FMCW servo slope radar signal processing device and program

Abstract

To correct a target distance to a ground surface or the like by considering the Doppler shift of a received wave as a function of an FMCW servo slope radar signal processing device independently of a gyro sensor mounted on a movable body such as a flying object.SOLUTION: An FMCW servo slope radar signal processing device 2 includes a movable body speed calculation unit 22 which calculates a speed component parallel to the radio wave transmission direction of an FMCW servo slope radar transceiver device 1 in the speed components of a movable body such as a flying object equipped with the FMCW servo slope radar transceiver device 1 on the basis of the temporal change in a prescribed period of a target distance to a ground surface or the like. The movable body speed calculation unit 22 takes into account the impact of the Doppler shift in the received wave caused by the speed component parallel to the radio wave transmission direction of the movable body such as a flying object on calculation of the target distance to the ground surface or the like (calculation of the speed component parallel to the radio wave transmission direction of the movable body such as a flying object).SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a technique for measuring a target distance between a target and an FMCW servo slope radar transceiver device using a Frequency-Modulation Continuous-Wave (FMCW) servo slope method. [Background technology]

[0002] Techniques for measuring a target distance between a target and an FMCW servo slope radar transmitting / receiving device using an FMCW servo slope method are disclosed in Patent Documents 1 and 2. Patent Documents 1 and 2 disclose a radio altimeter that measures a target distance, particularly to the ground surface. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-185661 A [Patent Document 2] Japanese Patent Application Publication No. 06-168028 Summary of the Invention [Problem to be solved by the invention]

[0004] The configuration of a conventional FMCW servo slope radar system is shown in Figure 1. The conventional FMCW servo slope radar system R comprises an FMCW servo slope radar transceiver 1, an FMCW servo slope radar signal processing device 2, and an FMCW servo slope radar host device 3. The FMCW servo slope radar transceiver 1 (as well as the entire FMCW servo slope radar system R) is mounted on a moving body such as an aircraft. The FMCW servo slope radar signal processing device 2 comprises a target distance calculation unit 21. The FMCW servo slope radar host device 3 comprises a gyro sensor 31 and a target distance correction unit 32.

[0005] The target distance calculation unit 21 calculates the delay time τ between the transmission wave from the FMCW servo slope radar transmitting / receiving device 1 and the reception wave from a target such as the ground surface. M Based on [n], the target distance h M The gyro sensor 31 calculates a velocity component V[n] parallel to the radio wave emission direction of the FMCW servo slope radar transmitting / receiving device 1 among the velocity components of a moving object such as an aircraft. The target distance correction unit 32 calculates a target distance such as the ground surface as h[n] taking into account the Doppler shift of the received wave due to the velocity component V[n] parallel to the radio wave emission direction of the moving object such as an aircraft. M [n] to h C [n] (see number 12 below).

[0006] However, even if the gyro sensor 31 is mounted on a moving object such as an aircraft, there may be a need to correct the target distance to the ground surface, etc., taking into account the Doppler shift of the received wave as a function of the FMCW servo slope radar signal processing device 2, independent of the gyro sensor 31.

[0007] Therefore, in order to solve the above-mentioned problems, the present disclosure aims to correct a target distance, such as the ground surface, by taking into account the Doppler shift of a received wave as a function of an FMCW servo slope radar signal processing device, independently of a gyro sensor mounted on a moving object such as an aircraft. [Means for solving the problem]

[0008] In order to solve the above problem, the velocity component parallel to the radio wave emission direction of the FMCW servo slope radar transmitting and receiving device is calculated from the velocity components of a moving object such as an aircraft based on the time change of the target distance such as the ground surface over a predetermined period of time. Here, the influence of the Doppler shift of the received wave caused by the velocity component parallel to the radio wave emission direction of the moving object such as an aircraft on the calculation of the target distance such as the ground surface (and the calculation of the velocity component parallel to the radio wave emission direction of the moving object such as an aircraft) is taken into consideration.

[0009] Specifically, the present disclosure provides an FMCW servo slope radar signal processing device that uses an FMCW servo slope method to measure a target distance between a target and an FMCW servo slope radar transceiver, the FMCW servo slope radar signal processing device comprising: a target distance calculation unit that calculates the target distance based on a delay time between a transmission wave from the FMCW servo slope radar transceiver and a reception wave from the target; and a moving body velocity calculation unit that calculates a velocity component parallel to a radio wave emission direction of the FMCW servo slope radar transceiver, of the velocity components of a moving body on which the FMCW servo slope radar transceiver is mounted, based on a time change of the target distance over a predetermined period of time, wherein the moving body velocity calculation unit takes into consideration an influence of a Doppler shift of the received wave due to the velocity component parallel to the radio wave emission direction of the moving body on the calculation of the target distance.

[0010] According to this configuration, the FMCW servo slope radar signal processing device can calculate the velocity component parallel to the radio wave emission direction of a moving object such as an aircraft, taking into account the Doppler shift of the received wave, independently of the gyro sensor mounted on the moving object such as an aircraft.

[0011] In addition, the present disclosure provides a method for calculating a moving object speed based on the target distance h M Time change Δh for a given period Δt M Based on / Δt, the velocity component V of the moving body parallel to the radio wave emission direction is calculated.

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[0012] According to this configuration, the actually measured target distance h M Time change Δh for a given period Δt MTaking into account not only / Δt but also the Doppler shift of the received wave, it is possible to calculate the velocity component V of a moving object such as a flying object that is parallel to the direction of radio wave emission.

[0013] The present disclosure also provides an FMCW servo slope radar signal processing device, further comprising a target distance correction unit that corrects the target distance taking into account a Doppler shift of the received wave due to a velocity component of the moving body parallel to the radio wave emission direction.

[0014] According to this configuration, the FMCW servo slope radar signal processing device can correct the target distance, such as the ground surface, from a pre-correction value to a post-correction value by taking into account the Doppler shift of the received wave, independently of the gyro sensor mounted on a moving object such as an aircraft.

[0015] In addition, the present disclosure provides a method for correcting the target distance by taking into account a Doppler shift of the received wave due to a velocity component V of the moving body parallel to the radio wave emission direction, and correcting the target distance to h before correction. M From corrected h C To

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[0016] According to this configuration, the actually measured target distance h M Time change Δh for a given period Δt M Considering not only / Δt but also the Doppler shift of the received wave, the target distance to the ground surface, etc. is calculated as h before correction. M From corrected h C can be corrected to

[0017] The present disclosure also relates to an FMCW servo slope radar signal processing device, wherein the moving body speed calculation unit masks or smoothes a speed component of the moving body parallel to the radio wave emission direction when the speed component of the moving body parallel to the radio wave emission direction is outside a range of an assumed speed of the moving body parallel to the radio wave emission direction.

[0018] The change over time in the target distance, which is actually measured, over a given period of time, such as the ground surface, is not only affected by the velocity component parallel to the radio wave emission direction of a moving object such as an air vehicle, but also by the uneven shape of the target, such as the ground surface. With this configuration, even in such a case, it is possible to output a velocity within an expected range as the velocity component parallel to the radio wave emission direction of a moving object such as an air vehicle.

[0019] The present disclosure also provides an FMCW servo slope radar signal processing program for causing a computer serving as the FMCW servo slope radar signal processing device to execute each processing step of each processing unit provided in the FMCW servo slope radar signal processing device described above.

[0020] According to this configuration, it is possible to provide a program having the above-mentioned effects.

[0021] The above disclosed inventions can be combined to the greatest extent possible. Effect of the Invention

[0022] In this way, the present disclosure can correct a target distance, such as the ground surface, by taking into account the Doppler shift of a received wave as a function of an FMCW servo slope radar signal processing device, independent of a gyro sensor mounted on a moving object such as an aircraft. [Brief description of the drawings]

[0023] [Figure 1] FIG. 1 is a diagram showing the configuration of a conventional FMCW servo slope radar system. [Diagram 2]FIG. 1 is a diagram showing the configuration of an FMCW servo slope radar system according to the present disclosure. [Diagram 3] FIG. 2 is a diagram showing the procedure of FMCW servo slope radar signal processing of the present disclosure. [Figure 4] FIG. 2 is a diagram showing the principle of FMCW servo slope radar signal processing of the present disclosure. [Diagram 5] FIG. 2 is a diagram showing the principle of FMCW servo slope radar signal processing of the present disclosure. [Figure 6] FIG. 2 illustrates details of the FMCW servo slope radar signal processing of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present disclosure will be described with reference to the accompanying drawings. The embodiments described below are examples of the present disclosure, and the present disclosure is not limited to the following embodiments.

[0025] (Configuration of the FMCW servo slope radar system disclosed herein) In this disclosure, the FMCW servo slope method is used to measure the target distance between the target and the FMCW servo slope radar transceiver. This is particularly applied to a radio altimeter that measures the target distance to the ground surface, etc., but it may also be applied to a radio range finder that measures a general target distance.

[0026] The configuration of the FMCW servo slope radar system of the present disclosure is shown in Fig. 2. The FMCW servo slope radar system R of the present disclosure comprises an FMCW servo slope radar transceiver 1 and an FMCW servo slope radar signal processing device 2. The FMCW servo slope radar transceiver 1 is mounted on a moving object such as an air vehicle. The FMCW servo slope radar signal processing device 2 comprises a target distance calculation unit 21, a moving object speed calculation unit 22, a target distance memory unit 23, an update interval measurement unit 24 and a target distance correction unit 25. The FMCW servo slope radar higher-level device 3 is also mounted on a moving object such as an air vehicle, but need not be used in the present disclosure.

[0027] The procedure of the FMCW servo slope radar signal processing of the present disclosure is shown in Fig. 3. The FMCW servo slope radar signal processing device 2 can be realized by installing the FMCW servo slope radar signal processing program shown in Fig. 3 in a computer.

[0028] The target distance calculation unit 21 calculates the delay time τ between the transmission wave from the FMCW servo slope radar transmitting / receiving device 1 and the reception wave from a target such as the ground surface. M Based on [n], the target distance h M Calculate [n] (step S1, see Equation 4 described later).

[0029] The moving object speed calculation unit 22 calculates a target distance h M [n] over a given period Δt (between times T[n-1] and T[n]) (h M [n]-h M Based on the velocity component of a moving object such as a flying object, the velocity component V[n] parallel to the radio wave emission direction of the FMCW servo slope radar transceiver device 1 is calculated based on the velocity component V[n] / Δt (step S2, see equation 11 described later).

[0030] Here, the moving object speed calculation unit 22 calculates the Doppler shift of the received wave due to the speed component parallel to the radio wave emission direction of a moving object such as a flying object by calculating the distance h of the target object such as the ground surface. M The effect on the calculation of [n] (and on the calculation of the velocity component V[n] parallel to the radio wave emission direction of a moving object such as an aircraft) is taken into account.

[0031] The target distance storage unit 23 stores a target distance h M In preparation for processing by the moving object speed calculation unit 22, the update interval measurement unit 24 measures a predetermined period Δt[n] between times T[n-1] and T[n].

[0032] The target distance correction unit 25 does not use the gyro sensor 31, but calculates the target distance such as the ground surface by taking into account the Doppler shift of the received wave due to the velocity component parallel to the radio wave emission direction of a moving object such as an aircraft. M [n] to h C[n] (step S3, see formula 12 below).

[0033] Therefore, independently of the gyro sensor 31 mounted on a moving object such as an aircraft, the FMCW servo slope radar signal processing device 2 can calculate the velocity component V parallel to the radio wave emission direction of a moving object such as an aircraft, taking into account the Doppler shift of the received wave.

[0034] Then, independent of the gyro sensor 31 mounted on a moving object such as an aircraft, the FMCW servo slope radar signal processing device 2 functions to calculate the target distance such as the ground surface as the uncorrected h M From corrected h C can be corrected to

[0035] (Principle of FMCW servo slope radar signal processing disclosed herein) The principle of the FMCW servo slope radar signal processing of the present disclosure is shown in Fig. 4. In the upper part of Fig. 4, the true target distance, such as the ground surface, is a certain distance h, and the Doppler shift f of the received wave RX is d In the lower part of Fig. 4, the true target distance (e.g., the ground surface) is the same distance h as in the upper part of Fig. 4, but the Doppler shift f of the received wave RXd is d This shows cases where the influence of

[0036] In the upper part of Fig. 4, the frequency modulation range of the transmission wave TX is controlled to a constant range ΔF, and the frequency of the transmission wave TX and the reception wave RX (Doppler shift f d The beat frequency between the b0 Therefore, the frequency modulation period of the transmission wave TX is controlled to a variable period T, the delay time τ between the transmission wave TX and the reception wave RX is expressed by the first equation of the formula 3, and the target distance h to the ground surface or the like is expressed by the second equation of the formula 3 (c is the speed of light).

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[0037] In the lower part of Fig. 4, the frequency modulation range of the transmission wave TX is controlled to a constant range ΔF, and the transmission wave TX and the reception wave RXd (Doppler shift f d The beat frequency between the two (affected by the b0 Therefore, the frequency modulation period of the transmission wave TX is controlled by the variable period T d The delay time τ between the transmitted wave TX and the received wave RXd is controlled by d is expressed by the first equation of the formula 4, and the target distance h d is expressed by the second equation of equation 4 (c is the speed of light).

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[0038] Then, the delay time τ between the transmitted wave TX and the received wave RX and the delay time τ between the transmitted wave TX and the received wave RXd are d The first equation of the formula 5 holds between and . The target distance h of the ground surface, etc. and the target distance h of the ground surface, etc. d The second equation of number 5 holds between and .

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[0039] When the velocity component parallel to the direction of radio wave emission of a moving object such as a flying object is a certain velocity V, the Doppler shift f of the received wave RXd is d is expressed by the following equation (where λ is the wavelength of the transmitted wave): d Between and, the following equation holds: A=(2·V) / (λ·f b0 ) is the calculated target distance h d is a correction coefficient for correcting the target distance from the target position to the true target distance h, such as the ground surface.

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[0040] The principle of the FMCW servo slope radar signal processing of the present disclosure is also shown in Figure 5. At time t1, the true target distance of the ground surface G is h1, and the calculated target distance of the ground surface G is h d1 At time t2, the true target distance of the ground surface G is h2, and the calculated target distance of the ground surface G is h d2 From time t1 to time t2, the true velocity component of the projectile F parallel to the beam B emission direction is V, and the calculated velocity component of the projectile F parallel to the beam B emission direction is V d It is.

[0041] The true velocity component V of the projectile F parallel to the direction of the beam B is expressed by the first equation of equation 8, and the calculated velocity component V of the projectile F parallel to the direction of the beam B is expressed by the first equation of equation 8. d is expressed by the second equation of equation 8.

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[0042] Then, the true velocity component V parallel to the direction of beam B of the projectile F and the calculated velocity component V parallel to the direction of beam B of the projectile F are d Between and, Equation 9 is satisfied using the correction coefficient A in Equation 7, and the Doppler shift f d Using the above equations, the first and second sides of equation 10 are satisfied. Therefore, as shown in the first and third sides of equation 10, the calculated velocity component V parallel to the beam B emission direction of the projectile F is d is corrected to the true velocity component V of the projectile F parallel to the direction of beam B emission.

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[0043] In the left column of Fig. 5, the calculated target distance h d Time change Δh for a given period Δt d / Δt is affected by the true velocity component V parallel to the direction of the beam B of the flying object F, but is almost not affected by the flat and uneven shape of the ground surface G. In the right column of Figure 5, the calculated target distance h d Time change Δh for a given period Δt d / Δt is not only affected by the true velocity component V of the flying object F parallel to the direction of beam B emission, but also by the gently uneven shape of the ground surface G.

[0044] However, even in the case of the right column of Fig. 5, the predetermined period Δt between times t1 and t2 is set to about msec or μsec. Therefore, even in the case of the right column of Fig. 5, it is possible to output a velocity within an expected range as the true velocity component V parallel to the emission direction of beam B of flying object F, taking into account only the Doppler shift of the received wave and hardly taking into account the gentle uneven shape of the ground surface G.

[0045] (Details of FMCW Servo Slope Radar Signal Processing in This Disclosure) Based on the principle explained in Figs. 4 and 5, the details reserved in Figs. 2 and 3 will be explained. d is the τ M V in Fig. 5 corresponds to V[n] in Figs. 2 and 3, and h in Fig. 5 corresponds to 1d , h 2d is shown in Figs. M [n-1], h M [n], and h1 and h2 in Fig. 5 correspond to h in Figs. 2 and 3. C Equivalent to [n].

[0046] The moving object speed calculation unit 22 calculates a target distance h M [n] over a given period Δt (between times T[n-1] and T[n]) (h M [n]-h M Based on the velocity component of a moving object such as a flying object, the velocity component V[n] parallel to the radio wave emission direction of the FMCW servo slope radar transceiver device 1 is calculated based on the velocity component V[n] / Δt (step S2, equation 11 based on equation 10).

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[0047] The target distance correction unit 25 does not use the gyro sensor 31, but calculates the target distance such as the ground surface by taking into account the Doppler shift of the received wave due to the velocity component parallel to the radio wave emission direction of a moving object such as an aircraft. M [n] to h C [n] (step S3, equation 12 based on equation 7).

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[0048] Therefore, the target distance h M Time change Δh of [n] for a given period Δt M It is possible to calculate the velocity component V[n] parallel to the radio wave emission direction of a moving object such as a flying object by taking into account not only [n] / Δt but also the Doppler shift of the received wave.

[0049] And the target distance h M Time change Δh of [n] for a given period Δt M Considering not only [n] / Δt but also the Doppler shift of the received wave, the target distance to the ground surface, etc. is calculated as h before correction. M [n] to corrected h C It can be corrected to [n].

[0050] Further details of the FMCW servo slope radar signal processing of the present disclosure are shown in Figure 6. In the left column of Figure 6, the calculated target distance h d Time change Δh for a given period Δt d / Δt is affected by the true velocity component V parallel to the direction of the beam B of the flying object F, but is almost not affected by the flat and uneven shape of the ground surface G. In the right column of Figure 6, the calculated target distance h d Time change Δh for a given period Δt d / Δt is not only affected by the true velocity component V of the projectile F parallel to the direction of beam B emission, but also by the steep unevenness of the ground surface G.

[0051] Therefore, in the case of the left column of FIG. 6, the true velocity component V parallel to the beam B emission direction of the flying object F is within the range of the assumed velocity parallel to the beam B emission direction of the flying object F. Therefore, the true velocity component V parallel to the beam B emission direction of the flying object F may be output as it is. On the other hand, in the case of the right column of FIG. 6, the true velocity component V parallel to the beam B emission direction of the flying object F is outside the range of the assumed velocity parallel to the beam B emission direction of the flying object F. Therefore, the true velocity component V parallel to the beam B emission direction of the flying object F may be masked or smoothed. Therefore, in either case of the left column or the right column of FIG. 6, a velocity within the assumed range may be output as the true velocity component V parallel to the beam B emission direction of the flying object F. [Industrial Applicability]

[0052] The FMCW servo slope radar signal processing device and program disclosed herein can measure a target distance between a target and an FMCW servo slope radar transmitting / receiving device using an FMCW servo slope method, and can be applied in particular to a radio altimeter that measures a target distance to the ground surface, etc., but can also be applied to a radio rangefinder that measures a general target distance. [Explanation of symbols]

[0053] R: FMCW servo slope radar system 1: FMCW servo slope radar transmitter and receiver 2: FMCW servo slope radar signal processing device 3: FMCW servo slope radar host device 21: Target distance calculation unit 22: Moving object speed calculation section 23: Target distance storage section 24: Update interval measurement section 25: Target distance correction section 31: Gyro sensor 32: Target distance correction section F: Flying object G: Ground surface B: Beam

Claims

1. A FMCW (Frequency-Modulation Continuous-Wave) servo slope radar signal processing device that uses an FMCW servo slope method to measure a target distance between a target and an FMCW servo slope radar transmitting / receiving device, A target distance calculation unit that calculates the target distance based on a delay time between a transmission wave from the FMCW servo slope radar transmitting / receiving device and a reception wave from the target; a moving body speed calculation unit that calculates a speed component parallel to a radio wave emission direction of the FMCW servo slope radar transceiver device among speed components of a moving body on which the FMCW servo slope radar transceiver device is mounted, based on a time change of the target distance for a predetermined period of time; The moving body speed calculation unit takes into consideration an influence of a Doppler shift of the received wave due to a speed component of the moving body parallel to the radio wave emission direction on the calculation of the target distance.

13. An FMCW servo slope radar signal processing device comprising:

2. The moving object speed calculation unit calculates the target distance h Ｍ Time change Δh for a given period Δt Ｍ Based on / Δt, the velocity component V of the moving body parallel to the radio wave emission direction is calculated as ##EQU00013## (where λ is the wavelength of the transmission wave, and f ｂ０ is the beat frequency between the transmitted wave and the received wave, which is feedback-controlled to a constant frequency.

2. The FMCW servo slope radar signal processing device according to claim 1 .

3. a target distance correction unit that corrects the target distance in consideration of a Doppler shift of the received wave due to a velocity component of the moving body parallel to the radio wave emission direction.

2. The FMCW servo slope radar signal processing device according to claim 1 .

4. The target distance correction unit corrects the target distance by taking into account a Doppler shift of the received wave due to a velocity component V of the moving body parallel to the radio wave emission direction. Ｍ From corrected h Ｃ To ##EQU14## (where λ is the wavelength of the transmission wave, and f ｂ０ is the beat frequency between the transmitted wave and the received wave, which is feedback-controlled to a constant frequency.

4. The FMCW servo slope radar signal processing device according to claim 3.

5. The moving body speed calculation unit masks or smoothes the velocity component of the moving body parallel to the radio wave emission direction when the velocity component of the moving body parallel to the radio wave emission direction is outside a range of an assumed velocity of the moving body parallel to the radio wave emission direction.

2. The FMCW servo slope radar signal processing device according to claim 1 .

6. 6. An FMCW servo slope radar signal processing program for causing a computer as the FMCW servo slope radar signal processing device to execute each processing step of each processing unit provided in the FMCW servo slope radar signal processing device according to any one of claims 1 to 5.

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