Vehicle-mounted microwave radar target echo signal simulation system and method

Abstract

The invention discloses a vehicle-mounted microwave radar target echo signal simulation system and method, and the system comprises a radar signal processing module, a target echo modeling module and an echo signal synthesis module which are sequentially used for carrying out the sampling and frequency conversion processing of a detection signal transmitted by a radar, and outputting an I / Q data stream of the detection signal; the target echo modeling module is used for generating target echo characteristics according to target parameters issued by the upper computer and comprises a high-resolution programmable delay line, and the high-resolution programmable delay line is used for controlling the time delay precision of target echo signals; and synthesizing a target echo signal according to the I / Q data stream and the target echo characteristics. The time delay control precision of the system provided by the invention is relatively high.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of microwave radar simulation test, and particularly relates to a vehicle-mounted microwave radar target echo signal simulation system and method. BACKGROUND

[0002] A radar target simulator is a key tool for verifying the performance of a vehicle-mounted radar and can effectively replace road tests which are high in cost, high in risk and low in efficiency. Traditional simulators are mainly divided into two categories, one being an open-loop pre-stored simulator and the other being a general millimeter wave / laser radar simulator. Although both of the simulators can realize certain target simulation functions, the traditional simulators still have significant deficiencies in the application to vehicle-mounted microwave radars (such as 24 GHz or 77 GHz FMCW radars).

[0003] Specifically, the open-loop pre-stored simulator directly plays back the echo signal pre-recorded or generated during testing. Such a system cannot perceive the dynamic changes (such as frequency modulation slope drift, chirp start time jitter, bandwidth adjustment, etc.) of the actual radar transmission signal, resulting in a mismatch between the echo and the local reference signal of the radar, causing distance / speed calculation errors and serious distortion of the test results.

[0004] The general millimeter wave / laser radar simulator has a certain real-time performance, but is not optimized for the typical working scenarios and performance boundaries of vehicle-mounted microwave radars, mainly showing insufficient time delay control accuracy. The time delay resolution of a typical general millimeter wave / laser radar simulator is >10 ns, but the typical detection range of a vehicle-mounted radar is 10-200 meters, and the corresponding two-way propagation time delay is only 66.7 ns to 1.33 μs. If the time delay error reaches 10 ns, an equivalent distance error of ±1.5 meters will be introduced, which cannot meet the test requirements of 2 ns / ±0.3 m accuracy for near-range safety functions such as automatic emergency braking (AEB). SUMMARY

[0005] The vehicle-mounted microwave radar target echo signal simulation system and method provided by the embodiments of the application can solve the problem of insufficient time delay control accuracy of the traditional simulators.

[0006] In a first aspect, the vehicle-mounted microwave radar target echo signal simulation system provided by the embodiments of the application comprises: A radar signal processing module, which is configured to sample and frequency convert a detection signal transmitted by a radar, and output an I / Q data stream of the detection signal. a target echo modeling module, configured to generate a target echo feature according to a target parameter issued by a host computer, wherein the target echo modeling module comprises a high-resolution programmable delay line configured to control time delay precision of a target echo signal; an echo signal synthesis module, configured to synthesize the target echo signal according to the I / Q data stream and the target echo feature; Outputs of the radar signal processing module and the target echo modeling module are connected to first and second inputs of the echo signal synthesis module respectively.

[0007] In a second aspect, an embodiment of the present application provides a vehicle-mounted microwave radar target echo signal simulation method, which can be applied to the system provided in the first aspect, and the method comprises the following steps: sampling and frequency conversion processing of a detection signal of the radar to obtain an I / Q data stream of the detection signal; generating a target echo feature according to a target parameter issued by a host computer; storing the I / Q data stream according to the target echo feature, and synthesizing a target echo signal according to the target echo feature and the I / Q data stream.

[0008] Compared with the prior art, the embodiment of the present application has the beneficial effects that: the embodiment of the present application can dynamically capture the instantaneous changes of the actual transmission signal of the radar, such as the frequency modulation slope drift and chirp start time jitter, by performing real-time sampling and frequency conversion processing on the detection signal transmitted by the radar to output an I / Q data stream; thus, the changes of the target echo signal and the radar detection signal are kept synchronous, and the calculation error caused by signal mismatch can be avoided; the high-resolution programmable delay line in the target echo modeling module can finely adjust the signal time delay, and significantly reduce the time delay control error; by combining high-precision time delay control and real-time signal processing, a target echo highly matched with the radar detection signal can be generated, so that the double-path propagation time delay in the typical detection range of the vehicle-mounted radar can be accurately simulated; therefore, the embodiment of the present application can meet the strict requirements of automatic emergency braking and other near-range safety functions on test accuracy, and provide a reliable and real radar test environment. BRIEF DESCRIPTION OF DRAWINGS

[0009] Figure 1 a structural schematic diagram of a vehicle-mounted microwave radar target echo signal simulation system provided by the embodiment of the present application; Figure 2 a specific structural schematic diagram of a vehicle-mounted microwave radar target echo signal simulation system provided by the embodiment of the present application; Figure 3 a flowchart of implementation of a vehicle-mounted microwave radar target echo signal simulation method provided by the embodiment of the present application. DETAILED DESCRIPTION

[0010] In the following description, for purposes of explanation and not limitation, specific details are set forth such as particular architectures, techniques, etc. in order to provide a thorough understanding of the embodiments of the present application. However, it will be apparent to those skilled in the art that the present application can be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known methods, devices, circuits, and

[0011] It will be understood that the terms "comprises" and / or "comprising," when used in this specification, include the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0012] It is also to be understood that the term "and / or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items, and that the term "at least one of' denotes one, or a plurality of, or any combination of the listed items.

[0013] As used in the description of the application and the appended claims, the term "if' can be interpreted to mean "when" or "upon" or "in response to determining" or "in response to detecting," depending on the context. Similarly, the phrase "if it is determined" or "if [a described condition or event] is detected" can be interpreted to mean "upon determining" or "in response to determining" or "upon detecting [the described condition or event]" or "in response to detecting [the described condition or event]," depending on the context.

[0014] In addition, the terms "first," "second," "third," etc. are used herein only to describe different instances of elements, and are not intended to imply or suggest relative importance of the elements so designated.

[0015] The phrases "one embodiment," "some embodiments," "an embodiment," "another embodiment," "at least one embodiment," "at least one other embodiment," "another embodiment," "at least one other embodiment," "some other embodiments," and the like as used herein do not necessarily refer to the same embodiment(s), though they can. The use of the terms "at least one" followed by a list of one or more items (for example, "at least one of: A, B, and C") is intended to convey the inclusion of any one of the listed items, as well as any combination of two or more of the listed items. The use of the term "set" is intended to convey a collection of one or more items.

[0016] The application will be described in further detail below with reference to the embodiments. The embodiments of the application are not limited thereto.

[0017] Embodiment 1 Figure 1 Fig. 1 shows a schematic diagram of a vehicle-mounted microwave radar target echo signal simulation system according to an embodiment of the application. As an example but not limitation, the system includes a radar signal processing module 110, a target echo modeling module 120, and an echo signal synthesis module 130.

[0018] In some embodiments, the radar signal processing module 110 can sample and frequency-convert the probe signal transmitted by the radar, and output an I / Q data stream of the probe signal. The target echo modeling module 120 can generate target echo characteristics according to target parameters issued by the host computer. The echo signal synthesis module 130 can synthesize target echo signals according to the I / Q data stream and the target echo characteristics.

[0019] Specifically, the output ends of the radar signal processing module 110 and the target echo modeling module 120 can be connected to the first and second input ends of the echo signal synthesis module 130, respectively. The three modules can be implemented through an embedded platform based on a high-performance RFSoC.

[0020] For example, the target echo modeling module 120 can include a high-resolution programmable delay line, and the time delay accuracy of the target echo signal is controlled through the high-resolution programmable delay line.

[0021] In a possible implementation, the target parameters can include the distance, radial velocity, radar cross section (RCS) (unit: dBsm), and azimuth angle of the target. Accordingly, the target echo characteristics can at least include the distance delay amount, Doppler shift amount, and amplitude attenuation amount of the target echo signal.

[0022] For example, the distance of the target can be in the range of [10, 200] meters, and the radial velocity of the target can be in the range of [-150, +150] km / h.

[0023] Optionally, if the radar also provides beam pointing information, the target echo characteristics can further include an azimuth angle correction amount.

[0024] Specifically, the system and the host computer can interact through a gigabit Ethernet. The user can set target parameters or issue test instructions through a human-computer interaction interface.

[0025] In addition, the user can also configure the radar working mode, start / stop simulation tasks, and read system status and logs through the host computer.

[0026] ​​In one example, the distance delay amount and the Doppler shift amount of the target echo signal can be calculated by the following formulas respectively: (1) (2) wherein, is the distance delay amount (i.e. the two-way propagation delay), is the Doppler shift amount, , is the speed of light and the wavelength respectively.

[0027] In one example, the target echo modeling module 120 can calculate the amplitude that the target echo signal should have according to the radar equation and the RCS value , and then determine the amplitude attenuation amount through the echo amplitude .

[0028] The present application can dynamically capture the instantaneous changes of the actual radar transmitting signal, such as the frequency modulation slope drift and chirp start time jitter, by real-time sampling and frequency conversion processing of the radar transmitted probe signal, and output I / Q data stream; thereby ensuring that the target echo signal and the changes of the radar probe signal remain synchronized, and the calculation error caused by signal mismatch can be avoided; through the high-resolution programmable delay line in the target echo modeling module, the signal time delay can be finely adjusted, and the time delay control error can be significantly reduced. By combining high-precision time delay control and real-time signal processing, a target echo highly matched with the radar probe signal can be generated, thereby accurately simulating the two-way propagation delay within the typical detection range of the vehicle-mounted radar. Therefore, the present application can meet the strict requirements of automatic emergency braking and other near-range safety functions on test accuracy, and provide a reliable and real radar test environment.

[0029] Embodiment 2 Figure 2 The specific structure schematic diagram of a vehicle-mounted microwave radar target echo signal simulation system provided by the embodiment of the present application is shown.

[0030] In some embodiments, the system can further include a first radio frequency interface 140 and a second radio frequency interface 150, the first radio frequency interface 140 can capture the probe signal of the radar, and the second radio frequency interface 150 can transmit the target echo signal.

[0031] For example, the output end of the first radio frequency interface 140 can be connected with the input end of the radar signal processing module 110, and the input end of the second radio frequency interface 150 can be connected with the output end of the echo signal synthesis module 130.

[0032] In one possible implementation, referring to Figure 2The radar signal processing module 110 can include an analog-to-digital converter 111, a digital down converter 112.

[0033] In one example, the analog-to-digital converter 111 can sample the probe signal to obtain a radio frequency / intermediate frequency signal. The digital down converter 112 can down-convert the radio frequency / intermediate frequency signal to zero intermediate frequency I / Q baseband to obtain an I / Q data stream. The digital down converter 112 can also provide accurate time stamps for the I / Q data stream for subsequent echo timing alignment.

[0034] In one example, the analog-to-digital converter 111 can be a high-speed analog-to-digital converter.

[0035] In one possible implementation, the target echo modeling module 120 can calculate the range delay and the Doppler shift respectively by using the above formulas (1) and (2).

[0036] In one example, the target echo modeling module 120 can be implemented by using a multi-core ARM.

[0037] In one possible implementation, the echo signal synthesis module 130 can include a cascaded FPGA chip 131, a signal delay buffer 132, a digital up converter 133, and a digital-to-analog converter 134.

[0038] In one example, the FPGA chip 131 can delay the I / Q data stream according to the range delay, and multiply the delayed signal with the Doppler modulation signal and the amplitude attenuation to obtain a baseband I / Q signal of the target. In addition, the FPGA chip 131 can also superimpose a plurality of baseband I / Q signals of the target in the digital domain to obtain a baseband signal.

[0039] In one example, the FPGA chip 131 can write the I / Q data stream into the signal delay buffer 132, and the specific storage location can be determined by the range delay. The I / Q data stream can be read for delay processing after waiting for a certain time.

[0040] Specifically, the FPGA chip 131 is provided with a high-resolution programmable delay line, which can achieve a time delay control accuracy of 2 ns.

[0041] In one example, the Doppler modulation signal can be generated by a numerically controlled oscillator (NCO), which can be a complex exponential modulation signal .

[0042] In one example, the FPGA chip 131 can multiply the delayed signal with the amplitude attenuation by using a digital multiplier, thereby achieving gain control. ​

[0043] Optionally, if the target echo feature includes an azimuth angle correction amount, the FPGA chip can also weight the amplitude of the baseband I / Q signal according to the antenna pattern based on the azimuth angle correction amount.

[0044] Optionally, the FPGA chip 131 can also superimpose noise on the baseband signal to simulate a more realistic echo signal.

[0045] In one example, the signal delay buffer 132 can be implemented based on Ultra Random Access Memory (UltraRAM) or high-speed First In First Out (FIFO) memory, used to implement a microsecond programmable delay line, supporting near target (<10 m) simulation.

[0046] In one example, the digital upconverter 133 can upconvert the baseband signal to an intermediate frequency to obtain a radio frequency signal.

[0047] In one example, the digital-to-analog converter 134 can perform analog-to-digital conversion on the radio frequency signal to obtain a target echo signal.

[0048] For example, the target echo signal can be returned to the radar under test through the second radio frequency interface 150, forming a closed-loop test.

[0049] In some embodiments, the system can also include a clock and storage module 160, which can be composed of a high-stability crystal oscillator 161, a phase-locked loop 162, a storage firmware 163, and a double data rate memory 164.

[0050] In one example, the high-stability crystal oscillator 161 and the phase-locked loop 162 can provide a synchronous clock to the system, ensuring the consistency of the delay control of each module and device.

[0051] For example, the high-stability crystal oscillator 161 can be a 10 MHz high-stability crystal oscillator.

[0052] In one example, the storage firmware 163 can store default scenario parameters, and the double data rate memory 164 can store raw sampling data of the radar.

[0053] The application can dynamically capture the instantaneous changes of the actual radar transmitting signal, such as the frequency modulation slope drift and chirp start time jitter, by real-time sampling and frequency conversion processing of the radar transmitting signal, and outputting the I / Q data stream, so as to ensure that the changes of the target echo signal and the radar detecting signal are kept synchronous, and the calculation error caused by signal mismatch can be avoided, and the high-resolution programmable delay line in the target echo modeling module can finely adjust the signal time delay, and significantly reduce the time delay control error. By combining high-precision time delay control and real-time signal processing, the target echo highly matched with the radar detecting signal can be generated, so that the double-path propagation time delay can be accurately simulated in the typical detection range of the vehicle-mounted radar. Therefore, the application can meet the strict requirements of the automatic emergency braking and other near-range safety functions on the test accuracy, and provide a reliable and real radar test environment.

[0054] Embodiment 3 Figure 3 An implementation flowchart of a vehicle-mounted microwave radar target echo signal simulation method provided by an embodiment of the application is shown. The method can be applied to the system provided by the above-mentioned embodiments 1 / 2. The method can include steps S301-S304, which are described below.

[0055] S301, sampling and frequency conversion processing of the radar detecting signal are performed to obtain the I / Q data stream of the detecting signal.

[0056] For example, the system captures the chirp signal (i.e. the detecting signal) of the radar through the first radio frequency interface 140, and then the analog-to-digital converter 111 samples and the digital down converter 112 performs down conversion processing to output the I / Q data stream and time stamp.

[0057] S302, the target echo feature is generated according to the target parameters issued by the host computer.

[0058] S303, the I / Q data stream is stored according to the target echo feature.

[0059] For example, the FPGA chip 131 can store the I / Q data stream into the signal delay buffer 132 according to the distance delay, and read out the I / Q data stream at the delay expiration time.

[0060] S304, the target echo signal is synthesized according to the target echo feature and the I / Q data stream.

[0061] For example, the FPGA chip 131 can apply Doppler shift and amplitude attenuation to the delayed signal. Finally, the baseband I / Q signals of multiple targets are superimposed to obtain the baseband signal. At the expiration time of the double-path propagation time delay, the digital up converter-digital-to-analog converter link is triggered to output the target echo signal.

[0062] For the typical detection range of 10-200 meters (corresponding to two-way delay of 66.7 ns-1.33 us) of the vehicle, the application can realize a time delay control precision of 2 ns level through the high-resolution programmable delay line arranged internally, and the equivalent distance resolution is better than ±0.3 meters, which can accurately reproduce the near-range obstacle scenarios required by AEB (such as 10 m stationary vehicle, 5 m sudden cut-in target).

[0063] In addition, by completing the modeling and generation of the echo signal in the programmable logic or hard core of the lower computer (i.e., the system) instead of relying on the host computer to participate in real-time calculation, the end-to-end processing delay (the delay of the application is less than 500 microseconds) can be reduced, meeting the stringent test requirements of AEB, ACC and other ADAS functions on millisecond-level response. By using the phase-continuous complex exponential modulation signal integrated in the digital upconverter or independent NCO, the resolution of Doppler shift can be improved to ≤10 Hz, realizing accurate simulation of low-speed dynamic targets such as 1 m / s crossing pedestrians (about 52 Hz at 77 GHz), and avoiding the phase jump or spectral distortion introduced by the traditional lookup table method. Through the parallel architecture based on FPGA, the system can simultaneously and independently model more than 8 dynamic targets, each target can be individually set with distance, speed, RCS and azimuth angle, and the complex traffic scene (such as multi-vehicle cut-in, pedestrian crossing, and coexistence of stationary obstacles) can be truly restored. Using the standard radar signal processing architecture of digital downconversion + upconversion, the target echo signal can be generated in deep cooperation with the high-speed analog / digital converters in the RFSoC chip, which can avoid the noise and distortion introduced by external analog devices, and ensure that the echo signal spectrum is pure, and the time-frequency characteristics are consistent with the real physical target. The host computer only undertakes parameter configuration and state monitoring functions, and does not intervene in the key data stream, which can not only simplify the system architecture, but also improve the reliability and robustness of long-time HIL test.

[0064] In the above embodiments, the description of each embodiment has its own focus, and the parts not described or recorded in a certain embodiment can be referred to the related description of other embodiments.

Claims

1. A vehicle-mounted microwave radar target echo signal simulation system, characterized in that, include: A radar signal processing module is used to sample and frequency-convert the detection signal emitted by the radar, and output the I / Q data stream of the detection signal. A target echo modeling module is used to generate target echo features based on target parameters sent by a host computer. The target echo modeling module includes a high-resolution programmable delay line, which is used to control the time delay accuracy of the target echo signal. An echo signal synthesis module is used to synthesize the target echo signal based on the I / Q data stream and the target echo characteristics. The output terminals of the radar signal processing module and the target echo modeling module are respectively connected to the first and second input terminals of the echo signal synthesis module.

2. The system according to claim 1, characterized in that, The radar signal processing module includes an analog-to-digital converter and a digital down-converter. The analog-to-digital converter is used to sample the detection signal to obtain an RF / IF signal; The digital downconverter is used to downconvert the radio frequency / intermediate frequency signal to zero intermediate frequency to obtain the I / Q data stream; The digital downconverter is also used to provide timestamps for the I / Q data stream.

3. The system according to claim 1, characterized in that, The target echo characteristics include at least: distance delay, Doppler frequency shift, and amplitude attenuation.

4. The system according to claim 3, characterized in that, The echo signal synthesis module includes a cascaded FPGA chip, a signal delay buffer, a digital up-converter, and a digital-to-analog converter; The FPGA chip is used to delay the I / Q data stream according to the distance delay amount, and multiply the delayed signal by the Doppler modulation signal and the amplitude attenuation amount to obtain the target baseband I / Q signal. The Doppler modulation signal is determined according to the Doppler frequency shift amount. The FPGA chip includes the high-resolution programmable delay line. The signal delay buffer is used to store the I / Q data stream; The FPGA chip is also used to superimpose baseband I / Q signals of multiple targets in the digital domain to obtain a baseband signal; The digital upconverter is used to upconvert the baseband signal to an intermediate frequency to obtain a radio frequency signal; The digital-to-analog converter is used to perform analog-to-digital conversion on the radio frequency signal to obtain the target echo signal.

5. The system according to claim 4, characterized in that, The target echo characteristics also include: azimuth correction.

6. The system according to claim 5, characterized in that, The FPGA chip is also used to weight the amplitude of the baseband I / Q signal according to the antenna pattern based on the azimuth correction amount.

7. The system according to claim 1, characterized in that, The system also includes a first radio frequency interface and a second radio frequency interface; The first radio frequency interface is used to capture the detection signal, and the second radio frequency interface is used to transmit the target echo signal; The output of the first radio frequency interface is connected to the input of the radar signal processing module, and the input of the second radio frequency interface is connected to the output of the echo signal synthesis module.

8. The system according to claim 1, characterized in that, The system also includes a clock and storage module, which includes a high-stability crystal oscillator, a phase-locked loop, storage firmware, and a double data rate memory. The high-stability crystal oscillator and phase-locked loop are used to provide a synchronous clock for the system; The storage firmware is used to store default scenario parameters; The double data rate memory is used to store the radar's raw sampling data.

9. The system according to claim 8, characterized in that, The high-resolution programmable delay line is implemented based on a cache.

10. A method for simulating target echo signals from a vehicle-mounted microwave radar, characterized in that, The method is applied to the system as described in claims 1-9, and the method includes: The radar detection signal is sampled and frequency-converted to obtain the I / Q data stream of the detection signal; Generate target echo characteristics based on target parameters sent by the host computer; The I / Q data stream is stored according to the target echo characteristics, and the target echo signal is synthesized according to the target echo characteristics and the I / Q data stream.

Images