Radar device

Abstract

A radar device (1) according to the present disclosure comprises a plurality of transmission antennas (2), a plurality of reception antennas (3), and a signal processor (9) that performs arithmetic processing on reception signals received by each of the plurality of reception antennas (3), wherein the signal processor (9) is provided with: a signal analyzing unit (93) that calculates the distance or relative speed of an object from amplitude peaks obtained by analyzing the reception signals; and a modulation scheme setting unit (91) that sets switching between a first modulation scheme and a second modulation scheme in a time series for each of the plurality of transmission antennas (2).

Description

radar equipment

[0001] The present disclosure relates to a radar device.

[0002] In recent years, MIMO (Multiple-Input Multiple-Output) radars that use multiple transmitting antennas and multiple receiving antennas have become increasingly common. A key technology is to handle multiple transmission signals from multiple transmitting antennas without affecting a desired transmission signal with other transmission signals. One such technology involves applying discrimination modulation to each transmission signal in the time domain (see, for example, Patent Document 1).

[0003] Special Publication No. 2023-527226 (Paragraphs 0114-0118)

[0004] However, this modulation poses a problem in that it places limitations on the speed measurement performance, which is one of the radar's functions.

[0005] The present disclosure is intended to solve the above-mentioned problems, and has an object to provide a radar device that can identify a desired transmission signal without restricting velocity measurement performance.

[0006] The radar device disclosed herein includes a plurality of transmitting antennas, a plurality of receiving antennas that receive, as received signals, waves that are transmitted from the plurality of transmitting antennas and reflected by an object, and a signal processor that performs arithmetic processing on the received signals received by the plurality of receiving antennas, wherein the signal processor is characterized by including a signal analysis unit that calculates the distance or relative velocity of the object from amplitude peaks obtained by analyzing the received signals, and a modulation method setting unit that sets time-series switching for each of the plurality of transmitting antennas between a first modulation method in which the phase changes regularly at regular intervals and a second modulation method in which the phase changes irregularly at regular intervals.

[0007] According to the radar device of the present disclosure, by selectively using two types of modulation methods, it is possible to provide a radar device that can identify a desired transmission signal without restricting velocity measurement performance.

[0008] 1 is a block diagram showing the configuration of a signal processor of a radar device according to a first embodiment. FIG. 2 is a block diagram showing the configuration of a radar device according to a first embodiment. FIG. 3 is a schematic diagram showing time-series changes in the frequency of a transmission signal according to an FCM system. FIG. 4A and FIG. 4B are diagrams showing examples of chirp signals for each transmitting antenna in the DDMA modulation system, each shown in waveform diagram format, and a diagram showing the frequency analysis result of a received reflected wave as a relationship of amplitude with respect to relative velocity. FIG. 5A and FIG. 5B are diagrams showing examples of chirp signals for each transmitting antenna in the CDMA modulation system, each shown in waveform diagram format, and a diagram showing the frequency analysis result of a received reflected wave as a relationship of amplitude with respect to relative velocity. FIG. 6 is a flowchart for explaining the operation of signal processing in the radar device according to the first embodiment. FIG. 7 is a diagram showing the results of frequency analysis using FFT of a DDMA modulation signal in the radar device according to the first embodiment. FIG. 8 is a diagram showing an example in which the results of frequency analysis of a CDMA modulation signal in the radar device according to the first embodiment are used to select peaks in frequency analysis of a DDMA modulation signal. 1 is a schematic diagram showing a time series change in the modulation scheme of each of a plurality of transmitting antennas in the radar device according to the first embodiment; FIG. 2 is a block diagram showing a hardware configuration of a part that executes arithmetic processing in the radar device according to the first embodiment;

[0009] There are many types of radar using high frequencies, such as FM-CW (Frequency Modulated Continuous Wave) type, FCM (Fast Chirp Modulation) type, and pulse Doppler type. However, the technology disclosed herein is a technology that suppresses restrictions on velocity measurement due to modulation for identification, and is therefore applicable to any of these types. However, the following description will be given using the FCM type as an example.

[0010] 1 to 9 are diagrams illustrating the configuration and operation of a radar device according to a first embodiment, in which Fig. 1 is a block diagram showing the configuration of a signal processor of the radar device, Fig. 2 is a block diagram showing the configuration of the radar device, and Fig. 3 is a schematic diagram showing the time series variation of the frequency of a transmission signal according to the FCM method.

[0011] Fig. 4A is a waveform diagram showing an example of a chirp signal in a transmission signal radiated from each transmitting antenna in a DDMA modulation system, and Fig. 4B is a diagram showing the relationship between amplitude and relative velocity, showing the result of frequency analysis when the transmission signal radiated in the form shown in Fig. 4A is received as a wave reflected from an object. Similarly, Fig. 5A is a waveform diagram showing an example of a chirp signal in a transmission signal radiated from each transmitting antenna in a CDMA modulation system, and Fig. 5B is a diagram showing the relationship between amplitude and relative velocity, showing the result of frequency analysis when the transmission signal radiated in the form shown in Fig. 5A is received as a wave reflected from an object. Furthermore, Fig. 6 is a flowchart for explaining the signal processing operation in the radar device.

[0012] FIG. 7 is a diagram showing an image of a range-Doppler map of distance and relative velocity obtained by frequency analysis using FFT of a DDMA modulation signal, and the relationship between the relative velocity and amplitude obtained from that image; FIG. 8 is a diagram showing an image of a range-Doppler map of distance and relative velocity obtained by frequency analysis using FFT of a CDMA modulation signal, and the relationship between the relative velocity and amplitude obtained from that image; and FIG. 9 is a diagram showing an example in which the results of frequency analysis of a CDMA modulation signal are used to select peaks in frequency analysis of a DDMA modulation signal.

[0013] FIG. 10 is a schematic diagram showing an example of time-series switching of modulation schemes for a plurality of transmitting antennas by a modulation scheme setting unit, and how processing operations from situation analysis to scheme setting are performed periodically.

[0014] As shown in Fig. 2 , the radar device 1 according to the first embodiment includes a plurality of transmitting antennas 2 that radiate transmission signals toward an object and a plurality of receiving antennas 3 that receive waves reflected by the object. For simplicity, Fig. 2 illustrates a radar device including four transmitting antennas 2 and four receiving antennas 3, but this is not limiting. Furthermore, the plurality of antennas is not limited to a radar device including multiple physical antennas, but may also be virtual antennas in which one physical antenna functions as two or more antennas spaced apart. In the present disclosure, the term "multiple antennas" includes not only the transmitting antennas 2 but also the receiving antennas 3, and also includes such virtual antennas.

[0015] The radar device 1 also includes a signal processor 9 that outputs a signal for generating a transmission signal to be radiated from the transmitting antenna 2, and analyzes a signal received by the receiving antenna 3 to output information such as the position and relative velocity of a target object (target object information). The transmitting antenna 2 is further equipped with a control voltage generator 6 that emits a voltage waveform of a limiting voltage in response to a modulation start command output from the signal processor 9, and an oscillator 5 that outputs a transmission signal that has been frequency-modulated in response to the voltage waveform output from the control voltage generator 6. The radar device 1 also includes a distributor 4 that distributes the transmission signal output from the oscillator 5 to phase shifters 10 corresponding to each of the multiple transmitting antennas 2 and mixers 7 corresponding to each of the multiple receiving antennas 3.

[0016] On the other hand, the receiving antenna 3 side is provided with the above-mentioned mixers 7, which correspond to each of the multiple receiving antennas 3 and generate beat signals by superimposing the transmission signals received from the distributor 4 on the reception signals from the corresponding receiving antennas 3. The receiving antenna 3 side is also provided with A / D converters 8, which convert the analog beat signals output from each mixer 7 into digital signals and output the converted digital signals to a signal processor 9.

[0017] As a result, in response to the modulation start command output from the signal processor 9, the control voltage generator 6 generates a voltage waveform of the desired control voltage, and the oscillator 5 outputs a transmission signal that has been frequency modulated in accordance with the control voltage. The transmission signal is distributed via the distributor 4 to the multiple transmission antennas 2, and the transmission signal, to which a phase has been added by the phase shifter 10, is radiated toward the object.

[0018] The radiated transmission signal is reflected by an object and the reflected waves are received as reception signals by each of the four receiving antennas 3. A mixer 7 provided corresponding to each of the four receiving antennas 3 mixes the reception signals received by each of the four receiving antennas 3 with the transmission signal distributed by the distributor 4, thereby obtaining reception signals for four channels. The beat signals for four channels mixed by each of the four mixers 7 are converted into digital data by an A / D converter 8 provided for each of the four receiving antennas 3. The digital data for a total of four channels converted by the A / D converter 8 is input to a signal processor 9.

[0019] In the signal processor 9, the digital data for four channels input as shown in Figure 1 is subjected to frequency analysis by the signal analyzer 93. From the amplitude peaks of the complex spectrum (hereinafter referred to as amplitude peaks), which are the 16 frequency analysis results after decoding, the distance to the reflection point of the received signal, i.e., the distance and relative velocity of the object, are calculated. Furthermore, using the complex amplitude of the amplitude peaks, the direction of arrival of the amplitude peak, i.e., the angle of the object, is calculated and output as target object information.

[0020] Up to this point, the configuration and operation based on that configuration are the same as those of conventional radar devices. Next, the characteristic configuration and operation of the radar device 1 of the present disclosure will be described. In the radar device 1 of the present disclosure, the signal processor 9 is provided with a modulation method setting unit 91 that sets time-series switching of the method (modulation method) for applying identification modulation to the transmission signal.

[0021] As will be described later, regarding the phase assignment method, the same modulation method is assigned to each transmitting antenna 2 within one period, but the modulation method is switched depending on the period. Therefore, the transmission wave radiated from each transmitting antenna 2 via the control voltage generator 6, oscillator 5, distributor 4, and phase shifter 10 is radiated using a modulation method based on the settings of the modulation method setting unit 91.

[0022] There is also provided a situation analysis unit 94 (details to be described later) that analyzes the situation based on at least one of information obtained from the outside (external information) and the analysis results by the signal analysis unit, and a pattern database 92 (denoted as pattern DB in the figure) that holds combination data of switching patterns along a time series of modulation methods according to the situation.

[0023] Therefore, a transmission signal to which phase rotation has been applied by the phase shifter 10 in accordance with the modulation method set by the modulation method setting unit 91 is output to each of the multiple transmission antennas 2. At the same time, information on the set modulation method is also output to the signal analysis unit 93. In other words, the frequency analysis in the signal analysis unit 93 is performed using an analysis method corresponding to the modulation method set by the modulation method setting unit 91.

[0024] The reason for adopting this configuration will be explained. As shown in FIG. 3, the frequency of the transmitted signal transmitted by the FCM system changes over time. When the DDMA (Doppler Division Multiple Access) system is used as the modulation system, a regular phase rotation such as 0, 90, 180, or 270 degrees is added to each chirp transmitted from transmitting antenna 2 (referred to as transmitting antennas #1 to #4 in the figure to distinguish between the four antennas), as shown in FIG. 4A. In this case, as shown in FIG. 4B, the receiver's internal noise Nz and the peak are separated, but a signal-induced false spectrum (false peak Pf) occurs at the velocity frequency corresponding to the amount of phase rotation. This makes it impossible to determine the true peak Pt (true relative velocity).

[0025] On the other hand, when using Code Division Multiple Access (CDMA) modulation, as shown in Figure 5A, a binary phase rotation, such as 0° or 180°, is added to each chirp transmitted from transmitting antennas #1 to #4, so that the phase arrangements are considered to be different for each transmitting antenna. In this case, as shown in Figure 5B, no peaks other than the true peak Pt appear, but a signal-induced noise floor Fn occurs at all speed frequencies. As a result, the base Bs, which is the sum of the internal noise Nz and the noise floor Fn, becomes high, making it difficult to extract peaks with amplitudes smaller than the base Bs. This makes it difficult to separate targets with different reflection intensities (amplitude levels), such as vehicles and pedestrians.

[0026] 4A is an example of adding a fixed value (basic phase) as an example of applying regular phase rotation, but the present invention is not limited to this. For example, as shown below, a phase change may be used in which the amount of addition is gradually increased in addition to a basic phase for each of the multiple transmitting antennas 2.

[0027] Transmitting antenna #1: 0, 0, 0, 0, ... (basic phase change + 0) Transmitting antenna #2: 0, 90.1, 180.4, 270.9, ... (basic phase change + 0.1n 2 ) Transmitting antenna #3: 0, 180.2, 0.8, 181.8, ... (basic phase change + 0.2n 2 ) Transmitting antenna #4: 0, 270.3, 181.2, 92.7, ... (basic phase change + 0.3n 2 ) where n is an integer that increases by one for each chirp.

[0028] Furthermore, in this disclosure, DDMA modulation is used as an example of applying regular phase rotation, and CDMA modulation is used as an example of applying irregular phase rotation, and switching between these two modulation methods has been described as an example, but this is not limiting. For example, in the category known as phase modulation, a combination with other modulation methods that apply regular phase rotation, including methods other than DDMA modulation, and other modulation methods that apply irregular phase rotation, including methods other than CDMA modulation, may be used. Furthermore, similar phase modulation may be applied to radar methods other than FCM.

[0029] Therefore, in the radar device 1 of the present disclosure, the modulation method is set based on two modulation methods, a pattern determined based on at least one of the external situation and the signal analysis result, or a predetermined pattern. The operation of the radar device 1 will be described with reference to the flowchart in Figure 6, which shows the repeated operation for each period. Note that although the radar device 1 can be applied to a wide range of applications, for ease of understanding, the case where it is used as an on-vehicle radar will be described.

[0030] First, the situation analysis unit 94 acquires the speed of the vehicle as external information. Then, for example, if the vehicle is traveling at a low speed lower than a first threshold, the situation is analyzed to determine that there is a high possibility that a vehicle with high reflection intensity and a pedestrian with low reflection intensity are mixed in front of the vehicle (step S100), and a pattern is selected in which the DDMA modulation method is used continuously for, for example, a certain number of cycles (step S110).

[0031] Alternatively, if the vehicle is traveling at a high speed higher than a second threshold value that is higher than the first threshold value, the situation is analyzed to determine that it is necessary to more accurately detect objects at a long distance (step S100).The modulation method setting unit 91, having received the analysis result, selects a pattern that uses the CDMA modulation method continuously for, for example, a certain number of periods from the data stored in the pattern database 92 (step S110).

[0032] In the above example, steps S100 to S110 show an example in which, when it is determined that a certain situation will continue for a certain period as a result of analyzing external information, a modulation method is switched or a pattern of continuous use is selected for a certain period. However, the present invention is not limited to this. For example, it is also possible to determine which modulation method to select for each period.

[0033] The modulation method setting unit 91 then sets a modulation method according to the selected method or a method based on the pattern and outputs it to the phase shifter 10 (step S120), and at the same time outputs information about the set modulation method to the signal analysis unit 93. Then, a transmission signal is radiated from the transmitting antenna 2 using the set modulation method via the control voltage generator 6 and the oscillator 5. The radiated transmission signal is reflected by an object and the reflected wave is received by the receiving antenna 3 (step S130), and digital signals for four channels are input to the signal processor 9.

[0034] In the signal processor 9, the signal analyzer 93 analyzes the digital signal in accordance with the settings output from the modulation scheme setting unit 91 (step S140). When the DDMA modulation scheme is used, a range-Doppler map of distance and relative velocity as shown in the upper part of Figure 7 can be obtained by performing FFT (Fast Fourier Transform) analysis in the order of distance FFT → decoding → velocity FFT. Then, from the singular portion extracted from the obtained map, object information such as the relative velocity or distance of the object can be calculated as shown in the lower part.

[0035] Alternatively, when the CDMA modulation method is used, by performing FFT (Fast Fourier Transform) analysis in the order of distance FFT → decoding → velocity FFT, it is possible to obtain a range-Doppler map of distance and relative velocity as shown in the upper part of Figure 8. Then, from the singular parts in the obtained map, it is possible to calculate object information such as the relative velocity or distance of the object, as shown in the lower part.

[0036] Then, after outputting the calculated object information (step S150), the process moves to the next cycle, and the operations from step S100 to step S150 are repeated. Here, if the modulation method for this cycle was specified by a pattern set in the previous cycle, the specified content is judged to be a "situation," and a modulation method is set in accordance with that pattern. On the other hand, if there is no specification by pattern, or if it is determined that the specification should be canceled even if there is a specification, a new modulation method can be set according to the situation.

[0037] For example, the position and speed information of the target object can be obtained from the analysis results, and the modulation method for the next period can be selected based on this information. For example, if the analysis results of signals obtained by transmission and reception using the CDMA modulation method indicate that there has been an increase in the number of short-range detections, it is determined that detection of multiple objects with different reflection intensities is necessary, and the CDMA modulation method is selected for the next period. If this is not the case, priority is given to correctly detecting objects with strong reflection intensities, and the CDMA modulation method is selected for the next period as well.

[0038] Alternatively, if a pattern in which the DDMA modulation method is continuously used is selected for low-speed driving, but multiple peaks are obtained as described above and it is difficult to determine which one is the true peak Pt, the modulation method is switched to the CDMA modulation method. Then, the difference between the relative speed (frequency) of the peak that is equal to or greater than a predetermined value in the analysis results using the CDMA modulation method shown in the upper part of Figure 9 and the relative speed (frequency) of the peak that is equal to or greater than a predetermined value in the analysis results using the DDMA modulation method shown in the lower part obtained previously is calculated. Then, the peak with the smallest calculated difference in relative speed is determined as the true peak Pt. In other words, in addition to switching the method, the position information (analysis result) of the true peak Pt obtained using the CDMA modulation method is used to select and determine the position information (analysis) of the true peak Pt obtained using the DDMA modulation method.

[0039] This makes it possible to obtain accurate target object information by taking advantage of the advantages of each of the two methods. Note that the time series changes in modulation method according to the pattern are not limited to those listed above. For example, a pattern that switches the method sequentially every period, as shown below, is also effective.

[0040] If the transmission and reception of radio waves is considered one cycle, then the modulation method is switched for each cycle, for example, DDMA modulation is used in odd-numbered cycles and CDMA modulation is used in even-numbered cycles, as shown in Figure 10. In this case, analysis results using both methods are obtained, so even if the time resolution is halved, the benefits of both methods can be obtained, and accurate target object information can be obtained regardless of the situation.

[0041] Even in this case, the situation is analyzed for each period and the method is set according to the analysis results (steps S100 to S120). However, unless it is determined that the situation requires a setting other than that specified by the pattern as described above, the modulation method is switched for each period according to the pattern.

[0042] The modulation method switching period is not limited to one period, but may be every several periods, or may be irregular. Here, if the period using the DDMA modulation method is represented as "D" and the period using the CDMA modulation method is represented as "C," the pattern of sequential switching every period shown in FIG. 10 would be "DCDCCDC...," and if every two periods it would be "DDCCCDCDCDC...." Alternatively, for example, the number of times one modulation method is used may be set to be different from the number of times the other modulation method is used, such as "DDCCCDCDC...," or an irregular pattern may be repeated, such as "DDCCCDCDC...." In an extreme example, it may even be set to switch randomly.

[0043] 11, the signal processor 9 can be realized by hardware 900 including an arithmetic processing device (processor 901) such as a CPU (Central Processing Unit), a storage device 902 that exchanges data with the processor 901, etc. The processor 901 may be an application specific integrated circuit (ASIC), an integrated circuit (IC), a digital signal processor (DSP), a field programmable gate array (FPGA), various signal processing circuits, etc.

[0044] The storage device 902 includes volatile storage devices such as RAM (Random Access Memory) configured to allow data to be read from and written to the processor 901, and ROM (Read Only Memory) configured to allow data to be read from the processor 901, and non-volatile auxiliary storage devices such as flash memory. Also, instead of flash memory, a hard disk auxiliary storage device may be provided.

[0045] The signal analysis unit 93, modulation method setting unit 91, situation analysis unit 94, etc. are realized by, for example, executing a program stored in the storage device 902 by the processor 901. In this case, the program is input from the auxiliary storage device to the processor 901 via the volatile storage device. Furthermore, the processor 901 may output data such as calculation results to the volatile storage device of the storage device 902, or may store the data in the auxiliary storage device via the volatile storage device.

[0046] Although exemplary embodiments are described in the present disclosure, the various features, aspects, and functions described in the embodiments are not limited to the application of a particular embodiment, but may be applied to the embodiments alone or in various combinations. Therefore, countless variations not illustrated are anticipated within the scope of the technology disclosed in this specification. For example, variations in, addition to, or omission of at least one component are included.

[0047] Although the external information has been exemplified by information on physical quantities measured at the target where the radar device 1 is installed, such as vehicle speed, the external information is not limited to this. For example, it may be determined that there are many cars on a highway but no pedestrians based on information on the area where the car is located from an in-vehicle navigation system. Furthermore, the user may be allowed to select a pattern via an operation panel inside the vehicle, and the selected pattern may be used as the external information.

[0048] In addition, although the present disclosure has shown an example in which a pattern is changed depending on the situation, the present disclosure is not limited to this. Two modulation methods may be used in a preset switching pattern. For example, the situation analysis unit 94 in Fig. 1 may be eliminated, and "analyze the situation" in step S100 in Fig. 6 may be replaced with "read the switching pattern." Furthermore, although the example has been shown in which the modulation method setting unit 91, the situation analysis unit 94, etc. are provided within the signal processor 9, they may also be provided in a section different from the signal processor 9.

[0049] As described above, the radar device 1 of the present disclosure includes a plurality of transmitting antennas 2, a plurality of receiving antennas 3 that receive, as received signals, waves reflected by an object from transmission waves radiated from each of the plurality of transmitting antennas 2, and a signal processor 9 that performs arithmetic processing on the received signals received by each of the plurality of receiving antennas 3. The signal processor 9 includes a signal analyzer 93 that calculates the distance or relative velocity of an object from amplitude peaks obtained by analyzing the received signals, and a modulation method setting unit 91 that sets time-series switching for each of the plurality of transmitting antennas 2 between a first modulation method (e.g., DDMA modulation) in which the phase changes regularly at regular intervals and a second modulation method (e.g., CDMA modulation) in which the phase changes irregularly at regular intervals. In other words, by selectively using a plurality of modulation methods, it is possible to identify a desired transmission signal without restricting velocity measurement performance.

[0050] A situation analysis unit 94 is provided to analyze the situation based on either the analysis results by the signal analysis unit 93 or information obtained from outside, and the modulation method setting unit 91 performs setting in accordance with the analysis results of the situation analysis unit 94, thereby enabling more reliable identification by allocating or switching the optimal modulation method depending on the situation.

[0051] In this case, a database (pattern database 92) is provided that holds combination data of the types of switching along a time series and the analysis contents of the situation analysis unit 94, and the modulation method setting unit 91 compares the analysis contents by the situation analysis unit 94 with the combination data to make settings, thereby enabling settings that are more suited to the situation.

[0052] If the modulation scheme setting unit 91 assigns the same modulation scheme to the plurality of transmitting antennas 2, it is possible to prevent the signal analysis from becoming complicated.

[0053] When the modulation scheme setting unit 91 assigns a CDMA modulation scheme to each of the multiple transmitting antennas 2, if the modulation scheme setting unit 91 sets the multiple transmitting antennas 2 so that their phases are orthogonal to each other, interference can be suppressed and more accurate decoding can be achieved.

[0054] By using the DDMA modulation method as the first modulation method and the CDMA modulation method as the second modulation method, the advantages of both methods can be utilized, and the desired transmission signal can be reliably identified without restricting velocity measurement performance.

[0055] If the modulation method setting unit 91 is configured to switch between a first modulation method (e.g., DDMA modulation method) and a second modulation method (CDMA modulation method) for each of the multiple transmitting antennas 2 at each period, it is possible to take advantage of the advantages of both methods and obtain accurate target object information.

[0056] If the signal analysis unit 93 analyzes the received signal using frequency analysis, accurate analysis becomes possible.

[0057] The signal analysis unit 93 extracts the true peak position from the multiple peak position information obtained by analyzing the signal obtained when the received signal is transmitted and received using a first modulation method (e.g., DDMA modulation method) from the peak position information obtained by analyzing the signal obtained when the received signal is transmitted and received using a second modulation method (e.g., CDMA modulation method).This makes it possible to select the true peak Pt from among multiple peaks including a false peak Pf.

[0058] 1: Radar device, 10: Phase shifter, 2: Transmitting antenna, 3: Receiving antenna, 4: Distributor, 5: Oscillator, 6: Control voltage generator, 7: Mixer, 8: A / D converter, 9: Signal processor, 91: Modulation method setting unit, 92: Pattern database, 93: Signal analysis unit, 94: Situation analysis unit, Pf: False peak, Pt: True peak.

Claims

1. A radar device comprising: a plurality of transmitting antennas; a plurality of receiving antennas that receive, as received signals, reflected waves of transmitted waves radiated from each of the plurality of transmitting antennas and reflected by an object; and a signal processor that performs arithmetic processing on the received signals received by each of the plurality of receiving antennas, wherein the signal processor is provided with: a signal analysis unit that calculates the distance or relative velocity of the object from amplitude peaks obtained by analyzing the received signals; and a modulation method setting unit that sets switching along a time series for each of the plurality of transmitting antennas between a first modulation method in which the phase changes regularly at regular intervals and a second modulation method in which the phase changes irregularly at regular intervals.

2. The radar device according to claim 1, further comprising a situation analysis unit that analyzes a situation based on either an analysis result by the signal analysis unit or information obtained from the outside, wherein the modulation method setting unit performs the setting according to the analysis content of the situation analysis unit.

3. The radar device according to claim 2, further comprising a database that holds combination data of the types of switching along the time series and the analysis content of the situation analysis unit, wherein the modulation method setting unit performs the setting by comparing the analysis content by the situation analysis unit with the combination data.

4. The radar device according to any one of claims 1 to 3, wherein the DDMA modulation method is used as the first modulation method and the CDMA modulation method is used as the second modulation method.

5. The radar device according to any one of claims 1 to 4, wherein the modulation method setting unit performs the setting so that the first modulation method and the second modulation method are switched for each of the plurality of transmitting antennas at each period.

6. The radar device according to any one of claims 1 to 5, wherein the signal analysis unit analyzes the received signals using frequency analysis.

7. The radar device according to any one of claims 1 to 6, wherein the signal analysis unit extracts the true peak position from among peak position information obtained by analyzing signals obtained when transmitting and receiving using the second modulation method from among a plurality of peak position information obtained by analyzing signals obtained when transmitting and receiving using the first modulation method among the received signals.

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