WO2020107234A1 - Radar system and waveform generation method - Google Patents

Abstract

A radar system (500), comprising a grouping unit (501) which divides multi-transmitting antennas of the radar system (500) into multiple groups of transmitting antennas; and a control unit (502) which controls one transmitting antenna in each group of transmitting antennas to transmit a chirp signal. Chirp signals transmitted by a transmitting antenna i and a transmitting antenna i + 1 which transmit the chirp signals adjacent in time satisfy the following relationships: first, an initial frequency in which the transmitting antenna i + 1 transmits the chirp signal is: a difference value between a cut-off frequency in which the transmitting antenna i transmits the chirp signal plus the initial frequency in which the transmitting antenna i + 1 transmits the chirp signal and the cut-off frequency in which the transmitting antenna i transmits the chirp signal; second, the slopes of waveforms of the chirp signals transmitted by the transmitting antenna i +1 and the transmitting antenna i are the same. Hence, the chirp signal sent on the time T_reset is achieved.

Description

Radar system and waveform generation method Technical field

The invention relates to the field of antennas, in particular to a radar system and a waveform generation method.

Background technique

Vehicle-mounted millimeter-wave radar is an indispensable sensor in automatic driving and can be used to provide all-weather obstacle detection. The principle is that the radar sends a frequency modulated continuous wave (FMCW), and the distance, speed, azimuth and other information of the obstacle are obtained by measuring the reflected echo of the obstacle. The FMCW waveform has the function of bandwidth compression, that is, the transmitted signal is scanned through a large bandwidth through chirp, and the received signal and the transmitted signal are mixed to obtain the difference frequency, making the intermediate frequency bandwidth much lower than the transmitted signal bandwidth. The bandwidth of the IF signal is related to the slope of the chirp and the distance to the maximum target, Δf _max = slope*(2*max_range)/c, where Δf _max is the maximum difference frequency, subject to the bandwidth of the IF, and slope is linear continuous frequency modulation The slope of the wave B/T _ramp , that is, the bandwidth B scanned within the time T _ramp , max_range is the distance from the farthest detection target to the radar, and c is the speed of light. At present, the time T (usually 10 to 100 μs) occupied by a fast chirp signal sent by any antenna usually includes the time T _ramp from the linear sweep of the frequency f _start to the frequency f _end , and the T _reset time, Sometimes also includes a period of constant frequency T _dwell . T _reset represents the time required for the end frequency f _{end of the} transmitted signal to quickly return to the start frequency f _start . This time is because the FMCW waveform needs to be transmitted through a phase locked loop (PLL) to obtain a signal frequency with better linearity. The PLL needs a certain time to stabilize, usually within 10μs. The chirp signal can be sent using the rising ramp shown in FIG. 1 for measurement, or the chirp signal can be sent using the falling ramp shown in FIG. 2 for measurement. Corresponding to the way of ascending ramp, f _start <f _end , for descending ramp, f _start > f _end . Since the time for the PLL to stabilize is related to the bandwidth f _end -f _start , the working time of the device cannot be fully utilized, so the time during T _reset cannot be used for measurement.

In recent years, vehicle-mounted millimeter-wave radars have also been evolving. For example, the frequency band has gradually evolved from 24GHz to 77GHz/79GHz, and higher range resolution can be obtained through a larger scanning bandwidth. On the waveform, the chirp signal (chirp) scan period is a few ms level, reduced to dozens of μs level, so that the measurement distance and measurement speed are decoupled. This reduces the probability of false targets and effectively avoids non-ideal characteristics near DC. The number of channels has also evolved from a single-transmit multiple-receive (single input multiple output (SIMO)) mode to a multiple-transmit multiple-receive (multiple input multiple output (MIMO)) mode, and the antenna scale continues to expand, making virtual MIMO (Virtual MIMO) obtainable The aperture of the virtual antenna is enlarged, thereby improving the angular resolution.

At present, the virtual MIMO antenna transmission can use time division, frequency division, and code division. The time division method is the simplest, that is, the transmission antenna transmits chirp signals in sequence, and the signal processing is performed at the receiving end by receiving signals from different receiving channels. However, the time-divided MIMO radar signal is sent in a single ascending or descending ramp, and the time-division antennas transmit signals in sequence (as shown in Figure 3), that is, assuming there are 4 transmitting antennas, and the time for each antenna is T, then The period of 4 transmitting antennas is 4*T. Since there is T _reset time in the transmission of each antenna, a total of 4*T _reset time in 4*T will be wasted and cannot be used for measurement.

Summary of the invention

Embodiments of the present application provide a radar system and a waveform generation method, which can send a chirp signal at time T _reset , which can expand a scanning bandwidth or a speed measurement range.

In a first aspect, an embodiment of the present application provides a radar system, including a multi-transmitting antenna, and the radar system includes:

A grouping unit is used to divide the multiple transmitting antennas of the radar system into M groups of transmitting antennas; each group of the M groups of transmitting antennas includes K transmitting antennas; the M is an integer greater than 1, and the K is greater than An integer of 0;

A control unit, configured to control the M groups of transmitting antennas to transmit chirp signals;

Among them, the following relationship is met for the chirp signals transmitted by the transmitting antenna i and the transmitting antenna i+1 that belong to different groups and whose transmit chirp signals are temporally adjacent:

slope ⁱ⁺¹ = -slope ⁱ

Among them, the

Starting frequency of the chirp signal transmitted by the transmitting antenna i+1, the

Is the cut-off frequency of the chirp signal transmitted by the transmitting antenna i, and slope ⁱ⁺¹ and slope ⁱ are the slope of the waveform of the chirp signal transmitted by the transmitting antenna i+1 and the transmitting antenna i, respectively.

The difference between the start frequency of the chirp signal transmitted by the transmitting antenna i+1 and the cutoff frequency of the chirp signal transmitted by the transmitting antenna i. Multiple sets of transmit antennas send chirp signals alternately on ascending and descending ramps to completely eliminate the T _reset in the prior art. This process has two advantages. If the chirp signal continues to be transmitted during the T _reset time of the antenna, The scanning bandwidth can be expanded; if the transmitting antennas adjacent in time transmit the chirp signal at the T _reset time of this antenna, the time taken by each antenna to transmit the chirp signal can be reduced, and the speed measurement range can be expanded. among them

Can be any real number.

In a possible embodiment, the above

It can be a random real number with a small value, that is, a signal with a low frequency is randomly superimposed on the transmitted signal, which does not increase the burden of the intermediate frequency bandwidth and can play the role of interference randomization.

In a possible embodiment, the

or

Wherein, T _{g_dwell} is the difference between the start time of the chirp signal transmitted by the transmit antenna i+1 and the end time of the chirp signal transmitted by the transmit antenna i.

This method is relatively simple, with little change to the original transceiver structure. It's just the signal switching between antennas.

In a possible embodiment, when the K is greater than 1, and the K transmit antennas transmit J sub-chirp signals, for the antenna m and the antenna that belong to the same group and the transmit sub-chirp signals are temporally adjacent The sub-chirp signal transmitted by m+1 satisfies the following relationship:

slope ^m+1 = slope ^m

Among them, the

Is the starting frequency of the sub-chirp signal transmitted by the transmitting antenna m+1, the

The cutoff frequency of the sub-chirp signal transmitted by the transmitting antenna m; the slope ^m+1 and slope ^m are the slopes of the waveforms of the sub-chirp signals transmitted by the transmitting antenna m+1 and the transmitting antenna m, respectively;

Is the difference between the start frequency of the transmit signal of the transmit antenna m+1 and the cut-off frequency of the transmit chirp signal of the transmit antenna m, the

It is any real number; the J=A*K, and the K is a positive integer.

In a possible embodiment, the above

It can be a random real number with a smaller value, that is, a signal with a lower frequency is randomly superimposed on the transmitted signal. Without increasing the burden of the intermediate frequency bandwidth, it can play a role in randomizing interference.

In one embodiment, it is selected in a limited phase set

The parameter does not increase the burden of the intermediate frequency bandwidth and reduce the complexity of signal generation.

In a possible embodiment, the

or

Wherein, T _{s_dwell} is the difference between the start time of the transmit antenna m+1 sub-chirp signal and the end time of the transmit antenna m transmit sub-chirp signal.

In a possible embodiment, the M*K transmitting antennas each transmit a chirp signal once for one round, and the order of transmitting the chirp signals of the transmitting antennas between multiple rounds is the same or different.

In a possible embodiment, the above radar system further includes multiple receiving antennas, and the radar system further includes:

The above control unit is also used to control the multiple receiving antennas to receive the signal obtained by reflecting the chirp signal i from the detected object, the chirp signal i being the signal transmitted by the above transmitting antenna i;

A mixer, configured to mix the signals received by the multiple receiving antennas with the chirp signal i respectively to obtain difference frequency signals of multiple receiving channels;

Analog-to-digital converter, used to convert the difference frequency signals of the multiple receiving channels into digital signals of the multiple receiving channels;

The digital signal processor is used to perform distance Fourier transform on the digital signals of the multiple receiving channels to obtain Δf, which is the frequency domain representation of the above-mentioned difference frequency signal; according to the Δf, the target distance is obtained, and the target distance is The distance between the radar system and the detected object.

In a possible embodiment, in terms of acquiring the target distance according to the above Δf, the above digital signal processor is specifically used to:

When the slope of the waveform of the chirp signal i above slope ^{i is} greater than 0, according to the formula

Determine the above target distance; when the slope of the waveform of the chirp signal i slope ^{i is} less than 0, according to the formula

Determine the above target distance; where R is the target distance and c is the speed of light. Since the chirp signal continues to be transmitted during the T _reset time of the antenna, the frequency sweep bandwidth is expanded, thereby obtaining higher distance accuracy.

In a second aspect, an embodiment of the present application provides another radar system, including K transmitting antennas. The radar system includes:

A control unit for controlling the K transmitting antennas of the radar system to transmit the J-segment sub-chirp signal, where J=A*K, the K is an integer greater than 1, and the A is a positive integer;

Among them, the sub-chirp signals transmitted by the transmitting antenna j and the transmitting antenna j+1 of the K transmitting antennas that are temporally adjacent to each other satisfy the following relationship:

slope ^j+1 = slope ^j

Among them, the

Is the starting frequency of the sub-chirp signal transmitted by the transmitting antenna j+1, the

Is the cutoff frequency of the sub-chirp signal transmitted by the transmitting antenna j, and slope ^j+1 and slope ^j are the slopes of the waveforms of the sub-chirp signals transmitted by the transmitting antenna j+1 and the transmitting antenna j, respectively.

Is the difference between the start frequency of the sub-chirp signal transmitted by the transmitting antenna j+1 and the cut-off frequency of the sub-chirp signal transmitted by the transmitting antenna j,

Any real number. In this embodiment, the signals transmitted by multiple transmitting antennas are regarded as a virtual chirp signal, and the slope of each sub-chirp signal of the chirp signal is the same, so that the signal when using multiple antennas to measure the angle is as compact and different The interval time between the sub-chirp signals is the antenna switching time, which is ns level, which is much smaller than the μs level of T _reset and T _dwell , so that the transmission signal time of multiple transmitting antennas used for angle measurement is compressed and reduced as much as possible Effect of speed on angle measurement.

In a possible embodiment, the

or

Wherein, T′ _{s_dwell} is the difference between the start time of the sub-chirp signal transmitted by the transmit antenna j+1 and the end time of the sub-chirp signal transmitted by the transmit antenna j.

In a possible embodiment, each of the K transmit antennas transmits a sub-chirp signal once for one round, and the order of the transmit sub-chirp signals of the transmit antennas between multiple rounds is the same or different.

In a possible embodiment, the above radar system further includes multiple receiving antennas, and the radar system further includes:

The above control unit is also used for multiple receiving antennas to receive the signal obtained by reflecting the sub-chirp signal j of the detected object; the sub-chirp signal j is the signal transmitted by the above-mentioned transmitting antenna j;

The mixer is used to mix the signals received by the multiple receiving antennas with the sub-chirp signal j to obtain difference frequency signals of multiple receiving channels;

An analog-to-digital converter, used to convert the difference frequency signals of the multiple receiving channels into digital signals of the multiple receiving channels;

The digital signal processor is used to perform distance Fourier transform on the digital signals of the multiple receiving channels to obtain Δf, which is the frequency domain representation of the above-mentioned difference frequency signal; the target distance is obtained according to the Δf, and the target distance Is the distance between the radar system and the detected object.

In a possible embodiment, in terms of acquiring the target distance according to Δf, the digital signal processor is specifically used to:

When the waveform slope Slope ^j sub-chirp signal j is greater than 0, according to the formula

Determining a target distance; when the waveform slope slope sub-chirp signal j ^j is less than 0, according to the formula

Determine the target distance; where R is the target distance and c is the speed of light.

In a third aspect, an embodiment of the present application provides a waveform generation method. The method is applied to a radar system and includes:

Divide the multiple transmitting antennas of the radar system into M groups of transmitting antennas, each of the M groups of transmitting antennas includes K transmitting antennas; the M is an integer greater than 1, and the K is a positive integer;

Controlling the M group transmitting antennas to transmit chirp signals;

Among them, the following relationship is met for the chirp signals transmitted by the transmitting antenna i and the transmitting antenna i+1 that belong to different groups and whose transmit chirp signals are temporally adjacent:

slope ⁱ⁺¹ = slope ⁱ

Among them, the

Starting frequency of the chirp signal transmitted by the transmitting antenna i+1, the

Is the cut-off frequency of the chirp signal transmitted by the transmitting antenna i, and slope ⁱ⁺¹ and slope ⁱ are the slope of the waveform of the chirp signal transmitted by the transmitting antenna i+1 and the transmitting antenna i, respectively.

The difference between the start frequency of the chirp signal transmitted by the transmitting antenna i+1 and the cutoff frequency of the chirp signal transmitted by the transmitting antenna i. The offset ⁱ _g can be any real number.

In a possible embodiment, the

or

Wherein, T _{g_dwell} is the difference between the start time of the transmit signal of the transmit antenna i+1 and the end time of the transmit signal of the transmit antenna i.

In a possible embodiment, when the K is greater than 1, and the K transmit antennas transmit J sub-chirp signals, for the antenna m and the antenna that belong to the same group and the transmit sub-chirp signals are temporally adjacent The sub-chirp signal transmitted by m+1 satisfies the following relationship:

slope ^m+1 = slope ^m

Among them, the

Is the starting frequency of the sub-chirp signal transmitted by the transmitting antenna m+1, the

The cutoff frequency of the sub-chirp signal transmitted by the transmitting antenna m; the slope ^m+1 and slope ^m are the slopes of the waveforms of the sub-chirp signals transmitted by the transmitting antenna m+1 and the transmitting antenna m, respectively;

Is the difference between the start frequency of the transmit signal of the transmit antenna m+1 and the cut-off frequency of the transmit chirp signal of the transmit antenna m, as described above

It is any real number; the J=A*K, and the K is a positive integer.

In a possible embodiment, the

or

Wherein, T _{s_dwell} is the difference between the start time of the transmit antenna m+1 sub-chirp signal and the end time of the transmit antenna m transmit sub-chirp signal.

In a possible embodiment, the M*K transmitting antennas each transmit a chirp signal once for one round, and the order of transmitting the chirp signals of the transmitting antennas between multiple rounds is the same or different.

In a possible embodiment, the foregoing radar system further includes multiple receiving antennas, and the foregoing method further includes:

Controlling the multiple receiving antenna to receive a signal obtained by reflecting the chirp signal i of the detected object, the chirp signal i being the signal transmitted by the transmitting antenna i;

Mixing the signals received by the multiple receiving antennas with the chirp signal i respectively to obtain a plurality of receiving channel difference frequency signals;

Convert the difference frequency signals of the multiple receiving channels into digital signals of the multiple receiving channels;

Perform a distance Fourier transform on the digital signals of the multiple receiving channels to obtain Δf, which is the frequency domain representation of the difference frequency signal; obtain a target distance according to the Δf, which is the radar system and the above The distance between the detected objects.

In a possible embodiment, obtaining the target distance according to the above Δf includes:

When the slope of the waveform of the chirp signal i above slope ^{i is} greater than 0, according to the formula

Determine the above target distance; when the slope of the waveform of the chirp signal i slope ^{i is} less than 0, according to the formula

Determine the above target distance; where R is the target distance and c is the speed of light. Since the chirp signal continues to be transmitted during the T _reset time of the antenna, the frequency sweep bandwidth is expanded, thereby improving the accuracy of measuring the distance.

According to a fourth aspect, an embodiment of the present application provides a waveform generation method. The method is applied to a radar system. The radar system includes K transmitting antennas. The method includes:

K transmitting antennas that control the radar system transmit J-segment sub-chirp signals, the J=A*K, the K is an integer greater than 1, and the A is a positive integer;

Among them, the sub-chirp signals transmitted by the antenna j and the antenna j+1 that are adjacent to each other in time in the K transmit antennas satisfy the following relationship:

slope ^j+1 = slope ^j

Among them, the

Is the starting frequency of the antenna j+1 transmitted signal, the

Is the cutoff frequency of the signal transmitted by the antenna j, the slope ^j+1 and slope ^j are the slopes of the waveforms of the sub-chirp signals transmitted by the antenna j+1 and the antenna j, and the offset _′s is the antenna j +1 the difference between the start frequency of the transmitted signal and the cut-off frequency of the antenna j transmitted signal, the

Any real number.

In a possible embodiment, the

or

Wherein, T′ _{s_dwell} is the difference between the start time of the signal transmitted by the antenna j+1 and the end time of the signal transmitted by the antenna j.

In a possible embodiment, each of the K transmit antennas transmits a sub-chirp signal once for one round, and the order of the transmit sub-chirp signals of the transmit antennas between multiple rounds is the same or different.

In a possible embodiment, the foregoing radar system further includes multiple receiving antennas, and the foregoing method further includes:

Controlling the multiple receiving antenna to receive the signal obtained by reflecting the sub-chirp signal j of the detected object; the sub-chirp signal j is the signal transmitted by the transmitting antenna j;

Mixing the signals received by the multiple receiving antennas with the sub-chirp signal j to obtain difference frequency signals of multiple receiving channels;

Convert the difference frequency signals of the multiple receiving channels into digital signals of the multiple receiving channels;

Perform a distance Fourier transform on the digital signals of the multiple receiving channels to obtain Δf, which is the frequency domain representation of the above-mentioned difference frequency signal; obtain a target distance according to the Δf, which is the distance between the radar system and all Describe the distance between the detected objects.

In a possible embodiment, obtaining the target distance according to Δf includes:

When the waveform slope Slope ^j sub-chirp signal j is greater than 0, according to the formula

Determining a target distance; when the waveform slope slope sub-chirp signal j ^j is less than 0, according to the formula

Determine the target distance; where R is the target distance and c is the speed of light.

BRIEF DESCRIPTION

In order to more clearly explain the embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required in the embodiments or the description of the prior art.

Fig. 1 is a waveform diagram of a chirp signal measured using a rising slope;

Figure 2 is a waveform diagram of a chirp signal measured using a falling ramp;

Figure 3 is a schematic diagram of TDM MIMO radar transmission waveform;

Figure 4 is a schematic diagram of a traditional triangular wave;

5 is a schematic structural diagram of a radar system provided by an embodiment of the present application;

6 is a waveform diagram of a chirp signal provided by an embodiment of the present application;

7 is a waveform diagram of another chirp signal provided by an embodiment of the present application;

8 is a waveform diagram of another chirp signal provided by an embodiment of the present application;

9 is a waveform diagram of another chirp signal provided by an embodiment of the present application;

10 is a waveform diagram of another chirp signal provided by an embodiment of the present application;

11 is a waveform diagram of another chirp signal provided by an embodiment of the present application;

12 is a schematic structural diagram of another radar system provided by an embodiment of this application;

13 is a waveform diagram of another chirp signal provided by an embodiment of the present application;

14 is a waveform diagram of another chirp signal provided by an embodiment of the present application;

15 is a waveform diagram of another chirp signal provided by an embodiment of the present application;

16 is a waveform diagram of another chirp signal provided by an embodiment of the present application;

FIG. 17 is a schematic structural diagram of another radar system provided by an embodiment of the present application.

detailed description

In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be described clearly and completely in conjunction with the drawings in the embodiments of the present invention.

Referring to FIG. 5, an embodiment of the present application provides a schematic structural diagram of a radar system. The radar system includes multiple transmitting antennas. As shown in FIG. 5, the radar system 500 includes:

The grouping unit 501 is used to divide the multiple transmitting antennas of the radar system into M groups of transmitting antennas, each group of the M groups of transmitting antennas includes K transmitting antennas 503; M is an integer greater than 1, and K is an integer greater than 0;

The control unit 502 is used to control the M groups of transmitting antennas to transmit chirp signals;

Among them, the following relationship is met for the chirp signals transmitted by the transmitting antenna i and the transmitting antenna i+1 that belong to different groups and whose transmit chirp signals are temporally adjacent:

slope ⁱ⁺¹ = -slope ⁱ

Among them, the above

Is the starting frequency of the chirp signal transmitted by the above transmitting antenna i+1, the above

Is the cut-off frequency of the chirp signal transmitted by the transmit antenna i, and the slope ⁱ⁺¹ and slope ⁱ are the slope of the waveform of the chirp signal transmitted by the transmit antenna i+1 and the transmit antenna i, respectively.

Is the difference between the start frequency of the chirp signal transmitted by the transmitting antenna i+1 and the cut-off frequency of the chirp signal transmitted by the transmitting antenna i,

Any real number.

In a possible embodiment, the above

It can be a random real number with a small value, that is, a signal with a low frequency is randomly superimposed on the above-mentioned transmitted signal, which does not increase the burden of the intermediate frequency bandwidth and can play the role of interference randomization. At the frequency of the carrier frequency fc at 76-81GHz,

In the case of less than KHz order.

In actual systems, the PLL is usually used to generate the FMCW waveform, and the difference between the reference signal and the feedback signal is usually compared within the phase detector. To achieve frequency deviation

When the antenna is switched, the frequency of the control reference signal is increased on the basis of the frequency of the original reference signal

Optionally, the above

Can be 0 or slope ⁱ *T _{g_dwell} . Wherein, T _{g_dwell} is the difference between the start time of the chirp signal transmitted by the transmit antenna i+1 and the end time of the chirp signal transmitted by the transmit antenna i.

When the above K=1 and the above

At this time, the waveforms of the chirp signals transmitted by the above-mentioned transmitting antenna i and transmitting antenna i+1 refer to FIG. 6. As shown in FIG. 6, the solid line is the waveform of the signal transmitted by the antenna i, and the dashed line is the waveform of the signal transmitted by the antenna i+1. The dot-and-dash line between the solid line and the dotted line indicates the voltage controlled oscillator (VCO) The output frequency remains the same as the cut-off frequency of the above-mentioned transmitting antenna i

Consistent.

In actual systems, the PLL is usually used to generate the FMCW waveform. A counter is usually used to further process the output of the VCO and used as the input of the phase detector to form closed-loop feedback. When the antenna is switched, the counter continues to count, which can achieve slope ⁱ *T _{g_dwell} ; and the counter does not continue to count between antenna switching, then

In a possible embodiment, the foregoing radar system 500 further includes a multiple receiving antenna 504, and the foregoing radar system 500 further includes:

The above control unit 501 is also used to control the multiple receiving antenna 504 to receive the signal obtained by reflecting the chirp signal i from the detected object; the chirp signal i is the signal transmitted by the above transmitting antenna i;

The mixer 505 is configured to mix the signals received by the multiple receiving antennas with the chirp signal i to obtain a plurality of difference frequency signals of the receiving channels;

An analog-to-digital converter 506 is used to convert the difference frequency signals of the multiple receiving channels into digital signals of the multiple receiving channels;

The digital signal processor 507 is used to perform distance Fourier transform on the digital signals of the multiple receiving channels to obtain Δf, which is the frequency domain representation of the above-mentioned difference frequency signal; the target distance is obtained according to the Δf, and the target distance It is the distance between the radar system and the detected object.

Due to the improvement of the PLL's ability, the chirp signal scans hundreds of MHz or even 4GHz bandwidth in the time range of 10～100μs. Due to the Doppler effect, the frequency change introduced within a chirp signal period relative to the target distance can be ignored . Therefore, in a chirped signal, the target distance is obtained by analyzing the frequency of the signal in the intermediate frequency bandwidth. The commonly used algorithm is fast Fourier transform (fast Fourier transform, FFT), where FFT is also called distance-fast Fourier Leaf (range-FFT). The speed information of the target is obtained through the phase change between multiple chirped signals. The commonly used algorithm is FFT. The FFT here is also called Doppler-Fast Fourier (doppler-FFT).

Further, in terms of acquiring the target distance according to the difference frequency, the digital signal processor 506 is specifically used to:

When the slope of the waveform of the chirp signal i is greater than 0, according to the formula

Determine the above target distance; when the slope of the waveform of the above chirp signal i is less than 0, according to the formula

Determine the above target distance; where R is the target distance and c is the speed of light.

Specifically, assume that the radar system 500 described above includes S1 receiving antennas. After the chirp signal i is transmitted to the detected object, the S1 antenna receives the S1 signals obtained by reflecting the chirp signal i from the detected object, and the mixer 505 separates the S1 signals from the chirp signal i Mixing to obtain S1 receiving channel difference frequency signals; the above analog-to-digital converter 506 converts the S1 receiving channel difference frequency signals into S1 receiving channel digital signals; the above digital signal processor 507 receives The digital signal of the channel is subjected to distance Fourier transform to obtain Δf, which is the frequency representation of the above-mentioned frequency domain signal. When the slope of the waveform of the chirp signal i is greater than 0, the digital signal processor 507 according to the formula

Determine the above target distance; when the slope of the waveform of the chirp signal i is less than 0, the digital signal processor 507 can use the formula

Determine the above target distance.

Specifically, the acquisition of Δf has the following relationship with the configuration of the distance FFT: under the distance FFT configuration corresponding to N points, the overall frequency sweep range B is divided into N uniform grids by the N point distance FFT. The difference frequency value Δf of the specific N points and the corresponding target distance can be obtained according to the identification of N grids. In actual implementation, it is also possible to interpolate on the basis of the difference frequency value obtained from the distance FFT (interpolation methods include linear interpolation, quadratic interpolation, Newton interpolation, etc.) to obtain a more precise frequency representation. The invention does not limit the interpolation method to obtain the specific difference frequency value, or whether to use the interpolation method after the distance FFT.

In one embodiment, the solid line shown in FIG. 6 is the chirp signal waveform transmitted by the transmitting antenna i+1, and the dashed line is the chirp signal waveform transmitted by the transmitting antenna i. The cutoff frequency of the chirp signal transmitted by the transmitting antenna i is the same as the start frequency of the chirp signal transmitted by the transmitting antenna i+1.

When the above K=1 and the above

When slope ⁱ > 0, the waveforms of the chirp signals transmitted by the above-mentioned transmitting antenna i and transmitting antenna i+1 are shown in FIG. 7. As shown in FIG. 7, the solid line is the chirp signal waveform transmitted by the above-mentioned transmitting antenna i, and the broken line is the chirp signal waveform transmitted by the above-mentioned transmitting antenna i+1. The interval between the start time of the transmit antenna i+1 transmitting the chirp signal and the end time of the transmit antenna i transmitting the chirp signal is T _{g_dwell} , the slope of the chirp signal transmitted by the transmit antenna i is slope ⁱ , then

Since slope ⁱ⁺¹ and slope ⁱ are opposite to each other, then

In one embodiment, the solid line shown in FIG. 7 is the signal waveform transmitted by antenna i+1, and the dashed line is the signal waveform transmitted by antenna i.

It should be pointed out that the above-mentioned transmitting antenna i and transmitting antenna i+1 successively transmit the chirp signal once as one round. In the process of transmitting multiple rounds of signals, the order of the chirp signals transmitted by the adjacent two rounds of transmitting antennas may be the same; Different, that is, the transmit antenna i may transmit the chirp signal before the transmit antenna i+1, or the transmit antenna i+1 may transmit the chirp signal before the transmit antenna i. When the transmitting antenna i+1 transmits the chirp signal before the transmitting antenna i, the cutoff frequency of the transmitting antenna i+1 transmitting the chirp signal is equal to the starting frequency of the transmitting antenna i transmitting the chirp signal.

In the solution of the embodiment of the present application, multiple sets of transmit antennas alternately send chirp signals on the rising and falling slopes to completely eliminate the T _reset in the prior art. This process has two advantages. The chirp signal continues to be transmitted during T _reset time, which can expand the scanning bandwidth and obtain higher distance accuracy; the second is that the adjacent antenna transmits the chirp signal at the T _reset time of this antenna, which can reduce the chirp signal transmitted by each antenna Occupy time, thereby expanding the speed measurement range. It can also reduce the time span of multi-antenna signal transmission and reduce the impact of speed on the channel.

In a possible embodiment, when the above K is greater than 1 and the K transmit antennas transmit J-segment sub-chirp signals, for the transmit antenna m and the transmit antenna m that belong to the same group and the transmit sub-chirp signals are temporally adjacent The sub-chirp signal transmitted by +1 satisfies the following relationship:

slope ^m+1 = slope ^m

Among them, the above

Is the starting frequency of the sub-chirp signal transmitted by the above transmitting antenna m+1, the above

Is the cutoff frequency of the sub-chirp signal transmitted by the transmitting antenna m; the slope ^m+1 and slope ^m are the slopes of the waveforms of the sub-chirp signals transmitted by the transmitting antenna m+1 and the transmitting antenna m, respectively;

Is the difference between the start frequency of the transmit signal of the transmit antenna m+1 and the cut-off frequency of the sub-chirp signal transmitted by the transmit antenna m,

Any real number.

In a possible embodiment, the above

or

Wherein, the above T _{g_dwell} is the difference between the start time of the transmit antenna m+1 transmit sub-chirp signal and the end time of the transmit antenna m transmit sub-chirp signal.

Above

or

Wherein, T _{s_dwell} is the difference between the start time of the transmit antenna m+1 sub-chirp signal and the end time of the transmit antenna m transmit sub-chirp signal.

For example, assume that the radar system includes four transmitting antennas, namely antenna 1, antenna 2, antenna 3 and antenna 4, which are divided into two groups, antenna 1 and antenna 2 are a group, and antenna 3 and antenna 4 are a group. Antenna 1 and antenna 2 use a rising slope to transmit signals, and antenna 3 and antenna 4 use a descending slope to transmit signals. Each group of transmitting antennas includes 2 transmitting antennas, transmitting 4 sub-chirp signals, and the sub-chirp signals transmitted by the same transmitting antenna are not adjacent in time.

As shown in FIG. 8, offset _s is 0, that is, the cutoff frequency of the signal transmitted by the antenna 1 is equal to the start frequency of the signal transmitted by the antenna 2 or the start frequency of the signal transmitted by the antenna 1 is equal to the cutoff frequency of the signal transmitted by the antenna 2; the signal transmitted by the antenna 3 The cutoff frequency of is equal to the start frequency of the antenna 4 transmitting signal or the start frequency of the antenna 3 transmitting signal is equal to the cutoff frequency of the antenna 4 transmitting signal. The above offset _g is 0, that is, the cutoff frequency of the signal transmitted by the antenna 2 is equal to the start frequency of the signal transmitted by the antenna 3. The signals transmitted by the antenna 2 and the antenna 3 are adjacent in time and the antenna 2 and the antenna 3 belong to different groups, respectively.

As shown in FIG. 9, the above offset _s is slope*T _{s_dwell} , that is, the starting frequency of the antenna 1 transmitted signal is the _sum of the cut-off frequency of the antenna 2 transmitted signal and slope*T _{s_dwell} , or the starting frequency of the antenna 2 transmitted signal is The _sum of the cut-off frequency of antenna 1 transmitted signal and slope*T _{s_dwell} ; the start frequency of antenna 3 transmitted signal is the _sum of the cut-off frequency of antenna 4 transmitted signal and slope*T _{s_dwell} , or the start frequency of antenna 4 transmitted signal is antenna 3 _Sum of the cutoff frequency of the transmitted signal and slope*T _{s_dwell} . The above offset _g is 0, that is, the cutoff frequency of the signal transmitted by the antenna 2 is equal to the start frequency of the signal transmitted by the antenna 3. The signals transmitted by the antenna 2 and the antenna 3 are adjacent in time and the antenna 2 and the antenna 3 belong to different groups, respectively.

As shown in FIG. 10, the above offset _s is 0, the cutoff frequency of the signal transmitted by the antenna 1 is equal to the start frequency of the signal transmitted by the antenna 2 or the start frequency of the signal transmitted by the antenna 1 is equal to the cutoff frequency of the signal transmitted by the antenna 2, and the signal transmitted by the antenna 3 The cutoff frequency of is equal to the start frequency of the antenna 4 transmitting signal or the start frequency of the antenna 3 transmitting signal is equal to the cutoff frequency of the antenna 4 transmitting signal. The above offset _g is slope*T _{g_dwell} , that is, the starting frequency of the antenna 3 transmitted signal is the _sum of the cut-off frequency of the antenna 2 transmitted signal and slope*T _{g_dwell} , where the antenna 2 and antenna 3 transmitted signals are adjacent in time And antenna 2 and antenna 3 belong to different groups.

As shown in FIG. 11, the above offset _s is slope*T _{s_dwell} , that is, the starting frequency of antenna 1 transmitting signal is the _sum of the cut-off frequency of antenna 2 transmitting signal and slope*T _{s_dwell} , or the starting frequency of antenna 2 transmitting signal is The _sum of the cut-off frequency of antenna 1 transmitted signal and slope*T _{s_dwell} ; the start frequency of antenna 3 transmitted signal is the _sum of the cut-off frequency of antenna 4 transmitted signal and slope*T _{s_dwell} , or the start frequency of antenna 4 transmitted signal is antenna 3 _Sum of the cutoff frequency of the transmitted signal and slope*T _{s_dwell} . The above offset _g is slope*T _{g_dwell} , that is, the starting frequency of the antenna 3 transmitted signal is the _sum of the cut-off frequency of the antenna 2 transmitted signal and slope*T _{g_dwell} , where the antenna 2 and antenna 3 transmitted signals are adjacent in time And antenna 2 and antenna 3 belong to different groups.

It should be noted that the above-mentioned slope is an absolute value of any one of the above-mentioned slope ¹ , slope ² , slope ³ and slope ⁴ . Among them, slope ¹ , slope ² , slope ³ and slope ⁴ are the slopes of the waveforms of the signals transmitted by the above antenna 1, antenna 2, antenna 3 and antenna 4 respectively, and slope ¹ = slope ² , slope ³ = slope ⁴ , slope ² = -slope ³ .

In a possible embodiment, the M*K transmitting antennas each transmit the chirp signal once for one round, and the order of transmitting the chirp signals of the transmitting antennas among multiple rounds is the same or different.

It should be noted that the transmitting antenna and the receiving antenna of the above radar system may be the same entity or different entities.

In an embodiment, when the transmitting antenna and the receiving antenna are different entities, the control unit may control the transmitting antenna and the receiving antenna to receive and send signals, or the control unit may only control the transmitting antenna to transmit chirp signals, but does not control receiving The antenna receives the signal, and the receiving antenna receives the signal autonomously.

Referring to FIG. 12, it is a schematic structural diagram of a radar system provided by an embodiment of the present application. The radar system includes K transmitting antennas, as shown in FIG. 12, the radar system includes:

The control unit 1201 is used to control the K transmitting antennas 1202 in the radar system to transmit the J-segment sub-chirp signal, where J=A*K, K is an integer greater than 1, and A is a positive integer;

Among them, the sub-chirp signals transmitted by the transmitting antenna j and the transmitting antenna j+1 of the K transmitting antenna 1202 that are temporally adjacent to each other satisfy the following relationship:

slope ^j+1 = slope ^j

Among them, the above

Is the starting frequency of the sub-chirp signal transmitted by the above transmitting antenna j+1, the above

Is the cutoff frequency of the sub-chirp signal transmitted by the transmitting antenna j, and the slope ^j+1 and slope ^j are the slopes of the waveforms of the sub-chirp signals transmitted by the transmitting antenna j+1 and the transmitting antenna j, respectively.

Is the difference between the start frequency of the sub-chirp signal transmitted by the transmit antenna j+1 and the cut-off frequency of the sub-chirp signal transmitted by the transmit antenna j,

Any real number.

In a possible embodiment, the above

or

Wherein, T′ _{s_dwell} is the difference between the start time of the above-mentioned transmit antenna j+1 transmission sub-chirp signal and the end time of the above-mentioned transmit antenna j transmission sub-chirp signal.

When the above

When it is 0, the waveforms of the signals transmitted by the antenna j and antenna j+1 refer to FIG. 13, as shown in FIG. 13, the dotted line in the figure is the waveform of the signal transmitted by the antenna j, and the solid line is the waveform of the signal transmitted by the antenna j+1 , Or the broken line is the waveform of the signal transmitted by the antenna j+1, and the solid line is the waveform of the signal transmitted by the antenna j+1. The starting frequency of the signal transmitted by the antenna j+1 is equal to the cut-off frequency of the signal transmitted by the antenna j.

It should be noted that the signal waveform shown in FIG. 13 is in the form of a rising slope, and the waveforms of the signals transmitted by the antenna j and antenna j+1 can also be in the form of a descending slope, as shown in FIG. 14, and the dotted line in the figure is the antenna j For the waveform of the transmission signal, the solid line is the waveform of the antenna j+1 transmission signal, or the broken line is the waveform of the antenna j+1 transmission signal, and the solid line is the waveform of the antenna j+1 transmission signal. The starting frequency of the signal transmitted by the antenna j+1 is equal to the cut-off frequency of the signal transmitted by the antenna j.

When the above

When slope ^j *T′ _{s_dwell} , the waveforms of the signals transmitted by the antenna j and antenna j+1 refer to FIG. 15. As shown in FIG. 15, the dotted line in the figure is the waveform of the signal transmitted by the antenna j, and the solid line is the antenna j+ 1 The waveform of the transmitted signal, or the broken line is the waveform of the above-mentioned antenna j+1 transmitted signal, and the solid line is the waveform of the above-mentioned antenna j transmitted signal.

Where T′ _{s_dwell is} the difference between the start time of the antenna j transmission signal and the cutoff time of the antenna j+1 transmission signal, or the difference between the start time of the antenna j+1 transmission signal and the cutoff time of the antenna j transmission signal .

It should be noted that the signal waveform shown in FIG. 15 is a rising ramp, and the waveforms of the signal transmitted by the antenna j and antenna j+1 can also adopt a descending ramp, as shown in FIG. 16, and the dotted line in the figure is the antenna j For the waveform of the transmission signal, the solid line is the waveform of the antenna j+1 transmission signal, or the broken line is the waveform of the antenna j+1 transmission signal, and the solid line is the waveform of the antenna j+1 transmission signal.

It should be pointed out that the chirp signal shown in FIG. 15 or FIG. 16 includes 4 sub-chirp signals, which are sent in two by the above-mentioned transmitting antenna j and transmitting antenna j+1, and the above four sub-chirp signals are transmitted in one round. In the process of multiple rounds of signal transmission, the order of two adjacent antenna transmissions may be the same; or different, for example, the first antenna transmission sequence is: antenna j-antenna j+1-antenna j-antenna j+1, the first The secondary antenna transmission sequence is: antenna j+1-antenna j-antenna j+1-antenna j.

Further, each of the K transmitting antennas transmits a sub-chirp signal once for one round, and the order of transmitting the sub-chirp signals of the transmitting antennas between multiple rounds is the same or different.

For example, the above-mentioned radar system includes 6 transmitting antennas, and each of the 6 transmitting antennas transmits a sub-chirp signal for one round, and the order of the first round of transmitting antennas to transmit the sub-chirp signal is: antenna 1-antenna 2-antenna 3-antenna 4-antenna 5-antenna 6, then the order of the second chirping antenna to transmit the sub-chirp signal can be: antenna 1-antenna 2-antenna 3-antenna 4-antenna 5-antenna 6, or antenna 2-antenna 1- Antenna 3-antenna 4-antenna 6-antenna 5; the sequence of the third-round transmitting antenna transmitting sub-chirp signals may be: antenna 2-antenna 1-antenna 4-antenna 3-antenna 5-antenna 6.

In a possible embodiment, the foregoing radar system further includes a multiple receiving antenna 1203, and the foregoing radar system 1200 further includes:

The control unit 1201 is further configured to control the multiple receiving antenna 1203 to receive the signal obtained by reflecting the sub-chirp signal j of the detected object; the sub-chirp signal j is the signal transmitted by the transmitting antenna j;

The mixer 1204 is configured to mix the signals received by the multiple receiving antennas with the sub-chirp signal j to obtain difference frequency signals of multiple receiving channels;

An analog-to-digital converter 1205 is used to convert the difference frequency signals of the multiple receiving channels into digital signals of the multiple receiving channels;

The digital signal processor 1206 is used to perform a distance Fourier transform on the digital signals of the multiple receiving channels to obtain Δf, which is the frequency domain representation of the above-mentioned difference frequency signal; the target distance is obtained according to the Δf. The target distance is the distance between the radar system and the detected object.

For example, assume that the radar system 1200 includes S2 receiving antennas 1203, and that the radar system includes S1 receiving antennas. After the sub-chirp signal j is transmitted to the detected object, the S2 receiving antennas receive the S2 signals obtained by reflecting the chirp signal j from the detected object, and the mixer 1204 separates the S2 signals from the sub-chirp signals The chirp signal j is mixed to obtain S2 receiving channel difference frequency signals; it should be pointed out that the above S2 signals are divided in time.

Suppose there are 1024 sampling points in the digital signal corresponding to the difference frequency signals of multiple receiving channels, and the above-mentioned radar system has 4 transmitting antennas, transmitting the sub-chirp signal j; when the sub-chirp signal j is generated by If the first one of the four transmitting antennas transmits, then the first 256 sampling points of the 1024 sampling points corresponding to the above-mentioned difference frequency signal are obtained by sampling the difference frequency signal, and the values of the other 768 sampling points are set. Is 0; when the sub-chirp signal j is transmitted by the second of the four transmitting antennas in the radar system, the 257-512th sampling point of the 1024 sampling points corresponding to the difference frequency signal is By sampling the above difference frequency signal, the values of the first 256 sampling points and the last 512 sampling points are set to 0; when the sub-chirp signal j is transmitted by the third of the four antennas of the radar system , The 513th to 768th sampling points out of the 1024 sampling points corresponding to the above difference frequency signal are obtained by sampling the above difference frequency signal, and the values of the first 512 sampling points and the last 256 sampling points are set to 0 ; When the sub-chirp signal j is transmitted by the fourth of the four transmitting antennas of the radar system, the 769-1024 sampling points out of the 1024 sampling points corresponding to the difference frequency signal are determined by the above After the difference frequency signal is sampled, the other 768 sampling points are set to 0.

After the analog-to-digital converter 1205 converts the difference frequency signals of the multiple receiving channels into digital signals of the multiple receiving channels, the digital signal processor 1206 performs distance Fourier on the digital signals of the multiple receiving channels in one chirp Leaf transform to get Δf. When the slope of the waveform of the chirp signal i is greater than 0, the digital signal processor 1206 according to the formula

Determine the target distance; when the slope of the chirp signal i is less than 0, the digital signal processor 1206 can use the formula

Determine the above target distance.

It should be noted that the transmitting antenna and the receiving antenna of the above radar system may be the same entity or different entities.

In an embodiment, when the transmitting antenna and the receiving antenna are different entities, the control unit may control the transmitting antenna and the receiving antenna to receive and send signals, or the control unit may only control the transmitting antenna to transmit chirp signals, but does not control receiving The antenna receives the signal, and the receiving antenna receives the signal autonomously.

In this embodiment, the signals transmitted by multiple transmitting antennas are regarded as a virtual chirp signal, and the slope of each sub-chirp signal of the chirp signal is the same, so that the signal when using multiple antennas to measure the angle is as compact and different as possible The interval time between the sub-chirp signals is the antenna switching time, which is ns level, which is much smaller than the μs level of T _reset and T _dwell , so that the transmission signal time of multiple transmit antennas used for angle measurement is compressed as much as possible To reduce the effect of speed on angle measurement.

Referring to FIG. 17, it is a schematic structural diagram of a radar system provided by an embodiment of the present application. As shown in FIG. 17, the radar system includes: a signal generator 1701, a power amplifier 1702, a transmitting antenna 1703, a receiving antenna 1704, a low noise amplifier 1705, a mixer 1706, a filter 1707, an analog-to-digital converter 1708, and signal processing Unit 1709.

The above signal generator includes an FMCW signal generator and a carrier generator. The FMCW signal generated by the FMCW signal generator is modulated onto the carrier wave generated by the carrier generator to obtain a chirp signal, and the chirp signal is a transmission signal. The transmission signal is subjected to power amplification by a power amplifier, and then the amplified transmission signal is transmitted through a transmission antenna.

The receiving antenna 1704 receives the signal transmitted by the above-mentioned transmitting antenna 1703 to obtain a received signal. The post-node signal passing through the low noise amplifier 1705 is mixed with the chirp signal through the mixer 1706 to obtain the difference frequency signal of the receiving channel. The difference frequency signal of the receiving channel is filtered by a filter 1707 to obtain a filtered difference frequency signal; the filtered difference frequency signal is converted into a digital signal by an analog-to-digital converter 1708; the signal processing unit 1709 performs distance to the digital signal Fourier transform to obtain Δf, which is the frequency domain representation of the above difference frequency signal; the target distance is obtained according to Δf, and the target distance is the distance between the radar system and the detected object.

In one embodiment, the radar system shown in FIG. 17 may be one chip, or the radar system shown in FIG. 17 may be composed of two chips, one of which implements the function of the signal processing unit 1709, and the other chip implements The functions of modules or units other than the signal processing unit in the radar system shown. Multiple RF chips can also be cascaded, that is, multiple transmit antennas and transmit channels are in one chip, multiple receive antennas and receive channels are in another chip, and the signal processing module unit processes multiple transmit chips and multiple Control and signal processing of each receiving channel.

In one embodiment, an embodiment of the present application provides a waveform generation method. The method is applied to a radar system and includes:

Divide the multiple transmitting antennas of the above radar system into M groups of transmitting antennas, each of the M groups of transmitting antennas includes K transmitting antennas; M is an integer greater than 1, and K is a positive integer;

Control group M transmitting antenna to transmit chirp signal;

Among them, the following relationship is satisfied for the transmit antenna i and the transmit antenna i+1 that belong to different groups and whose transmit chirp signals are temporally adjacent to each other:

slope ⁱ⁺¹ = slope ⁱ

Among them, the above

Is the starting frequency of the chirp signal transmitted by the above transmitting antenna i+1, the above

Is the cut-off frequency of the chirp signal transmitted by the transmit antenna i, and the slope ⁱ⁺¹ and slope ⁱ are the slope of the waveform of the chirp signal transmitted by the transmit antenna i+1 and the transmit antenna i, respectively.

Is the difference between the start frequency of the chirp signal transmitted by the transmitting antenna i+1 and the cut-off frequency of the chirp signal transmitted by the transmitting antenna i,

Any real number.

In a possible embodiment, the above

It can be a random real number with a small value, that is, a signal with a low frequency is randomly superimposed on the transmitted signal, which does not increase the burden of the intermediate frequency bandwidth and can play the role of interference randomization.

In a possible embodiment, the above

or

Wherein, the T _{g_dwell} is the difference between the start time of the chirp signal transmitted by the transmit antenna i+1 and the end time of the chirp signal transmitted by the transmit antenna i.

In a possible embodiment, when the above K is greater than 1, and the K transmit antennas transmit the J-end sub-chirp signal, for the antenna m and the antenna that belong to the same group and the transmit sub-chirp signals are temporally adjacent The sub-chirp signal transmitted by m+1 satisfies the following relationship:

slope ^m+1 = slope ^m

Among them, the above

Is the starting frequency of the sub-chirp signal transmitted by the above transmitting antenna m+1, the above

Is the cutoff frequency of the sub-chirp signal transmitted by the transmitting antenna m; the slope ^m+1 and slope ^m are the slopes of the waveforms of the sub-chirp signals transmitted by the transmitting antenna m+1 and the transmitting antenna m, respectively;

Is the difference between the start frequency of the sub-chirp signal transmitted by the transmit antenna m+1 and the cut-off frequency of the sub-chirp signal transmitted by the transmit antenna m;

Any real number.

In a possible embodiment, the above

It can be a random real number with a smaller value, that is, a signal with a lower frequency is randomly superimposed on the transmitted signal. Without increasing the burden of the intermediate frequency bandwidth, it can play a role in randomizing interference.

In one embodiment, it is selected in a limited phase set

The parameter does not increase the burden of the intermediate frequency bandwidth and reduce the complexity of signal generation.

In a possible embodiment, the above

or

Wherein, T _{s_dwell} is the difference between the start time of the transmit antenna m+1 sub-chirp signal and the end time of the transmit antenna m transmit sub-chirp signal.

In a possible embodiment, the M*K transmitting antennas each transmit a chirp signal once for one round, and the order of transmitting the chirp signals of the transmitting antennas between multiple rounds is the same or different.

In a possible embodiment, the foregoing radar system further includes multiple receiving antennas, and the foregoing method further includes:

Controlling the multiple receiving antenna to receive a signal obtained by reflecting the chirp signal i of the detected object, the chirp signal i being the signal transmitted by the transmitting antenna i;

Mixing the signals received by the multiple receiving antennas with the chirp signal i respectively to obtain a plurality of receiving channel difference frequency signals;

Convert the difference frequency signals of the multiple receiving channels into digital signals of the multiple receiving channels;

Perform a distance Fourier transform on the digital signals of the multiple receiving channels to obtain Δf, which is the frequency domain representation of the difference frequency signal; obtain a target distance according to the Δf, which is the radar system and the above The distance between the detected objects.

In a possible embodiment, obtaining the target distance according to the above Δf includes:

When the slope of the waveform of the chirp signal i above slope ^{i is} greater than 0, according to the formula

Determine the above target distance; when the slope of the waveform of the chirp signal i slope ^{i is} less than 0, according to the formula

Determine the above target distance; where R is the target distance and c is the speed of light. Since the chirp signal continues to be transmitted during the T _reset time of the antenna, the frequency sweep bandwidth is expanded, thereby obtaining higher distance accuracy.

In one embodiment, an embodiment of the present application provides a waveform generation method. The method is applied to a radar system. The radar system includes K transmitting antennas. The method includes:

Control the K transmitting antennas of the above radar system to transmit J-segment sub-chirp signals, J=A*K, K is an integer greater than 1, and A is a positive integer;

Among them, the sub-chirp signals transmitted by the transmitting antenna j and the sub-chirp signal transmitted by the transmitting antenna j+1 in the K transmitting antennas that are adjacent in time satisfy the following relationship:

slope ^j+1 = slope ^j

Among them, the above

Is the starting frequency of the sub-chirp signal transmitted by the above transmitting antenna j+1, the above

Is the cutoff frequency of the sub-chirp signal transmitted by the transmitting antenna j, and the slope ^j+1 and slope ^j are the slopes of the waveforms of the sub-chirp signals transmitted by the transmitting antenna j+1 and the transmitting antenna j, respectively.

Is the difference between the start frequency of the sub-chirp signal transmitted by the above-mentioned transmitting antenna j+1 and the cut-off frequency of the signal transmitted by the above-mentioned transmitting antenna j,

Any real number.

In a possible embodiment, the above

or

Wherein, T _{s_dwell} is the difference between the start time of the transmit chirp signal of the transmit antenna j+1 and the end time of the transmit chirp signal of the transmit antenna j.

In a possible embodiment, each of the K transmitting antennas transmits a sub-chirp signal once for one round, and the order of transmitting the sub-chirp signals for transmitting antennas between multiple rounds is the same or different.

In a possible embodiment, the foregoing radar system further includes multiple receiving antennas, and the foregoing method further includes:

Controlling the multiple receiving antenna to receive the signal obtained by reflecting the sub-chirp signal j of the detected object; the sub-chirp signal j is the signal transmitted by the transmitting antenna j;

Mixing the signals received by the multiple receiving antennas with the sub-chirp signal j to obtain difference frequency signals of multiple receiving channels;

Convert the difference frequency signals of the multiple receiving channels into digital signals of the multiple receiving channels;

Perform a distance Fourier transform on the digital signals of the multiple receiving channels to obtain Δf, which is the frequency domain representation of the above-mentioned difference frequency signal; obtain a target distance according to the Δf, which is the distance between the radar system and all Describe the distance between the detected objects.

In a possible embodiment, obtaining the target distance according to Δf includes:

When the waveform slope Slope ^j sub-chirp signal j is greater than 0, according to the formula

Determining a target distance; when the waveform slope slope sub-chirp signal j ^j is less than 0, according to the formula

Determine the target distance; where R is the target distance and c is the speed of light.

An embodiment of the present invention further provides a computer storage medium, where the computer storage medium may store a program, and when the program is executed, part or all of the steps including any one of the waveform generation methods described in the foregoing method embodiments may be implemented. The aforementioned storage media include: U disk, read-only memory (English: read-only memory), random access memory (English: random access memory, RAM), mobile hard disk, magnetic disk or optical disk, etc., which can store program codes. medium.

It should be noted that, for the sake of simple description, the foregoing method embodiments are all expressed as a series of action combinations, but those skilled in the art should know that the present invention is not limited by the sequence of actions described. Because according to the invention, certain steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the present invention.

In the above embodiments, the description of each embodiment has its own emphasis. For a part that is not detailed in an embodiment, you can refer to related descriptions in other embodiments.

In the several embodiments provided in this application, it should be understood that the disclosed device may be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the unit is only a logical function division. In actual implementation, there may be another division manner, for example, multiple units or components may be combined or may Integration into another system, or some features can be ignored, or not implemented. In addition, the displayed or discussed mutual couplings or direct couplings or communication connections may be indirect couplings or communication connections through some interfaces, devices or units, and may be in electrical or other forms.

The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or may be distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

As mentioned above, the above embodiments are only used to illustrate the technical solutions of the present invention, not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still The technical solutions described in the embodiments are modified, or some of the technical features are equivalently replaced; and these modifications or replacements do not deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims (24)

1. A radar system includes a multi-transmitting antenna, which is characterized by including:

   A grouping unit is used to divide the multiple transmitting antennas of the radar system into M groups of transmitting antennas; each group of the M groups of transmitting antennas includes K transmitting antennas; the M is an integer greater than 1, and the K is greater than An integer of 0;

   A control unit, configured to control the M groups of transmitting antennas to transmit chirp signals;

   Among them, the following relationship is met for the chirp signals transmitted by the transmitting antenna i and the transmitting antenna i+1 that belong to different groups and whose transmit chirp signals are temporally adjacent:

   

   slope ⁱ⁺¹ = -slope ⁱ

   Among them, the

   

   Starting frequency of the chirp signal transmitted by the transmitting antenna i+1, the

   

   Is the cut-off frequency of the chirp signal transmitted by the transmitting antenna i, and slope ⁱ⁺¹ and slope ⁱ are the slope of the waveform of the chirp signal transmitted by the transmitting antenna i+1 and the transmitting antenna i, respectively.

   

   Is the difference between the start frequency of the chirp signal transmitted by the transmitting antenna i+1 and the cutoff frequency of the chirp signal transmitted by the transmitting antenna i, the

   

   Any real number.
2. The radar system according to claim 1, wherein said

   

   or

   

   

   Wherein, T _{g_dwell} is the difference between the start time of the chirp signal transmitted by the transmit antenna i+1 and the end time of the chirp signal transmitted by the transmit antenna i.
3. The radar system according to claim 1 or 2, characterized in that, when the K is greater than 1, and the K transmit antennas transmit J sub-chirp signals, for the sub-chirp signals that belong to the same group and are transmitted in time The sub-chirp signals transmitted by the adjacent antenna m and antenna m+1 satisfy the following relationship:

   

   slope ^m+1 = slope ^m

   Among them, the

   

   Is the starting frequency of the sub-chirp signal transmitted by the transmitting antenna m+1, the

   

   The cutoff frequency of the sub-chirp signal transmitted by the transmitting antenna m; the slope ^m+1 and slope ^m are the slopes of the waveforms of the sub-chirp signals transmitted by the transmitting antenna m+1 and the transmitting antenna m, respectively;

   

   Is the difference between the start frequency of the transmit signal of the transmit antenna m+1 and the cut-off frequency of the transmit chirp signal of the transmit antenna m, the

   

   It is any real number; the J=A*K, and the K is a positive integer.
4. The radar system according to claim 3, characterized in that

   

   or

   

   Wherein, T _{s_dwell} is the difference between the start time of the transmit antenna m+1 sub-chirp signal and the end time of the transmit antenna m transmit sub-chirp signal.
5. The radar system according to any one of claims 1 to 4, characterized in that each of the M*K transmitting antennas transmits a chirp signal once, and the order of transmitting chirp signals of the transmitting antennas between multiple rounds is the same or different .
6. The radar system according to claim 1, 2 or 5, the radar system further comprises a multi-reception antenna, wherein the radar system further comprises:

   The control unit is further configured to control the multiple receiving antenna to receive a signal obtained by reflecting the chirp signal i from the detected object, the chirp signal i being a signal transmitted by the transmitting antenna i;

   A mixer, configured to mix the signals received by the multiple receiving antennas with the chirp signal i respectively to obtain a plurality of receiving channel difference frequency signals;

   An analog-to-digital converter for converting the difference frequency signals of the multiple receiving channels into digital signals of the multiple receiving channels;

   The digital signal processor is used to perform a distance Fourier transform on the digital signals of the multiple receiving channels to obtain Δf, where Δf is the frequency domain representation of the difference frequency signal; the target distance is obtained according to the Δf , The target distance is the distance between the radar system and the detected object.
7. The radar system according to claim 6, wherein in terms of acquiring the target distance according to the Δf, the digital signal processor is specifically used to:

   When the waveform of the chirp signal i ⁱ Slope slope greater than 0, according to the formula

   

   Determining the target distance; when the waveform slope slope of the chirp signal i ⁱ is less than 0, according to the formula

   

   Determine the target distance;

   Where R is the target distance and c is the speed of light.
8. A radar system includes K transmitting antennas, characterized in that it includes:

   A control unit, configured to control the K transmitting antennas of the radar system to transmit J-segment sub-chirp signals, wherein, J=A*K, K is an integer greater than 1, and A is a positive integer;

   Among them, the sub-chirp signals transmitted by the transmitting antenna j and the transmitting antenna j+1 of the K transmitting antennas that are temporally adjacent to each other satisfy the following relationship:

   

   slope ^j+1 = slope ^j

   Among them, the

   

   Is the starting frequency of the sub-chirp signal transmitted by the transmitting antenna j+1, the

   

   Is the cutoff frequency of the sub-chirp signal transmitted by the transmitting antenna j, and slope ^j+1 and slope ^j are the slopes of the waveforms of the sub-chirp signals transmitted by the transmitting antenna j+1 and the transmitting antenna j, respectively.

   

   Is the difference between the start frequency of the sub-chirp signal transmitted by the transmitting antenna j+1 and the cut-off frequency of the sub-chirp signal transmitted by the transmitting antenna j,

   

   Any real number.
9. The radar system according to claim 8, wherein said

   

   or

   

   

   Wherein, T′ _{s_dwell} is the difference between the start time of the transmit sub-chirp signal of the transmit antenna j+1 and the end time of the transmit chirp signal of the transmit antenna j.
10. The radar system according to claim 8 or 9, wherein each of the K transmitting antennas transmits a sub-chirp signal once, and the order of transmitting the sub-chirp signals of the transmitting antenna between multiple rounds is the same or different.
11. The radar system according to any one of claims 8-10, the radar system further comprises a multi-reception antenna, wherein the radar system further comprises:

    The control unit is further configured to control the multiple receiving antenna to receive a signal obtained by reflecting the sub-chirp signal j of the detected object, and the sub-chirp signal j is a signal transmitted by the transmitting antenna j;

    A mixer for mixing the signals received by the multiple receiving antennas with the sub-chirp signal j respectively to obtain difference frequency signals of multiple receiving channels;

    An analog-to-digital converter for converting the difference frequency signals of the multiple receiving channels into digital signals of the multiple receiving channels;

    The digital signal processor is used to perform a distance Fourier transform on the digital signals of the multiple receiving channels to obtain Δf, where Δf is the frequency domain representation of the difference frequency signal; the target distance is obtained according to the Δf , The target distance is the distance between the radar system and the detected object.
12. The radar system according to claim 11, wherein in terms of acquiring the target distance according to the Δf, the digital signal processor is specifically configured to:

    When the waveform slope slope ^{j of} the sub-chirp signal j is greater than 0, according to the formula

    

    Determine the target distance; when the waveform slope slope ^{j of} the sub-chirp signal j is less than 0, according to the formula

    

    Determine the target distance;

    Where R is the target distance and c is the speed of light.
13. A waveform generation method, which is applied to a radar system and is characterized by comprising:

    Divide the multiple transmitting antennas of the radar system into M groups of transmitting antennas, each of the M groups of transmitting antennas includes K transmitting antennas; the M is an integer greater than 1, and the K is a positive integer;

    Controlling the M group transmitting antennas to transmit chirp signals;

    Among them, the following relationship is met for the chirp signals transmitted by the transmitting antenna i and the transmitting antenna i+1 that belong to different groups and whose transmit chirp signals are temporally adjacent:

    

    slope ⁱ⁺¹ = slope ⁱ

    Among them, the

    

    Starting frequency of the chirp signal transmitted by the transmitting antenna i+1, the

    

    Is the cut-off frequency of the chirp signal transmitted by the transmitting antenna i, and slope ⁱ⁺¹ and slope ⁱ are the slope of the waveform of the chirp signal transmitted by the transmitting antenna i+1 and the transmitting antenna i, respectively.

    

    Is the difference between the start frequency of the chirp signal transmitted by the transmitting antenna i+1 and the cutoff frequency of the chirp signal transmitted by the transmitting antenna i, the

    

    Any real number.
14. The method according to claim 13, wherein said

    

    or

    

    

    Wherein, T _{g_dwell} is the difference between the start time of the transmit signal of the transmit antenna i+1 and the end time of the transmit signal of the transmit antenna i.
15. The method according to claim 13 or 14, wherein when the K is greater than 1, and the K transmit antennas transmit the J-segment sub-chirp signals, the sub-chirp signals belonging to the same group and transmitted in time are phase-phased. The sub-chirp signals transmitted by the adjacent antenna m and antenna m+1 satisfy the following relationship:

    

    slope ^m+1 = slope ^m

    Among them, the

    

    Is the starting frequency of the sub-chirp signal transmitted by the transmitting antenna m+1, the

    

    The cutoff frequency of the sub-chirp signal transmitted by the transmitting antenna m; the slope ^m+1 and slope ^m are the slopes of the waveforms of the sub-chirp signals transmitted by the transmitting antenna m+1 and the transmitting antenna m, respectively;

    

    Is the difference between the start frequency of the transmit signal of the transmit antenna m+1 and the cutoff frequency of the transmit chirp signal of the transmit antenna m;

    

    It is any real number, and J=A*K, and K is a positive integer.
16. The method according to claim 15, wherein said

    

    or

    

    

    Wherein, T _{s_dwell} is the difference between the start time of the transmit antenna m+1 sub-chirp signal and the end time of the transmit antenna m transmit sub-chirp signal.
17. The method according to any one of claims 13 to 16, wherein each of the M*K transmitting antennas transmits a chirp signal once for one round, and the order of transmitting the chirp signals of the transmitting antennas between multiple rounds is the same or different.
18. The method according to claim 13, 14 or 17, the radar system further comprises a multiple receiving antenna, characterized in that the method further comprises:

    Controlling the multiple receiving antenna to receive the signal obtained by reflecting the chirp signal i of the detected object, the chirp signal i being a signal transmitted by the transmitting antenna i;

    Mixing the signals received by the multiple receiving antennas with the chirp signal i to obtain a plurality of receiving channel difference frequency signals;

    Converting the difference frequency signals of the multiple receiving channels into digital signals of the multiple receiving channels;

    Perform a distance Fourier transform on the digital signals of the multiple receiving channels to obtain Δf, where Δf is the frequency domain representation of the difference frequency signal; obtain the target distance according to the Δf, and the target distance is The distance between the radar system and the detected object.
19. The method according to claim 18, wherein the obtaining the target distance according to the Δf comprises:

    When the waveform of the chirp signal i ⁱ Slope slope greater than 0, according to the formula

    

    Determining the target distance; when the waveform slope slope of the chirp signal i ⁱ is less than 0, according to the formula

    

    Determine the target distance;

    Where R is the target distance and c is the speed of light.
20. A waveform generation method applied to a radar system. The radar system includes K transmitting antennas, and is characterized in that it includes:

    Controlling the K transmitting antennas of the radar system to transmit J-segment sub-chirp signals, the J=A*K, the K is an integer greater than 1, and the A is a positive integer;

    Wherein, the sub-chirp signals transmitted by the antenna j and the antenna j+1 that are adjacent in time of the transmitted signals of the K transmitting antennas satisfy the following relationship:

    

    slope ^j+1 = slope ^j

    Among them, the

    

    Is the starting frequency of the sub-chirp signal transmitted by the transmitting antenna j+1, the

    

    Is the cutoff frequency of the sub-chirp signal transmitted by the transmitting antenna j, and slope ^j+1 and slope ^j are the slopes of the waveforms of the sub-chirp signals transmitted by the transmitting antenna j+1 and the transmitting antenna j, respectively.

    

    Is the difference between the start frequency of the sub-chirp signal transmitted by the transmitting antenna j+1 and the cut-off frequency of the sub-chirp signal transmitted by the transmitting antenna j,

    

    Any real number.
21. The method of claim 20, wherein said

    

    or

    

    

    Wherein, T′ _{s_dwell} is the difference between the start time of the transmit sub-chirp signal of the transmit antenna j+1 and the end time of the transmit chirp signal of the transmit antenna j.
22. The method according to claim 20 or 21, wherein each of the K transmit antennas transmits a sub-chirp signal once for one round, and the order of the transmit sub-chirp signals of the transmit antennas between multiple rounds is the same or different.
23. The method according to any one of claims 20-22, the radar system further comprises a multi-reception antenna, wherein the method further comprises:

    Controlling the multiple receiving antenna to receive a signal obtained by reflecting the sub-chirp signal j of the detected object, where the sub-chirp signal j is a signal transmitted by the transmitting antenna j;

    Mixing the signals received by the multiple receiving antennas with the sub-chirp signal j to obtain difference frequency signals of multiple receiving channels;

    Converting the difference frequency signals of the multiple receiving channels into digital signals of the multiple receiving channels;

    Perform a distance Fourier transform on the digital signals of the multiple receiving channels to obtain Δf, where Δf is the frequency domain representation of the difference frequency signal; obtain the target distance according to the Δf, and the target distance The distance between the radar system and the detected object.
24. The method according to claim 23, wherein the obtaining the target distance according to the Δf comprises:

    When the waveform slope slope ^{j of} the sub-chirp signal j is greater than 0, according to the formula

    

    Determine the target distance; when the waveform slope slope ^{j of} the sub-chirp signal j is less than 0, according to the formula

    

    Determine the target distance; where R is the target distance and c is the speed of light.

Images