvanometers, may rotate a polygonal mirror, or may be realized by other configurations. Alternatively, the beam scanner 4 may be composed of a device other than a mirror.

[0019] The coupler 5 combines the reflected light Ltr input from the beam scanner 4 to the circulator 3 and output from the circulator 3 with the reference light Lr branched from the coupler 2, and outputs the interference light Lb obtained as a result of the combination to the photodetector 6. The photodetector 6 is a light-receiving element that generates a beat signal as an electrical signal corresponding to the interference light Lb received from the coupler 5, and outputs the generated beat to the processing circuit 7.

[0020] The processing circuit 7 calculates the distance from the vehicle to the target TG (hereinafter simply referred to as the distance to the target TG), the relative speed of the target TG with respect to the vehicle (hereinafter simply referred to as the speed of the target TG), and the like, based on the beat signal output from the photodetector 6. The processing circuit 7 has a memory that stores software in which such processing is described. The processing circuit 7 is equipped with the memory, and is configured as a microcomputer equipped with a CPU or the like that reads and executes the software from the memory. Alternatively, the processing circuit 7 may be a dedicated electronic circuit configured to realize the above-mentioned processing.

[0021] The operation of the optical interference measuring device 10 configured as described above will be described below. When the vehicle's IG is turned on, the operation of the optical interference measuring device 10 starts. Then, the light source 1 emits output light Lp including an up-chirp followed by a down-chirp, and a part of the output light Lp is output to the target TG via the coupler 2, the circulator 3, and the beam scanner 4 in this order. In addition, another part of the output light Lp from the light source 1 is branched off by the coupler 2 as reference light Lr and guided to the coupler 5.

[0022] Furthermore, reflected light Ltr generated when the emitted light Lp is reflected by the target TG passes through the beam scanner 4 and the circulator 3 in this order, and is then combined with the reference light Lr by the coupler 5. Then, interference light Lb generated by the combination is output from the coupler 5 to the photodetector 6. The photodetector 6 receives this interference light Lb, and outputs a beat signal corresponding to the interference light Lb to the processing circuit 7.

[0023] At this time, due to the above-mentioned scanning function of the beam scanner 4, the emitted light is emitted in an azimuth angle range AW having a spread including the target TG, as shown in Figures 2 and 3. Then, the emitted light Lp is emitted in a plurality of directions within the range AW, and the reflected light Ltr returns from the plurality of directions.

[0024] In the example of FIG. 2, the reflected light Ltr returns to the optical interference measurement device 10 from three orientations X-1, X, and X+1 among the multiple orientations within the range AW. In the example of FIG. 3, the optical interference measurement device 10 is closer to the target TG than in the example of FIG. 2, so the reflected light Ltr returns to the optical interference measurement device 10 from five orientations X-2, X-1, X, X+1, and X+2 among the multiple orientations within the range AW. The optical interference measurement device 10 emits the emitted light Lp in multiple orientations, and the processing circuit 7 calculates the distance and speed of the target TG in each orientation from which the reflected light Ltr returns. In this embodiment, the speed is positive when the speed is in the direction in which the distance to the target TG becomes shorter.

[0025] 4 and 5, a process in which the processing circuit 7 reads out a program from the memory and executes it to process the beat signal from the photodetector 6. The processing circuit 7 executes the process shown in FIG. 4 when the vehicle IG is turned on and the operation of the optical interference measuring device 10 starts.

[0026] In the process of FIG. 4, the processing circuit 7 first initializes the value of an integer variable n, which indicates the number of calculation cycles, to zero in step S110. Next, in step S120, for each of the multiple azimuths in which a beat signal is received, the processing circuit 7 calculates the beat frequency f_up(0) in the up chirp region and the beat frequency f_down(0) in the down chirp region based on each beat signal. Note that the value in parentheses indicates the number of calculation cycles. These calculations are realized by identifying the peak frequency resulting from performing a discrete Fourier transform such as FFT on the up chirp region and the down chirp region of each beat signal. As a result, pairs of beat frequencies f_up(0) and f_down(0) are calculated for the number of azimuths in which a beat signal is received.

[0027] In step S120, the controller 10 further calculates the determined distance Dis(0) and determined velocity V(0) of the target TG in each of the multiple directions in which the beat signal is received, using the calculated beat frequencies f_up(0) and f_down(0). The determined distance and determined velocity are definite distance and velocity, respectively.

[0028] Specifically, the following formulas (1) to (4) are used to calculate for each direction. Dis(0)=tDis×(1 / 2)×C×T / FMW (1) tDis=(f_up(0)+f_down(0)) / 2 (2) V(0) = Vdiff × (1 / 2) × C / Flow (3) Vdiff=(f_down(0)-f_up(0)) / 2 (4) Here, C is the speed of light, T is the sweep time of the up-chirp region and the down-chirp region, FMW is the frequency sweep width of the up-chirp region and the down-chirp region, and Flow is the sweep start frequency, which are all recorded in memory beforehand. This allows the calculation of pairs of confirmed distance Dis(0) and confirmed velocity V(0) for the number of directions in which beat signals are received.

[0029] It should be noted that the formulas (2) and (4) used here are calculation formulas based on the premise that in the up-chirp region, the reflected light Ltr has a lower frequency than the reference light Lr, and in the down-chirp region, the reflected light Ltr has a higher frequency than the reference light Lr. If the magnitude relationship between the frequencies of the reference light Lr and the reflected light Ltr in the up-chirp region and the down-chirp region is not as described above, then the formulas cannot correctly calculate the confirmed distance Dis(0) and the confirmed velocity V(0).

[0030] However, at the start of the processing in Figure 4, it is considered that there is little possibility that objects around the vehicle will suddenly approach or move away from the vehicle, so even if calculations are made under this assumption, the correct definite distance Dis(0) and definite speed V(0) can often be calculated.

[0031] Next, in step S130, processing circuit 7 increments the value of variable n by 1. In this way, the processes of steps S110 and S120 are the first cycle of processing, and thereafter, the loop of steps S130 to S180 is repeated, with each of these loops being the process for one calculation cycle.

[0032] Following step S130, in step S140, the processing circuit 7 calculates a beat frequency at time point n for each of the multiple azimuths in which the beat signal was received, based on each beat signal. That is, the beat frequency f_up(n) in the up chirp region and the beat frequency f_down(n) in the down chirp region are calculated. These calculations are realized by identifying the peak frequency resulting from performing a discrete Fourier transform such as FFT on the up chirp region and the down chirp region of each beat signal. In this way, pairs of beat frequencies f_up(n) and f_down(n) are calculated for the number of azimuths in which the beat signal was received.

[0033] Next, in step S150, the processing circuit 7 calculates a provisional distance Dc1(n) and a provisional distance Dc2(n) for each of the multiple directions in which the beat signal was received, based on the beat frequencies f_up(n) and f_down(n). The provisional distances Dc1(n) and Dc2(n) are candidates for the confirmed distance Dis(n) of the target TG at the current time.

[0034] The method of calculating the provisional distances Dc1(n) and Dc2(n) in each direction is as shown in Fig. 5. In step S150, the processing circuit 7 executes the process of Fig. 5 for each of the multiple directions in which a beat signal has been received. In each process of Fig. 5, the processing circuit 7 first calculates, in step S151, the provisional distance Dc1(n) of the target TG in the target direction by the following formula: Dc1(n)=tDis×(1 / 2)×C×T / FMW (5) Here, tDis is tDis=(f_up(n)+f_down(n)) / 2 (6) This formula (6) is used to calculate the correct distance when the frequency of the reflected light Ltr is lower than that of the reference light Lr in the up-chirp region, and the frequency of the reflected light Ltr is higher than that of the reference light Lr in the down-chirp region, as shown in Fig. 6. This is one possible combination of the magnitude relationship between the frequency of the reference light Lr and the frequency of the reflected light Ltr in the up-chirp region and the down-chirp region.

[0035] 6 and 7, two solid lines respectively indicate the change in frequency over time of the reference light Lr in the interference light Lb and the change in frequency over time of the reflected light Ltr, and the dashed line indicates the change in frequency over time of the reflected light Ltr0 that would be obtained if the speed of the target TR was zero.

[0036] The beat frequency f_up(n) of the up-chirp region measured in step S140 is defined as |f_beat-fd|. Also, the beat frequency f_down(n) of the down-chirp region is defined as |f_beat+fd|. Here, the difference between the frequencies of the reference light Lr and the reflected light Ltr0 is defined as f_beat, and the value obtained by subtracting the frequency of the reflected light Ltr0 from the frequency of the reflected light Ltr is defined as fd.

[0037] That is, the calculated beat frequency f_up(n) cannot reflect the difference between the positive and negative signs of f_beat-fd. Similarly, the calculated beat frequency f_down(n) cannot reflect the difference between the positive and negative signs of f_beat+fd. In other words, it is not possible to determine which of the reference light Lr and the reflected light Ltr has a higher frequency from the calculated beat frequencies f_up(n) and f_down(n).

[0038] Next, in step S153, the processing circuit 7 judges whether or not the former of the beat frequencies f_up(n) and f_down(n) in the target direction is smaller. If the former is smaller, the process proceeds to step S155, and if not, the process proceeds to step S157.

[0039] In step S155, the provisional distance Dc2(n) of the target TG in the target direction is calculated by the following formula. Dc2(n)=tDis×(1 / 2)×C×T / FMW (7) However, tDis is tDis=(f_up(n)-f_down(n)) / 2 (8) determined by the following formula. As shown in FIG. 7, this formula (8) is a formula for calculating the correct distance when the frequency of the reflected light Ltr is higher than that of the reference light Lr in the up-chirp region and the frequency of the reflected light Ltr is also higher than that of the reference light Lr in the down-chirp region. That is, it is a formula for calculating the correct distance when a negative frequency occurs in f_beat - fd in the up-chirp region. This is also one of the possible combinations of the magnitude relationship between the frequencies of the reference light Lr and the reflected light Ltr in the up-chirp region and the down-chirp region when f_up(n) < f_down(n). After step S155, the process of FIG. 5 ends.

[0040] Also, in step S157, the processing circuit 7 determines whether the latter of the beat frequencies f_up(n) and f_down(n) in the target direction is smaller. If the latter is smaller, the process proceeds to step S159. Otherwise, that is, if the former and the latter have the same value, the process of FIG. 5 ends without calculating the provisional distance Dc2(n) of the target TG in the target direction. Note that the provisional distance Dc2(n) is not calculated when the former and the latter have the same value because it is clear that the provisional distance Dc1(n) should be the determined distance Dis(n).

[0041] In step S159, the provisional distance Dc2(n) of the target TG in the target direction is calculated by the following formula. Dc2(n)=tDis×(1 / 2)×C×T / FMW (9) However, tDis is tDis=(f_down(n)-f_up(n)) / 2 (10) This formula (10) is a formula for calculating the correct distance when the frequency of the reflected light Ltr is lower than that of the reference light Lr in the up chirp region, and also when the frequency of the reflected light Ltr is lower than that of the reference light Lr in the down chirp region. In other words, this is a formula for calculating the correct distance when a negative frequency occurs in f_beat+fd in the down chirp region. This is also one of the possible combinations of the magnitude relationship between the frequency of the reference light Lr and the frequency of the reflected light Ltr in the up chirp region and the down chirp region when f_up(n)>f_down(n). After step S159, the processing of FIG. 5 ends.

[0042] 5 for each of the multiple directions in which the beat signal was received, the processing circuit 7 calculates the same number of provisional distances Dc1(n) and Dc2(n) as the number of directions in which the beat signal was received. However, in the exceptional case where there is a direction in which the beat frequencies f_up and f_down are the same, the provisional distance Dc2(n) is not calculated for that direction.

[0043] Following step S150, in step S160, the processing circuit 7 calculates the estimated distance De(n) for each direction of the current target TR by using the determined distance Dis(n-1) and determined speed V(n-1) for each direction of one or more targets TR determined in the previous (i.e., n-1th) calculation cycle.

[0044] Specifically, for example, for each direction, the estimated distance De(n) is calculated by the formula De(n)=Dis(n-1)-V(n-1)×Δt, where Δt is the time difference between successive calculation cycles.

[0045] Next, in step S170, one of the provisional distances Dc1(n) and Dc2(n) is selected as the confirmed distance Dis(n) based on a comparison between the provisional distances Dc1(n) and Dc2(n) calculated in step S150 and the estimated distance De(n) calculated in step S160. In other words, in consideration of the estimated distance De(n), one of the provisional distances Dc1(n) and Dc2(n) that is more appropriate as the actual distance is selected as the confirmed distance Dis(n).

[0046] The provisional distances Dc1(n) and Dc2(n) for a certain direction may be compared with the estimated distance De(n) for the same direction, or if there is no such distance, with an estimated distance De(n) for a nearby direction that is not the same. The nearby direction may be, for example, the next closest direction, the next two closest directions, or the mth closest direction (3 or more).

[0047] For example, as shown in FIG. 8, in the previous calculation cycle (i.e., at time point n-1), the confirmed distance Dis(n-1) and the confirmed speed V(n-1) were determined for the direction X-1, but the confirmed distance Dis(n) and the confirmed speed V(n-1) were not determined for the directions X-2 and X-3. An example of the confirmed distance Dis(n-1) not being determined is when there was no detectable object in that direction. In the example of FIG. 8, the confirmed distance Dis(n-1) and the confirmed speed V(n-1) for the direction X-1 were determined to be 114.3 m and 100 km / h, respectively, in steps S170 and S180 of the previous calculation cycle. Note that the hyphens in each cell in FIG. 8 indicate that the value corresponding to that cell was not determined. This is also true for the tables in other figures.

[0048] 8, assume that in the current calculation cycle (i.e., time point n), provisional distances Dc1(n) and Dc2(n) have been determined for directions X-1 and X-2, but provisional distances Dc1(n) and Dc2(n) have not been determined for direction X-3. An example of a case in which provisional distances Dc1(n) and Dc2(n) cannot be determined for a certain direction is when no detectable object exists in that direction.

[0049] In the case of FIG. 8, for azimuth X-2, it is assumed that at step S151, Dc1(n) = 114.3 m is determined, at step S153, f_up < f_down is determined, and at step S155, Dc2(n) = 111.5 m is determined. Also, for azimuth X-1, it is assumed that at step S151, Dc1(n) = 114.3 m is determined, at step S153, f_up < f_down is determined, and at step S155, Dc2(n) = 111.5 m is determined. Therefore, in this case, for these two azimuths, the provisional distance Dc2(n) is the distance to the target TR when it is assumed that a negative frequency occurs in the up-chirp region.

[0050] Also, in the case of FIG. 8, at step S160, for azimuth X-1, the estimated distance De(n) is calculated as De(n) = Dis(n - 1) - V(n - 1)×Δt = 114.3 m - (100 km / h × 1000 / 3600)×0.1 s = 111.5 m.

[0051] Also, in the case of FIG. 8, at step S170, for azimuth X-1, since the estimated distances De(n) in the same azimuth are calculated for the provisional distances Dc1(n) and Dc2(n), these are used as the comparison targets.

[0052] Specifically, the processing circuit 7 selects, as the determined distance Dis(n), the one with the absolute value of the error from the estimated distance De(n) in the same azimuth among the provisional distances Dc1(n) and Dc2(n) of azimuth X-1 that is less than or equal to a predetermined reference value X. Since basically one of the provisional distances Dc1(n) and Dc2(n) is correct and the difference between their values is sufficiently larger than this reference value X, an appropriate provisional distance can be selected by such comparison.

[0053] Moreover, the reference value X is previously determined so as to be three times or more the standard deviation of the variation (i.e., frequency distribution) of the calculated values ​​of the definite distance Dis(n) to the target TR by the optical interference measurement device 10. The variation of the calculated values ​​of the definite distance Dis(n) can be specified in advance by an experiment using an optical interference measurement device 10 having the same configuration. The reference value X may be determined to be 1% of the estimated distance De(n).

[0054] In the example of Fig. 8, the difference between the provisional distance Dc2(n) for the direction X-1 and the estimated distance De(n) for the direction X-1 is less than or equal to the reference value X, and the difference between the provisional distance Dc1(n) for the direction X-1 and the estimated distance De(n) for the direction X-1 exceeds the reference value X. Therefore, the provisional distance Dc2(n) for the direction X-1, i.e., 111.5 m, is selected as the confirmed distance Dis(n) for the direction X-1.

[0055] 8, in step S170, the estimated distance De(n) in the same direction as the tentative distances Dc1(n) and Dc2(n) is not calculated for the direction X-2, so the estimated distance De(n) in the direction X-1, which is a direction in a predetermined vicinity of the direction X-2 (for example, an adjacent direction), is used for comparison.

[0056] Specifically, the processing circuit 7 selects the provisional distance Dc1(n) or Dc2(n) for the direction X-2, the one for which the absolute value of the error with the estimated distance De(n) for the direction X-1 is equal to or less than a predetermined reference value X. In the example of FIG. 8, the difference between the provisional distance Dc2(n) for the direction X-2 and the estimated distance De(n) for the direction X-1 is equal to or less than the reference value X, and the difference between the provisional distance Dc1(n) for the direction X-2 and the estimated distance De(n) for the direction X-1 exceeds the reference value X. Therefore, the provisional distance Dc2(n) for the direction X-2, i.e., 111.5 m, is selected as the confirmed distance Dis(n) for the direction X-2. The confirmed distance Dis(n) for the other directions is not determined.

[0057] Note that for a certain direction, if f_up(n) = f_down(n), as a result, it is determined in step S157 that f_up(n) > f_down(n) does not hold, and the provisional distance Dc1(n) is calculated, but the provisional distance Dc2(n) may not be calculated. In that case, in step S170, the processing circuit 7 adopts Dc1(n) as the determined distance Dis(n) rather than the provisional one.

[0058] In step S180 following step S170, based on the determined distance Dis(n) determined for each direction in step S170, the processing circuit 7 determines the determination of the positive and negative of the beat frequency and the determined speed V(n) for each direction. First, when the former is selected as the determined distance Dis(n) among the provisional distances Dc1(n) and Dc2(n), the determination of the positive and negative of the beat frequency is determined to be positive, and when the latter is selected, the determination of the positive and negative of the beat frequency is determined to be negative. Therefore, in the case of the example in FIG. 8, for both directions X-1 and X-2, the determination of the positive and negative of the beat frequency is determined to be negative.

[0059] When it is determined to be positive, the determined speed V(n) is calculated by the following formula based on the beat frequencies f_up(n) and f_down(n) in the same direction. V(n)=Vdiff×(1 / 2)×C / Flow (11) Vdiff=(f_down(n)-f_up(n)) / 2 (12) When it is determined to be negative, the determined speed V(n) is calculated by the following formula based on the beat frequencies f_up(n) and f_down(n) in the same direction. V(n)=Vdiff×(1 / 2)×C / Flow (13) Vdiff=(f_down(n)+f_up(n)) / 2 (14) However, formula (14) is the calculation formula when it is determined in step S153 that f_up < f_down for the same direction. When it is determined in step S157 that f_up > f_down for the same direction, formula (14) is replaced by the following formula (15). Vdiff=-(f_down(n)+f_up(n)) / 2 (15) In this manner, a definite distance Dis(n) and a definite velocity V(n) are calculated for one or more headings.

[0060] After step S180, the process returns to step S130 in the next calculation cycle. By repeating such a process, the processing circuit 7 sequentially calculates the definite distance and definite speed, which are the definite positional behaviors in multiple directions. Note that the positional behaviors include distance, speed, acceleration, and other general behaviors related to the position.

[0061] These determined distances and determined speeds are output to other devices in the vehicle, and are used in the other devices to notify users such as occupants, control vehicle behavior, etc. Alternatively, the processing circuit 7 may use the determined distances and determined speeds to notify users such as occupants using an alarm device, and control vehicle behavior using actuators such as a drive device, a braking device, and a steering device.

[0062] [1] As described above, at each time point n, the processing circuit 7 extracts two combinations of the magnitude relationship between the frequency of the reference light Lr and the frequency of the reflected light Ltr in the up-chirp region, and the magnitude relationship between the frequency of the reference light Lr and the frequency of the reflected light Ltr in the down-chirp region. Specifically, two combinations are extracted in steps S151 and S155, or two combinations are extracted in steps S151 and S157.

[0063] Then, the processing circuit 7 calculates provisional distances Dc1(n) and Dc2(n) as provisional positional behaviors of the target TR at the time point n, using a calculation method that assumes each of the multiple combinations. This process is also executed in steps S151 and S155, or in steps S151 and S157.

[0064] Then, the processing circuit 7 selects one of the provisional distances Dc1(n) and Dc2(n) based on the definite distance Dis(n-1) and the definite velocity V(n-1) which are the positional behavior of the target TR at a time point before the time point n, and determines the selected one as the definite distance Dis(n) which is the definite positional behavior of the target TR.

[0065] In this way, the optical interference measuring device 10 selects an appropriate relationship between the frequencies of the reference light Lr and the reflected light Ltr at the current time point from the positional behavior of the target TR at the past time point. In this way, the positional behavior at the current time point can be appropriately determined by a method other than the method using two different wavelengths.

[0066] When determining the magnitude relationship between the frequencies of the reference light Lr and the reflected light Ltr using processing such as that of this embodiment, it is not excluded to use a method using a two-wavelength light source or an IQ signal as in Patent Document 1 in combination.

[0067] [2] Furthermore, the processing circuit 7 calculates an estimated distance De(n) as the estimated positional behavior of the target TR at the time point n based on the positional behavior of the target TR at a time point prior to the time point n. Then, based on a comparison between the estimated distance De(n) and the multiple provisional positional behaviors, one of the multiple provisional positional behaviors is determined as the definite positional behavior of the target TR. In this way, the definite positional behavior of the target TR can be appropriately determined.

[0068] [3] In addition, the method for extracting the multiple combinations described above differs depending on whether the beat frequency in the up-chirp region, f_up(n), is smaller than the beat frequency in the down-chirp region, f_down(n).

[0069] That is, when the former is smaller, the frequency of the reflected light Ltr is greater than that of the reference light Lr in the down-chirp region, and two combinations in which the frequency relationship between the reference light Lr and the reflected light Ltr differ in the up-chirp region are extracted as two combinations. For example, two combinations corresponding to the examples in Figs. 6 and 7 are extracted.

[0070] In addition, when the latter is smaller, the frequency of the reflected light Ltr is smaller than that of the reference light Lr in the up-chirp region, and two combinations in which the frequency relationship between the reference light Lr and the reflected light Ltr in the down-chirp region is different are extracted as multiple combinations.

[0071] This is because, when the beat frequency f_up(n) of the up-chirp region is smaller than the beat frequency f_down(n) of the down-chirp region, there is no possibility that the reflected light Ltr has a lower frequency than the reference light Lr in the down-chirp region. Also, when the beat frequency f_down(n) of the down-chirp region is smaller than the beat frequency f_up(n) of the up-chirp region, there is no possibility that the reflected light Ltr has a higher frequency than the reference light Lr in the up-chirp region.

[0072] In this way, it is possible to omit the calculation of provisional positional behaviors that are not realistic, and it is therefore possible to efficiently reduce the processing load.

[0073] [4] Furthermore, the processing circuit 7 calculates the provisional distances Dc1(n) and Dc2(n) of the target TR for one of the multiple orientations (e.g., orientation X-2). In this case, the processing circuit 7 selects one of the provisional distances Dc1(n) and Dc2(n) for the one orientation based on the confirmed distance Dis(n-1) and confirmed speed V(n-1) for another orientation (e.g., orientation X-1) different from the one of the multiple orientations. Then, the processing circuit 7 determines the selected provisional distance as the confirmed distance Dis(n) of the target TR for the one orientation.

[0074] In this way, by selecting a tentative positional distance at time n in a certain orientation based on the deterministic positional behavior of the target TR in the past in another orientation, it is possible to select the deterministic positional behavior of the target TR for a wider range of orientations.

[0075] [5] Furthermore, the processing circuit 7 determines, as the confirmed distance Dis(n) of the target TR, one of the provisional distances Dc1(n) and Dc2(n) whose absolute value of the error with respect to the estimated distance De(n) is equal to or smaller than a predetermined reference value X. In this way, the confirmed distance Dis(n) can be calculated appropriately.

[0076] [6] The reference value X is three times or more the standard deviation of the variation in the calculated values ​​of the confirmed distances Dis(n) of the optical interference measurement apparatus 10. In this way, the reference value X is set in accordance with the performance of the optical interference measurement apparatus 10.

[0077] Second embodiment Next, a second embodiment will be described. In this embodiment, the hardware configuration is the same as in the first embodiment, but the processing contents of the processing circuit 7 are different from those in the first embodiment. Specifically, the processing circuit 7 of this embodiment performs the processing of FIG. 9 instead of the processing of FIG. 4. In the processing of FIG. 9, the processing contents of steps S110 to S160 and S180 are the same as the processing contents of the same step numbers in FIG. 4.

[0078] In step S165 following step S160, the processing circuit 7 calculates the accelerations Acc1(n) and Acc2(n) of the target TR in the same direction in the current calculation cycle. The acceleration Acc1(n) is an acceleration based on the provisional distance Dc1(n), and the acceleration Acc2(n) is an acceleration based on the provisional distance Dc2(n). The calculation uses the determined distance Dis(n-1) and determined velocity V(n-1) in each direction in the previous calculation cycle (i.e., at time point n-1) and the provisional distances Dc1(n) and Dc2(n) in each direction in the current calculation cycle.

[0079] The calculation formulas for the accelerations Acc1(n) and Acc2(n) are, for example, Acc1(n)=(2 / g)×(-Dc1(n)+Dis(n - 1)+V(n - 1) ×Δt) / Δt 2 (16) Acc2(n)=(2 / g)×(-Dc2(n)+Dis(n - 1)+V(n - 1) ×Δt) / Δt 2 (17) and may be calculated by the formula: or Acc1(n)=(1 / 2 / g)×(Vc1(n) 2 -V(n - 1)) 2 / (Dc1(n)-Dis(n - 1)) (18) Acc2(n)=(1 / 2 / g)×(Vc2(n) 2 -V(n - 1)) 2 / (Dc2(n)-Dis(n - 1)) (19) and may be calculated by the formula:

[0080] Here, g is the acceleration due to gravity (i.e., 9.80665 m / s 2 ). Here, the tentative speeds Vc1(n) and Vc2(n) are distances that are candidates for the determined speed V(n) of the target TG at the current time. The tentative speed Vc1(n) is calculated by the following formulas (20) and (21). Vc1(n)=Vdiff×(1 / 2)×C / Flow (20) Vdiff=(f_down(n)-f_up(n)) / 2 (21) Also, the tentative speed Vc2(n) is calculated by the following formulas (22) and (23) when f_up(n)<f_down(n), and by the following formulas (22) and (24) when f_up(n)>f_down(n). Vc2(n)=Vdiff×(1 / 2)×C / Flow (22) Vdiff=(f_down(n)+f_up(n)) / 2 (23) Vdiff=-(f_down(n)+f_up(n)) / 2 (24)

[0081] The accelerations Acc1(n) and Acc2(n) for a certain direction may be calculated using the determined distance Dis(n-1) and determined speed V(n-1) for the same direction. However, if there is no such direction, the accelerations may be calculated using the determined distance Dis(n-1) and determined speed V(n-1) for a nearby direction that is not the same. The nearby direction may be, for example, the direction next to the next direction, the direction next to the next direction, or the direction next to the next direction, which is m directions (three or more).

[0082] For example, as shown in Figure 10, assume that the confirmed distance Dis(n-1), confirmed speed V(n-1), provisional distance Dc1(n), provisional distance Dc2(n), and estimated distance De(n) are calculated for directions X-1, X-2, and X-3, as in the example of Figure 8 in the first embodiment.

[0083] 10, in step S165, the calculation for the direction X-1 is made according to the above formula (16) as Acc1(n)=2×{-(114.3m-114.3m)-(100km / h×1000 / 3600×0.1s)} / 0.01 / 9.80665=-56.65G. Also, the calculation for the direction X-1 is made according to the above formula (17) as Acc2(n)=2×{-(111.5m-114.3m)-(100km / h×1000 / 3600×0.1s)} / 0.01 / 9.80665=0G.

[0084] In this case, in equations (16) and (17), the determined distance Dis(n-1), the determined speed V(n-1), the provisional distances Dc1(n), and Dc2(n) have values ​​in the same direction X-1, so these values ​​are used.

[0085] 10, in step S165, the calculation for the direction X-2 is made according to the above formula (16) as Acc1(n)=2×{-(114.3m-114.3m)-(100km / h×1000 / 3600×0.1s)} / 0.01 / 9.80665=-56.65G. Also, the calculation for the direction X-1 is made according to the above formula (17) as Acc2(n)=2×{-(111.5m-114.3m)-(100km / h×1000 / 3600×0.1s)} / 0.01 / 9.80665=0G.

[0086] In this case, in equations (16) and (17), the provisional distances Dc1(n) and Dc2(n) use values ​​in the same direction X-2. However, the confirmed distance Dis(n-1) and confirmed speed V(n-1) do not have values ​​in the same direction X-2, so the values ​​in the adjacent direction X-1 are used.

[0087] Next, in step S170, one of the provisional distances Dc1(n) and Dc2(n) is calculated as the final distance Dis(n) based on a comparison between the provisional distances Dc1(n) and Dc2(n) calculated in step S150 and the estimated distance De(n) calculated in step S160, while also taking into account the accelerations Acc1(n) and Acc2(n) calculated in step S165.

[0088] Specifically, the processing circuit 7 selects, as the confirmed distance Dis(n), one of the provisional distances Dc1(n) and Dc2(n) whose absolute value of the error from the estimated distance De(n) is equal to or smaller than a predetermined reference value X and whose corresponding acceleration value is equal to or smaller than a predetermined allowable value. Here, the acceleration corresponding to the provisional distance Dc1(n) is the acceleration Acc1(n), and the acceleration corresponding to the provisional distance Dc2(n) is the acceleration Acc2(n). The allowable value may be a value equal to or smaller than 2G (for example, 2G). Here, 2G is an amount in units of gravitational acceleration (i.e., twice the gravitational acceleration).

[0089] Alternatively, the processing circuit 7 may not compare the provisional distances Dc1(n), Dc2(n) with the estimated distance De(n), but may select the provisional distance Dc1(n), Dc2(n) whose corresponding acceleration value is less than or equal to a predetermined tolerance as the confirmed distance Dis(n).

[0090] In the example of Fig. 10, the provisional distance Dc2 is selected as the confirmed distance Dis(n) regardless of the judgment criteria. The provisional distances Dc1(n) and Dc2(n) for a certain direction may be compared with the estimated distance De(n) for the same direction, or if there is no such distance, the estimated distance De(n) for a nearby direction that is not the same. The nearby direction may be, for example, the next closest direction, the next two closest directions, or the mth closest direction (3 or more).

[0091] Also, the corresponding acceleration for a certain direction may be the accelerations Acc1(n) and Acc2(n) for the same direction, or if there is no such direction, may be the accelerations Acc1(n) and Acc2(n) for a nearby direction that is not the same. The nearby direction may be, for example, the direction next to the next direction, the direction next to the next direction, or the direction next to the m-th direction (3 or more).

[0092] [1] As described above, the processing circuit 7 performs calculations using the determined distance Dis(n-1) and determined velocity V(n-1), which are the positional behavior of the target TR at the time point n-1 before the time point n. That is, based on the positional behavior of these targets TR at the time point n-1, the processing circuit 7 calculates a plurality of accelerations Acc1(n) and Acc2(n) of the target TR corresponding to the provisional distances Dc1(n) and Dc2(n), respectively. Then, based on the calculated accelerations Acc1(n) and Acc2(n), one of the provisional distances Dc1(n) and Dc2(n) is determined as the determined distance Dis(n). In this way, it is possible to determine which of the provisional distances Dc1(n) and Dc2(n) is appropriate from the viewpoint of the acceleration, which is an important physical quantity for the positional behavior of an object.

[0093] [2] Furthermore, the processing circuit 7 determines the provisional distance Dc1(n) corresponding to the acceleration Acc1(n) or Acc2(n) that is equal to or less than a predetermined tolerance as the final distance Dis(n) of the target TR. The tolerance is equal to or less than 2G. In this manner, the tolerance can be set according to the nature of the physical quantity, namely, acceleration. Note that the same effects can be obtained from the same configuration in this embodiment and the first embodiment.

[0094] Third embodiment Next, a third embodiment will be described. In this embodiment, the hardware configuration is the same as in the second embodiment, but the processing contents of the processing circuit 7 are different from those in the second embodiment. Specifically, the processing circuit 7 of this embodiment performs the processing of FIG. 11 instead of the processing of FIG. 9. In the processing of FIG. 11, the processing contents of steps S110 to S150 and S165 to S180 are the same as the processing contents of the same step numbers in FIG. 4, and the processing content of step S160 is different from step S160 in FIG. 4.

[0095] That is, in step S160 following step S150, processing circuit 7 calculates the estimated distance De(n) in each direction based on information of the target not only at time point n-1 but also at times prior to time point n-1 (i.e., confirmed distance, confirmed speed, etc.).

[0096] For example, using the confirmed distance Dis(n-1) and confirmed speed V(n-1) at time point n-1 and the confirmed distance Dis(n-2) and confirmed speed V(n-2) at time point n-2, the estimated distance De(n) at time point n is calculated using the following equations (25) and (26). De(n)=Dis(n-1)-V(n-1)×Δt +Acce / 2×Δt 2 (twenty five) Acce=2×{-(Dis(n-1)-Dis(n-2))-V(n-2)×Δt} ×Δt 2 (26) Here, Acce is the estimated acceleration of the target TR at time point n-1.

[0097] The confirmed distance Dis(n-1), confirmed speed V(n-1), confirmed distance Dis(n-2), and confirmed speed V(n-2) used when calculating the estimated distance De(n) in each direction are quantities in the same direction.

[0098] Note that the changes made to the second embodiment as in this embodiment are also applicable to the first embodiment. Specifically, the process of step S160 in FIG. 4 can be replaced with the process of step S160 in FIG.

[0099] [1] As described above, the processing circuit 7 calculates the estimated distance De(n) based on the positional behavior of the target at time points n-1 and n-2, which are one and two times before time point n in a calculation cycle for calculating the definite positional behavior of the target TR. Specifically, the estimated acceleration Acce is calculated based on the definite distance and definite speed at time points n-1 and n-2, and the estimated distance De(n) is calculated based on this estimated acceleration Acce and the definite distance and definite speed at time points n-1 and n-2. In this way, it is possible to calculate the estimated distance De(n) with higher accuracy. Note that similar effects can be obtained from the similar configurations in this embodiment and the first and second embodiments.

[0100] In the first to third embodiments, the processing circuit 7 functions as a calculation unit by executing step S150, and functions as a determination unit by executing steps S160 to S180.

[0101] (Other embodiments) The present invention is not limited to the above-described embodiment, and can be modified as appropriate. The above-described embodiments are not unrelated to each other, and can be combined as appropriate, except when the combination is clearly impossible. In the above-described embodiments, the elements constituting the embodiment are not necessarily essential, except when it is specifically stated that they are essential or when it is clearly considered essential in principle. In the above-described embodiments, when the number, numerical value, amount, range, etc. of the components of the embodiment are mentioned, they are not limited to the specific number, except when it is specifically stated that they are essential or when it is clearly limited to a specific number in principle. In addition, when multiple values ​​are exemplified for a certain amount, it is also possible to adopt a value between the multiple values, except when it is specifically stated otherwise or when it is clearly impossible in principle. In addition, in the above-described embodiments, when referring to the shape, positional relationship, etc. of the components, etc., they are not limited to the shape, positional relationship, etc., except when it is specifically stated or when it is limited to a specific shape, positional relationship, etc. in principle. In addition, the present invention also allows the following modifications and modifications within an equivalent range to the above-described embodiments. In addition, the following modifications can be independently selected to be applied or not applied to the above-described embodiments. In other words, any combination of the following modifications can be applied to the above embodiment.

[0102] The processing circuit 7 and the method described in the present disclosure may be implemented by a special-purpose computer provided by configuring a processor and a memory programmed to execute one or more functions embodied in a computer program. Alternatively, the processing circuit 7 and the method described in the present disclosure may be implemented by a special-purpose computer provided by configuring a processor with one or more dedicated hardware logic circuits. Alternatively, the processing circuit 7 and the method described in the present disclosure may be implemented by one or more special-purpose computers configured by a combination of a processor and a memory programmed to execute one or more functions and a processor configured with one or more hardware logic circuits. Also, the computer program may be stored in a computer-readable non-transitory tangible recording medium as instructions executed by a computer.

[0103] (Variation 1) In the first to third embodiments, in step S170, the processing circuit 7 may calculate the confirmed distance Dis(n) in each direction based on the estimated distance De(n), accelerations Acc1(n), Acc2(n), etc. in the same direction. Also, in step S170, the processing circuit 7 may calculate the confirmed distance Dis(n) in each direction based on the estimated distance De(n), accelerations Acc1(n), Acc2(n), etc. in different directions. In either case, the confirmed distance Dis(n) is used as the final value.

[0104] However, this is not necessarily the case. For example, the processing circuit 7 may adopt the confirmed distance Dis(n) calculated based on the estimated distance De(n), acceleration Acc1(n), Acc2(n) and the like in the same direction as a final value. However, the confirmed distance Dis(n) calculated based on the estimated distance De(n) and the like in a different direction may be a provisional value. In this case, the processing circuit 7 may perform an additional determination on the confirmed distance Dis(n) that is provisionally set for a certain direction A1. That is, it may determine whether or not the confirmed distance Dis(n) is calculated as a final value in the direction A2 corresponding to the estimated distance De(n), acceleration Acc1(n), Acc2(n) and the like used to determine the confirmed distance Dis(n). If it is calculated, the provisional confirmed distance Dis(n) for the direction A1 may be adopted as a final value, and if it is not calculated, it may be determined that the final confirmed distance Dis(n) for the direction A1 is not calculated.

[0105] (Variation 2) In the first to third embodiments described above, in step S150, two combinations of the magnitude relationship between the frequencies of the reference light Lr and the reflected light Ltr in the up-chirp region and the magnitude relationship between the frequencies of the reference light Lr and the reflected light Ltr in the down-chirp region are extracted. Then, the provisional distances Dc1(n) and Dc2(n) corresponding to the two extracted combinations are calculated. Moreover, which is extracted is determined according to the magnitude relationship between the beat frequencies f_up(n) and f_down(n). However, the number of combinations to be extracted does not necessarily have to be two, and may be three.

[0106] (Variation 3) In the first to third embodiments, in step S150, the processing circuit 7 extracts a plurality of combinations of the magnitude relationship between the frequencies of the reference light Lr and the reflected light Ltr in the up-chirp region and the magnitude relationship between the frequencies of the reference light Lr and the reflected light Ltr in the down-chirp region. Then, provisional distances Dc1(n) and Dc2(n) are calculated as provisional positional behaviors of the target TR corresponding to the extracted plurality of combinations. Then, from among the provisional distances Dc1(n) and Dc2(n), a definite distance Dis(n) is selected as the definite positional behavior of the target TR, and a definite velocity V(n) is calculated based on the selected definite distance Dis(n).

[0107] However, what is calculated as the provisional positional behavior of the targets TR corresponding to the extracted multiple pairs may be the provisional speeds Vc1(n) and Vc2(n) described in the second embodiment, instead of the provisional distances Dc1(n) and Dc2(n).

[0108] In this case, the processing circuit 7 may calculate an estimated speed Ve(n) that is an estimated value of the speed of the target TR as the estimated positional behavior of the target TR at the time point n based on the positional behavior of the target TR before the time point n. Then, the processing circuit 7 may select a determined speed V(n) as the definite positional behavior of the target TR from among the provisional speeds Vc1(n) and Vc2(n) based on a comparison between the provisional speeds Vc1(n) and Vc2(n) and the estimated speed Ve(n). Then, the processing circuit 7 may calculate a determined distance Dis(n) based on the selected determined speed V(n).

[0109] (Variation 4) In the above embodiment, the optical system uses optical fibers. However, the optical system may be a spatial optical system having a collimator, a polarizing beam splitter, a wave plate, and the like.

[0110] (Variation 5) In the above embodiment, the optical interference measuring device 10 is mounted on a vehicle, but may be installed at a location other than the vehicle. In addition, the optical interference measuring device 10 may be mounted on a vehicle except for the processing circuit 7, and the processing circuit 7 may be mounted at a location other than the vehicle, and signals may be exchanged with the circuit other than the processing circuit 7 using wireless communication or the like. [Explanation of symbols]

[0111] 1 light source 2, 3, 4, 5 optical system 6. Photodetector 7 Processing Circuit 10 Optical interference measurement device

Claims

1. A light source (1) that emits output light (Lp) including an up-chirp region in which the frequency increases over time and a down-chirp region in which the frequency decreases over time; an optical system (2, 3, 4, 5) that generates interference light (Lb) by combining reflected light (Ltr) generated by reflecting the emitted light on a target (TG) and a reference light (Lr) branched from the emitted light; a photodetector (6) for outputting a beat signal corresponding to the interference light; a processing circuit (7) for repeatedly measuring the position and velocity of the target based on the beat signal; The processing circuitry includes: extracting a plurality of combinations of a magnitude relationship between the frequency of the reference light and the frequency of the reflected light in an up-chirp region of the beat signal and a magnitude relationship between the frequency of the reference light and the frequency of the reflected light in a down-chirp region of the beat signal at a certain time point (n), and calculating a plurality of provisional positional behaviors (Dc1(n), Dc2(n), Vc1(n), Vc2(n)) of the target at the time point which are premised on the plurality of combinations, respectively; An optical interference measuring device that determines one of the plurality of provisional positional behaviors as the definitive positional behavior (Dis(n), D(n)) of the target based on the positional behavior (Dis(n-1), Dis(n-2), V(n-1), V(n-2)) of the target prior to the time point.

2. The processing circuitry includes: Calculating an estimated positional behavior (De(n), Ve(n)) of the target at the time based on the positional behavior (Dis(n-1), Dis(n-2), V(n-1), V(n-2)) of the target prior to the time; The optical interference measurement device of claim 1 , further comprising: determining, based on a comparison between the estimated positional behavior and the plurality of tentative positional behaviors, one tentative positional behavior of the plurality of tentative positional behaviors as the definite positional behavior of the target.

3. 3. The optical interference measurement device according to claim 1 or 2, wherein, when the beat frequency in the up chirp region (f_up(n)) is smaller than the beat frequency in the down chirp region (f_down(n)), the processing circuit extracts as the plurality of combinations two combinations in which the frequency of the reflected light is greater than the frequency of the reference light in the down chirp region and the frequency of the reference light and the frequency of the reflected light in the up chirp region differ in magnitude; and when the beat frequency in the down chirp region is smaller, the processing circuit extracts as the plurality of combinations two combinations in which the frequency of the reflected light is smaller than the frequency of the reference light in the up chirp region and the frequency of the reference light and the frequency of the reflected light in the down chirp region differ in magnitude.

4. The optical system includes a beam scanner (4) that scans the emitted light in a plurality of directions, The processing circuitry calculates the plurality of interim positional behaviors of the target for a certain orientation among the plurality of orientations at the time; 3. The optical interference measurement device according to claim 1, wherein the processing circuit determines one of the plurality of provisional positional behaviors for the one orientation as the definitive positional behavior of the target for the one orientation based on the positional behavior of the target prior to the time point for other orientations different from the one orientation among the plurality of orientations.

5. 3. The optical interference measurement device according to claim 1, wherein the processing circuit calculates an estimated positional behavior (eDis(n)) of the target at the time point based on the positional behavior of the target one time point and two times before the time point in a calculation cycle for calculating the definitive positional behavior of the target.

6. The processing circuitry includes: Calculating a provisional distance or velocity of the plurality of targets as the provisional positional behavior of the plurality of targets; calculating a quantity equivalent to the plurality of tentative positional behaviors of the target as the estimated positional behavior of the target at the time; 3. The optical interference measuring device according to claim 1, wherein, based on a comparison between the estimated positional behavior and the plurality of provisional positional behaviors, one of the plurality of provisional positional behaviors whose absolute value of error with respect to the estimated positional behavior is less than or equal to a predetermined reference value is determined as the definite positional behavior of the target.

7. 7. The optical interference measurement device according to claim 6, wherein the reference value is at least three times the standard deviation of the variance of the calculated values ​​of the deterministic positional behavior of the optical interference measurement device.

8. 2. The optical interference measurement device of claim 1, wherein the processing circuit calculates a plurality of accelerations of the target corresponding to each of the plurality of tentative positional behaviors based on the positional behavior of the target prior to the time point and the plurality of tentative positional behaviors, and determines one of the plurality of tentative positional behaviors as the definitive positional behavior of the target based on the calculated plurality of accelerations.

9. 9. The optical interference measurement device according to claim 8, wherein the processing circuit determines a tentative positional behavior corresponding to one of the plurality of accelerations that is equal to or smaller than a predetermined tolerance as a definite positional behavior of the target.

10. The optical interference measurement device according to claim 9 , wherein the tolerance is 2 G or less.

11. A program for use in an optical interference measurement device (10) including: a light source (1) that emits output light (Lp) including an up-chirp region in which the frequency increases over time and a down-chirp region in which the frequency decreases over time; an optical system (2, 3, 4, 5) that generates interference light (Lb) by combining reflected light (Ltr) generated by reflection of the output light on a target (TG) and a reference light (Lr) branched from the output light; a photodetector (6) that outputs a beat signal corresponding to the interference light; and a processing circuit (7) that repeatedly measures a position and a velocity of the target based on the beat signal, The processing circuitry a calculation unit that extracts a plurality of combinations of the magnitude relationship between the frequency of the reference light and the frequency of the reflected light in an up-chirp region of the beat signal and the magnitude relationship between the frequency of the reference light and the frequency of the reflected light in a down-chirp region of the beat signal at a certain time point (n), and calculates a plurality of provisional positional behaviors (Dc1(n), Dc2(n), Vc1(n), Vc2(n)) of the target at the time point assuming each of the plurality of combinations; A program that functions as a determination unit that determines one of the multiple provisional positional behaviors as the definitive positional behavior (Dis(n), D(n)) of the target based on the positional behavior (Dis(n-1), Dis(n-2), V(n-1), V(n-2)) of the target prior to the time point.

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