阅读说明：本技术 获取目标物速度的方法、传感器、计算机设备和存储介质 (Method for acquiring speed of target object, sensor, computer device and storage medium ) 是由 朱砚 张小龙 于 2020-10-22 设计创作，主要内容包括：本申请涉及一种获取目标物速度的方法、获取多普勒模糊数的方法、传感器、计算机设备和存储介质,涉及传感器技术领域,该获取目标物速度的方法通过引入多普勒模糊数来提升传感器测速的精确性,即利用第一发射通道一次发射两个啁啾信号,相当于在传统FMCW传感器中一个发射通道所发射信号的前面或后面增加一个啁啾信号,并获取该两个啁啾信号在回波信号中目标峰值位置的相位差,以得到多普勒模糊数(即q),并可利用该多普勒模糊数进行解速度模糊,从而确定目标物的速度。(The method for obtaining the speed of the target object improves the accuracy of speed measurement of the sensor by introducing the Doppler fuzzy number, namely, a first transmitting channel is used for transmitting two chirp signals at a time, namely, one chirp signal is added in front of or behind a signal transmitted by one transmitting channel in the traditional FMCW sensor, the phase difference of the two chirp signals at the position of a target peak value in an echo signal is obtained to obtain the Doppler fuzzy number (namely q), and the Doppler fuzzy number can be used for solving the speed ambiguity, so that the speed of the target object is determined.)

1. A method for obtaining a velocity of a target object, the method being applied to a sensor for transmitting frequency modulated continuous wave signals in a time division multiplexing manner, the sensor having a first transmission channel and at least one second transmission channel, the first transmission channel being capable of transmitting two chirp signals at a time, and each of the second transmission channels being capable of transmitting one chirp signal at a time, the method comprising:

acquiring a target peak position in an echo signal;

acquiring the phase difference of the two chirp signals at the target peak position;

determining a Doppler fuzzy number according to the phase difference; and

determining a velocity of the target object based on the Doppler ambiguity number.

2. The method according to claim 1, wherein the first transmission channel transmits two chirp signals at a time with a first preset time delay therebetween; the determining a doppler ambiguity number according to the phase difference comprises:

determining the Doppler fuzzy number according to the phase difference and the first preset time delay;

wherein the value of the first preset time delay is greater than zero.

3. The method according to claim 1 or 2, wherein the two chirp signals include a first chirp signal and a second chirp signal which are sequentially transmitted; the determining a doppler ambiguity number according to the phase difference comprises:

acquiring a phase value of the first chirp signal and a phase value of the second chirp signal at the target peak position;

acquiring a phase difference between the first chirp signal and the second chirp signal at the target peak position according to the phase value of the first chirp signal and the phase value of the second chirp signal; and

and determining the Doppler fuzzy number according to the phase difference.

4. The method according to claim 3, wherein the obtaining of the phase value of the first chirp signal and the phase value of the second chirp signal at the target peak position comprises:

acquiring a time domain subsequence of the first chirp signal and a time domain subsequence of the second chirp signal;

and performing two-dimensional fast fourier transform processing on the time domain subsequence of the first chirp signal and the time domain subsequence of the second chirp signal respectively to obtain a phase value of the first chirp signal and a phase value of the second chirp signal at the target peak position.

5. The method according to claim 3, wherein the first transmission channel transmits two chirp signals at a time with a first preset time delay therebetween; the obtaining a phase difference at the target peak position according to the phase value of the first chirp signal and the phase value of the second chirp signal includes:

acquiring a fuzzy Doppler frequency; and

and acquiring the phase difference according to the phase value of the first chirp signal, the phase value of the second chirp signal, the first preset time delay, the fuzzy Doppler frequency and the chirp period in the frequency modulation continuous wave signal.

6. The method of claim 3, wherein the first chirp signal and the second chirp signal are the same.

7. The method of claim 1, wherein said determining a doppler ambiguity number from said phase difference comprises:

and acquiring the Doppler fuzzy number according to the decimal part of the phase difference.

8. The method of claim 7, wherein the first transmission channel transmits two chirp signals at a time with a first preset time delay therebetween; the obtaining the doppler ambiguity number according to the fractional part of the phase difference comprises:

acquiring a value of a decimal part of the phase difference divided by 360 degrees;

and acquiring the Doppler fuzzy number based on the first preset time delay, the chirp period in the frequency modulation continuous wave signal, the emission period of the sensor and the value of the fractional part.

9. The method of claim 1, wherein the first transmit channel transmits two chirp signals per transmit period, and wherein each of the second transmit channels transmits one chirp signal per transmit period.

10. The method of claim 1, wherein the first transmit channel transmits two chirp signals in a first transmit period and one chirp signal in a second transmit period, and wherein each of the second transmit channels transmits one chirp signal at a time.

11. The method of any one of claims 1-10, wherein the sensor is a MIMO sensor.

12. The method of claim 1, wherein the first transmit channel is further configured to transmit at least three chirp signals at a time, and wherein each of the second transmit channels transmits one chirp signal at a time; the obtaining the phase difference of the two chirp signals at the target peak position comprises:

acquiring the phase difference of two adjacent chirp signals of the at least three chirp signals at the target peak position.

13. A method for obtaining doppler ambiguity numbers, applied to a sensor for transmitting frequency modulated continuous wave signals in a time division multiplexing manner, the sensor having a first transmission channel and at least one second transmission channel, the first transmission channel transmitting two chirp signals in each of at least part of transmission periods, the two chirp signals having a second time delay therebetween, each of the second transmission channels transmitting a chirp signal in each transmission period, the method comprising:

acquiring a target peak position in an echo signal;

acquiring the phase difference of the two chirp signals at the target peak position; and

determining a Doppler fuzzy number according to the phase difference and the second time delay;

wherein the value of the second delay is greater than or equal to zero.

14. The method of claim 13, wherein the two chirp signals comprise a first chirp signal and a second chirp signal that are transmitted sequentially; the obtaining the phase difference of the two chirp signals at the target peak position comprises:

acquiring a time domain subsequence of the first chirp signal and a time domain subsequence of the second chirp signal;

performing two-dimensional fast fourier transform processing on the time domain subsequence of the first chirp signal and the time domain subsequence of the second chirp signal respectively to obtain a phase value of the first chirp signal and a phase value of the second chirp signal at the target peak position; and

acquiring a phase difference between the first chirp signal and the second chirp signal at the target peak position based on the phase value of the first chirp signal and the phase value of the second chirp signal.

15. The method of claim 13, wherein determining a doppler ambiguity number based on the phase difference and the second time delay comprises:

acquiring a fuzzy Doppler frequency;

acquiring the chirp period of the frequency modulated continuous wave signal;

acquiring the emission period of the sensor; and

acquiring the Doppler ambiguity number based on the phase difference, the ambiguity Doppler frequency, the chirp period, the second time delay and the transmission period.

16. The method of claim 15, wherein the obtaining the doppler ambiguity number based on the phase difference, the ambiguity doppler frequency, the chirp period, the second time delay, and the transmit period further comprises:

acquiring the phase difference of two chirp signals at the position of a target peak value based on the phase difference, the fuzzy Doppler frequency, the chirp period and the second time delay;

obtaining a fractional portion of a first value, the first value being equal to the phase difference divided by 360 degrees;

obtaining a fractional part of a second value, the second value being equal to the sum of the chirp period and the second time delay multiplied by the doppler ambiguity number divided by the transmit period; and

and acquiring the Doppler fuzzy number according to the fact that the decimal part of the first numerical value is equal to the decimal part of the second numerical value.

17. A sensor, comprising:

a first transmission channel for transmitting two chirp signals in at least a part of a transmission period;

a second transmission channel for transmitting a chirp signal in each transmission period;

the receiving channel is used for receiving echo signals; and

and the signal processing module is used for acquiring the position of a target peak value in the echo signal, acquiring the phase difference of the two chirp signals at the position of the target peak value, and determining the Doppler fuzzy number according to the phase difference.

18. Sensor according to claim 17, characterized in that the signal processing module is also adapted to implement a method of acquiring a speed of an object according to any of claims 1-12, and/or

A method of obtaining a doppler ambiguity number as claimed in any one of claims 13-16 is implemented.

19. A sensor as claimed in claim 17 or 16, wherein the sensor is a millimeter wave radar chip.

20. The sensor of claim 19, wherein the millimeter wave radar chip is an AiP chip.

21. A computer device comprising a memory and a processor, the memory storing a computer program, characterized in that the processor implements the steps of the method of any one of claims 1-12 when executing the computer program or implements the steps of the method of any one of claims 13-16 when executing the computer program.

22. A computer-readable storage medium, on which a computer program is stored, which, when being executed by a processor, carries out the steps of the method of any of claims 1-12, or which, when being executed by a processor, carries out the steps of the method of any of claims 13-16.

Technical Field

The present application relates to the field of sensor technologies, and in particular, to a method, a sensor, a computer device, and a storage medium for obtaining a speed of a target object.

Background

Frequency Modulation Continuous Wave (FMCW) is a common speed measurement technology, and is widely applied to various sensor speed measurement scenes. The process of performing velocity measurement based on FMCW is generally: and transmitting the frequency-modulated continuous wave by using a transmitting antenna, acquiring an echo signal reflected by the target object, and performing signal processing on a mixed signal obtained by mixing the transmitting signal and the echo signal so as to determine the speed of the target object based on the Doppler frequency shift.

However, in practical applications, the velocity of the target object obtained based on the doppler shift is not accurate enough, especially when the doppler shift f is small_dWhen the target object detection accuracy exceeds (-F/2, F/2), the accuracy of the target object obtained by the traditional sensor is not high, and the target detection effect is further influenced. Where F denotes a repetition frequency of a chirp signal (chirp) in the transmission signal.

Disclosure of Invention

Based on this, it is necessary to provide a method of acquiring a velocity of a target object, a method of acquiring a doppler blur number, a sensor, a computer device, and a storage medium, for a problem that the accuracy of velocity measurement of the target object is not high.

In a first aspect, a method for obtaining a velocity of a target object may be applied to a sensor that transmits frequency-modulated continuous wave signals in a time-division multiplexing manner, where the sensor has a first transmission channel and at least one second transmission channel, the first transmission channel may transmit two chirp signals at a time, and each of the second transmission channels may transmit one chirp signal at a time, and the method may include:

acquiring a target peak position in an echo signal;

acquiring the phase difference of the two chirp signals (namely, the two chirp signals transmitted by the first transmission channel at one time) at the target peak position;

determining a Doppler fuzzy number according to the phase difference; and

determining a velocity of the target object based on the Doppler ambiguity number.

The method for obtaining the speed of the target object improves the accuracy of speed measurement of the sensor by introducing the doppler ambiguity number, namely, the first transmitting channel is used for transmitting two chirp signals at a time, namely, one chirp signal is added in front of or behind a signal transmitted by one transmitting channel in the traditional FMCW sensor, and the phase difference of the two chirp signals at the target peak position in the echo signal is obtained to obtain the doppler ambiguity number (i.e. q), and the doppler ambiguity number can be used for carrying out velocity ambiguity resolution, so that the speed of the target object is determined.

Optionally, a first preset time delay is provided between two chirp signals transmitted by the first transmission channel each time; the determining a doppler ambiguity number according to the phase difference comprises:

determining the Doppler fuzzy number according to the phase difference and the first preset time delay;

wherein the value of the first preset time delay is greater than zero.

In the embodiment, the accuracy of the obtained Doppler fuzzy number is improved by setting the first preset time delay between two chirps transmitted at the same time, so that the accuracy of the speed measurement of the sensor is further improved.

Optionally, the two chirp signals include a first chirp signal and a second chirp signal which are transmitted in sequence; the determining a doppler ambiguity number according to the phase difference comprises:

acquiring a phase value of the first chirp signal and a phase value of the second chirp signal at the target peak position;

acquiring a phase difference between the first chirp signal and the second chirp signal at the target peak position according to the phase value of the first chirp signal and the phase value of the second chirp signal; and

and determining the Doppler fuzzy number according to the phase difference.

In this embodiment, the accuracy of the obtained doppler ambiguity number is improved by using all the phase differences, and the accuracy of the velocity measurement of the sensor is further improved.

Optionally, the obtaining, at the target peak position, a phase value of the first chirp signal and a phase value of the second chirp signal includes:

acquiring a time domain subsequence of the first chirp signal and a time domain subsequence of the second chirp signal;

and performing two-dimensional fast fourier transform processing on the time domain subsequence of the first chirp signal and the time domain subsequence of the second chirp signal respectively to obtain a phase value of the first chirp signal and a phase value of the second chirp signal at the target peak position.

In this embodiment, two chirped time domain subsequences transmitted at the same time are obtained through sampling, and two-dimensional fast fourier transform processing is performed, so that a phase value corresponding to a chirp signal at a target peak position can be obtained by combining with a conventional signal processing process, and the design and implementation difficulty of data signal processing can be effectively reduced.

Optionally, a first preset time delay is provided between two chirp signals transmitted by the first transmission channel each time; the obtaining a phase difference at the target peak position according to the phase value of the first chirp signal and the phase value of the second chirp signal includes:

acquiring a fuzzy Doppler frequency; and

and acquiring the phase difference according to the phase value of the first chirp signal, the phase value of the second chirp signal, the first preset time delay, the fuzzy Doppler frequency and the chirp period in the frequency modulation continuous wave signal.

In this embodiment, the first preset delay and the chirp period can be directly obtained, and the fuzzy doppler frequency can be easily obtained by combining some embodiments of the present application or conventional techniques, so that the difficulty in designing and implementing subsequent data signal processing, such as phase difference and ambiguity resolution, can be further reduced.

Optionally, the first chirp signal and the second chirp signal are the same.

In this embodiment, since the two chirp signals have the same shape, start frequency and period of the sweep frequency, and other parameters, the difficulty in generating the chirp signal can be effectively reduced, and if only one chirp signal is added to form two chirp signals transmitted by the first transmission channel each time as compared with a conventional sensing system, the method can be implemented based on a conventional signal generation device, thereby reducing the difficulty and cost in implementing the system.

Optionally, the determining a doppler ambiguity number according to the phase difference includes:

and acquiring the Doppler fuzzy number according to the decimal part of the phase difference.

In this embodiment, the doppler ambiguity number can be quickly obtained by using the conventional round function, so as to further reduce the difficulty of system implementation.

Optionally, a first preset time delay is provided between two chirp signals transmitted by the first transmission channel each time; the obtaining the doppler ambiguity number according to the fractional part of the phase difference comprises:

acquiring a value of a decimal part of the phase difference divided by 360 degrees;

and acquiring the Doppler fuzzy number based on the first preset time delay, the chirp period in the frequency modulation continuous wave signal, the emission period of the sensor and the value of the fractional part.

In this embodiment, the doppler ambiguity number is obtained by dividing the first preset delay, the chirp period, and the phase difference by the fractional value of 360 degrees, and the difficulty in implementing the technical scheme of the present application can be further reduced by some data easily obtained in the embodiments of the present application.

Optionally, the first transmission channel transmits two chirp signals in each transmission period, and each of the second transmission channels transmits one chirp signal in each transmission period.

In the embodiment, the first transmitting channel transmits two chirp signals in each transmitting period, and each second transmitting channel transmits one chirp signal in each transmitting period, so that the purpose of adding one chirp signal in front of or behind the signal transmitted by the first transmitting channel in each transmitting period is achieved, and the phase difference of the two chirp signals at the position of the target peak in the echo signal is obtained on the basis of the chirp signals, so as to obtain the Doppler fuzzy number (namely q), thereby improving the accuracy of the detected speed of the target object.

Optionally, the first transmission channel transmits two chirp signals in a first transmission period, and transmits one chirp signal in a second transmission period, and each second transmission channel transmits one chirp signal at a time.

In this embodiment, in the whole signal transmission process, the first transmission channel only adds one chirp signal in front of or behind the signal transmitted in the first transmission period, which reduces the difficulty in controlling the transmitted signal and further reduces the difficulty in implementing the technical scheme of the present application.

Optionally, the sensor is an MIMO (multiple input multiple output) sensor (such as a millimeter wave radar and other frequency radio sensors), and on the premise of no conflict, the scheme in the embodiment of the present application may also be applied to various MIMO communication systems.

Optionally, the first transmission channel may further transmit at least three chirp signals at a time, and each of the second transmission channels transmits one chirp signal at a time; the obtaining the phase difference of the two chirp signals at the target peak position comprises:

acquiring the phase difference of two adjacent chirp signals of the at least three chirp signals at the target peak position.

In the embodiment, the method can be realized based on the traditional signal generating device, so that the difficulty and the cost of system realization are reduced.

In a second aspect, a method for obtaining a doppler ambiguity number is applicable to a sensor that transmits frequency modulated continuous wave signals in a time division multiplexing manner, the sensor has a first transmission channel and at least one second transmission channel, the first transmission channel transmits two chirp signals in each of at least part of transmission periods, the two chirp signals have a second time delay therebetween, and each of the second transmission channels transmits one chirp signal in each transmission period, the method includes:

acquiring a target peak position in an echo signal;

acquiring the phase difference of the two chirp signals at the target peak position; and

determining a Doppler fuzzy number according to the phase difference and the second time delay;

wherein the value of the second delay is greater than or equal to zero.

In this embodiment, the phase difference between two chirp signals transmitted by the same transmission channel in the same transmission period and the time delay between the two chirp signals are used to accurately obtain the doppler ambiguity number, so that the doppler ambiguity number is subsequently used to reduce or even eliminate the influence of an excessively large absolute value of the doppler shift (e.g. greater than half of the frequency of the chirp signal) on the velocity ambiguity resolution, and the accuracy of other data signal processing based on the doppler ambiguity number can also be improved.

Optionally, the two chirp signals include a first chirp signal and a second chirp signal which are transmitted sequentially; the obtaining the phase difference of the two chirp signals at the target peak position comprises:

acquiring a time domain subsequence of the first chirp signal and a time domain subsequence of the second chirp signal;

performing two-dimensional fast fourier transform processing on the time domain subsequence of the first chirp signal and the time domain subsequence of the second chirp signal respectively to obtain a phase value of the first chirp signal and a phase value of the second chirp signal at the target peak position; and

acquiring a phase difference between the first chirp signal and the second chirp signal at the target peak position based on the phase value of the first chirp signal and the phase value of the second chirp signal.

In this embodiment, two chirped time domain subsequences transmitted at the same time are obtained through sampling, and two-dimensional fast fourier transform processing is performed, so that a phase value corresponding to a chirp signal at a target peak position can be obtained by combining with a conventional signal processing process, and the design and implementation difficulty of data signal processing can be effectively reduced.

Optionally, the determining a doppler ambiguity number according to the phase difference and the second time delay includes:

acquiring a fuzzy Doppler frequency;

acquiring the chirp period of the frequency modulated continuous wave signal;

acquiring the emission period of the sensor; and

acquiring the Doppler ambiguity number based on the phase difference, the ambiguity Doppler frequency, the chirp period, the second time delay and the transmission period.

In this embodiment, the chirp period, the transmission period, and the second time delay can all be directly obtained, and the doppler frequency and the phase difference can be easily obtained by combining some embodiments of the present application or conventional techniques, so as to further reduce the difficulty in designing and implementing data signal processing such as velocity ambiguity resolution.

Optionally, the obtaining the doppler ambiguity number based on the phase difference, the ambiguity doppler frequency, the chirp period, the second time delay, and the transmission period further includes:

acquiring the phase difference of two chirp signals at the position of a target peak value based on the phase difference, the fuzzy Doppler frequency, the chirp period and the second time delay;

obtaining a fractional portion of a first value, the first value being equal to the phase difference divided by 360 degrees;

obtaining a fractional part of a second value, the second value being equal to the sum of the chirp period and the second time delay multiplied by the doppler ambiguity number divided by the transmit period; and

and acquiring the Doppler fuzzy number according to the fact that the decimal part of the first numerical value is equal to the decimal part of the second numerical value.

In the embodiment, the Doppler fuzzy number is obtained under the condition that the decimal part of the first numerical value is equal to the decimal part of the second numerical value, so that the accuracy of the obtained Doppler fuzzy number is improved, and the accuracy of the speed measurement of the sensor is further improved.

In a third aspect, a sensor may include:

a first transmission channel for transmitting two chirp signals in at least a part of a transmission period;

a second transmission channel for transmitting a chirp signal in each transmission period;

the receiving channel is used for receiving echo signals; and

and the signal processing module is used for acquiring the position of a target peak value in the echo signal, acquiring the phase difference of the two chirp signals at the position of the target peak value, and determining the Doppler fuzzy number according to the phase difference.

Optionally, the signal processing module may be further configured to implement the method for acquiring the speed of the target object according to any one of the embodiments of the present application, and/or

The method for acquiring the Doppler ambiguity number according to any one of the embodiments of the application is implemented.

Optionally, the sensor is a millimeter wave radar chip.

Optionally, the millimeter wave radar chip is an aip (antennas in package) chip.

It should be noted that, in various embodiments of the present application, at least two chirp signals (for example, 2, 3, 4, or 5 chirp signals, specifically, the number of chirp signals may be set based on actual requirements) may be transmitted in the same transmission period (or the same transmission) based on the same transmission channel, and the doppler ambiguity number is obtained by obtaining the phase difference of any adjacent chirp signal in the at least two chirp signals at the target peak. The doppler ambiguity number may be obtained based on a phase difference between two adjacent chirp signals at a target peak, or a phase difference between at least two adjacent chirp signals at the target peak may be obtained, and the obtained phase difference may be averaged to obtain a more accurate phase difference, and the doppler ambiguity number may be obtained based on the more accurate phase difference to further improve the accuracy of resolving the velocity ambiguity.

In a fourth aspect, a computer device may include a memory and a processor, the memory stores a computer program, and the processor implements the steps of the method according to any one of the embodiments of the present application when executing the computer program, and/or implements the steps of the method for acquiring a doppler ambiguity number according to any one of the embodiments of the present application when executing the computer program.

In a fifth aspect, a computer-readable storage medium has stored thereon a computer program which, when being executed by a processor, implements the steps of the method according to any one of the embodiments of the present application, and/or which, when being executed by the processor, implements the steps of the method for acquiring a doppler blur number according to any one of the embodiments of the present application.

According to the method for acquiring the speed of the target object, the method for acquiring the Doppler ambiguity number, the sensor, the computer equipment and the storage medium, the accuracy of resolving the speed ambiguity can be improved by introducing the Doppler ambiguity number, on the basis of the traditional FMCW sensor, two chirp signals are transmitted when a transmission channel transmits the chirp signals each time, the phase difference on the target peak value is acquired on the basis of the time domain subsequences of the two chirp signals, and then the accurate Doppler ambiguity number is acquired on the basis of the phase difference, so that the Doppler frequency shift is corrected, the accuracy of resolving the speed ambiguity is further improved, and the accuracy of other data signal processing results based on the Doppler modulus can also be effectively improved.

Drawings

FIG. 1 is a schematic diagram of an application environment of an embodiment of the present application;

FIG. 2 is a diagram of the internal structure of a computer device in one embodiment;

fig. 3 is a waveform diagram of two chirp signals transmitted by a first transmit channel in one embodiment;

fig. 4 is a waveform diagram of a chirp signal transmitted by the second transmission channel in one embodiment;

FIG. 5 is a waveform diagram of a transmit signal in one embodiment;

FIG. 6 is a schematic flow chart diagram illustrating a method for obtaining a velocity of a target object in one embodiment;

FIG. 7 is a diagram illustrating obtaining a target peak location in one embodiment;

FIG. 8 is a waveform diagram of a transmission signal in another embodiment;

FIG. 9 is a schematic flow chart diagram illustrating a method for obtaining a velocity of a target object in one embodiment;

FIG. 10 is a flow diagram illustrating a method for obtaining a Doppler ambiguity number in one embodiment;

FIG. 11 is a block diagram of a sensor in one embodiment.

Detailed Description

The method, the device, the equipment and the storage medium for acquiring the speed of the target object aim at solving the problem that the speed of the target object determined by the traditional method is inaccurate. The following describes in detail the technical solutions of the present application and how the technical solutions of the present application solve the above technical problems by embodiments and with reference to the drawings. The following several specific embodiments may be combined with each other, and details of the same or similar concepts or processes may not be repeated in some embodiments.

The method for acquiring the speed of the target object provided by the embodiment can be applied to the application environment shown in fig. 1. The transmitting signal transmitted by the transmitting antenna of the radar 100 is reflected by the target 200, so that the receiving antenna on the radar 100 can receive the echo signal reflected by the target 200, and the speed of the target 200 is determined according to the echo signal. When the radar 100 is a multi-transmitting and multi-receiving antenna, the distance between each transmitting antenna may be the same or different, which is not limited in the embodiments of the present application. The distances between each receiving antenna may be the same or different, which is not limited in this application.

In the conventional method, the doppler shift is obtained by performing fast fourier transform on the mixed signal, and the obtained range of the doppler shift is closely related to the repetition frequency of the chirp signal (chirp) of the transmitted signal under the influence of the sampling frequency, specifically, the range of the doppler shift is closely related to the repetition frequency of the chirp signal (chirp) of the transmitted signalWherein F denotes the repetition frequency of chirp of the transmitted signal, F_dRepresenting the doppler shift determined by fast fourier transforming the mixed signal. That is, when the velocity of the target exceeds the range of (-F/2, F/2), the spectrum aliasing occurs, and the Doppler shift F cannot be accurately resolved in the prior art_dThe number of folds between the pulse repetition frequencies F, i.e. the Doppler shift F, cannot be accurately obtained_dThe doppler ambiguity number between the pulse repetition frequencies F causes the target object obtained by the sensor to have low accuracy, thereby affecting the target detection effect.

In order to solve the technical problem, in the embodiment of the present application, the accuracy of resolving the velocity ambiguity is improved by introducing the doppler ambiguity number, and based on the conventional FMCW sensor, the two chirp signals are transmitted in the transmission channel each time when the chirp signal is transmitted, the phase difference on the target peak value is acquired based on the time domain subsequences of the two chirp signals, and then the accurate doppler ambiguity number is acquired based on the phase difference, so that the doppler frequency shift is corrected, the accuracy of resolving the velocity ambiguity is further improved, and meanwhile, the accuracy of performing other data signal processing results based on the doppler modulus can also be effectively improved.

Next, a brief description will be given of an implementation environment of a method for acquiring a velocity of a target object and a method for acquiring a doppler blur number provided in an embodiment of the present application.

In one embodiment of the present application, as shown in fig. 2, a computer device is provided, the internal structure of which may be as shown in fig. 2. The computer device includes a processor, a memory, and a network interface connected by a system bus. Wherein the processor of the computer device is configured to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of an operating system and computer programs in the non-volatile storage medium. The network interface of the computer device is used for communicating with an external terminal through a network connection. The computer program is executed by a processor to implement a method of acquiring a velocity of an object or to implement a method of acquiring a doppler ambiguity number.

Those skilled in the art will appreciate that the architecture shown in fig. 2 is merely a block diagram of some of the structures associated with the disclosed aspects and is not intended to limit the computing devices to which the disclosed aspects apply, as particular computing devices may include more or less components than those shown, or may combine certain components, or have a different arrangement of components.

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments.

First, the sensor and the transmission signal emitted by the sensor used in the embodiment of the present application are described as follows:

the method for acquiring the speed of the target object is applied to a sensor which transmits frequency modulation continuous wave signals in a time division multiplexing mode, and optionally, the sensor is an MIMO sensor.

The sensor has a first transmission channel and at least one second transmission channel, the first transmission channel can transmit two chirp signals at a time, each second transmission channel can transmit one chirp signal at a time, wherein, as shown in fig. 3, fig. 3 shows a schematic diagram of two chirp signals transmitted by the first transmission channel. As shown in fig. 4, fig. 4 is a diagram illustrating a chirp signal transmitted from the second transmission channel. The chirp signal (chirp) is a high frequency continuous wave with frequency varying with time, and may be generally a sawtooth shape or a triangle shape.

The emission period of the sensor refers to the duration of an emission signal in one period, namely the emission period T_DIs composed of multiple chirp periods of chirp signals, wherein the chirp period refers to the duration of each chirp signal, and the chirp period is T_rAnd (4) showing. Fig. 5 shows an exemplary waveform diagram of the transmission signal of a sensor, which is a four-way antenna according to fig. 5 and comprises a first transmission channel and 3 second transmission channels, as shown in fig. 5. Optionally, in this embodiment of the present application, the first transmission channel may transmit two chirp signals in each transmission period, and each second transmission channel transmits one chirp signal in each transmission period, where one transmission period may be represented as: t is_D＝5T_r. For example, a conventional one-frame signal (frame) includes 256 chirp signals (chirp), and 64 transmission periods are required to complete the transmission, in the embodiment of the present application, in each transmission period, the first transmission channel is changed from the conventional transmission of one chirp signal to the transmission of two chirp signals, so in the present technical solution, based on the four antennas shown in fig. 5, the number of transmitted chirp signals may reach 320. That is, 64 chirp signals are newly added in transmitting one frame signal.

Alternatively, in the case where there is a first predetermined time delay between the first chirp signal and the second chirp signal, one transmission period may be represented as T_D＝5T_r+a。

In another embodiment of the present application, the first transmission channel transmits two chirp signals in a first transmission period, and transmits one chirp signal in a second transmission period, each second transmission channel transmitting one chirp signal at a time. For example, a conventional one-frame signal (frame) includes 256 chirp signals (chirp), and it can be seen from the waveform diagram of the transmission signal of the sensor shown in fig. 5 that the sensor has four antennas, and then, it takes 64 transmission cycles to complete in the conventional art. In this embodiment, at least one of the 64 transmission periods is a first transmission period, and the remaining transmission periods are second transmission periods, where in the first transmission period, the sensor may transmit 5 chirp signals, and in the second transmission period, the sensor may transmit 4 chirp signals, that is, 1 to 64 chirp signals may be added to a frame of transmitted signals.

Then, on the basis of the above, as shown in fig. 6, the method for acquiring the speed of the target object provided by the embodiment of the present application may include the following steps:

step 601, the computer device acquires a target peak position in the echo signal.

In the embodiment of the application, after the transmitting signal is sent out by the transmitting antenna of the radar, the signal reflected by the target is received by the receiving antenna of the radar, namely, the echo signal.

In this embodiment, the computer device may perform two-dimensional fast fourier transform on the mixed signal to obtain a target peak position (k) in the echo signal_peak,P_peak). As shown in fig. 7, fig. 7 is a schematic diagram illustrating a target peak position, wherein the process of performing two-dimensional fast fourier transform on the mixed signal is as follows: the mixed signal is sampled, and the sampled data on one chirp is stored as a matrix row, for example, M chirp, correspondingly, the matrix row has M rows, the number of sampling points of each chirp is N, and the column of the matrix is N columns, so that an M × N sampled data matrix can be obtained.

For each row of the data matrix, N-point FFT, namely distance dimension fourier transform, can be performed respectively, and then, doppler FFT, namely velocity dimension fourier transform, is performed longitudinally across chirp on each column of the data matrix, and the combined operation of the distance FFT (row by row) and the doppler FFT (column by column) can be regarded as two-dimensional FFT of each frame of corresponding sampling data, and the two-dimensional FFT can simultaneously distinguish the distance and the velocity of the target object. Therefore, the target peak position of the two-dimensional FFT corresponds to the distance information and the speed information of the target object in front of the radar.

In step 602, the computer device obtains the phase difference between the two chirp signals at the target peak position.

In this embodiment, the two chirp signals are a first chirp signal and a second chirp signal that are sequentially transmitted, where the first chirp signal or the second chirp signal may be a newly added signal unit or a signal unit in an original FMCW signal, and the order of the first chirp signal and the second chirp signal may be arbitrarily arranged. The embodiment of the present application will be described by taking an example in which the first chirp signal is transmitted before and the second chirp signal is transmitted after. Optionally, the first chirp signal and the second chirp signal are the same.

In one embodiment of the present application, the process of acquiring the phase difference of the two chirp signals at the target peak position by the computer device includes the following steps: the computer device may obtain phase values of the two chirp signals at target peak positions, respectively, and may perform a difference between the phase values of the two chirp signals to obtain a phase difference between the two chirp signals at the target peak position.

The process of acquiring the phase values of the two chirp signals at the target peak position by the computer device comprises the following steps:

and acquiring the time domain subsequence of the first chirp signal and the time domain subsequence of the second chirp signal. And respectively carrying out two-dimensional fast Fourier transform processing on the time domain subsequence of the first chirp signal and the time domain subsequence of the second chirp signal so as to obtain the phase value of the first chirp signal and the phase value of the second chirp signal at the position of the target peak value.

Wherein, the time-domain subsequence of the first chirp signal may be represented as:

where n denotes a sampling number for sampling the chirp signal, l denotes a number of the chirp signal, and f_BRepresenting the corresponding frequency component, T, of the object_sRepresenting the sampling interval, f, at which the chirp signal is sampled_rdRepresenting the Doppler frequency, T_DIndicating the duration, T, of a period of the transmitted signal_rWhich indicates the time duration of one chirp signal,r represents the distance between the target and the radar.

The time-domain subsequence of the second chirp signal may be represented as:

wherein the content of the first and second substances,f_Dindicating the corrected frontal Doppler frequency, f_cDenotes the start frequency of the chirp signal, v denotes the velocity of the target object, and c denotes the speed of light.

As can be seen from equations 1 and 2, there is a phase difference f between the first chirp signal and the second chirp signal_D·T_r。

After performing two-dimensional fourier transform on the first chirp signal and the second chirp signal corresponding to equations 1 and 2, phase values of the first chirp signal and the second chirp signal can be obtained. Taking the expressions of equation 1 and equation 2 together, the phase value of the first chirp signal can be expressed as:

the phase value of the second chirp signal is expressed as:

in this embodiment, the phase difference between the first chirp signal and the second chirp signal may be obtained by subtracting the phase value of the second chirp signal from the phase value of the first chirp signal, where the phase difference between the first chirp signal and the second chirp signal may be represented as:

in this embodiment, the phase value of the first chirp signal may be obtained according to the above formula 3, the phase value of the second chirp signal may be obtained according to the above formula 4, and the phase difference between the phase value of the first chirp signal and the phase value of the second chirp signal may be obtained according to the above formula 5.

Step 603, the computer device determines a doppler ambiguity number according to the phase difference.

In an alternative implementation, the computer device may obtain the doppler ambiguity number from a fractional part of the phase difference, wherein the fractional part of the phase difference may be a value of the fractional part of the phase difference divided by 360 degrees, and the fractional part of the phase difference may be expressed as:

equation 7 is constructed from the chirp period in the frequency modulated continuous wave signal, the transmission period of the sensor and the value of the fractional part,

wherein the emission period T of the sensor_DPeriod of chirp T_rAre known numbers, and thus, it can be seen that the same applies to formula 7A decision is made and the doppler ambiguity number q can then be derived based on equation 7.

In step 604, the computer device determines a velocity of the target object based on the doppler ambiguity number.

The doppler frequency can be corrected based on the obtained doppler blur number q to obtain a corrected doppler frequency, and then the velocity of the target object can be calculated based on the corrected doppler frequency.

According to the method and the device, the two chirp signals are transmitted when the chirp signals are transmitted through the transmitting channel every time, the phase difference on the target peak value is acquired based on the time domain subsequences of the two chirp signals, and the accurate Doppler fuzzy number is acquired based on the phase difference, so that the Doppler frequency is corrected, the accuracy of resolving the velocity ambiguity is improved, and the accuracy of the detected velocity of the target object is improved.

In the case of only one receiving antenna, after the echo signal reflected from each target is processed in step 601, the target peak position corresponding to the echo signal of each target can be obtained, and the target peak positions corresponding to the echo signals of different targets are different. For each target object, the phase difference of the first chirp signal and the second chirp signal at the target peak position corresponding to the echo signal of the target object is calculated, then the Doppler fuzzy number is determined according to the phase difference, and the velocity of the target object is calculated through the Doppler fuzzy number.

In practical applications, there may be multiple receive antennas. For convenience of description, an object is taken as an example, echo signals reflected by the object can be received by a plurality of receiving antennas respectively, then a two-dimensional fast fourier transform is performed on the echo signals received by each receiving antenna, so that a target peak position corresponding to each receiving antenna can be obtained, then, a computer device can calculate a phase difference of the first chirp signal and the second chirp signal at each target peak position respectively, and then determine a doppler ambiguity number according to all the phase differences.

The process of determining the doppler ambiguity number according to all the phase differences may be: the average phase difference is obtained by averaging all the phase differences, and the doppler ambiguity number is determined based on the average phase difference, and the procedure for determining the doppler ambiguity number according to the average phase difference can refer to the disclosure of step 603.

In another embodiment of the present application, the first transmission channel transmits two chirp signals at a time with a first preset time delay a therebetween, and the waveform of the transmission signal may be as shown in fig. 8, where the value of the first preset time delay a is greater than zero. Based on this situation, as shown in fig. 9, another method for acquiring a speed of a target object is provided in an embodiment of the present application, where the method includes the following steps:

in step 901, a computer device obtains a target peak position in an echo signal.

Please refer to the disclosure of step 601.

In step 902, the computer device obtains a phase difference between two chirp signals at a target peak position.

In this embodiment, the two chirp signals transmitted at a time by the first transmission channel include a first chirp signal and a second chirp signal that are transmitted sequentially, and optionally, the first chirp signal and the second chirp signal are the same. Since there is a first predetermined time delay a between the first chirp signal and the second chirp signal, the time domain expression of the second chirp signal can be represented by equation 8:

time-domain subsequence of first chirp signal shown in connection with equation 1It can be seen that the time-domain subsequences of the first chirp signal and the second chirp signal have a phase difference f_D·(a+T_r)。

In the embodiment of the present application, after performing two-dimensional fourier transform on the time-domain subsequence of the first chirp signal and the time-domain subsequence of the second chirp signal, it is assumed that the target peak position is (k)_peak,P_peak) Then, the expression of the phase value of the first chirp signal is:

the phase value of the second chirp signal is expressed as:

on this basis, the phase difference of the first chirp signal and the second chirp signal can be expressed as:

optionally, in another embodiment, the process of acquiring the phase difference between the two chirp signals at the target peak position by the computer device may include the following steps: the computer equipment can obtain the first preset time delay a and the chirp period T in the frequency modulation continuous wave signal_rBased on the first predetermined delay a and the chirp period T_rAcquiring a blurred Doppler frequency, wherein the blurred Doppler frequency is represented as: f. of_rd(a+T_r)。

Then, the computer device may acquire a phase value of the first chirp signalPhase value of the second chirp signalAnd determining the phase difference of the first chirp signal and the second chirp signal at the position of the target peak according to the phase value of the first chirp signal, the phase value of the second chirp signal and the fuzzy Doppler frequency. The calculation process of the phase difference can be shown as formula 12:

step 903, the computer device determines a doppler ambiguity number according to the phase difference and the first preset delay.

In this embodiment, the computer device may obtain a fractional part of the phase difference, where the fractional part of the phase difference may be a value of the fractional part of the phase difference divided by 360 degrees, and the fractional part of the phase difference may be expressed as:

the computer device may construct equation 14 from the first predetermined time delay, the chirp period in the frequency modulated continuous wave signal, the transmit period of the sensor, and the value of the fractional part:

due to the first preset time delay a, the emission period T of the sensor_DPeriod of chirp T_rAre known numbers, and thus it can be seen that the same applies to equation 14A decision is made and the doppler ambiguity number q can then be derived based on equation 14.

Step 904, the computer device determines a velocity of the target object based on the doppler ambiguity number.

The doppler frequency can be corrected based on the obtained doppler blur number q to obtain a corrected doppler frequency, and then the velocity of the target object can be calculated based on the corrected doppler frequency.

In the embodiment of the application, the accuracy of the obtained Doppler fuzzy number is improved by setting the first preset time delay between two chirps transmitted at the same time, and the accuracy of the speed measurement of the sensor is further improved.

The embodiment of the present application provides a method for obtaining a doppler ambiguity number, which is applied to a sensor that transmits frequency modulated continuous wave signals in a time division multiplexing manner, the sensor has a first transmission channel and at least one second transmission channel, the first transmission channel transmits two chirp signals in each of at least part of transmission cycles, a second time delay is provided between the two chirp signals, the value of the second time delay is greater than or equal to zero, each second transmission channel transmits one chirp signal in each transmission cycle, as shown in fig. 10, the method includes the following steps:

step 1001, a computer device acquires a target peak position in an echo signal.

In step 1002, the computer device obtains a phase difference between two chirp signals at a target peak position.

In an alternative implementation manner, the two chirp signals include a first chirp signal and a second chirp signal which are sequentially transmitted, wherein the process of obtaining the phase difference of the two chirp signals at the target peak position includes:

step a1, a time domain subsequence of the first chirp signal and a time domain subsequence of the second chirp signal are obtained.

The time-domain subsequence of the first chirp signal is:

the time-domain subsequence of the second chirp signal is:

step a2, performing two-dimensional fast fourier transform processing on the time domain subsequence of the first chirp signal and the time domain subsequence of the second chirp signal, respectively, to obtain a phase value of the first chirp signal and a phase value of the second chirp signal at each target peak position.

The phase value of the first chirp signal is expressed as:

the phase value of the second chirp signal is expressed as:

step a3, a phase difference between the first chirp signal and the second chirp signal at a target peak position is obtained based on the phase value of the first chirp signal and the phase value of the second chirp signal.

The computer equipment can obtain the second time delay a and the chirp period T in the frequency modulation continuous wave signal_rBased on the second time delay a and the chirp period T_rAcquiring a blurred Doppler frequency, wherein the blurred Doppler frequency is represented as: f. of_rd(a+T_r)。

Then, the computer device may determine a phase value according to the first chirp signalPhase value of the second chirp signalAnd determining the phase difference of the first chirp signal and the second chirp signal at the position of the target peak value by the fuzzy Doppler frequency. The phase difference is:

and step 1003, the computer equipment determines a Doppler fuzzy number according to the phase difference and the second time delay.

In this embodiment, the computer device may obtain the fuzzy doppler frequency, the chirp period of the frequency modulated continuous wave signal, and the transmission period of the sensor, and determine the doppler ambiguity number according to the phase difference, the fuzzy doppler frequency, the chirp period, the second time delay, and the transmission period, where the process may include the following steps:

step B1, acquiring the phase difference of the two chirp signals at the target peak position based on the phase difference, the fuzzy Doppler frequency, the chirp period and the second time delay;

wherein, the phase difference of the two chirp signals at the target peak position can be expressed as

Step B2, the fractional part of the first value is obtained.

Wherein the first value is equal to the phase difference divided by 360 degrees, which can be expressed as

Of a first valueThe fractional part can be expressed as:

step B3, the fractional part of the second value is obtained.

Wherein the second value is equal to the sum of the chirp period and the second delay times the doppler ambiguity number divided by the transmit period, and can be expressed as:

the fractional part of the second numerical value may be expressed as:

and step B4, acquiring the Doppler fuzzy number according to the fact that the decimal part of the first numerical value is equal to the decimal part of the second numerical value.

Order toDue to the second time delay a, the emission period T of the sensor_DPeriod of chirp T_rAre all known numbers, and thus it can be known thatAnd (5) judging to obtain the Doppler fuzzy number q.

In the embodiment of the application, the accuracy of the sensor speed measurement is improved by introducing the doppler ambiguity number, that is, the first transmission channel is used to transmit two chirp signals at a time, which is equivalent to adding one chirp signal in front of or behind a signal transmitted by one transmission channel in the conventional FMCW sensor, and obtaining the phase difference of the two chirp signals at the target peak position in the echo signal, so as to obtain the doppler ambiguity number (i.e. q). And a first preset time delay is set between two chirps transmitted at the same time, so that the accuracy of the obtained Doppler fuzzy number is improved, and the accuracy of the speed measurement of the sensor is further improved.

It should be understood that although the various steps in the flowcharts of fig. 6-10 are shown in order, as indicated by the arrows, the steps are not necessarily performed in order, as indicated by the arrows. The steps are not performed in the exact order shown and described, and may be performed in other orders, unless explicitly stated otherwise. Also, at least some of the steps in fig. 6-10 may include multiple sub-steps or multiple stages that are not necessarily performed at the same time, but may be performed at different times, and the order of performing the sub-steps or stages is not necessarily sequential, but may be performed in turn or alternately with other steps or at least some of the sub-steps or stages of other steps.

In one embodiment of the present application, as shown in fig. 11, there is provided a sensor including:

a first transmission channel 1101 for transmitting two chirp signals in at least a part of a transmission period.

And a second transmission channel 1102 for transmitting a chirp signal in each transmission period.

A receiving channel 1103 for receiving the echo signal. And

and the signal processing module 1104 is configured to obtain a target peak position in the echo signal, obtain a phase difference between the two chirp signals at the target peak position, and determine a doppler ambiguity number according to the phase difference.

In one embodiment, the signal processing module 1104 can also be used to implement the method for acquiring the velocity of the target object provided in the above embodiment, and/or implement the method for acquiring the doppler ambiguity number provided in the above embodiment.

In one embodiment, the sensor is a millimeter wave radar chip.

In one embodiment, the millimeter wave radar chip is AiP (English in Package) chip.

In one embodiment, a computer device is provided, which includes a memory and a processor, the memory stores a computer program, and the processor executes the steps of the method for acquiring the velocity of the target object in the above embodiment or implements the steps of the method for acquiring the doppler blur number in the above embodiment.

The implementation principle and technical effect of the computer device provided in this embodiment are similar to those of the method embodiments described above, and are not described herein again.

In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored, which when executed by a processor implements the steps of the method of acquiring a velocity of an object in the above-described embodiments, or implements the steps of the method of acquiring a doppler blur number in the above-described embodiments.

In an alternative embodiment, for a sensing device such as an FMCW MIMO radar, when transmitting signals, a transmitting antenna of the MIMO antennas may be controlled to transmit two chirp signals (chirp) at a time in a frame of signals or a transmitting period of the transmitting antenna, that is, a new chirp signal may be added before or after an original chirp signal traditionally transmitted by the transmitting antenna, and a preset time delay may be added between the original chirp signal and the new chirp signal, so as to modify a transmitted waveform. Subsequently, the doppler ambiguity number can be determined to resolve the velocity ambiguity according to the phase difference between the original chirp signal and the new chirp signal at the target peak position in the echo signals obtained based on the modified transmit waveforms, and by combining the calculation methods described in other embodiments, a more accurate target object velocity can be obtained.

The implementation principle and technical effect of the computer-readable storage medium provided by this embodiment are similar to those of the above-described method embodiment, and are not described herein again.

It will be understood by those skilled in the art that all or part of the processes of the methods of the embodiments described above can be implemented by hardware instructions of a computer program, which can be stored in a non-volatile computer-readable storage medium, and when executed, can include the processes of the embodiments of the methods described above. Any reference to memory, storage, database, or other medium used in the embodiments provided herein may include non-volatile and/or volatile memory, among others. Non-volatile memory can include read-only memory (ROM), Programmable ROM (PROM), Electrically Programmable ROM (EPROM), Electrically Erasable Programmable ROM (EEPROM), or flash memory. Volatile memory can include Random Access Memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in a variety of forms such as Static RAM (SRAM), Dynamic RAM (DRAM), Synchronous DRAM (SDRAM), Double Data Rate SDRAM (DDRSDRAM), Enhanced SDRAM (ESDRAM), Synchronous Link DRAM (SLDRAM), Rambus Direct RAM (RDRAM), direct bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.