JP2011242199A - Ranging environment simulation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ranging environment simulation device for use in a function test of a ranging device or a system test of a system including the ranging device, which is mounted on a platform of a flying object, an air craft, etc., and employs an FMCW system; the ranging environment simulation device flexibly adapting to various positions and postures of the ranging device, and accurately realizing a test and an evaluation of performances and functions of the ranging device.SOLUTION: The ranging environment simulation device comprises Doppler shift calculation means for calculating a Doppler frequency accompanying a received wave arrived at the ranging device of an FMCW system, and frequency-shift simulation means for synchronizing to the transmission wave, applying a frequency conversion of simulating a Doppler shift of the Doppler frequency to a transmission wave sent from the ranging device, and applying a result of the frequency conversion to the ranging device as the received wave.

Description

  The present invention relates to a ranging environment simulation used for a function test of a distance measuring device mounted on a platform such as a flying object or an aircraft and to which an FMCW method is applied, or a system test of a system including the distance measuring device. Relates to the device.

  Ranging environment simulator that simulates measurement error caused by Doppler shift in response to changes in speed in the ground direction is used for testing and evaluation of ranging devices such as radio altimeters using FMCW. It is done.

  Conventionally, as such a ranging environment simulation device, for example, there has been a “high-frequency signal delay device, radio altimeter ground test device” described in Patent Document 1 described later.

  Patent Document 1 includes, as inputs, a frequency dividing means for dividing a pulsed high frequency signal, a Fourier transform means for performing frequency analysis of the high frequency signal divided by the circuit, and a control signal. Coefficient arithmetic means for performing an operation on the Fourier coefficient obtained by the Fourier transform means and providing the high-frequency signal with a delay time and attenuation according to the control signal; and inverse Fourier transform of the Fourier coefficient calculated by the means By comprising an inverse Fourier transform means for generating a signal in the time domain by performing transformation, and a multiplication means for multiplying the high frequency signal in the time domain calculated by the means, A high-frequency signal delay device characterized in that it can easily simulate an arbitrary altitude "is disclosed.

JP-A-10-20020

  By the way, the above-described conventional example is realized at a low cost and can be applied to a pulse radar type radar, but when applied to an FMCW type radio wave altimeter, the frequency of the transmission wave varies widely. However, since the signal processing in the digital domain correlates the transmitted wave with the received wave arriving from the ground surface, the accuracy of such correlation decreases, and it is difficult to accurately simulate the continuously changing altitude. there were.

  It is an object of the present invention to provide a distance measurement environment simulation device that can flexibly follow various forms of the position and posture of a distance measurement device and can accurately test and evaluate the performance and function of the distance measurement device. Objective.

  According to the first aspect of the present invention, the Doppler shift calculating means calculates a Doppler frequency attached to the received wave arriving at the FMCW ranging device. The frequency shift simulating means performs frequency conversion for simulating the Doppler shift of the Doppler frequency in synchronization with the transmission wave transmitted by the distance measuring device, and uses the result of the frequency conversion as the received wave. To the distance measuring device.

  In other words, the distance measuring device reflects the Doppler shift that occurs at the desired ground speed to be tested or evaluated for functions and performance regardless of position, speed, and attitude, and provides a coherent received wave. It is done.

  In the invention according to claim 2, the Doppler shift calculation means calculates the Doppler frequency attached to the received wave arriving at the FMCW rangefinder. The frequency shift simulating means synchronizes with the transmission wave transmitted by the distance measuring device, the Doppler shift of the Doppler frequency, the received wave corresponding to the distance to be measured by the distance measuring device, and the transmission wave. The transmission wave is subjected to frequency conversion that simulates the difference between the two frequencies, and the result of the frequency conversion is given to the distance measuring device as the received wave.

  That is, the distance measuring device is not provided with a delay means for simulating the propagation time of the transmission wave and the reception wave, but in the desired position, speed, and posture, in addition to the Doppler shift described above, A coherent received wave reflecting a delay equal to the sum of propagation times is given.

According to a third aspect of the present invention, in the distance measurement environment simulating apparatus according to the first or second aspect, the frequency shift simulating means is configured to synchronize the transmitted wave with the transmitted wave and the received wave. A delay corresponding to the sum of propagation time is given to the received wave.
In other words, the distance measuring device includes a sum of the above required propagation times in addition to the above-described Doppler shift at a desired position, speed, and posture even when the distance to be tested or evaluated is not necessarily constant. A coherent received wave reflecting a delay equal to is given.

  According to a fourth aspect of the present invention, in the ranging environment simulating apparatus according to the first or second aspect, the frequency shift simulating unit is based on a predetermined scenario of propagation time required for the transmission wave and the reception wave. A delay that can be simulated is given to the received wave.

  That is, the delay amount of the delay given to either or both of the transmission wave and the reception wave is not simply a value required for the propagation time of these transmission wave and reception wave, but changes under the above scenario, In addition, it is maintained at a value that can simulate a Doppler shift that can accompany the received wave.

According to a fifth aspect of the present invention, in the ranging environment simulating apparatus according to any one of the first to fourth aspects, the frequency shift simulating means is configured to perform the Doppler shift according to a request given from the outside. The frequency conversion is performed in a form in which is not reflected.
That is, even if the distance measuring device to be tested or evaluated has “the function of canceling or compensating for the Doppler shift incidental to the received wave”, the distance measuring device has a desired position, A coherent received wave reflecting a delay equal to at least the sum of the required propagation times described above is given in velocity and attitude.

ADVANTAGE OF THE INVENTION According to this invention, the desired test and evaluation including the compensation function and influence of a Doppler shift are easily implement | achieved about the distance measuring device in a desired operating environment.
In addition, according to the present invention, it is possible to easily realize the test and evaluation of the distance measuring device in a desired operating environment, although the configuration is simplified.

Furthermore, according to the present invention, simulation of the environment of the distance measuring device to be tested and evaluated is realized with high accuracy.
In addition, according to the present invention, it is possible to flexibly adapt to the function and configuration of the distance measuring apparatus.
Therefore, it is possible to flexibly follow various scenarios, and the testing and evaluation of the distance measuring device based on such scenarios can be realized with high accuracy and stability.

It is a figure which shows 1st and 2nd embodiment of this invention. It is a figure explaining operation | movement of 1st embodiment of this invention. It is an operation | movement flowchart of the control part in 1st embodiment of this invention. It is an operation | movement flowchart of the control part in 2nd embodiment of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a diagram showing first and second embodiments of the present invention.

  In the figure, a transmission coupler 11 is connected to a transmission output of a radio altimeter 20 to be tested and to which the FMCW method is applied, and is connected to a first input of a down converter 12. The output of the down converter 12 is connected to the input of the delay circuit 14 via the up converter 13, and the first output of the delay circuit 14 is connected to the reception input of the radio altimeter 20 via the reception coupler 15. The first output of the oscillator 16 is connected to the second input of the down converter 12, and the second and third outputs of the oscillator 16 are connected to the first local input of the down converter 12 and the up converter 13, respectively. Is done. The oscillator 16 includes a frequency divider 16FD, and an output of the frequency divider 16FD is connected to a first input of the Doppler generator 17. The first and second outputs of the Doppler generator 17 are connected to the second local input of the down converter 12 and the up converter 13, respectively. The second output of the Doppler generator 17 is connected to the first output of the controller 18, and the second and third outputs of the controller 18 are connected to the delay circuit 14 and the control terminal of the oscillator 16, respectively. . The second output of the delay circuit 14 is connected to the input of the control unit 18 via the inspection determination unit 19, and the control unit 18 displays parameters and statuses necessary for cooperation with the platform 30 to which the radio altimeter 20 is attached. It has a port used for delivery. An acceleration sensor 41 is attached to the platform 30, and an output of the acceleration sensor 41 is connected to a corresponding input of the radio altimeter 20.

FIG. 2 is a diagram for explaining the operation of the first embodiment of the present invention.
FIG. 3 is an operation flowchart of the control unit in the first embodiment of the present invention.
The operation of this embodiment will be described below with reference to FIGS.

[First embodiment]
The oscillator 16 generates a reference signal S having a frequency f0 and a local signal L1 having a frequency f1 under the control of the control unit 18.

  In the present embodiment, at the time of start-up, each unit is linked as follows under the control of the control unit 18, thereby confirming the correctness of the operation and function of the distance measurement environment simulation device according to the present embodiment (hereinafter referred to as “inspection determination”). ).

[Operation of each part in inspection judgment]
The following values are given in advance to the control unit 18 as parameters to be applied to “inspection determination”.

(1) The virtual plural n ground altitudes H1, H2,..., Hn of the radio altimeter 20
(2) The width of the band in which the frequency of the transmission wave of the radio altimeter 20 actually shifts based on the FMCW method (hereinafter referred to as “frequency shift width”) ΔF

(3) Propagation speed c of the transmitted wave and the received wave between the radio altimeter 20 and the ground surface
(4) Time required for the frequency of the transmission wave to actually shift linearly over the frequency shift width ΔF (hereinafter referred to as “modulation period”) T

  Further, the control unit 18 performs the following processing in accordance with each of the ground altitudes H1, H2,..., Hn, and links the units as follows based on the processing procedure. In the following, items that apply to any of the ground altitudes H1, H2,..., Hn correspond to any of the numbers “1” to “n” of these ground altitudes H1, H2,. The description will be made using the subscript “i” (= 1 to n) indicating that it is obtained.

A frequency difference (hereinafter referred to as “beat frequency”) fbi generated between the transmission wave of the radio altimeter 20 and a reception wave that should arrive from the ground according to the transmission wave, and the frequency shift ΔF. Then, the Doppler frequency fdi given by the following equation is appropriately calculated for the propagation velocity c and the modulation period T, and notified to the Doppler generator 17.
fdi = (2Hi / c) · (ΔF / T) −fbi (a)

  The Doppler generator 17 is a station whose frequency is a predetermined value f2 in synchronization with the frequency-divided signal LD1 generated by the frequency divider 16FD provided in the oscillator 16 dividing the local signal L1. The generated signal L2 and the local signal Ldi having a frequency equal to the sum (= f2 + fdi) of the frequency f2 and the Doppler frequency fdi are generated.

  The down-converter 12 down-converts the transmission wave (frequency = F) given by the radio altimeter 20 based on the above-described local oscillation signals L1 and L2, so that the frequency is (F− (f1 + f2)). A frequency signal Ii is generated.

  The up-converter 13 up-converts the intermediate frequency signal Ii based on the previously described local signals L1 and Ldi, so that the frequency is ((F + fdi) = (F− (f1 + f2) + (f1 + f2 + fdi))). A Doppler wave Rdi is generated.

  Further, the control unit 18 obtains a delay amount Di that is determined based on the above-described scenario and is substantially equal to (2Hi / c) on the right side of the above equation (a).

  The delay circuit 14 gives a delay corresponding to the delay amount Di to the Doppler-attached wave Rdi, and gives it to the inspection determination unit 19 as a received wave ri.

  The inspection determination unit 19 determines whether the received wave ri is correct under the control of the control unit 18 and delivers the determination result to the control unit 18.

  When such determination is completed for each of the plurality of n ground altitudes H1, H2,..., Hn, if any of these determination results is abnormal, the control unit 18 This is notified to the user as either or both of the information (step S1 in FIG. 3). Note that both the audio information and the display information may be delivered to other devices via, for example, a predetermined transmission path or communication path.

On the other hand, if all of these determination results are normal, the “inspection determination” is terminated and “normal operation” is started (step S2 in FIG. 3).
Such “inspection determination” may be simply performed as described below.
(1) The oscillator 16 generates a “pseudo transmission wave” instead of the local oscillation signal L1 described above.
(2) The inspection determination unit 19 uses a “pseudo transmission wave” delay amount (down converter 12, up converter) obtained from the output of the delay circuit 14 for each of the plurality of ground altitudes H1, H2,. 13 and the total delay amount of the delay circuit 14) are determined to be acceptable.

[Link of each part in normal operation]
The control unit 18 appropriately sets and changes the positions and postures of the platform 30 and the radio altimeter 20 based on a predetermined scenario (step S3 in FIG. 3).
In the above scenario, for example, it is assumed that the ground altitude H decreases from 2500 meters with a substantially constant slope, as shown by a thick solid line in FIG.

  Each unit is linked as described later according to the discrete values of the position and orientation of the radio altimeter 20 that are set or changed in chronological order in this way.

The control unit 18 determines the difference in frequency between the ground altitude H of the radio altimeter 20 and the transmitted wave of the radio altimeter 20 at this ground altitude H and the received wave that should arrive from the ground surface in accordance with the transmitted wave (hereinafter referred to as the frequency difference) (Referred to as “beat frequency”.) Fb (step S4 in FIG. 3), and together with the ground altitude H and beat frequency fb, the frequency deviation width ΔF, propagation velocity c and modulation period T described above The Doppler frequency fd given by the following equation is calculated as appropriate and notified to the Doppler generator 17 (step S5 in FIG. 3).
fd = (2H / c) · (ΔF / T) −fb (b)

  Here, the Doppler frequency fd is a Doppler shift that occurs in response to the speed of the radio altimeter 20 in the direction of the ground surface of the received wave arriving at the radio altimeter 20, and is represented by a plurality of dashed curves in FIG. In addition, the value is given as a value that jumps as appropriate in a range between a predetermined lower limit value and an upper limit value in accordance with a decrease in the ground altitude H.

  The Doppler generation unit 17 synchronizes with the frequency-divided signal LD1 described above, and the frequency equal to the sum (= f2 + fd) of the local oscillation signal L2 having a predetermined value f2 and the frequency f2 and the Doppler frequency fd. The local oscillation signal Ld is generated in parallel.

  The down-converter 12 down-converts the transmission wave (frequency = F) given by the radio altimeter 20 based on the above-described local oscillation signals L1 and L2, so that the frequency is (F− (f1 + f2)). A frequency signal I is generated.

  The up-converter 13 up-converts the intermediate frequency signal I based on the above-mentioned local oscillation signals L1 and Ld so that the frequency is ((F + fd) = (F− (f1 + f2) + (f1 + f2 + fd))). A Doppler wave Rd is generated.

  Further, the control unit 18 obtains a delay amount D that is determined based on the above-described scenario and is substantially equal to (2H / c) on the right side of the above equation (a) (step S6 in FIG. 3).

  The delay circuit 14 gives a delay corresponding to the delay amount D to the Doppler-attached wave Rd and gives it to the radio altimeter 20 as a received wave.

  The radio altimeter 20 obtains the ground speed by integrating the component in the ground surface direction of the acceleration given by the acceleration sensor 41, and cancels the Doppler shift attached to the received wave according to the speed. Furthermore, the radio altimeter 20 obtains the ground altitude h based on the frequency difference between the received wave with the Doppler shift canceled in this way and the above-described transmitted wave, and notifies the control unit 18 of it.

  The control unit 18 determines whether or not the deviation of the ground altitude h from the ground altitude H determined based on the scenario is within a specified narrow range, the performance of the radio altimeter 20 in the attitude and position determined by the scenario, and Whether the function is right or wrong is determined (step S7 in FIG. 3).

  That is, the transmission wave is subjected to frequency conversion that simulates the above-described Doppler shift and does not impair coherency, and is then delivered to the radio altimeter 20 as a reception wave.

  Therefore, according to the present embodiment, the radio altimeter 20 flexibly simulates the posture and position to be operated and the Doppler shift generated in the received wave in accordance with the change in the posture and position based on various scenarios. Therefore, evaluation and testing of functions and performance in a desired environment can be realized with high accuracy and efficiency.

  In this embodiment, the frequencies f1 and f2 of the local oscillation signals L1 and L2 are reflected in the Doppler-accompanying wave Rdi (Rd) with sufficient accuracy by the downconverter 12 and the upconverter 13 by the Doppler frequency fdi (fd). Any value can be used.

Further, in the present embodiment, the down converter 12 and the up converter 13 include one frequency converter if such a Doppler frequency fdi (fd) is reflected in the Doppler-attached wave Rdi (Rd) with sufficient accuracy. Alternatively, three or more frequency converters may be substituted.
Further, in the present embodiment, the Doppler frequencies fdi and fd do not have to be obtained by the arithmetic operation represented by the above-described equations (a) and (b), and are desired as long as an increase in the time required for the operation is allowed. For example, it may be obtained based on the speed of the radio altimeter 20 in the surface direction, or may be obtained under any other process.
Further, in the present embodiment, the delay amount D of the delay circuit 14 does not necessarily have to be equal to the required round-trip propagation time in the surface direction. For example, as shown in FIG. 2 as D1, D2, D3,. If the scenario is established in the range of the Doppler frequencies fdi and fd in the process of increasing or decreasing the altitude H, it may be increased or decreased.

[Second Embodiment]
Hereinafter, a second embodiment of the present invention will be described.
The difference in configuration between the present embodiment and the first embodiment described above is as follows.

(1) Instead of the radio altimeter 20, a radio altimeter 20A that does not have a function of canceling the Doppler shift incidental to the received wave in cooperation with the acceleration sensor 41 is provided.
(2) Instead of the inspection determination unit 19, an inspection determination unit 19A is provided.

(3) The output of the acceleration sensor 41 is not connected to the radio altimeter 20A.
(4) Instead of the Doppler generator 17, a Doppler generator 17A is provided.

FIG. 4 is an operation flowchart of the control unit in the second embodiment of the present invention.
In the figure, steps similar to those in the first embodiment described above are denoted by the same reference numerals as in FIG.
Hereinafter, the operation of the present embodiment will be described with reference to FIG. 1, FIG. 2, and FIG.
As shown in FIG. 4, the operation of the present embodiment is the same as the operation of the first embodiment described above except for the points listed below.

(1) The radio altimeter 20A operates without linking with the acceleration sensor 41, and does not perform the process of not only identifying the ground speed but also canceling the Doppler shift incidental to the received wave according to the ground speed.
(2) For example, based on an instruction or information given through an operation unit (not shown), the control unit 18 reads: “The radio altimeter 20A is connected to the transmission coupler 11 and the reception coupler 15 instead of the radio altimeter 20 described above. When “” is identified, processing different from that of the first embodiment is performed in the inspection determination and the normal operation as described later.

(3) Operation of each part in inspection judgment
(3-1) The frequency difference (hereinafter referred to as “beat frequency”) fbi between the transmission wave of the radio altimeter 20A and the reception wave that should arrive from the ground according to the transmission wave, and the frequency shift ΔF Then, the process of appropriately calculating the Doppler frequency fdi given by the following equation for the propagation velocity c and the modulation period T is not performed, and the Doppler frequency fdi is notified to the Doppler generation unit 17 as “0”.

(3-2) The Doppler generator 17 generates the local oscillation signal Ldi having a frequency equal to the sum of the predetermined frequency f2 and the Doppler frequency fdi (= f2 + fdi) in synchronization with the frequency-divided signal LD1. Instead, the local signal L2 is supplied to the up-conversion unit 13 instead of the local signal LDi.

(3-3) The up-converter 13 up-converts the intermediate frequency signal Ii based on the local oscillation signal L2 and the local oscillation signal L1 described above, so that the frequency F (== the Doppler frequency fdi is not reflected). The Doppler non-accompanying wave Ri of (F− (f1 + f2) + (f1 + f2))) is generated instead of the Doppler accompanying wave Rdi.

(3-4) The delay circuit 14 gives a delay over the delay amount Di to the Doppler non-accompanying wave Ri, and gives it to the inspection determination unit 19A as a received wave ri.

(4) Linking each part in normal operation
(4-1) The control unit 18 does not perform the following processing.
a) Processing for appropriately setting and changing the positions and postures of the platform 30 and the radio altimeter 20A based on a predetermined scenario (step S3 in FIG. 3)

b) Identify the ground altitude H of the radio altimeter 20A and the frequency difference (“beat frequency”) fb between the transmitted wave of the radio altimeter 20A and the received wave that should arrive from the ground according to the transmitted wave ( FIG. 3 Step S4) Processing
c) In addition to the ground altitude H and beat frequency fb, the Doppler frequency fd given by the above-described equation (b) is appropriately set for the frequency deviation width ΔF, the propagation speed c, and the modulation period T. Processing to calculate and notify the Doppler generation unit 17 (step S5 in FIG. 3)

(4-2) The Doppler generator 17 generates the local oscillation signal Ld having a frequency equal to the sum (= f2 + fd) of the predetermined frequency f2 and the Doppler frequency fd in synchronization with the frequency-divided signal LD1. Instead, the local oscillation signal L2 is supplied to the up-conversion unit 13 instead of the local oscillation signal Ld.

(4-3) The up-converter 13 up-converts the intermediate frequency signal I on the basis of the local oscillation signal L2 and the local oscillation signal L1 described above, thereby generating a frequency F (= (F− (f1 + f2)). + (F1 + f2))) Doppler non-accompanying wave R is generated instead of Doppler accompanying wave Rd.

(4-4) The delay circuit 14 gives a delay corresponding to the delay amount D to the Doppler non-accompanying wave R and gives it to the radio altimeter 20A as a received wave.

(4-5) The radio altimeter 20A obtains the ground altitude h based on the difference in frequency between the received wave and the transmitted wave without performing Doppler shift compensation on the received wave, and notifies the control unit 18 of it.

  That is, the transmission wave of the radio altimeter 20A is not subjected to Doppler shift compensation corresponding to the speed in the ground direction, and is subjected to signal processing performed in synchronization with the local signal L1 (frequency-divided signal LD1). Thus, since it is given to the radio altimeter 20A as a received wave, the coherency of such a received wave is ensured.

  Therefore, according to the present embodiment, even if the radio altimeter 20A does not have the function of canceling the Doppler shift incidental to the received wave in cooperation with the acceleration sensor 41, the evaluation of the function and performance based on the desired scenario is performed. In addition, the test can be realized with high accuracy and efficiency, and the oscillation of the radio altimeter 20A in the course of these evaluations and tests can be omitted.

  In each of the embodiments described above, the radio altimeter 20 (20A) may be either a servo slope type FMCW radar or a non-servo slope type FMCW radar.

  Further, in each of the above-described embodiments, the delay circuit 14 is not provided when the ground altitude at which the performance or function of the radio altimeter 20 (20A) should be tested or evaluated based on the scenario is constant. Alternatively, the delay amount D may be kept constant under the control of the control unit 18.

  Further, such a delay circuit 14 is not provided in the case where the radio altimeter 20 (20A) is an FMCW radio altimeter that is not a servo slope type, and “the beat frequency fb generated according to the delay amount D” is not provided. In the meantime, it may be replaced by “a process in which the sum of the local signals L1 and L2 described above is set to a small (large) value under the control of the control unit 18”.

  Further, in each of the above-described embodiments, when the inspection determination is separately performed or unnecessary, the inspection determination units 19 and 19A are not provided, and the processing performed by the control unit 18 for the inspection determination, It is not necessary to perform the linkage of each part performed under the processing.

  Further, in each of the above-described embodiments, the inspection determination is not only whether the received wave ri is correct or not, but also any determination as to whether various signals and information provided from the radio altimeter 20 (20A) satisfy a desired standard. It may be realized.

  In each of the above-described embodiments, for the propagation loss of the transmission wave and the reception wave between the radio altimeter 20 (20A) and the ground surface, for example, the delay circuit 14 or a circuit in place of the delay circuit 14 is connected to the control unit 18. It may be simulated by operating under control, and may not be simulated if such propagation loss is not the subject of performance and function testing and evaluation based on scenarios.

  Further, in each of the above-described embodiments, the present invention is not limited to the test and evaluation of the function and performance of the radio altimeter 20 (20A) alone, but the upper system configured to include the radio altimeter 20 (20A). The present invention can be similarly applied to a “system test” that realizes the correctness determination of the behavior.

  Further, in each of the above-described embodiments, the delay circuit 14 may be arranged either in the preceding stage of the down converter 12 or between the stages of the down converter 12 and the up converter 13, or between these preceding stages and the stages. It may be distributed in all or part of the subsequent stage of the up-converter 13.

  Furthermore, the present invention is not limited to the radio altimeter 20 (20A) described above, but can be similarly applied to a berthing distance meter or a range finder configured as an FMCW rangefinder.

  Further, the present invention is not limited to the above-described embodiments, and various configurations of the embodiments are possible within the scope of the present invention, and any improvements may be made to all or some of the components.

  Hereinafter, among the inventions disclosed in the present application, the inventions excluded from the description of “Claims” are listed in a format according to the descriptions in the “Claims” and “Means for Solving the Problems” column. To do.

[Claim 6] In the ranging environment simulation device according to any one of claims 1 to 5,
The frequency shift simulating means is
The distance measurement environment simulation device, wherein the frequency conversion is performed in a frequency band lower than an occupied band of the transmission wave.
In the ranging environment simulation device having such a configuration, in the ranging environment simulation device according to any one of claims 1 to 5, the frequency shift simulation unit has a frequency lower than an occupied band of the transmission wave. The frequency conversion is performed in a band.
That is, since the frequency band where the frequency conversion is performed is set low, the Doppler shift accompanying the received wave is simulated even if the Doppler frequency is very small or a value significantly smaller than the frequency of the transmitted wave. Done accurately.
Therefore, it is possible to flexibly adapt to the form of the propagation path characteristics of the transmission wave and the reception wave, the distribution, shape, and size of the target that reflects the transmission wave, and the distance to be measured by the distance measuring device. .

DESCRIPTION OF SYMBOLS 11 Transmission coupler 12 Down converter 13 Up converter 14 Delay circuit 15 Reception coupler 16 Oscillator 16FD Frequency divider 17, 17A Doppler generation part 18 Control part 19, 19A Inspection judgment part 20, 20A Radio altimeter 30 Platform 41 Acceleration sensor

Claims (5)

A Doppler shift calculating means for calculating a Doppler frequency incidental to a received wave arriving at an FMCW ranging device;
In synchronization with the transmission wave transmitted by the distance measuring apparatus, the transmission wave is subjected to frequency conversion that simulates the Doppler shift of the Doppler frequency, and the result of the frequency conversion is given to the distance measuring apparatus as the received wave. A distance measurement environment simulation apparatus comprising: a frequency shift simulation means. A Doppler shift calculating means for calculating a Doppler frequency incidental to a received wave arriving at an FMCW ranging device;
Synchronously with the transmission wave transmitted by the distance measuring device, a Doppler shift of the Doppler frequency and a frequency difference between the received wave and the transmission wave corresponding to the distance to be measured by the distance measuring device. A ranging environment simulating apparatus, comprising: frequency shift simulating means for performing frequency conversion to be simulated on the transmission wave, and applying the result of the frequency conversion to the ranging apparatus as the received wave. In the ranging environment simulation device according to claim 1 or 2,
The frequency shift simulating means is
A ranging environment simulating apparatus characterized in that a delay corresponding to the sum of required propagation times of the transmission wave and the reception wave is given to the reception wave in synchronization with the transmission wave. In the ranging environment simulation device according to claim 1 or 2,
The frequency shift simulating means is
A ranging environment simulation device characterized in that a delay that can be simulated based on a predetermined scenario of propagation times of the transmission wave and the reception wave is given to the reception wave. The ranging environment simulation device according to any one of claims 1 to 4,
The frequency shift simulating means is
The distance measurement environment simulation device characterized by performing the frequency conversion in a form in which the Doppler shift is not reflected in response to a request given from the outside.