Radar simulator and program

Abstract

In the present invention, a modulation setting file is prepared for each modulation pattern of a radar wave, and frequency information for each sampling point for executing calculation is stored for a unit period. A correspondence setting part (S220 to S240) associates any of the modulation setting files with each unit period. A calculation execution part (S250 to S310) reads the frequency information from the modulation setting file associated by the correspondence setting part and executes waveform calculation for the unit period.

Description

Radar simulator, program Cross-reference to related applications

[0001] This international application claims the benefit of Japanese Patent Application No. 2024-232726, filed with the Japan Patent Office on December 27, 2024, the entire disclosure of which is incorporated herein by reference.

[0002] This disclosure relates to a technique for calculating radar waveforms by simulation.

[0003] Patent Document 1 below describes a technique for simulating an in-vehicle radar using ray tracing.

[0004] U.S. Patent No. 2017 / 132335

[0005] However, as a result of the inventors' detailed examination, the following problems have been found in the prior art. That is, the prior art is a proposal regarding a method for calculating the propagation of rays, and only a basic sine wave is exemplified as the transmission signal, and other modulation methods are not mentioned. Therefore, every time the specifications such as the modulation method and frequency are changed, it is necessary to modify and add the input to the simulator and the software executed by the simulator.

[0006] One aspect of this disclosure provides a technique for easily coping with changes in modulation patterns in a radar simulator.

[0007] One embodiment of this disclosure is a radar simulator including a plurality of modulation setting files, a correspondence setting unit, and a calculation execution unit. The radar simulator calculates the signal waveform of the radar wave for each unit period. The modulation setting file is prepared for each modulation pattern of the radar wave, and frequency information for each sampling point for executing the calculation is stored for one unit period. The correspondence setting unit associates one of the modulation setting files for each unit period. The calculation execution unit is configured to read frequency information from the modulation setting file associated by the correspondence setting unit and execute waveform calculation for each unit period.

[0008] With this configuration, changes in the modulation pattern can be easily and flexibly handled simply by adding or modifying the modulation setting file, without changing the processing in the calculation execution unit.

[0009] One aspect of this disclosure is a program that causes a computer to function as a correspondence setting unit and a calculation execution unit. The correspondence setting unit associates multiple modulation setting files, each storing frequency information for a unit period for each sampling point on which a calculation is to be performed, with each unit period. The calculation execution unit is configured to read the frequency information from the modulation setting files associated by the correspondence setting unit and calculate the signal waveform of the radar wave for a unit period.

[0010] With such a program, changes in the modulation pattern can be easily and flexibly handled simply by adding or modifying the modulation configuration file, without changing the processing in the calculation execution unit.

[0011] This is a block diagram showing the configuration of the radar simulator. This is an explanatory diagram showing an overview of the radar simulation model. This is an explanatory diagram showing parameters related to frame settings. This is an explanatory diagram showing the modulation setting matrix group. This is an explanatory diagram showing the contents of the modulation setting matrix. This is an explanatory diagram showing an example of setting index setting information. This is a flowchart of the main processing performed by the calculation unit. This is a flowchart of the signal waveform calculation processing. This is an explanatory diagram showing the configuration of the modulation setting matrix used in the second embodiment. This is an explanatory diagram showing other examples of setting index setting information.

[0012] Embodiments of this disclosure will be described below with reference to the drawings.

[0013] [1. First Embodiment] [1-1. Configuration] The radar simulator 1 calculates information acquired by the vehicle-mounted radar through simulation.

[0014] In the radar simulator 1, as shown in Figure 2, a transmission model 100 that simulates the transmission section of an in-vehicle radar and a reception model 200 that simulates the reception section of an in-vehicle radar are used. The radar simulator 1 calculates the propagation characteristics between the transmission point and the reception point by ray tracing. Furthermore, the radar simulator 1 calculates the waveform of the beat signal based on the calculated propagation characteristics, the directivity of the antenna, and the modulation scheme used in the in-vehicle radar.

[0015] Transmitting model 100 includes, for example, a signal generator 101, a phase shifter 102, a transmitting amplifier 103, and a transmitting antenna 104. The signal generator 101 generates a modulated transmit signal. The phase shifter 102 changes the phase of the transmit signal generated by the signal generator 101. The transmitting amplifier 103 amplifies the transmit signal output from the phase shifter 102. The transmitting antenna 104 emits radio waves according to the transmit signal amplified by the transmitting amplifier 103. Receiving model 200 includes, for example, a receiving antenna 201, a mixer 202, a receiving amplifier 203, a filter 204, and an AD converter 205. The receiving antenna 201 receives radio waves and outputs a received signal. The mixer 202 generates a beat signal by mixing the received signal from the receiving antenna 201 with the transmit signal. The receiving amplifier 203 amplifies the beat signal generated by the mixer 202. The filter 204 removes unwanted components from the beat signal amplified by the receiving amplifier 203. The AD converter 205 converts the beat signal output from the filter 204 into a digital value.

[0016] Ray tracing assumes an omnidirectional transmitting antenna 104 and a receiving antenna 201. Rays that reach the receiving antenna 201 (i.e., the receiving point) are extracted from the many rays radiated from the transmitting antenna 104 (i.e., the transmitting point). Ray tracing also generates ray information for each of the extracted rays. Details of the ray information will be described later.

[0017] The radar simulator 1 may be provided in a vehicle equipped with an on-board radar, or in a cloud-based server capable of communicating with a vehicle equipped with an on-board radar, or in both the vehicle and the server.

[0018] As shown in Figure 1, the radar simulator 1 comprises a storage unit 2 and a calculation unit 3.

[0019] The memory unit 2 stores at least scenario information 21, asset information 22, ray tracing setting information (hereinafter referred to as ray tracing setting information) 23, directional information 24, modulation information 25, and index setting information 26.

[0020] Scenario information 21 is location information of a vehicle equipped with a vehicle-mounted radar (hereinafter referred to as "the vehicle") and targets, structures, etc., that exist around the vehicle, and is prepared at regular time intervals (hereinafter referred to as "scenario cycles").

[0021] Asset information 22 is information that shows the three-dimensional shape, material, etc. of the player's vehicle, target, and structures that appear in scenario information 21.

[0022] The ray tracing settings information 23 is various information necessary for ray tracing calculations, in addition to the scenario information 21 and asset information 22. The ray tracing settings information 23 may include, for example, the maximum number of reflections and the radar wave frequency setting value.

[0023] The directional information 24 includes the number of transmitting antennas, the number of receiving antennas, the amount of phase rotation added to the transmitting antennas, transmitting antenna information, receiving antenna information, etc. The transmitting antenna information shows the amplitude and phase for each direction in the range of horizontal angle -180° to +180° and vertical angle 0° to 180°, with respect to the transmitting point (i.e., transmitting antenna 104). The receiving antenna information shows the amplitude and phase for each direction in the range of horizontal angle -180° to +180° and vertical angle 0° to 180°, with respect to the receiving point (i.e., receiving antenna 201).

[0024] Modulation information 25 is information related to the modulation of the transmitted signal, that is, information that determines the waveform of the transmitted signal generated by the signal generator 101. Modulation information 25 includes the number of chirps, the number of sampling points per chirp, frequency information, the frequency characteristics of the filter or information equivalent to the frequency characteristics of the filter (e.g., coefficients of the transfer function), temperature, transmitted power, receiver gain, receiver NF characteristics, AD converter information, etc. AD converter information includes the sampling rate, resolution, input voltage range, and input resistance of the AD converter (i.e., the converter 205). Frequency information includes a modulation setting matrix which is information indicating the frequency for each sampling point.

[0025] As shown in Figure 3, in the radar simulator 1, the transmitted signal is a chirp-modulated transmitted signal whose frequency increases at a constant rate, and this transmission is repeated multiple times (hereinafter referred to as the number of chirps Nc) at a set interval (hereinafter referred to as the chirp period Tc). Each chirp has multiple (hereinafter referred to as the number of samples Ns) sampling points. Then, Nc chirps constitute one frame, and the radar simulator 1 performs a simulation for each frame.

[0026] In the following, c is the identifier that identifies a chirp within the same frame, and d is the identifier that identifies a sampling point within the same chirp. c = 1 to Nc, and d = 1 to Ns.

[0027] Let fst(c) be the starting frequency of the c-th chirp in a given frame, and let the step frequency Δf(c-1) be the difference between the starting frequency fst(c) of the c-th chirp and the starting frequency fst(1) of the first chirp. Let fs(c,d) be the frequency at the d-th sampling point in the c-th chirp, BW be the bandwidth set to the same value for each chirp within the same frame, and Tc(c) be the chirp period, which is the interval between the c-th chirp and the (c+1)-th chirp. Note that fs(c,1) = fst(c).

[0028] In other words, by appropriately changing the starting frequency fst, step frequency Δf, chirp period Tc, etc. (hereinafter referred to as frame settings) for each frame, various modulations can be expressed.

[0029] Frequency information may be set for multiple modulation setting matrices [a, b] (hereinafter also referred to as the modulation setting matrix group), as shown in Figure 4.

[0030] Identifier a is used to identify the Nsg frame settings provided. a = 1 to Nsg. Identifier b is used to identify the multiple (hereinafter, number of patterns Nf) change patterns used when changing the starting frequency fst(1) frame by frame. b = 1 to Nf. In other words, the modulation setting matrix group comprises Nsg × Nf modulation setting matrices [1,1] to [Nsg,Nf].

[0031] The modulation matrix [a, b] is a table listing the frequency fs(c, d) and chirp period Tc(c) calculated according to the frame settings specified by a and b.

[0032] As shown in Figure 5, the modulation setting matrix [a, b] stores the chirp periods Tc(1) to Tc(Nc-1) and the frequencies f(1,1) to f(Nc,Ns). Note that since there is no subsequent chirp for the Nc-th chirp, Tc(Nc) has no value.

[0033] In Figure 5, for clarity, Tc(c) and f(c,d) are denoted as such. However, since Tc(c) and f(c,d) can be set differently for each modulation setting matrix [a,b], they are essentially values ​​that are denoted as Tc(a,b,c) and f(a,b,c,d). Note that instead of frequencies f(1,1) to f(Nc,Ns), values ​​such as wavelengths λ(1,1) to λ(Nc,Ns) and wavenumbers k(1,1) to k(Nc,Ns), which can be calculated from frequencies f(1,1) to f(Nc,Ns), may be recorded in the modulation matrix [a,b]. The wavenumber k is a value that can be calculated from the reciprocal of the wavelength λ, and may be calculated as k = 1 / λ or k = 2π / λ.

[0034] The index setting information 26 is information used to select the modulation setting matrix [a, b]. If the correspondence between individual frames and frame settings is fixed, the pattern will be limited to one type. Therefore, by changing the index setting information 26 to arbitrarily change the correspondence between individual frames and frame settings, or by changing the starting frequency fst(1) in the frame settings in various patterns, the variations in frame settings for each unit frame are increased.

[0035] The index setting information 26 includes, for example, a hopping setting file FB and a stagger setting file FA, as shown in Figure 6. The hopping setting file FB lists one or more indices that specify the change pattern b of the starting frequency fst(1) for each frame. The stagger setting file FA lists one or more indices that specify the frame setting a to be associated with each frame.

[0036] As shown in Figure 1, the arithmetic unit 3 includes a microcomputer equipped with a CPU 31, ROM 32, RAM 33, etc. The various functions of the microcomputer are realized by the CPU 31 executing a program stored in a non-transitional physical recording medium. In this example, ROM 32 corresponds to the non-transitional physical recording medium that stores the program. Furthermore, the execution of this program executes a method corresponding to the program. Note that some or all of the functions executed by the CPU 31 may be configured in hardware by one or more ICs, etc. Also, the number of microcomputers constituting the arithmetic unit 3 may be one or more.

[0037] The ROM 32 stores the simulation program. The simulation program may be pre-installed on the radar simulator 1, or it may be installed via a recording medium or network. Examples of recording media include optical discs, magnetic discs, and semiconductor memory.

[0038] The calculation unit 3 includes a ray tracing unit (hereinafter referred to as the ray tracing unit) 41 and a waveform calculation unit 43 as functional blocks indicating functions realized by executing a simulation program.

[0039] The ray tracing unit 41 sets a plurality of rays that simulate radar waves radiated from a transmission point with slightly different radiation directions. The ray tracing unit 41 extracts the rays from the transmission point to the reception point by calculating the propagation paths of the rays based on the scenario information 21, the asset information 22, and the ray tracing setting information 23. For each of the extracted rays, the ray tracing unit 41 calculates ray information in which the propagation characteristics of the propagation path are reflected.

[0040] The ray information may include the transmission direction of the ray at the transmission point, the reception direction of the ray at the reception point, the wavelength of the signal, the propagation path length of the ray from the transmission point to the reception point, the propagation loss in the propagation path, the number of reflections in the propagation path, and Doppler information. Instead of the wavelength of the signal, the frequency may be used.

[0041] The propagation loss may be represented by the amplitude of the signal received at the reception point when a signal having an amplitude of unit intensity is transmitted from the transmission point. The Doppler information may be the relative speed between the host vehicle and the reflecting object in the propagation path, or the Doppler shift amount calculated from the relative speed and the wavelength.

[0042] The waveform calculation unit 43 acquires the ray information, which is the calculation result, from the ray tracing unit 41, and calculates the signal waveform of the beat signal based on the directivity information 24, the modulation information 25, and the index setting information 26 acquired from the storage unit 2. Specifically, the signal waveform of the beat signal is calculated by mixing, through calculation, the transmission signal calculated from the modulation information 25 and the reception signal calculated from the transmission signal, the ray information, and the directivity information 24.

[0043] [1-2. Processing]Next, the main processing executed by the calculation unit 3 will be described using the flowchart of FIG. 7.

[0044] [[ID=ID=18]]When the main processing is started, in S110, the calculation unit S110 reads the index setting information 26.

[0045] In S120, the arithmetic unit 3 reads the modulation information 25.

[0046] In S130, the arithmetic unit 3 reads the directional information 24.

[0047] In S140, the arithmetic unit 3 reads the scenario information 21.

[0048] In S150 to S180, the arithmetic unit 3 repeatedly executes the processing for each scenario cycle based on the read scenario information 21 while sequentially changing the processing for each scenario cycle from 1 to Ns in ns. That is, Ns scenarios are processed in time series.

[0049] In S160, the arithmetic unit 3 executes a ray tracing operation. This processing is for realizing the function as the ray tracing unit 41, and uses the asset information 22 and the ray tracing setting information 23 in addition to the scenario information 21 to generate a plurality of ray information.

[0050] In S170, the arithmetic unit 3 executes signal waveform calculation. This processing is for realizing the function as the waveform calculation unit 43.

[0051] In S180, if ns < Ns, the arithmetic unit 3 repeats the processing of S160 to S170, and if ns = Ns, it ends the processing for each scenario cycle and ends the main processing.

[0052] The signal waveform calculation processing executed by the arithmetic unit 3 in the previous S170 will be described using the flowchart of FIG. 8.

[0053] In S210, the arithmetic unit 3 acquires a plurality of ray information which is the result of the ray tracing operation.

[0054] In S220, the arithmetic unit 3 determines the change pattern b of the start frequency according to the hopping setting file FB included in the index setting information 26.

[0055] In S230, the calculation unit 3 determines the frame setting a to correspond to the ns-th frame according to the stagger setting file FA contained in the index setting information 26. For example, in the pattern illustrated in Figure 6, when ns=1, a=3; when ns=2, a=6; when ns=3, a=3; when ns=4, a=6; and so on, the indices 3 and 6 listed in the stagger setting file FA are set alternately as ns increases.

[0056] In S240, the calculation unit 3 obtains a modulation matrix [a, b] according to the change pattern b set in S220 and the frame setting a set in S230.

[0057] In S250 to S280, the calculation unit 3 repeatedly performs the processing for each chirp, sequentially changing the chirp number c from 1 to Nc.

[0058] In S260, the calculation unit 3 obtains the frequencies f(c,1) to f(c,Ns) and the chirp period Tc(c) from the modulation matrix [a,b] acquired in S240.

[0059] In S270, the arithmetic unit 3 uses the information acquired in S280 to calculate the signal waveform of the c-th chirp in the ns-th frame.

[0060] In S280, the calculation unit 3 repeats the processing in S260 to S270 if c < Nc, and terminates the processing for each chirp if c = Nc.

[0061] In steps S290 to S310, the calculation unit 3 uses the ray information acquired in S210, the directional information 24 acquired from the storage unit 2, and the chirp signal waveform calculated in steps S250 to S280 to generate a received signal and a beat signal for each of the multiple receiving antennas, and then terminates the process.

[0062] [1-3. Correspondence of Terms] In this embodiment, a frame corresponds to a unit period in this disclosure, and a modulation setting matrix corresponds to a modulation setting file in this disclosure. In this embodiment, the processing S220 to S240 executed by the calculation unit 3 corresponds to the correspondence setting unit in this disclosure, and the processing S250 to S310 executed by the calculation unit 3 corresponds to the calculation execution unit in this disclosure.

[0063] [1-4. Effects] The first embodiment described in detail above produces the following effects.

[0064] (1a) In the radar simulator 1, a modulation matrix [a, b] is selected for each frame according to the index setting information 26. The radar simulator 1 also reads the frequency f(c, d) and chirp period Tc(c) for each sampling point, which are information necessary for calculating the signal waveform, from the selected modulation matrix [a, b]. Therefore, according to the radar simulator 1, the frame setting a, which indicates the frequency modulation pattern, can be arbitrarily changed for each frame. Furthermore, changes to the modulation pattern can be easily and flexibly handled without changing the software processing, simply by rewriting the index setting information 26 or adding or changing the modulation matrix [a, b].

[0065] [2. Second Embodiment] [2-1. Differences from the First Embodiment] The second embodiment has the same basic configuration as the first embodiment, so the differences will be explained below. Note that the same reference numerals as in the first embodiment indicate the same components, and refer to the preceding description.

[0066] In the first embodiment described above, one modulation setting matrix [a, b] is associated with one frame setting. The second embodiment differs from the first embodiment in that multiple modulation setting matrices are associated with one frame setting.

[0067] [2-2. Background] The frequency fs(c,d) of the d-th sampling point of the c-th chirp is given by equation (1).

[0068] fs(c,d) = fst(c) + Δf(c-1) + d・Δfs (1) In equation (1), Δf(0) = 0. Also, Δfs is the change in frequency between adjacent sampling points, which is determined by the slope of the chirp, the bandwidth BW, and the number of samples Ns per chirp.

[0069] For example, if we consider a millimeter wave of 76.5 GHz, the first term fst(1) on the right-hand side of equation (1) will be an 11-digit value, while the second term Δf(c) and the third term d・Δfs on the right-hand side will be values ​​of about 3 to 4 digits. When values ​​with such large differences in the number of digits are substituted into float variables and calculations are performed, the values ​​of the second and third terms will be rounded down and not reflected because the significant digits of the float variables are only about 6 to 7 digits.

[0070] In calculating the signal waveform S(c,d), trigonometric functions are used as shown in equation (2).

[0071] (2) S(c,d) = cos(2π・f(c,d)・t) Here, by setting f(c,d) = α + β and using the addition formula, we obtain equation (3).

[0072] S(c,d) = cos(2π・(α+β)・t) = cos(2π・α・t)・cos(2π・β・t) - sin(2π・α・t)・sin(2π・β・t) (3) If α = fst(1) and β = Δf(c) + d・Δfs, then the calculation of the signal waveform including α+β can be performed using equation (3) without being affected by rounding.

[0073] [2-3. Modulation Setting Matrix] In the second embodiment, as shown in Figure 9, the contents of the modulation setting matrix [a, b] are stored separately in a higher matrix U[a, b] and a lower matrix L[a, b]. In Figure 9, the chirp period Tc(c) is omitted for clarity. The chirp period Tc(c) may be included in both U[a, b] and L[a, b], or in only one of them.

[0074] The upper matrix U[a,b] stores the large-digit value fu(c,d), and the lower matrix L[a,b] stores the small-digit value fl(c,d). Here, fu(c,d) = fst(1) and fl(c,d) = Δf(c) + (d-1)・Δfs.

[0075] When performing waveform calculations, use equation (3), where fu(c,d) obtained from U[a,b] is α and fl(c,d) obtained from L[a,b] is β.

[0076] [2-4. Correspondence of Terms] In this embodiment, the upper matrix U[a,b] corresponds to the upper file of this disclosure, and the lower matrix L[a,b] corresponds to the lower file of this disclosure.

[0077] [2-5. Effects] The second embodiment described in detail above provides the effects (1a) of the first embodiment described above, and further provides the following effects.

[0078] (2a) According to the radar simulator 1, fu(c,d) (i.e., the starting frequency fst(1)) and fl(c,d) (i.e., the frequency change Δf(c) + (d-1)Δfs), which is orders of magnitude smaller than fu(c,d), are managed by separate modulation setting matrices U[a,b] and L[a,b]. When calculating the signal waveform, a calculation formula is used that has been converted so that fu(c,d) and fl(c,d) are not directly added together, thereby suppressing the rounding of fl(c,d) during the calculation process.

[0079] [3. Other Embodiments] Although embodiments of the present disclosure have been described above, the present disclosure is not limited to the embodiments described above and can be implemented in various modified forms.

[0080] (3a) In the above embodiment, the index setting information 26 includes the hopping setting file FB and the stagger setting file FA, but either one may be omitted. In this case, the setting for the file that is omitted may be set to a fixed value.

[0081] (3b) In the above embodiment, there is only one type of file that lists the indices that identify the frame setting a (i.e., stagger setting file FA), but as shown in Figure 10, there may be multiple files that list the indices. In this case, each file may be associated with a different in-vehicle sensor.

[0082] (3c) In the above embodiment, each frame is associated with either the modulation setting matrix [a, b] using an index setting file, but the association may also be made using a mathematical formula.

[0083] For example, in the process of S220, an integer between 1 and Nf generated randomly using equation (4) may be used as an index to identify the change pattern b.

[0084] b = randx(Nf) (4) In addition, in the processing of S240, the values ​​1 to Nsg calculated sequentially using equation (5) may be used as an index to identify frame setting a.

[0085] a = mod(ns-1, Nsg) + 1 (5) Alternatively, in equation (5), instead of ns, the values ​​listed in the stagger setting file FA may be used in order.

[0086] (3d) The arithmetic unit 3 and its method described herein may be implemented by a dedicated computer provided by configuring a processor and memory programmed to perform one or more functions embodied by a computer program. Alternatively, the arithmetic unit 3 and its method described herein may be implemented by a dedicated computer provided by configuring a processor by one or more dedicated hardware logic circuits. Alternatively, the arithmetic unit 3 and its method described herein may be implemented by one or more dedicated computers configured by a combination of a processor and memory programmed to perform one or more functions and a processor configured by one or more hardware logic circuits. Furthermore, the computer program may be stored as instructions executed by the computer on a computer-readable non-transitional tangible recording medium. The method for implementing the functions of each part included in the arithmetic unit 3 does not necessarily have to include software, and all of its functions may be implemented using one or more hardware components.

[0087] (3e) Multiple functions of one component in the above embodiment may be realized by multiple components, or one function of one component may be realized by multiple components. Also, multiple functions of multiple components may be realized by one component, or one function realized by multiple components may be realized by one component. Furthermore, some of the configurations of the above embodiment may be omitted. Furthermore, at least some of the configurations of the above embodiment may be added to or replaced with the configurations of other above embodiments.

[0088] (3f) In addition to the radar simulator 1 described above, the present disclosure can also be realized in various forms, such as a system comprising the radar simulator 1, a program for causing the computer to function as the radar simulator 1, a non-transitional physical recording medium such as a semiconductor memory on which this program is recorded, and a frequency information storage method.

[0089] [4. Technical Concept Disclosed in This Specification] [Item 1] A radar simulator for calculating the signal waveform of a radar wave, comprising: a plurality of modulation setting files (25) prepared for each modulation pattern of the radar wave, each storing frequency information for a unit period for each sampling point on which the calculation is performed; a correspondence setting unit (3: S220 to S240) that associates one of the modulation setting files with each of the unit periods; and a calculation execution unit (3: S250 to S310) configured to read the frequency information from the modulation setting files associated by the correspondence setting unit and to perform waveform calculation for the unit period.

[0090] [Item 2] A radar simulator as described in Item 1, wherein the unit period includes a plurality of chirps, and the modulation setting file is configured to store two-dimensional frequency information identified by an index specifying the chirp and an index specifying the sampling point within the chirp.

[0091] [Item 3] A radar simulator according to Item 1 or Item 2, wherein the corresponding setting unit is configured to specify the modulation setting file using one or more indices.

[0092] [Item 4] A radar simulator as described in Item 3, wherein the corresponding setting unit is configured to select the modulation setting file using the index calculated using a predetermined calculation formula.

[0093] [Item 5] A radar simulator as described in Item 3, wherein the corresponding setting unit is configured to select the modulation setting file using an index setting file that lists the indices in the order in which they are used.

[0094] [Item 6] A radar simulator according to any one of items 3 to 5, wherein the corresponding setting unit is configured to randomly select the modulation setting file.

[0095] [Item 7] A radar simulator according to any one of items 3 to 5, wherein the corresponding setting unit is configured to select the modulation setting files in a specified order.

[0096] [Item 8] A radar simulator according to any one of Items 1 to 7, wherein the modulation setting file includes an upper file that stores the value of the upper digit of the frequency information and a lower file that stores the value of the lower digit of the frequency information having a size that is subject to rounding with respect to the value of the upper digit, and the calculation execution unit is configured to calculate a waveform without directly adding the value of the upper digit and the value of the lower digit using the addition theorem of trigonometric functions.

[0097] [Item 9] A program for causing a computer to function as: a correspondence setting unit (S220 to S240) that associates multiple modulation setting files, each prepared for each modulation pattern of a radar wave and storing frequency information for each sampling point for which calculations are performed, with each of the multiple said unit periods; and a calculation execution unit (S250 to S310) configured to read the frequency information from the modulation setting files associated by the correspondence setting unit and calculate the signal waveform of the radar wave.

Claims

1. A radar simulator for calculating the signal waveform of a radar wave, comprising: a plurality of modulation setting files (25) prepared for each modulation pattern of the radar wave, each storing frequency information for a unit period for each sampling point on which the calculation is performed; a correspondence setting unit (3: S220 to S240) that associates one of the modulation setting files with each of the unit periods; and a calculation execution unit (3: S250 to S310) configured to read the frequency information from the modulation setting files associated by the correspondence setting unit and to perform waveform calculation for the unit period.

2. A radar simulator according to claim 1, wherein the unit period includes a plurality of chirps, and the modulation setting file is configured to store two-dimensional frequency information identified by an index specifying the chirp and an index specifying a sampling point within the chirp.

3. A radar simulator according to claim 1, wherein the corresponding setting unit is configured to specify the modulation setting file using one or more indices.

4. A radar simulator according to claim 3, wherein the corresponding setting unit is configured to select the modulation setting file using the index calculated using a predetermined calculation formula.

5. A radar simulator according to claim 3, wherein the corresponding setting unit is configured to select the modulation setting file using an index setting file that lists the indices in the order in which they are used.

6. A radar simulator according to claim 3, wherein the corresponding setting unit is configured to randomly select the modulation setting file.

7. A radar simulator according to claim 3, wherein the corresponding setting unit is configured to select the modulation setting files in a specified order.

8. A radar simulator according to claim 1, wherein the modulation setting file includes an upper file that stores the value of the upper digit of the frequency information, and a lower file that stores the value of the lower digit of the frequency information having a size that is subject to rounding with respect to the value of the upper digit, and the calculation execution unit is configured to calculate a waveform without directly adding the value of the upper digit and the value of the lower digit using the addition theorem of trigonometric functions.

9. A program to cause a computer to function as: a correspondence setting unit (S220-S240) that associates multiple modulation setting files, each prepared for each modulation pattern of a radar wave and storing frequency information for each sampling point for which calculations are performed, with each of the multiple said unit periods; and a calculation execution unit (S250-S310) configured to read the frequency information from the modulation setting files associated by the correspondence setting unit and calculate the signal waveform of the radar wave.

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