CN114755684A - Phase difference compensation method and device and vehicle-mounted millimeter wave radar system - Google Patents

Phase difference compensation method and device and vehicle-mounted millimeter wave radar system Download PDF

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CN114755684A
CN114755684A CN202210396130.6A CN202210396130A CN114755684A CN 114755684 A CN114755684 A CN 114755684A CN 202210396130 A CN202210396130 A CN 202210396130A CN 114755684 A CN114755684 A CN 114755684A
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phase difference
speed
signal
frequency
phase
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李钢
张昕
李旭阳
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Saien Lingdong Shanghai Intelligent Technology Co ltd
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Saien Lingdong Shanghai Intelligent Technology Co ltd
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/88—Radar or analogous systems specially adapted for specific applications
    • G01S13/93—Radar or analogous systems specially adapted for specific applications for anti-collision purposes
    • G01S13/931—Radar or analogous systems specially adapted for specific applications for anti-collision purposes of land vehicles
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
    • G01S13/06—Systems determining position data of a target
    • G01S13/08—Systems for measuring distance only
    • G01S13/32—Systems for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated
    • G01S13/36—Systems for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated with phase comparison between the received signal and the contemporaneously transmitted signal
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
    • G01S7/40—Means for monitoring or calibrating

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  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
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Abstract

The invention discloses a phase difference compensation method, a phase difference compensation device and a vehicle-mounted millimeter wave radar system, wherein the phase difference compensation method is used for a TDMA-MIMOFMCW radar, and comprises the following steps: acquiring an echo signal of each sweep frequency period received by a virtual antenna array of a radar; performing frequency mixing processing on a transmitting signal and an echo signal of a radar to obtain an intermediate frequency signal; the intermediate frequency signal comprises target distance, radial speed and phase information of a receiving antenna; acquiring a speed influence parameter according to the intermediate frequency signal; compensating the intermediate frequency signal of the corresponding sweep frequency period according to the speed influence parameter, and removing the influence of the speed on the distance and the phase; and calculating the phase difference of the intermediate frequency signal waveform of each frequency sweeping period after compensation according to the intermediate frequency signal of each frequency sweeping period after compensation. By the method and the device, the time influence of the range-doppler frequency spectrum transmitted in a time sharing mode can be compensated from the time domain, so that the phase influence caused by MIMO time sharing is compensated.

Description

Phase difference compensation method and device and vehicle-mounted millimeter wave radar system
Technical Field
The invention relates to the field of radars, in particular to a phase difference compensation method and device and a vehicle-mounted millimeter wave radar system.
Background
The 77GHz millimeter wave radar sensor is an important component of an automatic driving sensor, and at present, the frequency sweeping mode of the millimeter wave radar is realized by fast sweeping of linear Frequency Modulated Continuous Wave (FMCW), and speed measurement, distance measurement and angle measurement are realized by the millimeter wave radar. The Chirp-sequence is the most commonly used wave-transmitting method (as shown in fig. 1), where T is the single Chirp transmission time (fast time) of a Chirp (FMCW), the frequency sweep period is the time (slow time) of one fast beat (such as 32,64, or 128 times of continuous transmission), and a group of complete transmissions is a beam, i.e., a complete frequency sweep period. The sampling frequency of the slow time can be changed by adjusting the sequence of the transmitting units, but the essence of the signal processing is the same.
In FMCW, speed and range measurements are determined from the results of the 2D-FFT, and angle measurements are performed by the phase difference of the receiving antennas (array antennas).
In order to increase the angle measurement resolution of the radar, the antenna aperture is increased by using MIMO, the transmitting antennas transmit in sequence in a time-sharing manner, and each time of transmission, the receiving antennas are doubled. As shown in fig. 2, in the TDMA-MIMO method, the phases of the first 4 antenna arrays and the second 4 antenna arrays are related not only to the azimuth of the target but also to the Doppler velocity of the target.
However, if the inter-chirp interval is too long or the speed is too high, beam1 is N frequency sweeps away from beam2, as shown in fig. 1. When the next antenna transmits, the target not only has phase change, but also has distance gate, and at the moment, the accurate result is difficult to obtain by the above formula compensation phase.
Disclosure of Invention
In order to solve the above technical problems, the present invention provides a phase difference compensation method, a phase difference compensation device, and a vehicle-mounted millimeter wave radar system, wherein the time influence of a range-doppler (range-doppler) spectrum transmitted in a time division manner is compensated from a time domain, so as to compensate the phase influence caused by MIMO time division.
Specifically, the technical scheme of the invention is as follows:
in one aspect, the present application discloses a phase difference compensation method applied to a TDMA-MIMO FMCW radar, the phase difference compensation method comprising:
acquiring an echo signal of each sweep frequency period received by a virtual antenna array of the radar; one sweep period comprises N sweeps;
performing frequency mixing processing on the transmitting signal of the radar and the echo signal to obtain an intermediate frequency signal; the intermediate frequency signal comprises a target distance, a radial speed and phase information of a receiving antenna;
acquiring a speed influence parameter according to the intermediate frequency signal;
compensating the intermediate frequency signal of the corresponding sweep frequency period according to the speed influence parameter, and removing the influence of the speed on the distance and the phase;
and calculating the phase difference of the intermediate frequency signal waveform of each frequency sweeping period after compensation according to the intermediate frequency signal of each frequency sweeping period after compensation.
Preferably, the echo signals are chirp signals, and an intermediate frequency signal corresponding to each chirp signal is represented as follows:
Figure BDA0003597337260000021
wherein R isn＝R0+v*n*T；
c is the speed of light; f. ofc0Is the center frequency; r0Is the target distance; rnThe distance of the target in the nth frequency sweep is taken as the distance; j is a plurality; n is the frequency sweeping times contained in one frequency sweeping period, and T is the time of single frequency sweeping; b is sweep frequency bandwidth; v is the radial velocity;
the speed influencing parameters comprise a first speed influencing parameter and a second speed influencing parameter; wherein:
the first speed influencing parameter is
Figure BDA0003597337260000022
The second speed influencing parameter is
Figure BDA0003597337260000031
Preferably, the intermediate frequency signal of each sweep frequency period is compensated according to the speed influence parameter, and the influence of speed on distance and phase is removed; the method specifically comprises the following steps:
compensating the conjugate of the first and second speed influencing parameters into a time domain signal of the intermediate frequency signal; the conjugate of the first velocity influencing parameter and the second velocity influencing parameter is:
Figure BDA0003597337260000032
performing 2D-FFT on the compensated signals, wherein the phase difference of peak points in each beam spectrum is
Figure BDA0003597337260000033
Where i is the index number of beam, and the value of i is typically a positive integer greater than 1.
Preferably, the phase difference between the compensated beams is consistent with the theoretical phase difference, and the phase difference between the compensated beams is as follows:
Figure BDA0003597337260000034
preferably, the phase difference compensation method further includes:
obtaining phase information of a virtual antenna array of the radar according to the compensated phase difference information; the phase information is independent of the radial velocity;
acquiring the phase relation among the virtual receiving antenna array elements according to the phase information of the virtual antenna array;
and calculating the azimuth angle of the detection target according to the phase relation among the virtual receiving antenna array elements.
On the other hand, the application also discloses a phase difference compensation device, which is applied to the TDMA-MIMO FMCW radar, and the phase difference compensation device comprises:
the echo acquisition module is used for acquiring an echo signal of each sweep frequency period received by the virtual antenna array of the radar; one sweep period comprises N sweeps;
the frequency mixing processing module is used for carrying out frequency mixing processing on the transmitting signal of the radar and the echo signal to obtain an intermediate frequency signal; the intermediate frequency signal comprises a target distance, a radial speed and phase information of a receiving antenna;
the calculation processing module is used for acquiring speed influence parameters according to the intermediate frequency signals;
the signal compensation module is used for compensating the intermediate frequency signal of each sweep frequency period according to the speed influence parameter and removing the influence of the speed on the distance and the phase;
and the calculation processing module is also used for calculating the phase difference of the intermediate frequency signal waveform of each frequency sweep period after compensation according to the intermediate frequency signal of each frequency sweep period after compensation.
Preferably, the echo signals are chirp signals, and an intermediate frequency signal corresponding to each chirp signal is represented as follows:
Figure BDA0003597337260000041
wherein R isn＝R0+v*n*T；
c is the speed of light; f. ofc0Is the center frequency; r0Is the target distance; rnThe distance of the target in the nth frequency sweep is taken as the distance; j is a plurality; n is the frequency sweeping times contained in one frequency sweeping period, and T is the time of single frequency sweeping; b is sweep frequency bandwidth; v is the radial velocity;
the speed influencing parameters comprise a first speed influencing parameter and a second speed influencing parameter; wherein:
the first speed influencing parameter is
Figure BDA0003597337260000042
The second speed influencing parameter is
Figure BDA0003597337260000043
Preferably, the signal compensation module specifically includes:
a conjugate compensation sub-module for compensating the conjugate of the first and second speed influencing parameters into a time domain signal of the intermediate frequency signal; the conjugate of the first and second velocity influencing parameters is:
Figure BDA0003597337260000044
a transformation calculation sub-module for performing 2D-FFT on the compensated signal, wherein the phase difference of the peak point in each beam spectrum is
Figure BDA0003597337260000051
Wherein i >1 and is the number of beams.
Preferably, the phase difference between the compensated beams is consistent with the theoretical phase difference, and the phase difference between the compensated beams is as follows:
Figure BDA0003597337260000052
in another aspect, the present application further discloses a vehicle-mounted millimeter wave radar system, including: any one of the phase difference compensation device and the TDMA-MIMO FMCW radar.
According to the method and the device, the distance gate-walking related parameters are compensated in the intermediate frequency signals according to the speed influence parameters, and the influence of the speed on the distance and the phase is eliminated. After the gate-walking and phase shift caused by the velocity influence are removed, the phase is shifted back to the phase of the first received signal, and the phase obtained by calculation after compensation is not influenced by the velocity any more.
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The above features, technical features, advantages and modes of implementing the present invention will be further described in the following detailed description of preferred embodiments in a clearly understandable manner by referring to the accompanying drawings.
Fig. 1 is a schematic diagram of a Chirp-sequence wave-generating mode commonly used in the prior art;
FIG. 2 is a diagram of MIMO radar transmission and reception in the prior art;
FIG. 3 is a flow chart of an embodiment of the phase difference compensation method of the present invention applied to a TDMA-MIMO FMCW radar;
FIG. 4 is a schematic diagram of a virtual receive antenna in a simulation embodiment;
FIG. 5 is a schematic diagram of a spectral simulation before compensation;
FIG. 6 is a schematic diagram of a compensated spectrum simulation;
FIG. 7 is a diagram illustrating the phase difference between beams before compensation;
FIG. 8 is a diagram illustrating the phase difference between the compensated beams;
fig. 9 is a connection diagram showing the structure of an embodiment of the phase difference compensation device of the present invention.
Detailed Description
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following description will be made with reference to the accompanying drawings. It is obvious that the drawings in the following description are only some examples of the invention, and that for a person skilled in the art, without inventive effort, other drawings and embodiments can be derived from them.
For the sake of simplicity, only the parts relevant to the invention are schematically shown in the drawings, and they do not represent the actual structure as a product. In addition, in order to make the drawings concise and understandable, components having the same structure or function in some of the drawings are only schematically illustrated or only labeled. In this document, "one" means not only "only one" but also a case of "more than one".
It should be further understood that the term "and/or" as used in this specification and the appended claims refers to any and all possible combinations of one or more of the associated listed items and includes such combinations.
In this context, it is to be understood that, unless otherwise explicitly stated or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
In addition, in the description of the present application, the terms "first," "second," and the like are used only for distinguishing the description, and are not intended to indicate or imply relative importance.
In the field of existing vehicle-mounted millimeter wave radars, the MIMO (Multiple Input Multiple Output) technology is a key technology, and compared with a single Input Multiple Output radar, the MIMO radar can use a smaller-scale antenna array to realize a virtual antenna array with a larger aperture, thereby improving the angular resolution of the radar. The FMCW radar (Frequency Modulated Continuous Wave) has the characteristics of low cost, simple structure and small volume, can accurately measure the distance and the speed of a target, and can realize the angle measurement of the target by combining the application of an antenna array. The frequency modulated continuous wave MIMO radar integrates the advantages of the two radars, and the antenna array with a simpler structure is utilized to realize higher radar angle resolution.
In the prior art, a TDMA or ddma (doppler division) method is selected to solve the MIMO technology, and as long as a TDMA method is adopted, a phase change caused by a relative speed between a target and a radar sensor is affected, so a new method capable of compensating the problem caused by the MIMO technology is provided. Although the DDMA technology can solve the problem of time difference in the multiple snapshot technologies, only a small number of transmitting units can be guaranteed to transmit simultaneously by using the DDMA technology, and the number of transmitting units in the high-performance millimeter wave radar technology of today is very large (usually reaches 12, 24 or more than 48), so the time division transmission mode cannot be avoided basically under the timely use of DDMA or other MIMO modes.
A TDMA-MIMO FMCW (Time Division Multiple Input Multiple Output Modulated Continuous Wave) radar is a Frequency Modulated Continuous Wave MIMO radar that uses a Time Division Multiplexing technique to achieve orthogonal transmission waveforms, and in which the transmission and reception of signals are controlled by a specific Time Division Multiplexing timing sequence. However, this method has disadvantages in that: the phase of the received signal of the virtual antenna array is not only determined by the angle of the target, but also related to the target velocity. In addition, the relative speed of the target not only affects the change of the phase, but also brings about the gate of the distance, and at this time, the phase is compensated by the theoretical compensation phase (theoretical compensation phase formula:
Figure BDA0003597337260000071
) It is difficult to obtain accurate results.
Based on this, referring to the attached fig. 3 of the specification, the invention provides a phase difference compensation method applied to a TDMA-MIMO FMCW radar, the phase difference compensation method comprising:
s101, acquiring an echo signal of each frequency sweeping period received by a virtual antenna array of the radar; one sweep period comprises N sweeps;
specifically, the radar is a TDMA-MIMO FMCW radar, P transmitting antennas and Q receiving antennas are set in the radar, a corresponding virtual antenna array is a uniform linear array, PQ antenna array elements are provided, the radar obtains echo signals after each frequency sweep through the set time division multiplexing time sequence of the transmitting antennas and the receiving antennas by the virtual antenna array according to the sequence of the 1 st array element, the 2 nd array element, the 3 rd array element, the. The radar typically uses a fast chirp as the transmitted signal. Fast chirp signals generally refer to frequency modulated continuous wave signals that are small in duration and large in bandwidth. And through the time division multiplexing time sequence of the transmitting antenna array element and the receiving antenna array element, the virtual antenna array receives the reflected echo signal according to the specific time division multiplexing time sequence.
S102, performing frequency mixing processing on the transmitting signal of the radar and the echo signal to obtain an intermediate frequency signal; the intermediate frequency signal comprises a target distance, a radial speed and phase information of a receiving antenna;
specifically, the echo signal is amplified by a low noise amplifier, and is mixed with a local oscillation signal (a part of a transmission signal) by a mixer, thereby outputting an intermediate frequency signal (or referred to as a difference frequency signal) containing information such as a distance and a relative speed between a target and a radar, and a phase of a receiving antenna.
S103, acquiring a speed influence parameter according to the intermediate frequency signal;
in particular, since the relative velocity between the target and the radar affects the phase and the distance, it is necessary to obtain the influence parameter (i.e. velocity influence parameter) introduced by the relative velocity. The intermediate frequency signal contains radial velocity information, and thus, velocity influencing parameters can be calculated.
S104, compensating the intermediate frequency signal of each sweep frequency period according to the speed influence parameter, and removing the influence of the speed on the distance and the phase;
specifically, after the speed influence parameter is acquired, the relevant part in the intermediate frequency signal of each sweep frequency period is compensated, and the influence of the relative speed on the distance and the phase is eliminated.
And S105, calculating the phase difference of the intermediate frequency signal waveform of each frequency sweep period after compensation according to the intermediate frequency signal of each frequency sweep period after compensation.
Specifically, after the influence of the velocity on the phase is eliminated, the phase between beams corresponds to the theoretical phase. And then the phase difference between the compensated receiving antennas can be calculated. One sweep period can be regarded as beam, the phase information irrelevant to the speed is obtained through the compensation of the theoretical phase, and then the angle can be calculated through the phase relation between channels. A complete set of emissions is one beam, i.e., each beam can be considered as one complete sweep period.
In another embodiment of the present application, based on the above embodiment, the intermediate frequency signal includes target distance, radial velocity, and antenna phase information. The echo signals are chirp signals, and an intermediate frequency signal corresponding to each chirp signal is represented as follows:
Figure BDA0003597337260000091
wherein R isn＝R0+v*n*T；
c is the speed of light; f. ofc0Is the center frequency; r0Is the target distance; rnThe distance of the target in the nth frequency sweep is taken as the distance; j is a plurality; n is frequency sweeping times, and T is single frequency sweeping time; b is sweep frequency bandwidth; v is the radial velocity; n is the nth frequency sweep; t is the point in time of the sampling.
R is to benThe spread, expanded intermediate frequency signal is represented as follows:
Figure BDA0003597337260000092
wherein the distance-to-door related parameter, i.e. the speed-influencing parameter, comprises a first speed-influencing parameter
Figure BDA0003597337260000093
Influencing a parameter with a second speed
Figure BDA0003597337260000094
Two parts.
These two parts are compensated in the intermediate frequency signal, eliminating the influence of speed on distance and phase. Specifically, the conjugation of the first speed influencing parameter and the second speed influencing parameter is compensated to a time domain signal of the intermediate frequency signal; the conjugate of the first and second velocity influencing parameters is:
Figure BDA0003597337260000095
and 2D-FFT is carried out on the compensated signal, and the phase difference of peak points in each beam spectrum is as follows:
Figure BDA0003597337260000101
where i is the index number of beam, such as beam3, then i is 3; c is the speed of light; f. ofc0Is the center frequency; r0Is the target distance; n is frequency sweeping times; j is a plurality; n is frequency sweeping times, and T is single frequency sweeping time; b is sweep frequency bandwidth; v is the radial velocity.
Therefore, if the walk-gate and phase shift caused by the velocity influence are removed, the phase shifts back to the phase of the first received signal. Eliminating the influence of speed on the phase.
After eliminating the phase effect, the phase between beams corresponds to the theoretical phase:
Figure BDA0003597337260000102
in this case, the velocity-independent phase information can be obtained by compensating the theoretical phase, and then the angle can be calculated by the phase relationship between the channels.
The following description is made with reference to specific simulation examples. The radar parameters set by simulation are as follows:
frequency sweeping mode: FMCW; center frequency: 76.5 GHz; frequency sweep bandwidth: 400 MHz;
the speed range v [ -200 km/h-400 km/h ]; number of transmitting antennas: 3, Beam number: 3;
emission time between beams: [0,128 × T,256T ]; receiving a channel: 4, the number of the channels is 4; the virtual receive antenna is shown in fig. 4.
To see the more obvious results on the spectrum on the 2D-FFT, we chose-800 km/h simulation.
The compensation comparison results are shown in fig. 5 and 6, and fig. 5 is a frequency spectrum simulation diagram before compensation; FIG. 6 is a graph of a compensated spectrum simulation; in FIGS. 5 and 6, the first row is the 2d-FFT result of beam1, and the second row is the 2d-FFT result of beam3, and the comparison before and after compensation clearly shows that the gate of the distance is complemented back.
Fig. 7 and 8 show the case of compensating the phase difference between the front beam and the rear beam, respectively. In this example, the phase of the receiving antenna channels at four different positions is plotted at the same time, and in fig. 7 and 8, the abscissa is the relative velocity Vd (i.e., the radial velocity v), and the ordinate is the phase difference, specifically, the first line is the phase difference between beam1 and beam2, and the second line is the phase difference between beam1 and beam 3. Fig. 7 shows the result of no phase compensation, and fig. 8 shows the result of phase compensation. As can be seen from the figure, the phase between beams after compensation exhibits the same law as the theoretical value. The phase shift can be filled up by theoretical results.
Another embodiment of the method of the present invention, on the basis of any of the above embodiments, further comprises the steps of:
obtaining phase information of a virtual antenna array of the radar according to the compensated phase difference information; the phase information is independent of the radial velocity;
acquiring the phase relation among the virtual receiving antenna array elements according to the phase information of the virtual antenna array;
and calculating the azimuth angle of the detection target according to the phase relation among the virtual receiving antenna array elements.
Specifically, the present embodiment may obtain the velocity-independent phase information through the compensation of the theoretical phase, and then may calculate the angle through the phase relationship between the channels.
On the other hand, the present application also discloses a phase difference compensation device applied to a TDMA-MIMO FMCW radar, wherein an embodiment of the phase difference compensation device, as shown in fig. 9, includes:
an echo acquisition module 100, configured to acquire an echo signal of each sweep frequency period received by a virtual antenna array of the radar; one sweep period comprises N sweeps;
a frequency mixing processing module 200, configured to perform frequency mixing processing on the transmitting signal of the radar and the echo signal to obtain an intermediate frequency signal; the intermediate frequency signal comprises a target distance, a radial speed and phase information of a receiving antenna;
a calculation processing module 300, configured to obtain a speed influence parameter according to the intermediate frequency signal;
the signal compensation module 400 is configured to compensate the intermediate frequency signal of each sweep frequency period according to the speed influence parameter, and remove influence of speed on distance and phase;
the calculation processing module 300 is further configured to calculate a phase difference between the waveforms of the intermediate frequency signals in each compensated frequency sweep period according to the compensated intermediate frequency signals in each frequency sweep period.
In one embodiment, the echo signals are chirp signals, and an intermediate frequency signal corresponding to each chirp signal is represented as follows:
Figure BDA0003597337260000121
wherein R isn＝R0+v*n*T；
c is the speed of light; f. ofc0Is the center frequency; r is0Is the target distance; r isnThe distance of the target during the nth frequency sweep is taken as the distance; n is the nth frequency sweep; j is a plurality; n is the frequency sweeping times contained in one frequency sweeping period, and T is the time of single frequency sweeping; b is sweep frequency bandwidth; v is the radial velocity;
r is to benExpanding and substituting the intermediate frequency signal formula to obtain:
Figure BDA0003597337260000122
wherein the parameters related to the distance to the door, namely the speed influence parameters, comprise: first speed influencing parameter
Figure BDA0003597337260000123
Influencing a parameter with a second speed
Figure BDA0003597337260000124
Two parts.
After the speed influence parameters are obtained, the signal compensation module compensates the two parts in the intermediate frequency signals, and the influence of the speed on the distance and the phase is eliminated. These two parts are compensated in the intermediate frequency time domain signal.
Specifically, the signal compensation module specifically includes:
a conjugate compensation sub-module, configured to compensate the conjugate of the first speed influencing parameter and the second speed influencing parameter into a time domain signal of the intermediate frequency signal; the conjugate of the first and second velocity influencing parameters is:
Figure BDA0003597337260000125
a transformation calculation submodule for performing 2D-FFT on the compensated signal, wherein the phase difference of the peak point in each beam spectrum is
Figure BDA0003597337260000126
Where i is a positive integer greater than 1 and is the index number of beam.
The phase difference between the compensated beams corresponds to the theoretical phase difference, and the phase difference between the compensated beams is as follows:
Figure BDA0003597337260000131
in the above formulas of this embodiment, c is the speed of light; r0Is the target distance; n is frequency sweeping times; f. ofc0Is the center frequency; j is a plurality; n is frequency sweeping times, and T is single frequency sweeping time; b is sweep frequency bandwidth; v is the radial velocity.
It should be noted that, in each formula of the present application, the meanings represented by the same letters are the same, and in order to reduce the repetition, the repeated description is omitted, and the meanings represented by the letters in the formula can be referred to.
In another embodiment of the phase difference compensation device according to the present application, in addition to any one of the above embodiments of the device, the phase difference compensation device further includes: an azimuth acquisition module for acquiring a detection target (target object)
Is measured. The azimuth acquisition module specifically comprises:
the phase acquisition submodule is used for acquiring the phase information of the virtual antenna array of the radar according to the compensated phase difference information; the phase information is independent of the radial velocity;
the phase obtaining sub-module is further configured to obtain a phase relationship between the virtual receiving antenna array elements according to the phase information of the virtual antenna array;
and the azimuth angle calculation submodule is used for calculating the azimuth angle of the detection target according to the phase relation among the virtual receiving antenna array elements.
The embodiments of the phase compensation apparatus in the present application correspond to the embodiments of the phase compensation method, the technical concept is the same, and the technical information in the embodiments of the phase compensation method is also applicable to the embodiments of the phase compensation apparatus, which is not described again to reduce the repetition.
Another embodiment of the present application discloses an on-vehicle millimeter wave radar system, includes: any one of the above embodiments of the phase difference compensation apparatus and the TDMA-MIMO FMCW radar.
Specifically, the phase difference compensation apparatus according to any of the embodiments described above is integrated in a TDMA-MIMO FMCW radar, and performs signal processing, especially phase difference compensation, on echo signals acquired by the TDMA-MIMO FMCW radar to eliminate the influence of speed on phase and distance.
It should be noted that the above embodiments can be freely combined as necessary. The foregoing is only a preferred embodiment of the present invention, and it should be noted that it is obvious to those skilled in the art that various modifications and improvements can be made without departing from the principle of the present invention, and these modifications and improvements should also be considered as the protection scope of the present invention.

Claims (10)

1. A phase difference compensation method applied to a TDMA-MIMO FMCW radar, the phase difference compensation method comprising:
acquiring an echo signal of each sweep frequency period received by a virtual antenna array of the radar; one sweep period comprises N sweeps;
performing frequency mixing processing on the transmitting signal of the radar and the echo signal to obtain an intermediate frequency signal; the intermediate frequency signal comprises a target distance, a radial speed and phase information of a receiving antenna;
acquiring a speed influence parameter according to the intermediate frequency signal;
compensating the intermediate frequency signal of the corresponding sweep frequency period according to the speed influence parameter, and removing the influence of the speed on the distance and the phase;
and calculating the phase difference of the intermediate frequency signal waveform of each frequency sweeping period after compensation according to the intermediate frequency signal of each frequency sweeping period after compensation.
2. The phase difference compensation method according to claim 1,
the echo signals are chirp signals, and an intermediate frequency signal corresponding to each chirp signal is represented as follows:
Figure FDA0003597337250000011
wherein R isn＝R0+v*n*T；
c is the speed of light; f. ofc0Is the center frequency; r0Is the target distance; r isnThe distance of the target during the nth frequency sweep is taken as the distance; j is a plurality; n is the frequency sweeping times contained in one frequency sweeping period, and T is the time of single frequency sweeping; b is sweep frequency bandwidth; v is the radial velocity;
the speed influencing parameters comprise a first speed influencing parameter and a second speed influencing parameter; wherein:
the first speed influencing parameter is
Figure FDA0003597337250000012
The second speed influencing parameter is
Figure FDA0003597337250000013
3. The phase difference compensation method according to claim 2, wherein the compensating the intermediate frequency signal of each sweep frequency period according to the speed influence parameter removes the influence of speed on distance and phase; the method specifically comprises the following steps:
compensating the conjugate of the first and second speed influencing parameters into a time domain signal of the intermediate frequency signal; the conjugate of the first and second velocity influencing parameters is:
Figure FDA0003597337250000021
performing 2D-FFT on the compensated signal, wherein the phase difference of peak points in each beam spectrum is
Figure FDA0003597337250000022
Where i is the index number of beam.
4. The phase difference compensation method according to claim 3, wherein the phase difference between the compensated beams is identical to the theoretical phase difference, and the phase difference between the compensated beams is as follows:
Figure FDA0003597337250000023
5. the phase difference compensation method according to any one of claims 1 to 4, characterized by further comprising:
obtaining phase information of a virtual antenna array of the radar according to the compensated phase difference information; the phase information is independent of the radial velocity;
acquiring the phase relation among the virtual receiving antenna array elements according to the phase information of the virtual antenna array;
and calculating the azimuth angle of the detection target according to the phase relation among the virtual receiving antenna array elements.
6. A phase difference compensation apparatus applied to a TDMA-MIMO FMCW radar, the phase difference compensation apparatus comprising:
the echo acquisition module is used for acquiring an echo signal of each sweep frequency period received by the virtual antenna array of the radar; one sweep period contains N sweeps;
the frequency mixing processing module is used for carrying out frequency mixing processing on the transmitting signal of the radar and the echo signal to obtain an intermediate frequency signal; the intermediate frequency signal comprises a target distance, a radial speed and phase information of a receiving antenna;
the calculation processing module is used for acquiring speed influence parameters according to the intermediate frequency signals;
the signal compensation module is used for compensating the intermediate frequency signal of the corresponding frequency sweeping period according to the speed influence parameter and removing the influence of the speed on the distance and the phase;
and the calculation processing module is also used for calculating the phase difference of the intermediate frequency signal waveform of each frequency sweep period after compensation according to the intermediate frequency signal of each frequency sweep period after compensation.
7. Phase difference compensation apparatus according to claim 6,
the echo signals are chirp signals, and an intermediate frequency signal corresponding to each chirp signal is represented as follows:
Figure FDA0003597337250000031
wherein R isn＝R0+v*n*T；
c is the speed of light; f. ofc0Is the center frequency; r0Is the target distance; r isnThe distance of the target in the nth frequency sweep is taken as the distance; j is a plurality; n is frequency sweeping times, and T is single frequency sweeping time; b is sweep frequency bandwidth; v isA radial velocity;
the speed influencing parameters comprise a first speed influencing parameter and a second speed influencing parameter; wherein:
the first speed influencing parameter is
Figure FDA0003597337250000032
The second speed influencing parameter is
Figure FDA0003597337250000033
8. The phase difference compensation device according to claim 7, wherein the signal compensation module specifically comprises:
a conjugate compensation sub-module for compensating the conjugate of the first and second speed influencing parameters into a time domain signal of the intermediate frequency signal; the conjugate of the first and second velocity influencing parameters is:
Figure FDA0003597337250000041
Figure FDA0003597337250000042
a transformation calculation submodule for performing 2D-FFT on the compensated signal, wherein the phase difference of the peak point in each beam spectrum is
Figure FDA0003597337250000043
Where i is the index number of beam.
9. The phase difference compensation device according to claim 8, wherein the phase difference between the compensated beams coincides with a theoretical phase difference, and the phase difference between the compensated beams is as follows:
Figure FDA0003597337250000044
10. an on-vehicle millimeter wave radar system, comprising: a phase difference compensation device as claimed in any one of claims 6 to 9, and a TDMA-MIMO FMCW radar.
CN202210396130.6A 2022-04-14 2022-04-14 Phase difference compensation method and device and vehicle-mounted millimeter wave radar system Pending CN114755684A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115079158A (en) * 2022-08-24 2022-09-20 珠海正和微芯科技有限公司 FMCW radar ranging device and method based on phase tracking, electronic device and medium
CN115421134A (en) * 2022-08-15 2022-12-02 赛恩领动(上海)智能科技有限公司 Method and device for resolving ambiguity of radar speed and millimeter wave radar

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115421134A (en) * 2022-08-15 2022-12-02 赛恩领动(上海)智能科技有限公司 Method and device for resolving ambiguity of radar speed and millimeter wave radar
CN115421134B (en) * 2022-08-15 2023-12-19 赛恩领动(上海)智能科技有限公司 Method and device for resolving ambiguity of speed of radar and millimeter wave radar
CN115079158A (en) * 2022-08-24 2022-09-20 珠海正和微芯科技有限公司 FMCW radar ranging device and method based on phase tracking, electronic device and medium
CN115079158B (en) * 2022-08-24 2022-11-18 珠海正和微芯科技有限公司 FMCW radar ranging device, FMCW radar ranging method, electronic device and FMCW radar ranging medium based on phase tracking

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