CN118011380A

CN118011380A - Target detection method, signal transmitting method, radar chip and integrated circuit

Info

Publication number: CN118011380A
Application number: CN202311488631.8A
Authority: CN
Inventors: 江鹏飞; 陈嘉澍; 张立基
Original assignee: Calterah Semiconductor Technology Shanghai Co Ltd
Current assignee: Calterah Semiconductor Technology Shanghai Co Ltd
Priority date: 2022-11-09
Filing date: 2023-11-08
Publication date: 2024-05-10
Also published as: CN118011377A; CN118011379A

Abstract

The embodiment of the invention relates to the technical field of radio and discloses a target detection method, a signal transmission method, a radar chip and an integrated circuit. In the invention, by transmitting a signal sequence comprising a plurality of linear sweep-frequency unit groups, each of the plurality of linear sweep-frequency unit groups comprises at least two linear sweep-frequency units with the same sweep-frequency starting frequency; based on the FFT of each linear sweep unit, the FFT of each linear sweep unit group and the FFT of the signal sequence, the distance and/or the speed of the target are determined, and a more accurate radar target detection result is obtained by combining the measurement results of a plurality of FFT, so that the overall resolution capability of the radar is truly improved.

Description

Target detection method, signal transmitting method, radar chip and integrated circuit

Technical Field

The embodiment of the invention relates to the technical field of radio, in particular to a transmission processing technology of electromagnetic wave signals.

Background

The fm continuous wave (Frequency Modulated Continuous Wave, abbreviated as FMCW) radar generally transmits a detection signal of a linear sweep pulse waveform, receives an echo signal formed by a detection signal scattered and/or reflected by a target, mixes the echo signal with a Local Oscillator (LO) output by a Local Oscillator to obtain an intermediate frequency signal, and performs analog-to-digital conversion, sampling and other processes on the intermediate frequency signal, and then continues coherent processing to realize detection of the target and measurement of target parameters such as distance, speed, angle and the like.

However, the intermediate frequency signal obtained after mixing contains a cross multiplication term of speed and slow time related to speed, which is also called speed cross phase, and the speed cross phase causes loss of signal coherent processing gain, thereby affecting the accuracy of radar detection and measurement targets.

Disclosure of Invention

The embodiment of the invention aims to provide a target detection method, a signal transmitting method, a radar chip and an integrated circuit, so as to effectively improve the accuracy of radar target detection.

In order to solve the above technical problems, an embodiment of the present invention provides a method for detecting a target, including:

Transmitting a signal sequence comprising a plurality of linear sweep cell groups, each of the plurality of linear sweep cell groups comprising at least two linear sweep cells having a same sweep starting frequency;

and carrying out FFT (fast Fourier transform) of each linear sweep unit, FFT of each linear sweep unit group and FFT of the signal sequence based on echo signals corresponding to the signal sequence so as to determine the distance and/or speed of a target.

The embodiment of the invention also provides a signal transmitting method, which comprises the following steps:

Acquiring a sequence combination to be transmitted, wherein the sequence combination comprises a plurality of signal sequences; each signal sequence in the plurality of signal sequences comprises a plurality of linear sweep frequency unit groups, and each linear sweep frequency unit group in the plurality of linear sweep frequency unit groups comprises at least two linear sweep frequency units with the same sweep frequency starting frequency; the frequency hopping slope of any two signal sequences in the sequence combination is different, and the frequency hopping slope of any one signal sequence in the sequence combination is not 0;

the sequence combinations are transmitted for one target detection.

The embodiment of the invention also provides a target detection method, which comprises the following steps:

receiving echo signals corresponding to a plurality of signal sequences transmitted by the signal transmission method;

And performing FFT of each linear sweep unit, FFT of each linear sweep unit group and FFT of the signal sequences based on echo signals corresponding to the plurality of signal sequences so as to determine the distance and/or speed of the target.

Embodiments of the present invention also provide a computer-readable storage medium storing a computer program which, when executed by a processor, implements the above-described method of object detection, or implements the above-described method of transmission.

The embodiment of the invention also provides a radar chip, which comprises: at least one processor; and

A memory communicatively coupled to the at least one processor; wherein,

The memory stores instructions executable by the at least one processor to enable the at least one processor to perform the method of object detection or to implement the method of signal transmission described above.

The embodiment of the invention also provides an integrated circuit which comprises a radio frequency module, an analog signal processing module and a digital signal processing module which are connected in sequence;

the radio frequency module is used for generating a target detection signal and an echo signal; wherein the target detection signal comprises a signal sequence in the target detection method or a sequence combination in the signal transmission method;

The analog signal processing module is used for performing down-conversion processing on the echo signal to obtain an intermediate frequency signal; and

The digital signal processing module is used for carrying out analog-to-digital conversion on the intermediate frequency signal to obtain a digital signal, and carrying out target detection on the digital signal.

An embodiment of the present invention also provides a radio device including:

a carrier;

an integrated circuit as described above disposed on the carrier;

The antenna is arranged on the supporting body, or the antenna and the integrated circuit are integrated into a whole device and arranged on the supporting body;

the integrated circuit is connected with the antenna and is used for transmitting the target detection signal and/or receiving the echo signal.

The embodiment of the invention also provides a terminal device, which comprises:

An equipment body; and

A radio device as described above disposed on the apparatus body;

Wherein the radio is for target detection to provide reference information to the operation of the device body.

In the embodiment of the invention, a signal sequence comprising a plurality of linear sweep unit groups is transmitted, and each linear sweep unit group in the plurality of linear sweep unit groups comprises at least two linear sweep units with the same sweep initial frequency; based on the FFT of each linear sweep unit, the FFT of each linear sweep unit group, and the FFT of the signal sequence, a distance and/or a speed of the target is determined. Because each linear sweep unit group comprises at least two linear sweep units with the same sweep initial frequency, when target detection is carried out according to a signal sequence, FFT of each linear sweep unit group and FFT of the signal sequence can be obtained, so that measurement results of a plurality of FFT can be combined, more accurate radar target detection results can be obtained, and the overall resolution capability of the radar is truly improved.

Drawings

One or more embodiments are illustrated by way of example and not limitation in the figures of the accompanying drawings, in which like references indicate similar elements, and in which the figures of the drawings are not to be taken in a limiting sense, unless otherwise indicated.

Fig. 1 is a waveform diagram of a conventional radar signal according to the related art;

FIG. 2 is a set of radar signal waveforms with frequency bands varying in accordance with an embodiment of the present application;

FIG. 3 is a flow chart of a method of object detection according to an embodiment of the application;

FIG. 4 is a schematic diagram of signals obtained after the effective signal edges of chirp are intercepted according to an embodiment of the present application;

FIGS. 5a-5h are waveform diagrams of a first signal sequence in an embodiment in accordance with the application;

FIGS. 6a-6h are waveform diagrams of a second signal sequence in accordance with embodiments of the present application;

FIGS. 7a-7i are signal sequence waveforms for a group of linear sweep cells including 4 linear sweep cells in an embodiment in accordance with the present application;

FIGS. 8a-8d are second signal sequence waveforms in accordance with an embodiment of the present application;

FIG. 9a is a schematic diagram of the sequential transmission of three signal sequences in the time dimension in accordance with an embodiment of the present application;

fig. 9b is a schematic diagram of interleaved transmission in the time dimension of three signal sequences in an embodiment in accordance with the application;

FIGS. 10a-10c are schematic diagrams of the relationship between the end frequency point of the sweep of the last linear sweep cell of the previous set of linear sweep cells and the start frequency point of the sweep of the first linear sweep cell of the next set of linear sweep cells in accordance with an embodiment of the present application;

FIG. 11a is a two-dimensional plot of fast time frequency versus slow time frequency obtained after coherent processing of a conventional waveform;

FIG. 11b is a schematic diagram of the correspondence of the target measurement result from frequency to distance velocity;

FIG. 11c is a schematic diagram of velocity distance resolution due to frequency uncertainty;

Fig. 11d is a two-dimensional graph of distance-velocity obtained after three correlations of one signal sequence according to the present embodiment;

fig. 11e is a schematic diagram of the velocity distance resolution obtained after three correlations of two signal sequences with opposite hopping directions according to the present embodiment;

fig. 11f is a schematic diagram of a velocity distance resolution obtained by performing three correlation processes on two signal sequences with the same frequency hopping direction and different slopes according to the present embodiment;

FIGS. 12a-12h are schematic diagrams of two signal sequences sequentially transmitted in the time dimension in accordance with embodiments of the present application;

Fig. 13 is a schematic structural view of a radar chip according to an embodiment of the present application;

Fig. 14 is a schematic diagram of an integrated circuit according to an embodiment of the application.

Detailed Description

Because the FMCW radar transmits at least one group of chirp sequences and performs two coherent processes (such as fast fourier transform FFT) on sampling points (such as in fast time chirp) and between pulses (such as between slow time chirp) in the intermediate frequency digital signal, fast time frequency and slow time frequency related to the target distance and speed in the intermediate frequency signal are estimated. In the step-by-step coherent processing method, the calculation processes of the steps are mutually independent, and compared with the method for performing primary coherent processing on a complete pulse signal sequence, the method has lower calculation processing cost, so that the method is widely applied to signal processing of the current FMCW radar.

Meanwhile, in order to further reduce the cost of two coherent processes (such as distance-dimensional FFT and velocity-dimensional FFT), it is generally possible to select a uniform fast time sampling period and slow time sampling period, i.e., pulse intervals are uniform, as shown in the waveform of fig. 1. However, in the conventional signal processing flow, since the intermediate frequency signal obtained after mixing includes a speed cross phase related to the speed, and the speed cross phase cannot be correctly superimposed by the coherent processing performed independently for the fast time and the slow time, a loss of the signal coherent processing gain is caused, and accuracy of radar detection and measurement targets is further affected. It can be said that the magnitude of the speed cross-phase (i.e. the magnitude of the gain loss described above) is related not only to the target speed, but also to the compression ratio of the radar pulse train (i.e. the product of the pulse bandwidth and the total duration of the train). For example, decreasing the compression ratio of a radar pulse train may reduce the loss of signal coherence processing gain due to speed cross-phase, but may correspondingly degrade the range resolution (i.e., the range resolution is inversely proportional to the bandwidth) and/or the speed resolution (i.e., the speed resolution is inversely proportional to the overall length of the train) of the radar. One solution is therefore to transmit a series of pulses of varying frequency bands, as shown in fig. 2, the starting frequency of each pulse in the series of pulses varying continuously, i.e. the nth pulse has a starting frequency f _n＝f₀ + nΔf; where n is a positive integer, fn is the sweep start frequency of the nth sweep pulse (i.e., chirp), f0 is the sweep start frequency of the initial chirp, and Δf is the difference between the sweep start frequencies of adjacent chirps. Compared to the pulse sequence shown in fig. 1, the pulse sequence compression ratio is unchanged (i.e. the bandwidth of each pulse is unchanged and the total duration of the sequence is unchanged), so that the influence of the speed cross phase is unchanged, but the total bandwidth B (the bandwidth covered by all chirp in total, i.e. b=n×b, N is the number of chirp in a group of pulse sequences) exceeds the total bandwidth of the pulse sequence with unchanged frequency band (equal to the single chirp bandwidth B), so that better resolution in the distance direction can be achieved. However, this scheme improves only the resolving power of targets at the same speed and at different distances, and does not improve the resolving power of the speed, and thus does not actually improve the actual resolving power of the radar by transmitting a pulse sequence as shown in fig. 2.

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present application more apparent, the embodiments of the present application will be described in detail below with reference to the accompanying drawings. However, it will be understood by those of ordinary skill in the art that in various embodiments of the present application, numerous specific details are set forth in order to provide a thorough understanding of the present application. The claimed application may be practiced without these specific details and with various changes and modifications based on the following embodiments. The following embodiments are divided for convenience of description, and should not be construed as limiting the specific implementation of the present application, and the embodiments can be mutually combined and referred to without contradiction.

It is understood by those skilled in the art that electromagnetic wave signals are classified into radio waves and light waves, and radio waves are classified into short waves, medium waves, long waves and microwaves, and light waves are classified into ultraviolet rays, visible rays and infrared rays. Wherein, the microwave is further divided into centimetre wave and millimeter wave, the centimetre wave mainly comprises UWB (ultra wide band, frequency band is 3.1 GHz-10.6 GHz) and 24GHz frequency band, the millimeter wave mainly comprises 60GHz frequency band and 77GHz frequency band (or 77GHz frequency band-81 GHz frequency band). Ultraviolet light and visible light can be collectively called laser light, including visible laser light and invisible laser light, and the frequency range of the laser light is mainly (3.846-7.895) 10 x 5Hz. The embodiment of the application mainly relates to signal processing of centimeter waves, millimeter waves and laser frequency bands.

An embodiment of the invention relates to a target detection method, which can be applied to a radar chip, or a terminal device, an integrated circuit and other components needing target detection. In this embodiment, each of the plurality of linear sweep cell groups includes at least two linear sweep cells having the same sweep starting frequency by transmitting a signal sequence including the plurality of linear sweep cell groups; based on the FFT of each linear sweep unit, the FFT of each linear sweep unit group, and the FFT of the signal sequence, a distance and/or a speed of the target is determined. Because each linear sweep unit group comprises at least two linear sweep units with the same sweep initial frequency, when target detection is carried out according to a signal sequence, FFT of each linear sweep unit group and FFT of the signal sequence can be obtained, so that measurement results of a plurality of FFT can be combined, more accurate radar target detection results can be obtained, and the overall resolution capability of the radar is truly improved. Implementation details of the method for object detection according to the embodiments of the present invention are specifically described below, and the following details are provided for convenience of understanding only, and are not necessary to implement the present embodiment.

As shown in fig. 3, in step 101, a signal sequence is transmitted comprising a plurality of groups of linear sweep cells, each group of linear sweep cells comprising at least two linear sweep cells having the same sweep starting frequency. In one example, the linear sweep unit may be a chirp.

In other examples, the linear sweep unit may be at least two signals obtained by intercepting the effective signal edges of the chirp. As shown in fig. 4, a conventional chirp may be "split" into a plurality of signals, that is, the dashed line shown in fig. 4 is a conventional chirp, the bandwidth of which is B1, and the linear sweep unit includes a plurality of signals obtained by intercepting the effective signal edge of the chirp (as shown by the solid line in fig. 4), and the bandwidth of each signal obtained by intercepting the effective signal edge of the chirp is B1, where B1 is greater than or equal to B1.

In step 102, the FFT of each linear sweep cell, the FFT of each group of linear sweep cells, and the FFT of the signal sequence are performed based on the echo signal corresponding to the signal sequence to determine the distance and/or speed of the target.

In some alternative embodiments, the signal sequence may be a signal sequence with a positive frequency hopping direction as shown in any one of fig. 5a to 5d. Specifically, the signal sequence includes a plurality of linear sweep frequency unit groups with sequentially linearly increasing sweep frequency, and each linear sweep frequency unit group includes at least two linear sweep frequency units with the same sweep frequency starting frequency, as shown in fig. 5a. By changing the interval between the linear sweep unit groups (such as the delay between the adjacent linear sweep unit groups) so that the delays between the adjacent linear sweep unit groups are different, or alternatively, by setting the delay between the adjacent linear sweep unit groups to a preset interval law, or the like, a signal sequence in which the sweep start frequencies of the linear sweep unit groups are sequentially increased as shown in fig. 5b is formed, or alternatively, by changing the order of the transmission chirp of the transmission antennas Tx, a TDM signal sequence as shown in fig. 5c (each transmission antenna transmits at a preset regular interval) or as shown in fig. 5d (each transmission antenna transmits randomly) is formed. In addition, the slope of any one of the signal sequences shown in fig. 5a to 5d is positive, that is, the slope of the effective edge of each linear sweep unit is positive, and in other examples, the slope of each linear sweep unit may be negative, as shown in fig. 5e to 5h, and the intervals between the linear sweep unit groups may be the same, or may be different, so as to form a linear sweep unit group in which the sweep start frequencies are sequentially increased, as shown in fig. 5e (delay is the same) or fig. 5f (delay is different), and the slope of the linear sweep units in the linear sweep unit group is negative, or may also be formed into a TDM signal sequence, as shown in fig. 5g (each transmit antenna transmits at a preset regular interval) or as shown in fig. 5h (each transmit antenna randomly transmits), by changing the order of the transmitting linear sweep units of the transmit antennas Tx.

In alternative embodiments, the signal sequence may be a signal sequence with a negative frequency hopping direction as shown in any of fig. 6a to 6 d. Specifically, the signal sequence includes a plurality of linear sweep frequency unit groups with sequentially decreasing sweep frequency, and each linear sweep frequency unit group includes at least two linear sweep frequency units with the same sweep frequency starting frequency, as shown in fig. 6 a. By changing the interval between the linear sweep unit groups (such as the delay between the adjacent linear sweep unit groups) so that the delays between the adjacent linear sweep unit groups are different, or alternatively, by setting the delay between the adjacent linear sweep unit groups to a preset interval rule or the like, a signal sequence in which the sweep start frequencies of the linear sweep unit groups are sequentially decreased as shown in fig. 6b is formed, or alternatively, by changing the transmission order of the transmission antennas Tx, a TDM signal sequence as shown in fig. 6c (each transmission antenna transmits at a preset regular interval) or as shown in fig. 6d (each transmission antenna transmits randomly) is formed. In addition, the slope of any one of the signal sequences shown in fig. 6a to 6d is positive, that is, the slope of the effective edge of each linear sweep unit is positive, and in other examples, the slope of each linear sweep unit may be negative, as shown in fig. 6e to 6h, and the intervals between the linear sweep unit groups may be the same, or may be different, so as to form a linear sweep unit group in which the sweep start frequencies are sequentially decreased as shown in fig. 6e (delay is the same) or fig. 6f (delay is different), and the slope of the linear sweep units in the linear sweep unit group may be negative, or may also be formed into a TDM signal sequence as shown in fig. 6g (each transmit antenna is transmitted at a preset regular interval) or as shown in fig. 6h (each transmit antenna is randomly transmitted) by changing the order of the transmitting linear sweep units of the transmit antennas Tx.

In addition, in the signal sequences illustrated in fig. 5a to 5h and fig. 6a to 6h, each linear sweep unit group includes two linear sweep units with identical initial frequency, bandwidth, slope, period and other relevant parameters, but with sequential differences in time dimension, where each linear sweep unit group may further include more linear sweep units, if each linear sweep unit group includes 4 linear sweep units, a signal sequence illustrated in fig. 7a to 7h may be correspondingly formed by combining the changes of intervals, antenna emission rules and the like between the linear sweep unit groups, where the frequency hopping direction is positive, the intervals between the linear sweep unit groups with positive slope (see dashed boxes in fig. 7 a) are different, tx interval emission, random emission or signal sequences according to preset emission are illustrated in fig. 7a to 7d, the frequency hopping direction is negative, the intervals between the linear sweep unit groups with negative slope are different, tx interval emission, random emission or signal sequences according to preset emission are illustrated in fig. 7e to 7 h. It can be understood that when the linear sweep unit groups include 4 linear sweep units, signal sequences with positive frequency hopping direction and negative slope, equal interval between the linear sweep unit groups, different interval between the linear sweep unit groups, tx interval transmission, random transmission or transmission according to a preset rule can be formed; or forming signal sequences with negative frequency hopping direction, positive slope, equal interval between linear sweep frequency unit groups, different interval between linear sweep frequency unit groups, tx interval transmission, random transmission or transmission according to preset rules.

In addition, the signal sequence may also be a signal sequence as shown in fig. 7i, where one linear sweep unit group in fig. 7i includes a plurality of linear sweep units, each linear sweep unit is a plurality of signals obtained by intercepting an effective signal edge of a conventional chirp (see a dashed box in the figure), a bandwidth of the conventional chirp is B1, and a bandwidth of each signal obtained after interception is B1, where B1 is greater than or equal to B1.

In alternative embodiments, in step 101, a sequence combination comprising a plurality of signal sequences is transmitted, the sequence combination being used for one target detection; wherein the sequence combination at least comprises: a first signal sequence, a second line signal sequence, and a third signal sequence; the first signal sequence comprises a plurality of linear sweep frequency unit groups with sweep frequency initial frequencies gradually increasing linearly, the second signal sequence comprises a plurality of linear sweep frequency unit groups with sweep frequency initial frequencies gradually decreasing linearly, and the third signal sequence comprises a plurality of linear sweep frequency unit groups with the same sweep frequency initial frequencies.

The third signal sequence may be a signal sequence as shown in fig. 8a-8d, and includes a plurality of linear sweep frequency unit groups with the same sweep frequency starting frequency, where the bandwidths, sweep frequency starting frequency points, sweep frequency ending frequency points, periods, slopes, and other parameters of a plurality of linear sweep frequency units in the linear sweep frequency unit groups are all the same, and the intervals between adjacent linear sweep frequency units may be the same or different, as shown in fig. 8a-8b, and the transmitting sequence of the transmitting antennas Tx may be fixed to be sequentially transmitted, or randomly transmitted, or transmitted at preset regular intervals, as shown in fig. 8c-8 d.

In a transmitting period, for a radar with at least two transmitting antennas, each transmitting antenna can transmit a linear sweep unit according to a preset rule, for example, one linear sweep unit can be sequentially transmitted at intervals for two antenna arrays, two linear sweep units can be sequentially transmitted at intervals, one transmitting antenna can transmit one linear sweep unit at a time, and the other transmitting antenna can transmit two linear sweep units at a time. It should be noted that the number of the transmitting antennas can be further extended to 3,4, 5, etc., and the transmitting form of the transmitting antenna array can be changed in various ways according to actual requirements, so long as the transmitting antenna array forms a time division multiplexing TDM waveform, so as to achieve the purpose of improving the speed cross phase. To further improve the performance of the radar, each transmitting antenna Tx may also randomly transmit a set of linear sweep cells.

In some alternative embodiments, the first signal sequence in the sequence combination may be any one of the signal sequences shown in fig. 5a to 5 d. Specifically, by changing the interval between the linear sweep units (such as the delay between the adjacent linear sweep units) so that the delays between the adjacent linear sweep units are different, or alternatively, by setting the delay between the adjacent linear sweep units to a preset interval law or the like, a signal sequence in which the sweep start frequency is sequentially increased as shown in fig. 5b is formed, or alternatively, by changing the order of the transmitting linear sweep units of the transmitting antennas Tx, a signal sequence as shown in fig. 5c (each transmitting antenna transmits at a preset regular interval) or as shown in fig. 5d (each transmitting antenna transmits randomly) is formed. In addition, the frequency hopping direction of any one of the signal sequences shown in fig. 5a to 5d is positive, that is, the slope of the effective edge of each linear sweep unit in the linear sweep unit group is positive, in other examples, the slope of the effective edge of each linear sweep unit may also be negative, as shown in fig. 5e to 5h, the intervals between the linear sweep units may be the same, or may be different, so as to form a signal sequence in which the sweep start frequency is sequentially increased, as shown in fig. 5e (delay same) or fig. 5f (delay different), and the slope is negative, or may also be formed by changing the order of the transmitting linear sweep unit groups of the transmitting antennas Tx, so as to form a TDM signal sequence as shown in fig. 5g (each transmitting antenna transmits at a preset regular interval) or as shown in fig. 5h (each transmitting antenna randomly).

The second signal sequence in the sequence combination may be any one of the signal sequences shown in fig. 6a to 6 d. Similar to the first signal sequence, the intervals between the linear sweep unit groups may be the same or different, so as to form a signal sequence with successively decreasing sweep start frequencies as shown in fig. 6a (delay same) or fig. 6b (delay different), or a TDM signal sequence as shown in fig. 6c (each transmitting antenna transmits at a preset regular interval) or fig. 6d (each transmitting antenna transmits randomly) may be formed by changing the order of transmitting the linear sweep units of the transmitting antennas Tx, which will not be described here. In addition, the slope of the linear sweep units of any one of the signal sequences shown in fig. 6a to 6d is positive, in other examples, the slope of the second signal sequence may be negative, that is, the slope of the effective edges of the linear sweep units in the signal sequence may be negative, as shown in fig. 6e to 6h, the intervals between the linear sweep units may be the same or may be different, so as to form a signal sequence in which the sweep start frequencies are sequentially decreased as shown in fig. 6e (delay same) or fig. 6f (delay different), and the slope is negative, or may be formed by changing the order of the transmitting linear sweep units of the transmitting antennas Tx, so as to form a TDM signal sequence as shown in fig. 6g (each transmitting antenna transmits at a preset regular interval) or as shown in fig. 6h (each transmitting antenna randomly).

That is, in the time division multiplexing or code division multiplexing mode, a plurality of signal sequences can be transmitted through each transmit antenna of the MIMO antenna array. In addition, when a plurality of signal sequences are transmitted through the respective transmitting antennas of the MIMO antenna array in the time division multiplexing mode, the transmission order of the respective transmitting antennas may be random. For example, a frame signal has 256 chips, and 4 Tx's transmit randomly in the 256 chips, so long as each Tx is guaranteed to complete 64 transmissions. Under this scheme, the sampling bandwidth of each antenna is still equal to the pulse repetition frequency, but only a portion of the pulses that are unevenly distributed are effective samples of a particular antenna, so that the slow time-frequency ambiguity problem can be circumvented.

In addition, as the FMCW radar transmits a series of signals and measures the distance/speed of a target by processing echo data, the larger the bandwidth is, the higher the distance measurement precision and resolution are, and the larger the bandwidth is required for improving the distance precision and resolution, but increasing the bandwidth of pulses can introduce the problems of various limitations such as sweep slope, linearity, calculation force, memory and the like. In the embodiment of the application, the first signal sequence and the second signal sequence both adopt linear frequency hopping linear sweep unit groups, namely, the large bandwidth is realized through the linear sweep units with the same bandwidth and different initial frequencies, so that better resolution capability in the distance direction is realized.

In some alternative embodiments, multiple signal sequences may be transmitted sequentially in the time dimension. As shown in fig. 9a, in the signal transmitted by the radar, the first signal sequence may be transmitted first, the second signal sequence may be transmitted after the transmission of the first signal sequence is completed, and the third signal sequence may be transmitted after the transmission of the second signal sequence is completed. In fig. 9a, the first signal sequence is shown in fig. 5a, the second signal sequence is shown in fig. 6a, the third signal sequence is shown in fig. 8a, but in other examples, the first signal sequence may be any one of the signal sequences in fig. 5a to 5h, the second signal sequence may be any one of the signal sequences in fig. 6a to 6h, and the third signal sequence may be any one of the signal sequences in fig. 8a to 8 d. In other examples, the sequence of each signal sequence in the time dimension may be further adjusted according to requirements, for example, the second signal sequence is transmitted first, the third signal sequence is transmitted after the transmission of the second signal sequence is finished, and the first signal sequence is transmitted after the transmission of the third signal sequence is finished. In other words, the transmission order of each signal sequence in the sequence combination can be adjusted according to the actual situation. In addition, each signal sequence in the sequence combination is located in the same frame signal or in at least two adjacent frame signals, for example, the first signal sequence is in the current frame signal, and the second signal sequence and the third signal sequence are the next frame signal.

In other alternative embodiments, the multiple signal sequences may also be transmitted in an interleaved manner in the time dimension, for example, the linear sweep units included in the multiple signal sequences are alternately transmitted in the time dimension, so that the time difference of waveform combination is smaller, the matching precision is better, and different signal sequences have different sidelobe characteristics, and meanwhile, the speed ambiguity range is reduced. As shown in fig. 9b, in the sequence combination transmitted by the radar, the first signal sequence, the second signal sequence and the third signal sequence are alternately distributed at intervals. In fig. 9b, the first signal sequence is shown in fig. 5a, the second signal sequence is shown in fig. 6a, the third signal sequence is shown in fig. 8a, but in other examples, the first signal sequence may be any one of the signal sequences in fig. 5a to 5h, the second signal sequence may be any one of the signal sequences in fig. 6a to 6h, and the third signal sequence may be any one of the signal sequences in fig. 8a to 8 d. The interleaving sequence may be adjusted according to the actual situation, for example, a linear sweep unit group in a second signal sequence is transmitted first, then a linear sweep unit group in a third signal sequence is transmitted, then a linear sweep unit group in a first signal sequence is transmitted, or even, part of the linear sweep unit groups in each signal sequence may be transmitted in an interleaving manner, and the rest of the linear sweep unit groups are sequentially transmitted in a time dimension, for example, after a certain number of linear sweep unit groups in the first signal sequence are separately transmitted, the first signal sequence, the second signal sequence and the third signal sequence are transmitted in an interleaving manner; and after the transmission of the linear sweep frequency unit group of the first signal sequence is finished, the second signal sequence and the third signal sequence are independently and sequentially transmitted, or the linear sweep frequency unit groups in the second signal sequence and the third signal sequence are transmitted in a staggered manner, which is not described in detail herein.

In the first signal sequence, the initial frequency of the sweep frequency of the adjacent linear sweep frequency unit groups is gradually increased, in the second signal sequence, the initial frequency of the sweep frequency of the adjacent linear sweep frequency unit groups is gradually decreased, the slope and the bandwidth of each linear sweep frequency unit in the same linear sweep frequency unit group are the same, the slope and the bandwidth of two linear sweep frequency units in the same signal sequence, which are respectively in any two linear sweep frequency unit groups, are the same, the linear sweep frequency units of the linear sweep frequency unit groups in different signal sequences are different, and if the slope of the linear sweep frequency units of the linear sweep frequency unit groups in the first signal sequence and the second signal sequence are different.

In addition, in the sequence combination transmitted by the radar, it may further include: the fourth signal sequence comprises a plurality of linear sweep frequency unit groups with sweep frequency initial frequencies which are sequentially and linearly changed; wherein the frequency hopping slopes of any two signal sequences in the sequence combination are different. In other words, the sequence combination may include not only signal sequences having different frequency hopping directions, but also signal sequences having the same frequency hopping direction, and only the frequency hopping slopes of the signal sequences need to be different. Moreover, when the sequence combination includes a plurality of signal sequences (e.g., a first signal sequence) whose frequency hopping direction is positive and a plurality of signal sequences (e.g., a second signal sequence) whose frequency hopping direction is negative, the number of signal sequences whose frequency hopping direction is positive may be different from the number of signal sequences whose frequency hopping direction is negative, so long as there are preset numbers of the first signal sequences and the second signal sequences, the purpose of improving the speed cross phase can be achieved.

In one example, the sweep direction of the set of linear sweep cells in any one of the signal sequences in the sequence combination coincides with the frequency hopping direction of that signal sequence. For example, a signal sequence (e.g., a first signal sequence) with a positive frequency hopping direction is selected as in any of fig. 5a to 5d, and a signal sequence (e.g., a second signal sequence) with a negative frequency hopping direction is selected as in any of fig. 6e to 6 h.

It should be noted that, in the embodiment of the present application, in the time dimension, the sweep end frequency point of the last linear sweep unit of the previous linear sweep unit group may be the sweep start frequency point of the first linear sweep unit of the next linear sweep unit group, may also be the sweep bandwidth of the last linear sweep unit of the previous linear sweep unit group and the sweep bandwidth of the first linear sweep unit of the next linear sweep unit group shown in fig. 10b have a certain overlap, may also be the sweep end frequency point of the last linear sweep unit of the previous linear sweep unit group and the sweep start frequency point of the first linear sweep unit of the next linear sweep unit group shown in fig. 10c have a preset interval frequency Δf, and the specific manner may be set according to practical requirements. In addition, the waveform structure described above is not limited to the waveform transmitted in the time division manner, but is also applicable to the waveform structure transmitted in the form of code division, frequency division, combination thereof with each other, and the like.

In other alternative embodiments, the transmitted signal sequence comprising a plurality of sets of linear sweep units may be a sequence combination comprising at least two signal sequences, the sequence combination being used for one target detection; wherein, the frequency hopping slope of any two signal sequences in the sequence combination is different, and the frequency hopping slope of any one signal sequence in the sequence combination is not 0. The frequency hopping directions of the two signal sequences included in the sequence combination can be opposite or same, and when the frequency hopping directions are the same, the frequency hopping slopes of the signal sequences are different, namely the slopes of the effective edges of the linear sweep units in the signal sequences are different.

It should be noted that, in the embodiment of the present application, only the effective ramp portion of the signal is shown in the related diagram, and the specific signal pattern structure may be adjusted according to the actual requirement.

The following describes the corresponding signal processing flow in detail with reference to the waveform configuration.

Based on the waveforms shown in fig. 1, after the intra-pulse sampling points and the inter-pulse sampling points in the intermediate frequency digital signal are respectively subjected to two coherent processes (such as fast fourier transform FFT), a two-dimensional plot of fast time frequency versus slow time frequency can be obtained as shown in fig. 11a, wherein the fast time frequency corresponding to the distance is obtained by performing the FFT process (which may be referred to as distance dimension FFT process) on the intra-pulse sampling points, that is, the ordinate in the plot, and the slow time frequency corresponding to the speed is obtained by performing the FFT process (which may be referred to as speed dimension FFT process) on the inter-pulse sampling points, that is, the abscissa in the plot. Namely, when the resolution performance of the FMCW radar is analyzed, the fast time frequency is mainly determined by the distance under the same pulse sequence, and the slow time frequency is mainly determined by the speed, and by defining that two targets have the same speed and different distances or the same distance and different speeds, whether the radar can respectively detect the two targets can be tested through analysis or experiment, thereby defining the distance and the speed resolution capability of the radar, and patterning the characteristics, fig. 11a-11c can be obtained.

FIG. 11a shows a two-dimensional plane obtained by a piecewise coherent process, wherein the estimation accuracy of the fast time frequency and the slow time frequency cannot exceed the inverse of the sampling time due to the constraint of time-frequency relationship, so that a certain uncertainty exists for the corresponding fast time frequency and slow time frequency of a target respectively, and square intervals in the graph are formed; where Tsample is used to represent the period of the effective edge after sampling, and Tframe is used to represent the period of one frame of signal. Fig. 11b shows the correspondence of the target measurement result from frequency to distance velocity. The slow time frequency is uniquely determined by the speed, so that the measurement result is irrelevant to the distance and corresponds to two vertical dashed lines in the figure; the fast time frequency is determined by the distance and the speed together, so that the measurement result is related to the distance and the speed, and corresponds to two horizontal dotted lines which are slightly inclined in the figure; wherein c is the light speed, bchirp represents the bandwidth of each chirp, and f0 represents the frequency sweep center frequency point. FIG. 11c illustrates the velocity distance resolution due to frequency uncertainty; for targets at the same distance (i.e., targets having substantially the same slow time frequency), the speed resolution of the radar is determined by the slow time frequency uncertainty; for targets of the same speed (i.e. targets having the same fast time frequency), the range resolution of the radar is determined by the fast time frequency uncertainty.

Based on the above optimized scheme, when two targets are different in speed or different in distance, when the two targets have the same slow time frequency, the resolution of the radar is determined by the uncertainty of the fast time frequency, and the resolution can be converted into the distance resolution determined by the pulse bandwidth, and then by combining different signal sequences, namely, sequence combinations comprising a plurality of signal sequences, a plurality of slow time phase relations determined by two-dimensional linear combinations of different distances (R) -speeds (V) are obtained, so that the smaller uncertainty of the slow time frequency can be utilized to realize better overall resolution.

In some alternative embodiments, as shown in fig. 5 a-7 i, the waveform structure may also be modified as follows to form different types of signal sequences: for G.M linear sweep units, each M linear sweep units can be a linear sweep unit group, G groups of linear sweep unit groups are used to form a signal sequence, and the frequency of each linear sweep unit in each linear sweep unit group is linearly changed; for example, the M linear sweep cells of the g-th linear sweep cell group have a start frequency f [ g ] =f0+g\Δf, where f ₀ is the initial sweep start frequency and Δf is the difference between the initial sweep start frequency and the start frequency of the last linear sweep cell group of the signal sequence. And, the M linear sweep units of the same group have the same initial frequency. Meanwhile, each linear sweep frequency unit group can be changed in a periodic linear reciprocal manner; for example, the M linear sweep cells of the g-th linear sweep cell group have a period T [ g, k ] =tref/(a+b×g); wherein a and b are constants which are irrelevant to g, k has a value of 1 to M, and M linear sweep units of the same linear sweep unit group have the same period. In addition, the time delay between the first linear sweep units of each linear sweep unit group can be changed in a quadratic reciprocal rule; for example, the delay between the first linear sweep cell of group g and the first linear sweep cell of group g-1 is Tgrp/(c+d+e g≡2), where c, d, e may be constants independent of g. It should be noted that the sum of the periods of the linear sweep cells in one linear sweep cell group may not be equal to the delay between that linear sweep cell group and the next linear sweep cell group. In some embodiments, this may be achieved by adding, extending or shortening a silence period after the last linear sweep unit. Where Tgrp may be used to represent the time difference between groups and Tref may be used to represent the equivalent linear time difference between chirp.

In some alternative embodiments, based on the requirements of the application scenario, the above waveforms and other related deformed structures may be further enabled to enable the frequency and the linear sweep units to satisfy a predetermined relationship, for example, the following relationship may be satisfied (sum_ { i=0 } { g-1} t [ i ] +sum_ { j=0 } { k-1} t [ g, j ])=f0 (tgrp+tref × k+tbase), where i, j is the number of linear sweep units in a linear sweep unit group, tref and Tgrp may be determined based on a big data analysis according to the system capability and index requirements of the radar, and Tbase may be used to represent the equivalent start time of the first chirp in the sequence. I.e. such that the phase of the whole sequence exhibits a linear or equivalent linear variation.

For the emission waveform of the signal sequence comprising the linear sweep unit groups, when processing the corresponding echo signals, the sampling points in each linear sweep unit can be firstly subjected to coherent processing, and then the processing results of each linear sweep unit in the same linear sweep unit group are subjected to intra-group coherent processing so as to perform inter-group coherent processing on the processing results of each linear sweep unit group. The coherent processing may be FFT, etc. Meanwhile, the sequence of the above-mentioned different coherent processes can be adaptively adjusted according to actual requirements, and the embodiment of the present application is not particularly limited. Target detection by a three-stage coherent process is accomplished as shown in fig. 11d and 11e. Meanwhile, the sequence combination may be further modified by combining the factors such as time division multiplexing and the transmission sequence of the transmitting antenna Tx, and the like, and the disclosure of other related embodiments of the present application may be specifically referred to, and for simplicity and convenience, the description will be omitted herein, but the corresponding modification is also understood as related technical schemes covered by the present application.

It will be appreciated that when more signal sequences are included in the sequence combination, since each signal sequence requires a speed-dimensional FFT, more slow time frequencies are obtained, i.e. more oblique main lobes of the signal sequence are obtained, so that a smaller uncertainty of the slow time frequencies (i.e. smaller intersection of oblique main lobes) can be exploited to further achieve a better overall resolution. Because the meaning of the fast time frequency for measurement/resolution is smaller, the meaning of the fast time coherent processing mainly aims at providing processing gain and matching relation among a plurality of slow time frequency measurement results under specific conditions, so that the overall resolution of the radar mainly has the intersection determination of inclined main lobes of more slow time frequencies, and when more signal sequences are included in sequence combination, the intersection of the inclined main lobes of the slow time frequencies is smaller, so that the overall resolution of the radar can be effectively improved.

In addition, since the sequence combination comprises a plurality of signal sequences, a plurality of slow time frequencies of the same target need to be accurately matched to ensure accurate measurement, when the slow time frequencies are matched, the corresponding relation of fast time frequencies can be relied on, and according to three-section coherent processing, the measurement result of intra-group frequencies is increased outside the fast time frequencies and used for matching a plurality of inter-group frequencies with the best accuracy, so that better matching success rate and accuracy can be obtained.

In some alternative embodiments, for the process of three-stage coherent processing of a signal sequence including a linear sweep unit group, incoherent combination can be performed on the processing results after any two coherent processing, and target detection can be completed in the signal domain; then, further coherent processing is performed on the detected target point to simplify the processing flow and complexity. That is, when performing the FFT of each linear sweep unit, the FFT of each linear sweep unit group, and the FFT of the signal sequence based on the echo signal corresponding to the signal sequence, any two FFTs among the FFT of each linear sweep unit, the FFT of each linear sweep unit group, and the FFT of the signal sequence may be performed based on the echo signal corresponding to the signal sequence, the results of any two FFTs may be incoherently combined, and the target detection may be performed according to the combined result, and the remaining FFTs may be performed on the detected target point to determine the distance and/or speed of the target, so as to simplify the process flow and complexity of the process.

In some alternative embodiments, the following variations may also exist: the method can be combined with time sequence, and a non-uniform pulse period is adopted to reduce the speed fuzzy range so as to solve the problem of time-frequency coupling; the method can be combined with TDM, and each pulse is emitted by each antenna in a periodic or non-periodic sequence to improve the angular resolution/reduce the speed ambiguity range; the periods of the plurality of signal sequences can be made unequal to reduce the speed ambiguity range; more signal sequences can be adopted, or combinations of frequency sweeping directions and frequency hopping directions of the signal sequences can be changed, and the like, and the reasonable expansion can be carried out by combining the drawings and related description of the application.

In this embodiment, since the signal sequence includes a signal sequence of a plurality of linear sweep unit groups, and each linear sweep unit group includes at least two linear sweep units with the same sweep start frequency, so that the frequency hopping step is B/G, where B is the total coverage bandwidth of the signal sequence, G is the number of the linear sweep unit groups, and is larger than the frequency hopping step (B/g×m, M is the number of linear sweep units in one linear sweep unit group) of the pulse sequence shown in fig. 2, in the case of larger frequency hopping step, the phase change step between the period of each linear sweep unit and the delay between the linear sweep unit groups is large, and for the radar apparatus, the ability to adjust pulse time characteristics obviously receives a certain accuracy constraint.

In addition, the obtained signals can be incoherently combined after a part of three-section coherent processing is completed to obtain a smaller data set, and the target detection is completed in the smaller data set.

Another embodiment of the present invention relates to a signal transmitting method, which can be applied to a radar chip, a terminal device, an integrated circuit, or the like. In this embodiment, a sequence combination including at least two signal sequences to be transmitted is acquired; each signal sequence in the plurality of signal sequences comprises a plurality of linear sweep frequency unit groups, and each linear sweep frequency unit group in the plurality of linear sweep frequency unit groups comprises at least two linear sweep frequency units with the same sweep frequency starting frequency; wherein, the frequency hopping slope of any two signal sequences in the sequence combination is different, and the frequency hopping slope of any one signal sequence in the sequence combination is not 0; the sequence combinations are transmitted for one target detection.

In some alternative embodiments, at least two signal sequences with opposite frequency hopping directions exist in the sequence combination, for example, the sequence combination includes a first signal sequence in which the frequency sweep starting frequencies of adjacent linear sweep frequency unit groups are sequentially increased, and a second signal sequence in which the frequency sweep starting frequencies of adjacent linear sweep frequency unit groups are sequentially decreased. The first signal sequence may be any of the signal sequences of fig. 5a to 5h and the second signal sequence may be any of the signal sequences of fig. 6a to 6 h.

In alternative embodiments, there are at least two signal sequences in the sequence combination that have the same hopping direction but different hopping slopes (i.e., different slopes of the active edges of the linear sweep units). For example, there are two first signal sequences with different frequency hopping slopes in the sequence combination, each of which may be any one of the signal sequences as shown in fig. 5a to 5 h; or there are two second signal sequences of different frequency hopping slope in the sequence combination, each of which may be any one of the signal sequences as shown in fig. 6a to 6h.

Taking at least two signal sequences with opposite frequency hopping directions in the sequence combination as an example, each signal sequence can be sequentially transmitted in the time dimension. The first signal sequence may be any one of the signal sequences of fig. 5a to 5h, and any one of the second signal sequences shown in fig. 6a to 6h may be combined, which is not exemplified herein. In fig. 12a to 12d, the slopes of the first signal sequences are all positive and the slopes of the second signal sequences are all negative. In fig. 12a to 12d, the linear sweep cell group in the signal sequence comprises 2 linear sweep cells, and when the linear sweep cell group comprises 4 linear sweep cells, schematic diagrams of sequential emission of the first signal sequence and the second signal sequence in the time dimension are shown in fig. 12e to 12h, one broken box in the diagrams representing one linear sweep cell group.

In other examples, the sequence of each signal sequence in the time dimension may be adjusted according to requirements, for example, the second signal sequence is transmitted first, and the first signal sequence (not shown) is transmitted after the transmission of the second signal sequence is completed. In other words, the transmission order of each signal sequence in the sequence combination can be adjusted according to the actual situation. In addition, each signal sequence in the sequence combination is located in the same frame signal or in at least two adjacent frame signals, for example, the first signal sequence is in the current frame signal, and the second signal sequence is the next frame signal.

In other alternative embodiments, when the first signal sequence and the second signal sequence are located in the same frame signal, the first signal sequence and the second signal sequence may also be transmitted in an interleaved manner in the time dimension, for example, the linear sweep unit groups included in the signal sequence are alternately transmitted in the time dimension (one linear sweep unit group in the first signal sequence is transmitted first, one linear sweep unit group in the second signal sequence is transmitted again, and so on), so that the time difference of waveform combination is smaller, and the speed ambiguity range is further reduced. Similarly, when at least two signal sequences with the same frequency hopping direction but different frequency hopping slope exist in the sequence combination, each signal sequence can be sequentially transmitted in the time dimension, or transmitted in an interleaving manner, and the transmission sequence of each signal sequence in the sequence combination can be adjusted according to the actual situation, which is not described herein.

In the first signal sequence, the sweep initial frequencies of the adjacent linear sweep unit groups are sequentially increased, in the second signal sequence, the sweep initial frequencies of the adjacent linear sweep unit groups are sequentially decreased, and other parameters such as the bandwidths, the periods, the slope slopes of the linear sweep units and the intervals between the adjacent linear sweep units can be completely the same. Alternatively, the slope and bandwidth of each linear sweep cell in the same signal sequence may be the same, and the linear sweep cells in different signal sequences may be different, e.g., the slope, bandwidth, period, and delay between adjacent linear sweep cells in different signal sequences may be different, or any of them may be different.

In addition, in other alternative embodiments, the sequence combination transmitted by the radar may further include: a plurality of first signal sequences, or a plurality of second signal sequences, or a combination of a plurality of pairs of first signal sequences and second signal sequences. The frequency sweeping direction of the linear frequency sweeping unit in any signal sequence in the sequence combination is consistent with the frequency hopping direction of the signal sequence. For example, a signal sequence (e.g., a first signal sequence) with a positive frequency hopping direction is selected as in any of fig. 5a to 5d, and a signal sequence (e.g., a second signal sequence) with a negative frequency hopping direction is selected as in any of fig. 6e to 6 h.

In addition, in other alternative embodiments, in the time dimension, the sweep end frequency point of the last linear sweep unit of the previous linear sweep unit group may be the sweep start frequency point of the first linear sweep unit of the next linear sweep unit group, may also be the sweep bandwidth of the last linear sweep unit of the previous linear sweep unit group and the sweep bandwidth of the first linear sweep unit of the next linear sweep unit group shown in fig. 10b have a certain overlap, may also be the sweep end frequency point of the last linear sweep unit of the previous linear sweep unit group and the sweep start frequency point of the first linear sweep unit of the next linear sweep unit group shown in fig. 10c have a preset interval frequency Δf, and the specific manner may be set according to practical requirements. In addition, the waveform structure described above is not limited to the waveform transmitted in the time division manner, but is also applicable to the waveform structure transmitted in the form of code division, frequency division, combination thereof with each other, and the like.

The signal transmitting method of this embodiment may also be used in a time division multiplexing mode, where each antenna is not required to transmit in a strict sequence and sequentially in a periodic manner, but in a randomized sequence. For example, a frame signal has 256 transmission opportunities, and 4 Tx are randomly transmitted in the 256 transmission opportunities, so long as each Tx is guaranteed to complete 64 transmissions. Similar to the above embodiment, each signal sequence in the sequence combination is first constructed, and then the antenna transmission order is randomized in a given signal sequence, alternatively random time division multiplexing can also be applied to non-equally spaced signal sequences to obtain a larger slow time ambiguity range. Under this scheme, the sampling bandwidth of each antenna is still equal to the pulse repetition frequency, but only a portion of the pulses that are unevenly distributed are effective samples of a particular antenna, so that the slow time-frequency ambiguity problem can be circumvented.

In this embodiment, since the sequence combination includes at least two signal sequences with opposite frequency hopping directions, when the target detection is performed according to the sequence combination, a speed dimension FFT of each signal sequence can be obtained, so that a more accurate radar target detection result can be obtained by combining measurement results of a plurality of speed dimension FFTs, and the overall resolution capability of the radar is truly improved.

In some alternative embodiments, the following variations may also exist: the method can be combined with time sequence, and a non-uniform pulse period is adopted to reduce the speed fuzzy range so as to solve the problem of time-frequency coupling; the linear sweep unit groups can be combined with TDM, and each linear sweep unit group is transmitted by each antenna in a periodic or non-periodic sequence so as to improve the angular resolution precision/reduce the speed fuzzy range; the periods of the plurality of signal sequences can be made unequal to reduce the speed ambiguity range; more signal sequences can be adopted, or combinations of the frequency sweeping direction and the frequency hopping direction of the signal sequences can be changed, and the like, and the reasonable expansion can be carried out by combining the drawings and related description of the application.

Another embodiment of the present invention relates to a method for detecting an object, which can be applied to a radar chip, or a terminal device, an integrated circuit, or the like which needs to perform object detection. In this embodiment, the sequence combination including at least two signal sequences mentioned in the transmitting method embodiment for receiving the above signals is performed, and the FFT of each linear sweep unit, the FFT of each linear sweep unit group, and the FFT of the signal sequence are performed based on echo signals corresponding to the plurality of signal sequences, so as to determine the distance and/or the speed of the target.

As shown in fig. 11e, when two signal sequences with opposite frequency hopping directions exist in the sequence combination, such as when a first signal sequence and a second signal sequence exist, the fast time frequency uncertainty range in fig. 11e (such as two dashed lines in the horizontal direction in fig. 11 e) can be obtained by performing FFT of the distance dimension of each linear sweep unit on the echo signal corresponding to the signal sequence; by performing FFT of each linear sweep cell group on the echo signal corresponding to the signal sequence, the slow time frequency uncertainty range (such as two dashed lines in the vertical direction in fig. 11 e) of each linear sweep cell group in fig. 11e can be obtained; by performing FFT of the speed dimension of each signal sequence, the slow time-frequency uncertainty range corresponding to different signal sequences in fig. 11e (e.g., two pairs of oblique dashed lines in fig. 11e, each pair of oblique dashed lines corresponds to the slow time-frequency uncertainty range of one signal sequence), that is, the FFT result of the speed dimension of each signal sequence corresponds to one slow time frequency, and the overall resolution of the radar chip is the intersection of the oblique main lobes of each signal sequence.

Similarly, when two signal sequences having the same hopping direction but different hopping slopes exist in the sequence combination, the detection result shown in fig. 11f can be obtained by FFT of the distance dimension of each linear sweep unit, FFT of each linear sweep unit group, and FFT of the speed dimension of each signal sequence. Wherein, the fast time frequency uncertainty range in fig. 11f (such as two dotted lines in the horizontal direction in fig. 11 f) can be obtained by FFT of the distance dimension for each linear sweep unit; by performing FFT of each linear sweep cell group on the echo signal corresponding to the signal sequence, the slow time frequency uncertainty range (such as two dashed lines in the vertical direction in fig. 11 f) of each linear sweep cell group in fig. 11f can be obtained; by performing FFT of the speed dimension of each signal sequence, a slow time-frequency uncertainty range (for example, two pairs of inclined dashed lines in fig. 11e, each pair of inclined dashed lines corresponds to a slow time-frequency uncertainty range of one signal sequence) corresponding to different signal sequences in fig. 11f can be obtained, that is, the FFT result of the speed dimension of each signal sequence corresponds to one slow time frequency, and the overall resolution of the radar chip is the intersection of inclined main lobes of each signal sequence.

In this embodiment, by combining different signal sequences, i.e. a sequence combination comprising a plurality of signal sequences, a plurality of slow time phase relations determined by two-dimensional linear combinations of different distances (R) -velocities (V) are obtained, whereby a smaller uncertainty of the slow time frequency can be exploited to achieve a better overall resolution.

The above method is divided into steps, which are only for clarity of description, and may be combined into one step or split into multiple steps when implemented, so long as they include the same logic relationship, and they are all within the protection scope of this patent; it is within the scope of this patent to add insignificant modifications to the algorithm or flow or introduce insignificant designs, but not to alter the core design of its algorithm and flow.

Another embodiment of the present application relates to a computer-readable storage medium storing a computer program, and it is easy to understand by those skilled in the art from the above description of the embodiments that the exemplary embodiments described herein may be implemented by software or may be implemented by combining software with necessary hardware. The technical solution according to the embodiment of the present application may be embodied in the form of a software product, which may be stored in a non-volatile storage medium (may be a CD-ROM, a usb disk, a mobile hard disk, etc.) or on a network, and includes several instructions to cause a computing device (may be a personal computer, a server, or a network device, etc.) to perform the above-described method according to the embodiment of the present application.

The software product may employ any combination of one or more readable media. The readable medium may be a readable signal medium or a readable storage medium. The readable storage medium can be, for example, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or a combination of any of the foregoing. More specific examples (a non-exhaustive list) of the readable storage medium would include the following: an electrical connection having one or more wires, a portable disk, a hard disk, random Access Memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

The computer readable storage medium may include a data signal propagated in baseband or as part of a carrier wave, with readable program code embodied therein. Such a propagated data signal may take any of a variety of forms, including, but not limited to, electro-magnetic, optical, or any suitable combination of the foregoing. A readable storage medium may also be any readable medium that can communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device. Program code embodied on a readable storage medium may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber cable, RF, etc., or any suitable combination of the foregoing.

Program code for carrying out operations of the present application may be written in any combination of one or more programming languages, including an object oriented programming language such as Java, C++ or the like and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The program code may execute entirely on the user's computing device, partly on the user's device, as a stand-alone software package, partly on the user's computing device, partly on a remote computing device, or entirely on the remote computing device or server. In the case of remote computing devices, the remote computing device may be connected to the user computing device through any kind of network, including a Local Area Network (LAN) or a Wide Area Network (WAN), or may be connected to an external computing device (e.g., connected via the Internet using an Internet service provider).

The computer-readable medium carries one or more programs which, when executed by a device, cause the computer-readable medium to perform the aforementioned functions.

Another embodiment of the present invention relates to a radar chip, as shown in fig. 13, comprising: a processor 1301 and a memory 1302; a memory 1302 for storing instructions executable by the at least one processor 1301, the instructions being executable by the at least one processor 1301 to enable the at least one processor 1301 to perform embodiments of the object detection method as described above, or to perform embodiments of the signal transmission method as described above.

Where memory 1302 and processor 1301 are connected by a bus, the bus may comprise any number of interconnected buses and bridges, the buses connecting the various circuits of the one or more processors 1301 and memory 1302 together. The bus may also connect various other circuits such as peripherals, voltage regulators, and power management circuits, which are well known in the art, and therefore, will not be described any further herein. The bus interface provides an interface between the bus and the transceiver. The transceiver may be one element or may be a plurality of elements, such as a plurality of receivers and transmitters, providing a means for communicating with various other apparatus over a transmission medium. The data processed by the processor 1301 is transmitted over a wireless medium via an antenna, which further receives the data and transmits the data to the processor 1301.

Processor 1301 is responsible for managing the bus and general processing and may provide various functions including timing, peripheral interfaces, voltage regulation, power management, and other control functions. And memory 1302 may be used to store data used by processor 1301 in performing operations.

Another embodiment of the present invention relates to an integrated circuit, as shown in fig. 14, comprising a radio frequency module 1401, an analog signal processing module 1402 and a digital signal processing module 1403 connected in sequence. The radio frequency module 1401 is configured to generate a target detection signal and an echo signal; the target detection signal comprises a signal sequence or a sequence combination in the embodiment of the method for detecting the target or comprises a sequence combination in the embodiment of the transmitting method of the signal; the analog signal processing module 1402 is configured to perform a down-conversion process on the echo signal to obtain an intermediate frequency signal; and, the digital signal processing module 1403 is configured to perform analog-to-digital conversion on the intermediate frequency signal to obtain a digital signal, and perform object detection on the digital signal.

Another embodiment of the invention relates to a radio device comprising: a carrier; an integrated circuit as in the above example, disposed on the carrier; the antenna is arranged on the supporting body, or the antenna and the integrated circuit are integrated into a whole device and arranged on the supporting body; the integrated circuit is connected with the antenna and is used for transmitting a target detection signal and/or receiving an echo signal.

When the antenna and the integrated circuit are not integrated into an integrated device, the integrated circuit is connected with the antenna through a first transmission line, and the first transmission line can be a PCB wire. The carrier may be a printed circuit board PCB, such as a development board, a counter board, or a motherboard of a device, which are not described in detail herein.

Since the structure and the working principle of the integrated circuit included in the radio device have been described in detail in the above embodiments, details are not described here.

Another embodiment of the present invention relates to a terminal device, including: an equipment body; and a radio device as described above provided on the apparatus body; wherein the radio is for target detection to provide reference information to the operation of the device body.

In one embodiment of the application, the radio device may be disposed outside the apparatus body, in another embodiment of the application, the radio device may also be disposed inside the apparatus body, and in other embodiments of the application, the radio device may also be disposed partially inside the apparatus body, and partially outside the apparatus body. The embodiment of the present application is not limited thereto, and is specific as the case may be.

It should be noted that the radio device may implement functions such as object detection by transmitting and receiving radio signals, so as to provide measurement information of a detected object to the device body, thereby assisting and even controlling the operation of the device body. Examples of the measurement information include: at least one of relative distance, relative speed, relative angle.

In an alternative embodiment, the device body may be a component or product for applications such as transportation, consumer electronics, monitoring, in-cabin detection, and health care. For example, the device body may be an intelligent transportation device (such as an automobile, a motorcycle, a ship, a subway, a train, etc.), a security device (such as a camera), a liquid level/flow rate detection device, an intelligent wearable device (such as a bracelet, glasses, etc.), an intelligent home device (such as a sweeping robot, a door lock, a television, an air conditioner, an intelligent lamp, etc.), various communication devices (such as a mobile phone, a tablet computer, etc.), etc., a barrier gate, an intelligent traffic indicator, an intelligent sign, a traffic camera, various industrial mechanical arms (or robots), etc., and may be various instruments for detecting vital sign parameters and various devices carrying the instruments, such as an in-car detection, an indoor personnel monitoring, an intelligent medical device, a consumer electronic device, etc.

In yet another alternative embodiment, when the apparatus body is applied to an advanced driving assistance system (i.e. ADAS), the radio device as the vehicle-mounted sensor may provide security for the ADAS system with various functions such as automatic braking assistance (i.e. AEB), blind spot detection warning (i.e. BSD), auxiliary lane change warning (i.e. LCA), and reverse assistance warning (i.e. RCTA).

In addition, the examples mentioned in the above embodiments can be freely combined, and any combination can be understood as an embodiment. The appearances of the "embodiment" or "examples" in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Those skilled in the art will appreciate that the embodiments described herein may be combined with other embodiments. It will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention.

Claims

1. A method of target detection, comprising:

2. The method according to claim 1, wherein the linear sweep unit is a chirp or at least two signals obtained by intercepting the effective signal edges of the chirp.

3. The method according to claim 1, wherein the performing FFT of each linear sweep unit, FFT of each linear sweep unit group, and FFT of the signal sequence based on the echo signal corresponding to the signal sequence comprises:

Performing any two FFTs of the FFTs of each linear sweep unit, the FFTs of each linear sweep unit group and the FFTs of the signal sequences based on echo signals corresponding to the signal sequences;

non-coherent combination is carried out on the results of any two FFT, and target detection is carried out according to the combined results;

the remaining FFT is performed on the detected target points to determine the distance and/or speed of the target.

4. The method of claim 1, wherein the transmitting a signal sequence comprising a plurality of groups of linear sweep cells comprises:

Transmitting a sequence combination comprising a plurality of said signal sequences, said sequence combination being used for one target detection; wherein the sequence combination at least comprises: a first signal sequence, a second line signal sequence, and a third signal sequence; the first signal sequence comprises a plurality of linear sweep frequency unit groups with sweep frequency initial frequencies gradually increasing linearly, the second signal sequence comprises a plurality of linear sweep frequency unit groups with sweep frequency initial frequencies gradually decreasing linearly, and the third signal sequence comprises a plurality of linear sweep frequency unit groups with the same sweep frequency initial frequencies.

5. The method of claim 4, wherein the transmitting comprises a sequence combination of a plurality of signal sequences, comprising:

the plurality of signal sequences are transmitted sequentially in a time dimension, or the plurality of signal sequences are transmitted interleaved in the time dimension.

6. The method of object detection according to claim 5, wherein the plurality of signal sequences are transmitted interleaved in a time dimension, comprising: the plurality of signal sequences includes groups of linear sweep cells that are alternately transmitted in a time dimension.

7. The method of claim 4, wherein the transmitting comprises a sequence combination of a plurality of signal sequences, comprising:

The plurality of signal sequences are transmitted through respective transmit antennas of the MIMO antenna array in a time division multiplexing or code division multiplexing mode.

8. The method according to claim 7, wherein when the plurality of signal sequences are transmitted through the respective transmit antennas of the MIMO antenna array in the time division multiplexing mode, a transmission order of the respective transmit antennas is random.

9. The method of claim 4, wherein the slope and bandwidth of each linear sweep cell within the same set of linear sweep cells are the same;

The slopes and bandwidths of two linear sweep frequency units in any two linear sweep frequency unit groups in the same signal sequence are the same, and the linear sweep frequency units in the linear sweep frequency unit groups in different signal sequences are different.

10. The method of claim 4 to 9, wherein each signal sequence in the sequence combination is located in the same frame signal or in at least two adjacent frame signals.

11. The method according to any one of claims 4 to 9, wherein the sweep direction of the linear sweep cells within any one of the groups of linear sweep cells coincides with the frequency hopping direction of the signal sequence to which the group of linear sweep cells belongs.

12. The method of target detection according to any one of claims 4 to 9, wherein the sequence combining further comprises: a fourth signal sequence, which comprises a plurality of linear sweep frequency unit groups with sweep frequency initial frequencies which are sequentially and linearly changed;

wherein the frequency hopping slopes of any two signal sequences in the sequence combination are different.

13. The method of claim 1, wherein the transmitting a signal sequence comprising a plurality of groups of linear sweep cells comprises:

Transmitting a sequence combination comprising at least two signal sequences, said sequence combination being used for performing a target detection once; the frequency hopping slope of any two signal sequences in the sequence combination is different, and the frequency hopping slope of any one signal sequence in the sequence combination is not 0.

14. A method of transmitting a signal, comprising:

the sequence combinations are transmitted for one target detection.

15. The method according to claim 14, wherein at least two signal sequences having different hopping directions exist in the sequence combination.

16. A method of target detection, comprising:

Receiving echo signals corresponding to the plurality of signal sequences transmitted by the signal transmission method according to claim 14 or 15;

17. A computer readable storage medium storing a computer program, characterized in that the computer program when executed by a processor implements the method of object detection according to any one of claims 1 to 13, or implements the method of signal transmission according to any one of claims 14 to 15, or implements the method of object detection according to claim 16.

18. A radar chip, comprising: at least one processor; and

A memory communicatively coupled to the at least one processor; wherein,

The memory stores instructions executable by the at least one processor to enable the at least one processor to perform the method of object detection as claimed in any one of claims 1 to 13, or to implement the method of signal transmission as claimed in any one of claims 14 to 15, or to implement the method of object detection as claimed in claim 16.

19. An integrated circuit is characterized by comprising a radio frequency module, an analog signal processing module and a digital signal processing module which are connected in sequence;

The radio frequency module is used for generating a target detection signal and an echo signal; wherein the target detection signal comprises a signal sequence or combination of sequences in a method of target detection according to any one of claims 1 to 13, or a sequence combination in a method of transmission comprising a signal according to any one of claims 14 to 15;

20. A radio device, comprising:

a carrier;

The integrated circuit of claim 19 disposed on the carrier;

21. A terminal device, comprising:

An equipment body; and

The radio of claim 20 disposed on the device body;