JP2017166940A - Target distance simulation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simulate continuity of a target distance L between a target and a frequency modulation radar device.SOLUTION: A target distance simulation device is configured to, first of all, use an FMCW servo slope method, but not use a typical FMCM method; perform one category of a delay of a plurality of categories of delays with respect to a transmission wave in a frequency modulation device 1 to thereby simulate [a summary] of a target distance L; and perform a frequency shift to thereby simulate [detail] of the target distance L. Then, in a target distance simulation device 2, a broad frequency band is made unnecessary. Then, in a frequency modulation radar device 1, the distance L between a target and an own device 1 can be accurately measured even in a long distance area. Accordingly, [continuity] of the target distance L between the target and the frequency modulation radar device 1 can be simulated.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a target distance simulation device that simulates a target distance with respect to a frequency modulation radar device that measures a target distance between a target and its own device using a frequency modulation method.

  The frequency modulation radar device measures the distance between the target device and its own device based on the beat frequency between the frequency-modulated transmission wave and the reception wave reflected from the target. Compared to a pulse radar device, low power consumption can be realized because a continuous wave is used, and high-frequency components that amplify nanosecond pulses can be omitted.

FIG. 1 shows the principle of an ordinary FMCW (Frequency Modulated Continuous Wave) radar. In the normal FMCW system, the modulation speed ΔF / T of the frequency of the transmission wave is made constant (ΔF is constant, T is also constant), and based on the beat frequency f _b between the transmission wave and the reception wave, the target and The distance L between itself and the device is measured. Specifically, assuming that the delay between the transmission wave and the reception wave is t and the propagation speed of the transmission wave and the reception wave is c, f _b = (t / T) ΔF = (2L / cT) ΔF is established. L = (cT / 2ΔF) f _b is established.

FIG. 2 shows the principle of an FMCW servo slope radar as a radar different from a normal FMCW radar. The FMCW servo-slope, is a constant beat frequency f _b between the transmitted wave and the received wave, a modulation rate of [Delta] F / T of the frequency of the transmitted wave (the [Delta] F constant, T is the variable) based on the target The distance L between itself and the device is measured. Specifically, T = (ΔF / f _b ) t = (ΔF / f _b ) (2L) where t is the delay between the transmitted wave and the received wave, and c is the propagation speed of the transmitted wave and the received wave. / C) and L = (cf _b / 2ΔF) T.

JP 2011-242199 A

  In Patent Document 1, in order to perform a functional test when the frequency modulation radar apparatus is not actually used, a distance measurement environment simulation apparatus is used to determine whether the frequency modulation radar apparatus is positioned between the target and the frequency modulation radar apparatus. Simulates the ranging environment (target distance L and relative motion, etc.).

  However, the ranging environment simulator simulates the Doppler shift caused by the relative motion between the target and the frequency modulation radar device with respect to the frequency modulation radar device, but the target and the frequency modulation radar device It did not simulate the “continuity” of the target distance L.

  Therefore, in order to solve the above problem, an object of the present invention is to simulate “continuity” of the target distance L between the target and the frequency modulation radar apparatus.

  In order to achieve the above object, first, the FMCW servo slope method is used without using the normal FMCW method. The reason is as follows.

That is, in the conventional FMCW method, according to the distance L between the target and the frequency-modulated radar apparatus, the beat frequency f _b between the transmitted wave and the received wave is variable. Therefore, the target distance simulator requires a wide frequency band. Then, the frequency modulation radar device, where the computing in the digital domain the correlation between the transmitted wave and the received wave, to accurately measure at high frequency band the beat frequency f _b between the transmitted wave and the received wave Therefore, the distance L between the target and the device itself cannot be measured accurately in the long distance region.

On the other hand, in the FMCW servo-slope, irrespective of the distance L between the target and the frequency-modulated radar apparatus, the beat frequency f _b between the transmission wave and the reception wave constant. Therefore, the target distance simulator does not require a wide frequency band. Then, the frequency modulation radar device, where the computing in the digital domain the correlation between the transmitted wave and the received wave, it is not necessary to measure at high frequency band the beat frequency f _b between the transmitted wave and the received wave Therefore, the distance L between the target and the own device can be accurately measured even in the long distance region.

  Further, by applying one type of delay among a plurality of types of delays to the transmission wave in the frequency modulation radar apparatus, the target distance L can be simulated by simulating an “outline” of the target distance L, and by performing frequency shift. The “detail” of the distance L was simulated. Therefore, since the FMCW servo slope method can be used and the frequency shift width can be narrowed, a wide frequency band can be eliminated in the target distance simulator.

  Specifically, the present invention is a target distance simulation device that simulates the target distance with respect to a frequency modulation radar device that measures a target distance between a target and the device using a frequency modulation servo slope method. A transmission wave input unit to which a transmission wave in the frequency modulation radar apparatus is input; and a transmission wave in the frequency modulation radar apparatus is subjected to one type of delay among a plurality of types of delays, A delay processing unit that simulates the outline of the target distance, a frequency shift unit that simulates details of the target distance by applying a frequency shift to a transmission wave in the frequency modulation radar apparatus, and an outline of the target distance And a reception wave output unit that outputs a transmission wave in the frequency modulation radar apparatus whose details are simulated as a reception wave in the frequency modulation radar apparatus. It is the target distance simulator according to claim.

  According to this configuration, a wide frequency band can be eliminated in the target distance simulation device. In the frequency modulation radar apparatus, the distance L between the target object and the own apparatus can be accurately measured even in the long distance region. Thus, the “continuity” of the target distance L between the target and the frequency modulation radar apparatus can be simulated.

  Further, the present invention is the target distance simulation device, wherein the delay processing unit and the frequency shift unit cooperate with each other to simulate the continuity of the target distance.

  According to this configuration, the target distance L simulated “roughly” by the delay processing unit is complemented “finely” by the frequency shift unit. Therefore, the “continuity” of the target distance L between the target and the frequency modulation radar apparatus can be better simulated.

  Further, the present invention is the target distance simulation device, wherein the frequency shift unit performs a frequency shift within a time constant of servo control in the frequency modulation radar device.

  According to this configuration, the time constant of frequency shift in the target distance simulation device is within the time constant of servo control in the frequency modulation radar device. Therefore, the “continuity” of the target distance L between the target and the frequency modulation radar apparatus can be better simulated.

  In the present invention, the delay processing unit simulates attenuation corresponding to the target distance by applying one type of attenuation among a plurality of types of attenuation to the transmission wave in the frequency modulation radar apparatus. This is a target distance simulator.

  According to this configuration, it is possible to simulate the attenuation corresponding to the target distance L between the target and the frequency modulation radar apparatus (the longer the target distance L is, the larger the attenuation is).

  Thus, the present invention can simulate the “continuity” of the target distance L between the target and the frequency modulation radar apparatus.

It is a figure which shows the principle of the radar of a normal FMCW system. It is a figure which shows the principle of the radar of a FMCW servo slope system. It is a block diagram which shows the structure of the target distance simulation apparatus of this invention. It is a figure which shows the simulation method of the continuity of the target distance of this invention. It is a flowchart which shows the process of the target distance simulation apparatus of this invention. It is a figure which shows the process of the frequency shift part of this invention, and a delay process part. It is a figure which shows the process of the frequency shift part of this invention, and a delay process part. It is a figure which shows the specific simulation method of the continuity of the target distance of this invention. It is a figure which shows the specific simulation method of the continuity of the target distance of this invention.

  Embodiments of the present invention will be described with reference to the accompanying drawings. The embodiments described below are examples of the present invention, and the present invention is not limited to the following embodiments.

  The configuration of the target distance simulation apparatus of the present invention is shown in FIG. FIG. 4 shows a method for simulating target distance continuity according to the present invention. The functional testing system for a frequency modulation radar apparatus according to the present invention includes a frequency modulation radar apparatus 1 and a target distance simulation apparatus 2. The frequency modulation radar apparatus 1 measures the target distance L between the target and the apparatus 1 using the FMCW servo slope method. The target distance simulation device 2 simulates the target distance L with respect to the frequency modulation radar device 1.

The frequency modulation radar apparatus 1 includes a transmission wave output unit 11, a transmission wave generation unit 12, a transmission / reception correlation unit 13, and a reception wave input unit 14. The transmission wave output unit 11 outputs a transmission wave in the own device 1. The reception wave input unit 14 receives a reception wave in the own apparatus 1. Reception correlator 13, the correlation between the transmitted wave and the received wave in the own device 1 calculates to calculate the beat frequency f _b between the transmitted wave and the received wave in the own device 1. The transmission wave generation unit 12 servo-controls the modulation period T of the frequency of the transmission wave in the own device 1 to generate a transmission wave in the own device 1.

  The target distance simulation device 2 includes a transmission wave input unit 21, a frequency shift unit 22, a delay processing unit 23, a reception wave output unit 24, a target distance control unit 25, and a target distance storage unit 26.

The transmission wave input unit 21 receives a transmission wave in the frequency modulation radar apparatus 1. Delay processing unit 23, to the transmission wave in a frequency-modulated radar apparatus 1, a plurality of types of delay _{···, t i, t i +} 1, ··· ( _{although, t i <t i + 1} ) one kind of the Is applied to simulate the “outline” of the target distance L, and one of a plurality of types of attenuation..., A _i , a _{i + 1} ,... (Where a _i <a _{i + 1} ) By applying the kind of attenuation, the attenuation corresponding to the target distance L is simulated. The frequency shift unit 22 simulates “details” of the target distance L by performing frequency shift on the transmission wave in the frequency modulation radar apparatus 1. The reception wave output unit 24 outputs a transmission wave in the frequency modulation radar apparatus 1 in which “outline” and “detail” of the target distance L are simulated as a reception wave in the frequency modulation radar apparatus 1.

  The target distance storage unit 26 stores a “scenario” of the time change of the target distance L. The target distance control unit 25 controls the delay amount and attenuation amount in the delay processing unit 23 and the frequency shift amount in the frequency shift unit 22 based on the “scenario” of the time change of the target distance L.

  The frequency shift unit 22 includes a down-conversion unit 221, an up-conversion unit 222, and a local oscillation unit 223. The target distance control unit 25 includes an oscillation frequency of the local oscillation signal output from the local oscillation unit 223 to the down-conversion unit 221, and an oscillation frequency of the local oscillation signal output from the local oscillation unit 223 to the up-conversion unit 222. The frequency shift amount in the frequency shift unit 22 is controlled by controlling.

The delay processing unit 23 includes a delay switching unit 231, a delay switching unit 232, and each type of delay..., T _i , t _{i + 1} ,... (Where t _i <t _{i + 1} ) and each type of delay. It is comprised from each delay circuit part 233 which performs attenuation ..., _ai , _{ai + 1} , ... (however, _ai < _{ai + 1} ). The target distance control unit 25 determines to which delay circuit unit 233 the delay switching unit 231 sets a conduction path and to which delay circuit unit 233 the delay switching unit 232 sets a conduction path. By controlling, the delay amount and the attenuation amount in the delay processing unit 23 are controlled.

Here, when the delay t = 2L / c corresponding to the target distance L to be simulated is between p and q including t _i , the delay processing unit 23 applies to the transmission wave in the frequency modulation radar apparatus 1. Thus, the delay t _i (<t _{i + 1} ) and the attenuation a _i (<a _{i + 1} ) are performed, and the frequency shift unit 22 fills the difference t−t _i with respect to the transmission wave in the frequency modulation radar apparatus 1. On the other hand, when the delay t = 2L / c corresponding to the target distance L to be simulated is between q and r including t _{i + 1} , the delay processing unit 23 applies to the transmission wave in the frequency modulation radar apparatus 1. Thus, the delay t _{i + 1} (> t _i ) and the attenuation a _{i + 1} (> a _i ) are applied, and the frequency shift unit 22 fills the difference t−t _{i + 1} with respect to the transmission wave in the frequency modulation radar apparatus 1.

Note that the local oscillator 223 included in the frequency shift unit 22 performs a small-step frequency shift to finely fill the difference t−t _i or the difference t−t _{i + 1} with respect to the transmission wave in the frequency modulation radar apparatus 1. An executable DDS (Direct Digital Synthesizer) can be used. In the embodiment, the frequency shift unit 22 is in the preceding stage, and the delay processing unit 23 is in the subsequent stage. Of course, as a modification, the delay processing unit 23 may be in the previous stage and the frequency shift unit 22 may be in the subsequent stage.

  The processing of the target distance simulation apparatus of the present invention is shown in FIG. The processing of the frequency shift unit and delay processing unit of the present invention is shown in FIGS. Steps S1 to S12 described below are repeated.

  In the frequency modulation radar apparatus 1, the transmission wave output unit 11 outputs the transmission wave in the own apparatus 1 (step S1). In the target distance simulation device 2, the transmission wave input unit 21 receives a transmission wave from the frequency modulation radar device 1 (step S2).

The target distance control unit 25 acquires information about the target distance L to be simulated from the target distance storage unit 26, and acquires information about the modulation period T of the frequency of the transmission wave from the transmission wave input unit 21 (step). S3). Then, a delay t = 2L / c corresponding to the target distance L to be simulated is calculated (step S4). Further, if t is equal to _{t i} or t is close to _{t i,} in accordance with the changes the control method of the frequency shift unit 22 and the delay processing section 23 (step S5).

When t is equal to t _i (“t = t _i ” in step S5), as shown in FIG. 6, the frequency shift unit 22 performs frequency shift on the transmission wave in the frequency modulation radar apparatus 1. There is no need, and the delay processing unit 23 performs the delay t _i and the attenuation a _i (step S6).

when t is close to _{t i} (in step S5, "T～t _i"), as shown in FIG. 7, with respect to the transmission wave in a frequency-modulated radar apparatus 1, the frequency shift unit 22, frequency shift - ( (T−t _i ) / T) ΔF is applied (step S7), and the delay processing unit 23 applies the delay t _i and the attenuation a _i (step S8). Here, as shown in FIG. 7, the modulation speed ΔF / T of the frequency of the transmission wave is a positive amount. Therefore, as shown in FIG. 7, when t> t _i, the frequency shift amount is a negative amount. On the other hand, although not shown in FIG. 7, when t <t _i , the frequency shift amount is a positive amount.

  In the target distance simulation device 2, the received wave output unit 24 outputs the received wave in the frequency modulation radar device 1 (step S9). In the frequency modulation radar apparatus 1, the reception wave input unit 14 receives a reception wave in the own apparatus 1 (step S10).

Reception correlator 13, the correlation between the transmitted wave and the received wave in the own device 1 calculates to calculate the beat frequency f _b between the transmitted wave and the received wave in the own device 1 (step S11). Transmitting wave generator 12, as the beat frequency f _b between the transmitted and received waves of own device 1 becomes a predetermined value as shown in FIG. 2, the modulation period T of the frequency of the transmitted wave in the own device 1 Servo control is performed to generate a transmission wave in the device 1 (step S12).

  Here, it is desirable that the frequency shift unit 22 shifts the frequency within the time constant of servo control in the frequency modulation radar apparatus 1. That is, it is desirable that the time constant of the frequency shift in the target distance simulation device 2 is within the time constant of the servo control in the frequency modulation radar device 1. Then, when viewed from the frequency modulation radar apparatus 1, the “continuity” of the target distance L between the target and the frequency modulation radar apparatus 1 can be better simulated.

  A specific simulation method of the continuity of the target distance of the present invention is shown in FIGS. In FIGS. 8 and 9, the target distance simulation device 2 uses the ground altitude L between the ground surface and the radio altimeter in the ground test as opposed to the radio altitude meter that measures the ground altitude L between the ground surface and the device itself. Simulate.

  FIG. 8 shows the delay amount in the delay processing unit 23 and the frequency shift amount in the frequency shift unit 22 when the output altitude L is changed from 2500 m to 0 m over about 7 seconds. FIG. 9 shows the delay amount in the delay processing unit 23 and the frequency shift amount in the frequency shift unit 22 when the output altitude L is changed from about 250 m to 0 m over about 2 seconds.

  In FIGS. 8 and 9, one line that monotonously decreases with the passage of time indicates the passage of time of the output altitude L, and several lines that monotonously increase with the passage of time each time the delay amount is switched by the delay processing unit 23. The time lapse of the frequency shift amount in the frequency shift unit 22 is shown.

In Figure 8 and 9, the beat frequency _{f b} between the transmitted wave and the received wave is constant at 50 kHz, limited by ± about 11.47kHz the upper and lower limit values of the frequency shift amount of the frequency shift unit 22. Then, as shown in FIG. 8, when the 2000 m delay line in the delay processing unit 23 is used, the output altitude L can be changed from 2500 m to about 1700 m. As shown in FIG. 8, when the 1372 m delay line in the delay processing unit 23 is used, the output altitude L can be changed from about 1800 m to about 1100 m. Furthermore, as shown in the right side of FIG. 8 and FIG. 7, the output altitude L can be further reduced.

8 and 9, the accuracy of the frequency shift amount in the frequency shift unit 22 is 1 Hz or less. Then, as shown in FIG. 8, when using a 2000 m delay line in the delay processing unit 23, the resolution of the output altitude L is (2500-1700) / (11.47 * 2 * 10 ³ ) = 0.035 m. It can be. As shown in FIG. 8, when using the 1372 m delay line in the delay processing unit 23, the resolution of the output altitude L is (1800-1100) / (11.47 * 2 * 10 ³ ) = 0.030 m. It can be. Furthermore, as shown in the right side of FIG. 8 and FIG. 9, the resolution of the output height L can be further increased.

  The target distance simulation apparatus of the present invention (1) simulates the ground altitude L between the ground surface and the radio altimeter in a ground test in comparison with the radio altimeter that measures the ground altitude L between the ground surface and the device itself. And (2) the purpose of simulating the target distance L between the target and the radar apparatus in the functional test with respect to the radar apparatus that measures the target distance L between the target and the own apparatus. Applicable.

  The target distance simulation device of the present invention performs an attitude control test of a platform such as an aircraft or a flying object in a ground test according to a ground altitude L simulated by a radio altimeter mounted on the platform such as an aircraft or a flying object. Applicable to purpose.

1: Frequency modulation radar device 2: Target distance simulation device 11: Transmission wave output unit 12: Transmission wave generation unit 13: Transmission / reception correlation unit 14: Reception wave input unit 21: Transmission wave input unit 22: Frequency shift unit 23: Delay processing Unit 24: received wave output unit 25: target distance control unit 26: target distance storage unit 221: down-conversion unit 222: up-conversion unit 223: local oscillation unit 231: delay switching unit 232: delay switching unit 233: delay circuit unit

Claims (4)

A target distance simulator for simulating the target distance with respect to a frequency modulation radar apparatus that measures a target distance between a target and the apparatus using a frequency modulation servo slope method,
A transmission wave input unit that receives a transmission wave in the frequency modulation radar device;
A delay processing unit that simulates an outline of the target distance by applying one type of delay among a plurality of types of delay to the transmission wave in the frequency modulation radar device;
A frequency shift unit that simulates the details of the target distance by applying a frequency shift to the transmission wave in the frequency modulation radar device;
A reception wave output unit for outputting a transmission wave in the frequency modulation radar apparatus in which the outline and details of the target distance are simulated, as a reception wave in the frequency modulation radar apparatus;
A target distance simulation apparatus comprising:   The target distance simulating apparatus according to claim 1, wherein the delay processing unit and the frequency shift unit cooperate with each other to simulate continuity of the target distance.   3. The target distance simulation device according to claim 1, wherein the frequency shift unit performs a frequency shift within a time constant of servo control in the frequency modulation radar device.   The delay processing unit simulates attenuation corresponding to the target distance by applying one type of attenuation among a plurality of types of attenuation to a transmission wave in the frequency modulation radar apparatus. The target distance simulation apparatus according to claim 1.

Images