Signal transmission method, signal reception method and corresponding device

Abstract

A signal transmission method, a signal receiving method, and corresponding devices are provided, which are used for autonomous or assisted driving. In the signal transmission stage, the radar can transmit a signal by using a desired waveform, for example, generate a first frequency modulated continuous wave sequence, and transmit the first frequency modulated continuous wave sequence, where the first frequency modulated continuous wave sequence includes N frequency modulated continuous waves, N being a positive integer equal to or greater than 1, and the product of the time domain position and the corresponding frequency domain position in the first frequency modulated continuous wave among the N frequency modulated continuous waves satisfies a first condition. In this method, in the signal receiving stage, the radar can use a simple digital signal processing method (e.g., FFT) to perform signal processing and implement target speed measurement. In the present application, the probability of mutual interference between radars can be reduced, and the speed measurement performance of the radar can be guaranteed.

Description

[Technical field]

[0001]

[0001] This application relates to the field of sensors, and in particular to a signal transmitting method, a signal receiving method and corresponding devices. [Background technology]

[0002]

[0002] With the development of society, intelligent vehicles are gradually entering into people's daily life. Various radars installed in vehicles (i.e., automotive radars), such as millimeter wave radars, can sense the surrounding environment at any time during the vehicle's travel, collect data, identify and track moving objects, identify static scenarios (e.g., lanes and signs), and make route plans based on navigation and map data, thereby improving the safety and comfort of driving.

[0003]

[0003] With the widespread use of vehicle-mounted radars, mutual interference between vehicle-mounted radars is becoming more serious. Due to mutual interference, the detection probability of vehicle-mounted radars is reduced, or the false alarm probability of vehicle-mounted radars is increased, which has a non-negligible impact on driving safety and comfort. Therefore, how to reduce the interference between vehicle-mounted radars has become a technical problem that needs to be urgently solved. Summary of the Invention

[0004]

[0004] The present application provides a signal transmitting method, a signal receiving method, and corresponding devices for reducing interference between radars mounted on vehicles and further ensuring the speed measurement performance of the radars.

[0005]

[0005] According to a first aspect, a signal transmission method is provided. The method may be performed by a first device. The first device may be, for example, a radar, or the first device may be a chip mounted on a communication device. The communication device may be, for example, a radar or other device. This is not limited in the present application. The method includes: generating a first frequency modulated continuous wave sequence; and transmitting the first frequency modulated continuous wave sequence, where the first frequency modulated continuous wave sequence includes N frequency modulated continuous waves, where N is a positive integer equal to or greater than 1. The product of the time domain position and the corresponding frequency domain position in the first frequency modulated continuous wave among the N frequency modulated continuous waves satisfies a first condition.

[0006]

[0006] In the above solution, in the signal transmission stage, the first device transmits a signal to the outside by using a designed waveform (e.g., the product of the time domain position and the corresponding frequency domain position in the first frequency modulated continuous wave among the N frequency modulated continuous waves meets the first condition), so that in the subsequent signal reception stage, the signal receiving device (e.g., the second device) can learn the waveform of the signal transmitted by the first device (e.g., determine the time domain position and the frequency domain position of the first frequency modulated continuous wave based on the first condition), and can use a simple digital signal processing method (e.g., FFT) for speed measurement, so that the processing efficiency is improved. In a scenario where multiple radars exist simultaneously, each of the multiple radars can transmit a signal by using this method. In a specific implementation, it is only required to ensure that the signal waveforms corresponding to different radars correspond to different frequency domain positions at the same time domain position (i.e., the collision of frequency domain resources between different radars at the same moment is avoided), so that the mutual interference between the radars is reduced or eliminated. In addition, since each radar transmits a signal using a designed waveform, the receiving device corresponding to each radar can use a simple digital signal processing method (e.g., FFT) for speed measurement, which can improve processing efficiency, reduce the probability of mutual interference between radars, and ensure the speed measurement performance of the radar.

[0007]

[0007] In a possible design, the first condition is associated with a position of a first frequency modulated continuous wave among the N frequency modulated continuous waves. Furthermore, for each frequency modulated continuous wave of the N frequency modulated continuous waves, the product of the time domain position of the frequency modulated continuous wave and the corresponding frequency domain position may satisfy a certain condition. The conditions satisfied by the products of the time domain position and the corresponding frequency domain position of different frequency modulated continuous waves may be different, and the conditions satisfied by the products of the time domain position and the corresponding frequency domain position of each frequency modulated continuous wave may be associated with the position of the frequency modulated continuous wave among the N frequency modulated continuous waves.

[0008]

[0008] In this design method, the time domain position and frequency domain position of the first frequency modulated continuous wave can be determined based on the position of the first frequency modulated continuous wave in the N frequency modulated continuous waves.

[0009]

[0009] In a possible design, the frequency domain location includes a start frequency and / or a center frequency. The frequency domain location is a reference frequency used by the radar to perform frequency hopping, and it should be understood that the reference frequencies in each frequency modulated continuous wave in the first frequency modulated continuous wave sequence and used to perform frequency hopping need to use the same reference.

[0010] For example, the first frequency modulated continuous wave sequence includes a first frequency modulated continuous wave and a second frequency modulated continuous wave, where the frequency domain location of the first frequency modulated continuous wave is a start frequency of the first frequency modulated continuous wave and the frequency domain location of the second frequency modulated continuous wave is also a start frequency of the second frequency modulated continuous wave; or, the frequency domain location of the first frequency modulated continuous wave is a center frequency of the first frequency modulated continuous wave and the frequency domain location of the second frequency modulated continuous wave is also a center frequency of the second frequency modulated continuous wave.

[0011]

[0010] Of course, in practical applications, the frequency domain position may alternatively be another reference frequency that is uniformly set within the frequency domain range of each frequency modulated continuous wave, which is not limited in the present case.

[0012]

[0011] In a possible design, the time domain location includes a start time and / or a center time. It will be understood that there may be a correspondence between the time domain location and the frequency domain location. For example, if the frequency domain location of the first frequency modulated continuous wave is the start frequency of the first frequency modulated continuous wave, then the time domain location of the first frequency modulated continuous wave is the start time of the first frequency modulated continuous wave.

[0013]

[0012] Of course, in practical applications, the time-domain position may alternatively be another time position that is uniformly set within the time-domain range of each frequency-modulated continuous wave, which is not limited in the present case.

[0014] In a possible design, the first condition is:

[0015]

number

[0016]

[0014] n is the sequence number of the frequency modulated continuous wave among the N frequency modulated continuous waves, where n=0, 1, 2, ..., N-1; T n is the time domain position of the frequency modulated continuous wave with sequence number n among N frequency modulated continuous waves; f n is the frequency domain position of the frequency modulated continuous wave with sequence number n among the N frequency modulated continuous waves; α and β are pre-set frequency hopping parameters.

[0017]

[0015] It will be understood that in practical applications, the above formula may further have other variations.

[0018]

[0016] For example, it may be:

[0019]

number

[0017] Δt n is the time deviation caused by errors during product implementation, and for different values ​​of n, Δ n The values ​​of may be the same or different.

[0020]

[0018] For example, it may be:

[0021]

number

[0019] Δt n is the time deviation caused by errors in product implementation, and for different values ​​of n, Δ n The values ​​of may be the same or different.

[0022]

[0020] For example, it may be:

[0023]

number

[0021] Δf n is the frequency deviation caused by errors in product implementation, and for different values ​​of n, Δ n The values ​​of may be the same or different.

[0024]

[0022] In a possible design, the frequency domain positions of the N frequency modulated continuous waves are distributed at equal intervals in the frequency domain, and the interval between two adjacent frequency modulated continuous waves of the N frequency modulated continuous waves is a fixed value x0. In other words, the waveforms of the N frequency modulated continuous waves can perform equal interval frequency hopping in the frequency domain. The equal interval frequency hopping can specifically be equal interval increase or equal interval decrease. This is not limited in the present application.

[0025] In a possible design, for uniform frequency hopping, α and β may be set as the following parameters:

[0026]

number

[0027]

[0025] It will be understood that in practical applications, the above formula may further have other variations.

[0028]

[0026] In this way, it can be ensured that two adjacent frequency modulated continuous waves (in the time domain) do not overlap in time and that the radar has a large velocity measurement range.

[0029] In a possible design, the N frequency modulated continuous wave waveforms can perform random frequency hopping in the frequency domain. For example, the first device can determine the frequency domain location of each of the N frequency modulated continuous waves based on the frequency hopping capability of the radar.

[0030] In this case, α and β can be set to the following parameters:

[0031]

number

[0032]

[0030] It will be understood that in practical applications, the above formula may further have other variations.

[0033]

[0031] It should be noted that the design is not limited to the case where random frequency hopping is applied, provided that the frequency domain position of each of the N frequency modulated continuous waves can be determined.

[0034]

[0032] In this way, it can be ensured that two adjacent frequency modulated continuous waves (in the time domain) do not overlap in time and that the radar has a large velocity measurement range.

[0035]

[0033] According to a second aspect, a signal receiving method is provided. The method may be performed by a second device. The second device may be, for example, a radar, or the second device may be a chip mounted on a communication device. The communication device may be, for example, a radar or other device. This is not limited in the present application. The first device and the second device may be integrated into one chip, or may be separately integrated into different chips. This is not limited in the present application.

[0036] The method includes: receiving a second frequency modulated continuous wave sequence, the second frequency modulated continuous wave sequence being a signal formed after the first frequency modulated continuous wave sequence is transmitted by a first device, propagates through space, and is reflected by a target; and determining information about the target, including speed and / or distance, based on the second frequency modulated continuous wave sequence and the first frequency modulated continuous wave sequence, wherein the first frequency modulated continuous wave sequence includes N frequency modulated continuous waves, N being a positive integer equal to or greater than 1, and a product of a time domain position and a corresponding frequency domain position of the first frequency modulated continuous wave of the N frequency modulated continuous waves satisfies a first condition.

[0037]

[0034] In this solution, the second device determines information such as target speed and distance based on the second frequency modulated continuous wave sequence and the first frequency modulated continuous wave sequence. Since the first frequency modulated continuous wave sequence is a pre-designed waveform (i.e., the product of the time domain position and the corresponding frequency domain position of the first frequency modulated continuous wave among the N frequency modulated continuous waves satisfies the first condition), the second device can estimate the target parameters and ensure the speed measurement performance of the radar by using a simple digital signal processing method.

[0038]

[0035] For a description of the first frequency modulated continuous wave sequence, please refer to the relevant content in the first aspect. The details will not be described again here.

[0039]

[0036] In a possible design, the step of determining the velocity of the target based on the second frequency modulated continuous wave sequence and the first frequency modulated continuous wave sequence includes: determining an intermediate frequency signal sequence based on the second frequency modulated continuous wave sequence and the first frequency modulated continuous wave sequence; and processing the intermediate frequency signal sequence via FFT.

[0040]

[0037] Of course, the FFT is merely an example and not a specific limitation.

[0041]

[0038] In a possible design, before processing the intermediate frequency signal sequence by FFT, the method further includes a step of: performing phase compensation on the intermediate frequency signal sequence or the second frequency modulated continuous wave sequence based on the spacing between frequency domain positions among the N frequency modulated continuous waves.

[0042]

[0039] In this design, the phase difference between two adjacent frequency-modulated continuous waves in the second frequency-modulated continuous wave sequence caused by distance is compensated, and the accuracy of speed detection can be improved.

[0043]

[0040] According to a third aspect, there is provided a signal transmission device. The device includes a module / unit / means configured to perform the first aspect or any possible design of the first aspect. The module / unit / means may be implemented by software, by hardware, or by hardware executing corresponding software.

[0044] For example, the apparatus may include: a processing unit configured to generate a first frequency modulated continuous wave sequence; and a transmitting unit configured to transmit the first frequency modulated continuous wave sequence, where the first frequency modulated continuous wave sequence includes N frequency modulated continuous waves, where N is a positive integer equal to or greater than 1. A product of a time-domain position and a corresponding frequency-domain position in the first frequency modulated continuous wave among the N frequency modulated continuous waves satisfies a first condition.

[0045] In a possible design, the first condition is associated with the position of a first frequency modulated continuous wave among the N frequency modulated continuous waves.

[0046]

[0043] In a possible design, the frequency domain location includes a start frequency and / or a center frequency, and the time domain location includes a start time and / or a center time.

[0047] In a possible design, the first conditions include:

[0048]

number

[0045] n is the sequence number of the frequency modulated continuous wave among the N frequency modulated continuous waves, where n=0, 1, 2, ..., N-1; T n is the time domain position of the frequency modulated continuous wave with sequence number n among N frequency modulated continuous waves; f n is the frequency domain position of the frequency modulated continuous wave with sequence number n among the N frequency modulated continuous waves; α and β are pre-set frequency hopping parameters.

[0049]

[0046] In a possible design, the frequency domain positions of the N frequency modulated continuous waves are equally distributed in the frequency domain, and the spacing between the frequency domain positions of two adjacent frequency modulated continuous waves among the N frequency modulated continuous waves is a fixed value x0.

[0050] In a possible design, for uniform frequency hopping, α and β may be set as the following parameters:

[0051]

number

[0052] In a possible design, for random frequency hopping, α and β may be set as the following parameters:

[0053]

number

[0054]

[0051] According to a fourth aspect, there is provided a signal receiving device. The device includes a module / unit / means configured to perform the second aspect or any possible design of the second aspect. The module / unit / means may be implemented by software, by hardware, or by hardware executing corresponding software.

[0055] For example, the device may include: a receiving unit configured to receive a second frequency modulated continuous wave sequence, the second frequency modulated continuous wave sequence being a signal formed after the first frequency modulated continuous wave sequence is transmitted by the first device, propagates through space, and is reflected by a target; and a processing unit configured to determine information about the target, including a speed and / or a distance, based on the second frequency modulated continuous wave sequence and the first frequency modulated continuous wave sequence. The first frequency modulated continuous wave sequence includes N frequency modulated continuous waves, N being a positive integer equal to or greater than 1, and a product of a time domain position and a corresponding frequency domain position in the first frequency modulated continuous wave of the N frequency modulated continuous waves satisfies a first condition.

[0056]

[0053] Optionally, the processing unit is specifically configured to: determine an intermediate frequency signal sequence based on the second frequency modulated continuous wave sequence and the first frequency modulated continuous wave sequence; and process the intermediate frequency signal sequence by FFT.

[0057]

[0054] Optionally, the processing unit may be further configured to: perform phase compensation on the intermediate frequency signal sequence or the second frequency modulated continuous wave sequence based on the intervals between frequency domain positions of the N frequency modulated continuous waves before processing the intermediate frequency signal sequence by FFT.

[0058]

[0055] According to a sixth aspect, there is provided a communications device including at least one processor and an interface circuit, the interface circuit being configured to: receive a signal from another device external to the device and send a signal to the processor or send a signal from the processor to another device external to the device, and the processor being configured to perform a method according to the first aspect or any one of the possible designs of the first aspect, or a method according to the second aspect or any one of the possible designs of the second aspect, by using logic circuits or by executing code instructions.

[0059]

[0056] According to a sixth aspect, there is provided a radar system comprising a first apparatus configured to perform a method according to the first aspect or any one of the possible designs of the first aspect, and a second apparatus configured to perform a method according to the second aspect or any one of the possible designs of the second aspect.

[0060]

[0057] According to a seventh aspect, there is provided a terminal device including a first apparatus configured to perform a method according to the first aspect or any one of the possible designs of the first aspect, and a second apparatus configured to perform a method according to the second aspect or any one of the possible designs of the second aspect.

[0061]

[0058] Optionally, the terminal device may be a vehicle, an unmanned aerial vehicle, a helicopter, an aircraft, a ship, an intelligent transportation device, a smart home device, etc. The specific form of the terminal device is not limited in the embodiments of the present application.

[0062] According to an eighth aspect, an embodiment of the present application provides a computer readable storage medium. The computer readable storage medium stores a computer program or instructions. When the computer program or instructions are executed by a communication device, a method according to the first aspect or any one of the possible designs of the first aspect, or a method according to the second aspect or any one of the possible designs of the second aspect is performed.

[0063]

[0060] According to a ninth aspect, there is provided a computer program product. The computer program product stores instructions. When the computer program product runs on a computer, the computer is enabled to perform a method according to the first aspect or any one of the possible designs of the first aspect, or a method according to the second aspect or any one of the possible designs of the second aspect.

[0064]

[0061] For the specific beneficial effects of the third to ninth aspects, please refer to the technical effects that can be achieved by the corresponding designs in the first or second aspects. Details will not be described again here. [Brief description of the drawings]

[0065] [Figure 1]

[0062] FIG. 1 is a diagram illustrating the operating principle of a millimeter wave radar. [Diagram 2] FIG. 2 is a schematic diagram of a frequency modulated continuous wave. [Diagram 3] FIG. 3 is a schematic diagram of a multiple cycle frequency modulated continuous wave. [Figure 4]FIG. 4 is a schematic diagram of the transmitted signal, the reflected signal, and the intermediate frequency signal. [Diagram 5]

[0066] Figure 5 is a schematic diagram of mutual interference between automotive radars. [Figure 6]

[0067] Figure 6 is a schematic diagram of a possible spurious intermediate frequency signal. [Figure 7] FIG. 7 is a schematic diagram of a possible spurious intermediate frequency signal. [Figure 8]

[0068] FIG. 8 is a schematic diagram illustrating a possible interfering signal obscuring a target signal. [Figure 9] FIG. 9 is a schematic diagram illustrating possible interfering signals obscuring a target signal. [Figure 10]

[0069] Figure 10 is a schematic diagram of radar random frequency hopping. [Figure 11]

[0070] FIG. 11 is a schematic diagram of a possible application scenario of an embodiment of the present application. [Figure 12]

[0071] FIG. 12 is a flowchart of a signal transmission method according to an embodiment of the present application. [Figure 13]

[0072] FIG. 13 is a schematic diagram of the time and frequency domain extents of a frequency modulated continuous wave. [Figure 14]

[0073] FIG. 14 is a schematic diagram of a possible correspondence between time and frequency domain positions of a frequency modulated continuous wave. [Figure 15]

[0074] FIG. 15 is a flowchart of a signal receiving method according to an embodiment of the present application. [Figure 16]

[0075] FIG. 16 is a flow chart of a possible signal processing method according to an embodiment of the present application. [Figure 17]

[0076] FIG. 17 is a flow chart of another possible signal processing method according to an embodiment of the present application. [Figure 18]

[0077] FIG. 18 is a schematic diagram of the structure of a signal transmitting device according to an embodiment of the present application. [Figure 19]

[0078] FIG. 19 is a schematic diagram of the structure of a signal receiving device according to an embodiment of the present application. [Figure 20]

[0079] FIG. 20 is a schematic diagram of the structure of a communication device according to an embodiment of the present application. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0066]

[0080] Millimeter waves are electromagnetic waves with wavelengths in the range of 1 mm to 10 mm, corresponding to the frequency range of 30 GHz to 300 GHz. In this frequency band, the characteristics related to millimeter waves make them very suitable for use in the automotive field. For example, the high bandwidth means abundant frequency domain resources and low antenna side lobes, thereby facilitating imaging or false imaging. The short wavelength means a reduced size of the radar device and a reduced antenna diameter, thus reducing the weight. The narrow beam means that for the same antenna size, the millimeter wave beam is much narrower than the microwave beam, thus providing a higher radar resolution. The strong penetrating ability means that compared with lidar and optical systems, millimeter wave radar has a better ability to penetrate smoke, dust, and fog, and can operate day and night.

[0067]

[0081] A millimeter wave radar is a radar that operates in the millimeter wave band and usually includes devices such as an oscillator, a transmitting antenna, a receiving antenna, a frequency mixer, a processor, and a controller. Figure 1 shows the working principle of a millimeter wave radar. The oscillator generates a radar signal whose frequency increases linearly with time. The radar signal is usually a frequency modulated continuous wave (FMCW). A part of the radar signal is output as a local oscillator signal to the frequency mixer through a directional coupler, and a part is transmitted through the transmitting antenna. The receiving antenna receives the reflected radar signal (also called a reflected signal or an echo signal) after the transmitted radar signal encounters an object in front of the vehicle. The frequency mixer performs frequency mixing on the received radar signal and the local oscillator signal to obtain an intermediate frequency signal (or called an intermediate frequency echo signal). The intermediate frequency signal contains information such as the range, speed, and angle of the target relative to the radar system. The intermediate frequency signal passes through a low pass filter, undergoes amplification, and is transmitted to a processor. The processor processes the received signal, for example by performing fast Fourier transforms, spectral analysis, and the like on the received signal to obtain information regarding the range, speed, and angle of the target object relative to the radar system. Finally, the processor can output the obtained information to a controller to control the behavior of the vehicle.

[0068]

[0082] The waveform of the frequency-modulated continuous wave of a millimeter wave radar is usually a sawtooth wave or a triangular wave. Below, the principle of distance measurement of a millimeter wave radar will be explained in detail using a sawtooth wave as an example. The principle of distance measurement of a triangular wave is the same as that of a sawtooth wave.

[0069]

[0083] A linearly frequency modulated continuous wave is a signal whose frequency varies linearly with time, as shown in Figure 2.

[0070]

[0084] As shown in Figure 3, the oscillator of the millimeter wave radar outputs multiple periods of frequency modulated continuous waves, where the period of the frequency modulated continuous wave (the time from the start to the end of the frequency modulated continuous wave) is Tc, the slope is a0, the bandwidth is B, and the start frequency of the frequency modulated continuous wave is b0. The frequency modulated continuous wave signal shown in Figure 2 is also called a chirp signal.

[0071]

[0085] The equivalent baseband signal of one period of frequency modulated continuous wave output by a millimeter wave radar oscillator can be expressed as follows:

[0072]

number

[0086] A represents the amplitude of the equivalent baseband signal, a0 represents the slope of the equivalent baseband signal, b0 represents the intercept of the equivalent baseband signal on the coordinate axis corresponding to frequency f, φ0 represents the initial phase of the equivalent baseband signal, and exp represents the exponential function of e. Frequency is defined as the rate of change of phase with respect to time. Thus, the frequency of the equivalent baseband signal is:

[0073]

number

[0087] An image of Equation 1.2 is shown in Figure 3.

[0074]

[0088] After up-conversion is performed on the n-th period of the frequency modulated continuous wave equivalent baseband signal transmitted by the oscillator, the equivalent baseband signal is radiated by the transmitting antenna of the millimeter wave radar. The transmitted signal can be expressed as follows:

[0075]

number

[0089] After the signal encounters an obstacle, the signal is reflected and then received by the millimeter wave radar. The waveform of the transmitted signal is the same as that of the reflected signal, except that the waveform of the reflected signal has a delay τ with respect to the waveform of the transmitted signal, as shown in Figure 4. In Figure 4, the echo signal is the reflected signal. The reflected signal of the nth period of the frequency modulated continuous wave can be expressed as:

[0076]

number

[0090] A' represents the amplitude of the signal obtained after the equivalent baseband signal transmitted by the oscillator is affected by the transmit antenna gain, the target reflection, the propagation loss, and the receive antenna gain, and τ represents the delay between the moment when the millimeter wave radar transmitter transmits the radar signal and the moment when the millimeter wave radar receiver receives the echo signal (i.e., the reflected signal), as shown in Figure 4, where the delay is twice the distance divided by the speed of light. Note that in Figure 4, τ max represents the echo delay corresponding to the maximum detection range of the millimeter wave radar. In other words, τ max is the delay of the reflected signal received by the millimeter wave radar with respect to the transmitted signal when the distance between the millimeter wave radar and the target object is the maximum distance that can be detected by the millimeter wave radar. The relationship between τ and the target distance d can be expressed as:

[0077]

number

[0091] τ0 is the radar echo delay caused by the reference distance, v is the radial relative velocity between the target and the radar, and c is the speed of light. Considering that the velocity v is much smaller than the speed of light c, for the baseband signal, the second term in the above equation has little contribution in the subsequent detection, therefore, the second term in the above equation (1.5) is ignored in the baseband signal. However, for the carrier wave, the second term in the above equation plays an important role in the velocity detection, therefore, the second term is reserved and the following is obtained:

[0078]

number

[0092] The frequency mixer of the millimeter wave radar performs frequency mixing of the received signal and the local oscillator signal, and outputs an intermediate frequency signal after processing by a low pass filter. The intermediate frequency signal is expressed as follows:

[0079]

number

[0093]

[0080]

number

[0081]

number

[0094] In general, f d < <a0τ0であるので、f IF ≒a0τ0. Therefore, we obtain the following equation.

[0082]

number

[0095] Therefore, the distance d between the millimeter wave radar and the target is:

[0083]

number

[0096] The above derivation is performed based on one target, and the above principle can also be applied to multiple targets. In other words, multiple intermediate frequency signals can be obtained after frequency mixing, and intermediate frequencies corresponding to multiple targets respectively can be obtained after the multiple intermediate frequency signals are sent to a processor for Fourier transformation.

[0084]

[0097] It can be seen from the above reasoning process that there is a linear relationship between the frequency difference between the transmitted and received signals (i.e., the frequency of the intermediate frequency signal) and the delay: a longer distance to the target indicates a slower time to receive the reflected signal, and thus a larger frequency difference between the reflected and transmitted signals. Therefore, the distance between the radar and the target can be determined by determining the frequency of the intermediate frequency signal. In addition, the above-mentioned process of processing the radar signal is merely an example, and the particular radar processing process is not limited.

[0085]

[0098] It can be seen from equation 1.7 that for velocity detection, the phase difference between two adjacent periods of the intermediate frequency signal at the same time sampling point is a fixed value.

[0086]

number

[0099] When the Fourier transform is performed on the phase sequence of the echo intermediate frequency signal for several successive periods at the same time sampling point, the Doppler frequency f d and the Doppler frequency fd The relationship between the target's radial relative velocity v and the target's velocity v can be expressed as:

[0087]

number

[0100] λ is the radar signal wavelength.

[0088]

[0101] Therefore, the relative radial velocity v between the radar and the target is:

[0089]

number

[0102] As more vehicle-mounted radars are used, the mutual interference between vehicle-mounted radars becomes more serious, which results in a significant decrease in radar detection probability or an increase in the false alarm probability of radar detection, which has a non-negligible impact on driving safety and comfort.

[0090]

[0103] FIG. 5 is a schematic diagram of mutual interference between vehicle-mounted radars. Radar 1 transmits a transmission signal and receives a reflected signal obtained after the transmission signal is reflected by a target. When radar 1 receives a reflected signal, the receiving antenna of radar 1 also receives the transmission signal or reflected signal of radar 2. In this case, the transmission signal of radar 2 or the reflected signal of radar 2 received by radar 1 becomes an interference signal for radar 1.

[0091]

[0104] For example, Radar 1 is an observation radar, and the slope of the frequency modulated continuous wave of Radar 1 is a0, the intercept is b0, and the period is T c Assume that radar 2 is an interferometric radar, and the slope of the frequency modulated continuous wave of radar 2 is a1 and the intercept is b1. In this case, assume that b0 = b1. The echo delay corresponding to the maximum measuring distance of radar 1 is τ max(specifically, the delay calculated by substituting the maximum detection range of the radar into Equation 1.6). For example, if the maximum detection range of the radar is 250 m, the delay calculated by using Equation 1.6 is 1.67 μs. The delay of the interference signal of Radar 2 reaching the receiver of Radar 1 is τ1. Consider that the timing error present at the radar transmission time is Δτ (for example, the time error caused by the timing error of the Global Positioning System (GPS) is, for example, 60 ns). The time interval for the radar to detect the received signal is τ max Or T c It is.

[0092]

[0105] A false alarm occurs if the slope of the radar signal transmitted by Radar 1 matches the slope of the radar signal transmitted by Radar 2, i.e. a0=a1, and the operating bands of the two radar signals overlap. In this case, the intermediate frequency signal formed at the radar receiver is:

[0093]

number

[0106] A i ' is the signal amplitude of the interferometric radar signal formed after the interferometric radar signal is affected by the transmitting antenna gain, the target reflection, the propagation loss, and the receiving antenna gain; i is the initial phase of the interferometric radar signal; f d i is the Doppler frequency formed by the interfering radar signal due to the relative radial velocity between the target and the detection radar; τ i is the delay from when the transmitter transmits the interfering radar signal to when the receiver receives the interfering radar signal.

[0094]

[0107] 6 and 7 are schematic diagrams of possible spurious intermediate frequency signals. As shown in FIG. 6, Radar 1 transmits a signal to a target and receives a reflected signal from the target. However, in the time range between when Radar 1 transmits a signal and when Radar 1 receives the reflected signal, the receiving antenna of Radar 1 receives the transmitted signal or the reflected signal (dashed line) of Radar 2. The signal waveform of Radar 1 matches the signal waveform of Radar 2, and the frequency scanning bandwidths of the two radars are the same. Within the target echo observation range of Radar 1, Radar 1 receives a signal of the corresponding frequency (shown by the dashed line). In this case, Radar 1 considers that "Target 1" is present. Radar 1 processes the signal shown by the dashed line and the reflected signal shown by the solid line within the time interval for signal processing (τ max Or T c ) in the image. In this case, Radar 1 mistakenly recognizes the received signal indicated by the dashed line as a reflected signal from an object ahead. In this case, a false intermediate frequency signal is generated. Radar 1 detects the two peaks by performing a fast Fourier transform and then a spectral analysis.

[0095] As shown in Figure 7, each peak corresponds to one target. Radar 1 considers "Target 1" and "Target 2" to exist at the same time. Radar 1 mistakenly recognizes that "Target 1" exists ahead. In reality, "Target 1" does not exist. This is called a "ghost" or "false alarm". After a false alarm occurs, the autonomous vehicle will suddenly slow down or brake even if there is no object ahead, resulting in a less comfortable driving experience.

[0096]

[0108] If there is a difference between the slope of the radar signal transmitted by radar 1 and the slope of the radar signal transmitted by radar 2, i.e., a0 ≠ a1, a false negative occurs.

[0097]

[0109] 8 and 9 are schematic diagrams showing possible interfering signals obscuring the target signal. As shown in FIG. 8, Radar 1 transmits a signal to the target and receives a reflected signal from the target. However, within the target echo observation range of Radar 1, the receiving antenna of Radar 1 receives the transmitted signal or the reflected signal (dashed line) of Radar 2. There is a difference between the slope of the signal waveform of Radar 1 and that of Radar 2. The time interval (τ max Or T c ), Radar 1 detects both the reflected signal of Radar 1 and the relevant signal of Radar 2. After frequency mixing is performed on the detected relevant signal of Radar 2 and the reflected signal of Radar 1, an intermediate frequency signal containing various frequency components is generated.

[0098]

[0110]

[0099]

number

[0111] After fast Fourier transform, an interference platform appears, as shown in Figure 9. As a result, the true target is not "prominent" enough, making it difficult to detect and increasing the possibility of missed detection. When missed detection occurs, when there is an object in front of the autonomous vehicle, the autonomous vehicle will mistakenly consider the object to be absent and will not slow down or brake, which will cause traffic accidents and reduce the driving safety of the vehicle.

[0100]

[0112] Therefore, for the sake of vehicle driving comfort and safety, reducing interference between vehicle-mounted radars is a problem that must be solved.

[0101]

[0113] A possible solution is to use radar frequency agility technology, that is, the frequency of the radar waveform is changed quickly to prevent interference between multiple radars. As shown in Figure 10, by applying frequency agility (random frequency hopping) to the radar, the effect of reducing the probability of mutual interference can be achieved. Although this method has the effect of reducing the probability of mutual interference to a certain extent, the radar cannot perform speed measurement by using a simple digital signal processing method (e.g., Fast Fourier Transform (FFT)), which limits the function of the radar.

[0102]

[0114] In consideration of this, a technical solution is provided in an embodiment of the present application. In an embodiment of the present application, a radar time-frequency hopping waveform is designed. There is a correlation relationship between the time domain position and the corresponding frequency domain position in each frequency modulated continuous wave transmitted by the radar. For example, the product of the time domain position and the corresponding frequency domain position meets a pre-set condition. In this way, the radar can determine the time domain position and the frequency domain position of each frequency modulated continuous wave transmitted by the radar by using the designed waveform. In addition to reducing the probability of mutual interference between radars, a simple digital signal processing method (e.g., FFT) may be used for speed measurement.

[0103]

[0115] It can be understood that the technical solutions in the embodiments of the present application may be applied to an on-board radar system or to another radar system. The present application is applicable to all radar systems under the condition that there is an interaction between radars in the system. The radar may be a millimeter wave radar or another radar. This is not limited in the present application.

[0104]

[0116] FIG. 11 is a schematic diagram of a possible application scenario of the embodiment of the present application. The aforementioned application scenario may be automatic driving, autonomous driving, intelligent driving, connected driving, etc. The radar may be installed in an automatic transportation means (e.g., an unmanned vehicle, a smart vehicle, an electric vehicle, or a digital vehicle), an unmanned aerial vehicle, a truck vehicle, a bicycle, a signal light, a speed measurement device, a network device (e.g., a base station or a terminal device in various systems), etc. In addition, these devices may further be equipped with a processing device and a communication device in addition to the radar. The embodiment of the present application is applicable to a radar between vehicles, and also to a radar between a vehicle and another device, such as an unmanned aerial vehicle, or a radar between other devices. The radar, the processing device, and the communication device may also be mounted on a mobile device. For example, the radar is mounted on a vehicle as an on-board radar. Alternatively, the radar, the processing device, and the communication device may be installed on a fixed device, such as a device such as a roadside unit (RSU). The installation location and functions of the radar, the processing device, and the communication device are not limited in this embodiment of the present application.

[0105]

[0117] An embodiment of the present application provides a signal transmission method. FIG. 12 is a flowchart of the method. The method provided in the embodiment shown in FIG. 12 may be executed by a first device. The first device is, for example, a radar (or what is called a radar device), or the first device may be a chip mounted on a communication device. The communication device is, for example, a radar (or a radar device), or other devices. This is not limited in the present application.

[0106]

[0118] S11: A first device generates a first frequency modulated continuous wave sequence, the first frequency modulated continuous wave sequence including N frequency modulated continuous waves, N being an integer equal to or greater than 1, and a product of a time domain position and a corresponding frequency domain position in the first frequency modulated continuous wave among the N frequency modulated continuous waves satisfies a first condition.

[0107]

[0119] The first frequency modulated continuous wave can be any one of N frequency modulated continuous waves, which is not limited in this application.

[0108]

[0120] As mentioned above, a frequency modulated continuous wave is a signal whose frequency changes linearly with time. Hereinafter, for ease of explanation, the duration of the frequency modulated continuous wave (i.e., the period from the start to the end of the frequency modulated continuous wave) is referred to as the time domain range of the frequency modulated continuous wave, and the frequency variation range (i.e., the bandwidth) of the frequency modulated continuous wave is referred to as the frequency domain range of the frequency modulated continuous wave. For example, FIG. 13 is the time domain range [t1, t2] and the frequency domain range [f1, f2] of one frequency modulated continuous wave. It can be understood that the time domain range, frequency domain range, and linear relationship between frequency and time of the frequency modulated continuous wave shown in FIG. 13 are merely examples and are not specific limitations.

[0109]

[0121] The time domain position in the first frequency modulated continuous wave may be any time domain position in the time domain range of the first frequency modulated continuous wave, for example, a starting time domain position (i.e., the starting time of the first frequency modulated continuous wave); the end time domain position (i.e., the end time of the first frequency modulated continuous wave); a center time domain position (i.e., the midpoint between the start and end times of the first frequency modulated continuous wave), or It may be another time domain position. This is not limited in the present application. For example, the first frequency modulated continuous wave is the frequency modulated continuous wave shown in FIG. 13, and the time domain range of the first frequency modulated continuous wave is [t0, t2]. Therefore, the start time domain position of the first frequency modulated continuous wave is t0, the center time domain position is (t0+t2) / 2, and the end time domain position is t2.

[0110]

[0122] Since a frequency modulated continuous wave is a signal whose frequency varies linearly with time, there is a one-to-one correspondence between the time domain positions in the time domain range of the first frequency modulated continuous wave and the frequency domain positions in the frequency domain range of the first frequency modulated continuous wave. In other words, for each time domain position in the time domain range of the first frequency modulated continuous wave, it is possible to find the corresponding frequency domain position in the frequency domain range of the first frequency modulated continuous wave, or for each frequency domain position in the frequency domain range of the first frequency modulated continuous wave, it is possible to find the corresponding time domain position in the time domain range of the first frequency modulated continuous wave. For example, the first frequency modulated continuous wave is the frequency modulated continuous wave shown in FIG. 13. The frequency domain position corresponding to the start time domain position t0 in the first frequency modulated continuous wave is f0, the frequency domain position corresponding to the end time domain position t2 is f2, and the frequency domain position corresponding to the time domain position t1 (t1 is a time domain position between the start time domain position t0 and the end time domain position t2) is f1.

[0111]

[0123] It should be noted that in actual product implementation, there may be an error within a certain range in the correspondence between the time domain position and the frequency domain position. For example, as shown in FIG. 14, based on the linear relationship between the frequency and time of the frequency modulated continuous wave, the time domain position corresponding to the frequency domain position f1 should be t1. However, due to the value of t1 having a fractional part, and the fractional part being an infinite non-cyclic fraction, it is difficult to realize the exact product. Therefore, the time domain position corresponding to the frequency domain position f1 may be shifted to t1' which is in the vicinity of t1, where the deviation between t1 and t1' is Δt. Therefore, the time domain position corresponding to the frequency domain position f1 becomes t1', where the value of t1' is an integer, or the value of t1' has a fractional part and the fractional part is a finite fractional. It should be understood that the above is merely an example without any specific limitation. In actual application, there may be another source of error, which is not limited in this application.

[0112]

[0124] In a possible implementation, the first condition is associated with a position of a first frequency modulated continuous wave among the N frequency modulated continuous waves. Furthermore, for each frequency modulated continuous wave of the N frequency modulated continuous waves, a product of the time domain position of the frequency modulated continuous wave and a corresponding frequency domain position may satisfy a particular condition. The conditions satisfied by the products of the time domain position and the corresponding frequency domain position of different frequency modulated continuous waves may be different, and the conditions satisfied by the products of the time domain position and the corresponding frequency domain position of each frequency modulated continuous wave are associated with the position of the frequency modulated continuous wave among the N frequency modulated continuous waves.

[0113]

[0125] In a possible implementation, the first condition may be a preset value, i.e., the product of the time domain position and the corresponding frequency domain position in the first frequency modulated continuous wave is a preset value. The preset value may be calculated based on the position of the first frequency modulated continuous wave in the N frequency modulated continuous waves. The products of the time domain position and the corresponding frequency domain position of different frequency modulated continuous waves among the N frequency modulated continuous waves may be different preset values.

[0114]

[0126] For example, the first condition may include:

[0115]

number

[0127] n is the sequence number of the frequency modulated continuous wave among the N frequency modulated continuous waves, n=0, 1, 2, ..., N-1; T n is the time domain position of the frequency modulated continuous wave with sequence number n among N frequency modulated continuous waves; f n is the frequency domain position of the frequency modulated continuous wave with sequence number n among the N frequency modulated continuous waves; α and β are pre-set frequency hopping parameters.

[0116]

[0128] The values ​​of α and β can be set based on the radar hardware capabilities and target detection performance indicators. Optionally, in one frame, α and β may use fixed parameter values, and different frames may use different parameter values. Correspondingly, the value of N may be the number of frequency modulated continuous waves transmitted by the first device in one frame.

[0117]

[0129] It will be understood that in practical applications, the first condition may alternatively be a modification of the above formula 1.16. For example, considering that there may be an error within a certain range in the correspondence between the time domain position and the frequency domain position, the above formula 1.16 may be further modified as follows:

[0118]

number

[0130] Δt n is the time deviation caused by errors in product implementation, and for different values ​​of n, Δ n The values ​​of can be the same or different; alternatively, they can be:

[0119]

number

[0131] Δf n is the frequency deviation caused by errors in product implementation, and for different values ​​of n, Δ n The values ​​of may be the same or different.

[0120]

[0132] Of course, formula 1.17 is merely an example. In practical application, formula 1.16 may have other transformations. However, no matter how the form is transformed, as long as it can be transformed into the same or similar functional form as formula 1.16, formula 1.16 can be used.

[0121]

[0133] In a possible design, the N frequency modulated continuous wave waveforms may perform equal-spaced frequency hopping in the frequency domain, specifically, the frequency domain positions of the N frequency modulated continuous waves are distributed at equal intervals in the frequency domain, and the interval between two adjacent frequency modulated continuous wave frequency domain positions of the N frequency modulated continuous waves is a fixed value x0.

[0122]

[0134] Specifically, the frequency hopping at equal intervals may be increased at equal intervals (e.g., f n -f n-1 =x0, where x0 is a positive value), or may decrease at equal intervals (e.g., f n-1 -f n =x0, where x0 is a positive value. This is not a limitation in the present application.

[0123]

[0135] In this case, α and β can be set as the following parameters:

[0124]

number

[0136] T0 is the time domain position of the frequency modulated continuous wave with sequence number 0 among the N frequency modulated continuous waves; c is the frequency domain position of the frequency modulated continuous wave with sequence number 0 among the N frequency modulated continuous waves; T c is the duration of each of the multiple frequency modulated continuous waves (Time Division Multiplexing (TDM) Multi Input Multi Output (MIMO) radar, T c is the duration of each of the multiple frequency modulated continuous waves (note that this is the duration of each of the multiple frequency modulated continuous waves transmitted by the same transmitting antenna), and the durations of the N frequency modulated continuous waves are the same (the duration from the start time to the end time is the same).

[0125]

[0137] Similarly, in practical applications, Equations 1.19 and 1.20 may have other transformations, but no matter how the equations are transformed, as long as they can be transformed into functional forms that are the same as or similar to the functional forms of Equations 1.19 and 1.20, Equations 1.19 and 1.20 can be used.

[0126]

[0138] By using the parameter design of α and β, it can be ensured that two adjacent frequency modulated continuous waves (in the time domain) do not overlap in time and the radar has a large velocity measurement range.

[0127]

[0139] In another possible design, the N frequency modulated continuous wave waveforms can perform random frequency hopping in the frequency domain. For example, the first unit can determine the frequency domain location of each of the N frequency modulated continuous waves based on the frequency hopping capability of the radar. The first unit needs to select the frequency hopping range based on the radar capability (e.g., if the radar can only operate in the 77 GHz to 78 GHz frequency band, the frequency of the frequency modulated continuous waves can only be within the 1 GHz range and cannot exceed that range).

[0128]

[0140] In this case, nf n-1 -(n-1)f n >0, which is generally true for vehicle-mounted radars, and α and β may be set as the following parameters:

[0129]

number

[0141] T0 is the time domain position of the frequency modulated continuous wave with sequence number 0 among the N frequency modulated continuous waves; f c is the frequency domain position of the frequency modulated continuous wave with sequence number 0 among the N frequency modulated continuous waves; T c is the duration of the frequency modulated continuous waves of each of the N frequency modulated continuous waves, and the durations of the N frequency modulated continuous waves are the same.

[0130]

[0142] Similarly, in practical applications, Equations 1.21 and 1.22 may have other transformations, but no matter how the equations are transformed, as long as they can be transformed into functional forms that are the same as or similar to the functional forms of Equations 1.21 and 1.22, it is possible to use Equations 1.21 and 1.22.

[0131]

[0143] It should be noted that the design is not limited to the case where random frequency hopping is applied, provided that the frequency domain position of each of the N frequency modulated continuous waves can be determined.

[0132]

[0144] By using α and β, it can be ensured that two adjacent frequency modulated continuous waves (in the time domain) do not overlap in time and that the radar has a large velocity measurement range.

[0133]

[0145] Furthermore, in this embodiment of the present application, "N frequency modulated continuous waves" may alternatively be described as "N periods of frequency modulated continuous waves." The N frequency modulated continuous waves are in one-to-one correspondence with the N periods, and the duration of each period is the duration of the frequency modulated continuous waves corresponding to the period.

[0134]

[0146] In this embodiment of the present application, the first device may determine the time domain location based on the frequency domain location (e.g., first determine the frequency domain location of the first frequency modulated continuous wave, and then determine the time domain location of the first frequency modulated continuous wave based on the frequency domain location of the first frequency modulated continuous wave and the first condition), or may determine the frequency domain location based on the time domain location (e.g., first determine the time domain location of the first frequency modulated continuous wave, and then determine the time domain location of the first frequency modulated continuous wave based on the time domain location of the first frequency modulated continuous wave and the first condition). This is not limited in the present application. Similarly, for another frequency modulated continuous wave other than the first frequency modulated continuous wave in the first frequency modulated continuous wave sequence, the frequency domain location may be determined based on the time domain location, or the time domain location may be determined based on the frequency domain location. This is not limited in the present application.

[0135]

[0147] S12: A first device transmits a first frequency modulated continuous wave sequence.

[0136]

[0148] The above describes the signal transmission process of a single radar. When multiple radars exist simultaneously, each of the multiple radars may transmit signals by using the above-mentioned method.

[0137]

[0149] In a specific implementation, it is only required to ensure that the signal waveforms corresponding to different radars correspond to different frequency domain positions at the same time domain position (i.e., the collision of frequency domain resources between different radars at the same moment is avoided), so that the mutual interference between radars can be reduced or even eliminated. In addition, since each radar transmits a signal by using a designed waveform, the receiving device corresponding to each radar can use a simple digital signal processing method (e.g., FFT) for speed measurement, which can reduce the probability of mutual interference between radars, and ensure the speed measurement performance of the radar.

[0138]

[0150] Hereinafter, a signal reception process corresponding to the above signal transmission process (ie, steps S11 and S12) will be described.

[0139]

[0151] An embodiment of the present application provides a signal receiving method. FIG. 15 is a flowchart of the method. In the following description process, an example is used in which the method shown in FIG. 15 is applied to a network architecture. The method provided in the embodiment shown in FIG. 15 may be executed by a second device. The second device may be, for example, a radar (or what is called a radar device), or the second device may be a chip mounted on a communication device. The communication device may be, for example, a radar (or a radar device), or other devices. This is not limited in the present application. The first device and the second device may be integrated into one chip, or may be separately integrated into different chips. This is not limited in the present application.

[0140]

[0151] S21: A second device receives a second frequency modulated continuous wave sequence, which is a signal formed after the first frequency modulated continuous wave sequence is transmitted by the first device, propagates through space, and is reflected by a target.

[0141]

[0153] For the first frequency modulated continuous wave sequence, please refer to the above description, and the details will not be described again here.

[0142]

[0154] It can be understood that after the first frequency modulated continuous wave sequence is transmitted from the first device, the first frequency modulated continuous wave sequence propagates in space, and after encountering an obstacle, the first frequency modulated continuous wave sequence is reflected by the obstacle (e.g., a target). Then, the first frequency modulated continuous wave sequence propagates in space and is received by the receiving antenna of the second device. The waveform of the signal changes to a certain extent after being affected by target reflection, propagation loss, etc. Therefore, the signal transmitted by the first device (i.e., the first frequency modulated continuous wave sequence) may be different from the signal received by the second device (i.e., the second frequency modulated continuous wave sequence). For example, there is a delay in the waveform of the second frequency modulated continuous wave sequence relative to the waveform of the first frequency modulated continuous wave sequence. For specific expression forms, please refer to the above formula 1.3 and formula 1.4. Details will not be described again here.

[0143]

[0155] S22: A second device determines information about the target based on the second frequency modulated continuous wave sequence and the first frequency modulated continuous wave sequence.

[0144]

[0156] For example, the second device performs frequency mixing on the second frequency modulated continuous wave sequence and the first frequency modulated continuous wave sequence to obtain an intermediate frequency signal sequence; and then processes the intermediate frequency signal sequence by using a simple digital signal processing method to perform parameter estimation on the target, so as to obtain relevant information such as the target's speed, distance, or angle. Optionally, the simple digital signal processing method includes FFT.

[0145]

[0157] It can be understood that when performing signal processing, the second device needs to compensate for the phase difference between two adjacent frequency modulated continuous waves (or two adjacent periods of frequency modulated continuous waves) in the second frequency modulated continuous wave sequence caused by distance to obtain a more accurate target velocity.

[0146]

[0158] The above case where the frequency domain positions of the N frequency modulated continuous waves are equally distributed in the frequency domain is used as an example. If the frequency domain spacing between two adjacent frequency modulated continuous waves is x0, the phase difference between two adjacent intermediate frequency signals is:

[0147]

number

[0148]

[0159] In a specific implementation process, the second device may perform phase compensation after frequency mixing and low-pass filtering to obtain the intermediate frequency sampling signal and distance information. More specifically, the first device can perform phase compensation on the intermediate frequency signal sequence before speed detection, or directly compensate the speed detection deviation caused by distance on the speed detection result after speed detection. This is not limited in the present application.

[0149]

[0160] For example, the spacing between the frequency domain positions of two adjacent frequency modulated continuous waves in the N frequency modulated continuous waves is a fixed value x0.

[0150]

[0161] In a possible example, as shown in FIG. 16, the process of processing the intermediate frequency signal by the second device may include the following steps:

[0151]

[0162] S30: Sampling is performed on the intermediate frequency signal sequence to obtain an intermediate frequency sampling signal sequence.

[0152]

[0163] It can be understood that an intermediate frequency signal sequence here refers to a plurality of periods of an analog intermediate frequency signal, and an intermediate frequency sampling signal sequence here refers to a plurality of periods of a digital intermediate frequency sampling signal.

[0153]

[0164] S31: Perform two-dimensional (2D) FFT processing on the intermediate frequency sampling signal sequence to obtain an FFT result in a slow time dimension and an FFT result in a fast time dimension.

[0154]

[0165] The 2D FFT process includes an FFT process in the distance dimension, also called the fast time dimension, and an FFT process in the velocity dimension, also called the slow time dimension.

[0155]

[0166] FFT processing in the fast time dimension involves: performing an FFT on the intermediate frequency sampled signal at each period.

[0156]

[0167] FFT processing in the slow time dimension involves: performing an FFT on the intermediate frequency sampled signal at every period at the same fast time sampling point location.

[0157]

[0168] It can be understood that the two types of processing are generally performed in series. For example, FFT in the fast time dimension is performed first, and then FFT in the slow time dimension is performed. Because the target distance can be obtained through FFT in the fast time dimension, in this case, FFT in the slow time dimension is equivalent to performing FFT on the intermediate frequency sampling signal at every period at the position at the same distance after FFT in the fast time dimension. Naturally, in actual operation, FFT in the slow time dimension may be performed first, and then FFT in the fast time dimension is performed. The order is not limited in this application.

[0158]

[0169] S32: Perform incoherent convolution on the FFT results in the slow time dimension, and then obtain the signal transmission delay caused by the target distance, i.e., the target delay (i.e., the delay experienced when a signal is transmitted from a first device, reflected by a target, and finally received by a second device) through Constant False Alarm Rate (CFAR) detection.

[0159]

[0170] S33: Extract the sequence (complex number) corresponding to τ0 from the FFT result in the fast time dimension to form a slow time sequence (complex number array) of the target.

[0160]

[0171] S34: The phase difference between two adjacent frequency modulated continuous wave sequences caused by distance with respect to the slow time sequence (i.e.

[0161]

number

[0162]

number

[0163]

[0172] S35: Perform FFT on the low-speed time sequence obtained after phase compensation, and then perform CFAR (Constant False Alarm Rate) detection to obtain the target velocity.

[0164]

[0173] It can be understood that the CFAR is just an example, in real applications, the target velocity may be determined in other ways, which is not limited in this application.

[0165]

[0174] In this example, phase compensation is performed on the intermediate frequency signal train after frequency mixing and before speed detection, and as a result, the accuracy of speed detection can be improved.

[0166]

[0175] Another possible example uses an example in which the interval between the frequency domain positions of two adjacent frequency modulated continuous waves in the N frequency modulated continuous waves is a fixed value x0. As shown in Figure 17, the process of processing the intermediate frequency signal by the second device includes the following steps:

[0167]

[0176] S40: Sampling is performed on the intermediate frequency signal sequence to obtain an intermediate frequency sampling signal sequence.

[0168]

[0177] S41: Perform two-dimensional (2D) FFT processing on the intermediate frequency sampling signal sequence to obtain an FFT result in a slow time dimension and an FFT result in a fast time dimension.

[0169]

[0178] For the specific implementation process of S41, please refer to S31. The details will not be explained again here.

[0170]

[0179] S42: Perform two-dimensional (2D) CFAR detection on the FFT result and the FFT result in the fast time dimension to obtain the target range and the target velocity.

[0171]

[0180] The 2D CFAR is merely an example. In practical applications, the target velocity and the target distance may be determined in other ways, which is not limited in this application.

[0172]

[0181] The target distance is calculated by the velocity transformation factor (obtained by FFT processing in the slow time dimension).

[0173]

number

[0174]

[0182] The target velocity includes errors caused by the delay τ and the frequency hopping interval x, which corresponds to the target range. For simplicity, the target velocity here is denoted as:

[0175]

number

[0183] S43: Compensate the target velocity for the velocity detection deviation caused by the distance, and output the compensated target velocity.

[0176]

[0184] Specifically, the speed detection deviation can be obtained by calculating 2πx0τ0.

[0177]

[0185] For example, the compensated target velocity v0 is calculated from the target velocity v0′ obtained in S42 as follows:

[0178]

number

[0179]

[0186] In this example, before velocity detection, the velocity detection deviation due to distance is compensated for the target velocity, so that the accuracy of the velocity detection can be improved.

[0180]

[0187] It can be seen from the above signal transmission process and signal receiving process that when the radar transmits a signal, it transmits the signal to the outside by using a designed waveform, so that the radar can determine the time domain position and frequency domain position of each frequency modulated continuous wave. In the signal receiving stage, a simple digital signal processing method (e.g., FFT) can be used to perform the speed measurement, so that the probability of mutual interference between radars can be reduced and the speed measurement performance of the radar can be guaranteed.

[0181]

[0188] The above describes the method provided in the embodiment of the present application with reference to the accompanying drawings. Hereinafter, the apparatus provided in the embodiment of the present application will be described with reference to the accompanying drawings.

[0182]

[0189] Based on the same technical concept, an embodiment of the present application provides a signal transmission device, which includes a module / unit / means configured to perform the method performed by the first device in the above method embodiment. The module / unit / means may be implemented by software, or may be implemented by hardware, or may be implemented by hardware executing corresponding software.

[0183]

[0190] For example, as shown in FIG. 18, an apparatus may include: A processing unit 1801 configured to generate a first frequency modulated continuous wave sequence; and A transmitting unit 1802 configured to transmit a first frequency modulated continuous wave sequence, where the first frequency modulated continuous wave sequence includes N frequency modulated continuous waves, where N is a positive integer greater than or equal to 1.

[0184]

[0191] The product of the time domain position and the corresponding frequency domain position in a first frequency modulated continuous wave of the N frequency modulated continuous waves satisfies a first condition.

[0185]

[0192] The transmitting unit 1802 may be a transmitter (or transceiver), a transmitting antenna, etc. The processing unit 1801 may be a processor.

[0186]

[0193] Optionally, the first condition is associated with a position of a first frequency modulated continuous wave of the N frequency modulated continuous waves.

[0187]

[0194] Optionally, the frequency domain location includes a start frequency and / or a center frequency, and the time domain location includes a start time and / or a center time.

[0188]

[0195] Optionally, the first condition may include:

[0189]

number

[0196] n is the sequence number of the frequency modulated continuous wave among the N frequency modulated continuous waves, n=0, 1, 2, ..., N-1; T n is the time domain position of the frequency modulated continuous wave with sequence number n among N frequency modulated continuous waves; f n is the frequency domain position of the frequency modulated continuous wave with sequence number n among the N frequency modulated continuous waves; α and β are pre-set frequency hopping parameters.

[0190]

[0197] Optionally, the frequency domain positions of the N frequency modulated continuous waves are equally distributed in the frequency domain, and the spacing between the frequency domain positions of two adjacent frequency modulated continuous waves of the N frequency modulated continuous waves is a fixed value x0.

[0191]

[0198] Optionally, in the case of uniform frequency hopping, α and β may be set as the following parameters:

[0192]

number

[0199] T0 is the time domain position of the frequency modulated continuous wave with sequence number 0 among the N frequency modulated continuous waves; f c is the frequency domain position of the frequency modulated continuous wave with sequence number 0 among the N frequency modulated continuous waves; T c is the duration of the frequency modulated continuous waves of each of the plurality of frequency modulated continuous waves, and the durations of the N frequency modulated continuous waves are the same.

[0193]

[0200] Optionally, in case of random frequency hopping, α and β may be set as the following parameters:

[0194]

number

[0201] T0 is the time domain position of the frequency modulated continuous wave with sequence number 0 among the N frequency modulated continuous waves; f c is the frequency domain position of the frequency modulated continuous wave with sequence number 0 among the N frequency modulated continuous waves; T c is the duration of the frequency modulated continuous waves of each of the N frequency modulated continuous waves, and the durations of the N frequency modulated continuous waves are the same.

[0195]

[0202] It should be understood that all the relevant contents of the steps in the foregoing method embodiments may be cited in the functional descriptions of the corresponding functional modules, and details will not be described here.

[0196]

[0203] Based on the same technical concept, an embodiment of the present application provides a signal receiving device, which includes a module / unit / means configured to execute the method executed by the second device in the above method embodiment. The module / unit / means may be implemented by software, or may be implemented by hardware, or may be implemented by hardware executing corresponding software.

[0197]

[0204] For example, as shown in FIG. 19, an apparatus may include: a receiving unit 1901 configured to receive a second frequency modulated continuous wave sequence, where the second frequency modulated continuous wave sequence is a signal formed after the first frequency modulated continuous wave sequence is transmitted by the first device, propagates through space, and is reflected by a target; and A processing unit 1902 configured to determine information about the target based on the second frequency modulated continuous wave sequence and the first frequency modulated continuous wave sequence, where the information includes velocity and / or range.

[0198]

[0205] The first frequency modulated continuous wave sequence includes N frequency modulated continuous waves, N being a positive integer greater than or equal to 1, and a product of a time-domain position and a corresponding frequency-domain position in a first frequency modulated continuous wave among the N frequency modulated continuous waves satisfies a first condition.

[0199]

[0206] The receiving unit 1901 may be a receiver (or transceiver), a receiving antenna, etc. The processing unit 1902 may be a processor.

[0200]

[0207] Optionally, the first condition is associated with a position of a first frequency modulated continuous wave of the N frequency modulated continuous waves.

[0201]

[0208] Optionally, the frequency domain location includes a start frequency and / or a center frequency, and the time domain location includes a start time and / or a center time.

[0202]

[0209] Optionally, the first condition may include:

[0203]

number

[0210] n is the sequence number of the frequency modulated continuous wave among the N frequency modulated continuous waves, n=0, 1, 2, ..., N-1; T n is the time domain position of the frequency modulated continuous wave with sequence number n among N frequency modulated continuous waves; f n is the frequency domain position of the frequency modulated continuous wave with sequence number n among the N frequency modulated continuous waves; α and β are pre-set frequency hopping parameters.

[0204]

[0211] Optionally, the frequency domain positions of the N frequency modulated continuous waves are equally distributed in the frequency domain, and the spacing between the frequency domain positions of two adjacent frequency modulated continuous waves of the N frequency modulated continuous waves is a fixed value x0.

[0205]

[0212] Optionally, in the case of uniform frequency hopping, α and β may be set as the following parameters:

[0206]

number

[0213] T0 is the time domain position of the frequency modulated continuous wave with sequence number 0 among the N frequency modulated continuous waves; c is the frequency domain position of the frequency modulated continuous wave with sequence number 0 among the N frequency modulated continuous waves; T c is the duration of the frequency modulated continuous waves of each of the plurality of frequency modulated continuous waves, and the durations of the N frequency modulated continuous waves are the same.

[0207]

[0214] Optionally, in case of random frequency hopping, α and β may be set as the following parameters:

[0208]

number

[0215] T0 is the time domain position of the frequency modulated continuous wave with sequence number 0 among the N frequency modulated continuous waves; c is the frequency domain position of the frequency modulated continuous wave with sequence number 0 among the N frequency modulated continuous waves; T c is the duration of the frequency modulated continuous waves of each of the N frequency modulated continuous waves, and the durations of the N frequency modulated continuous waves are the same.

[0209]

[0216] Optionally, the processing unit 1902: determining an intermediate frequency signal sequence based on the second frequency modulated continuous wave sequence and the first frequency modulated continuous wave sequence; and Processing intermediate frequency signal sequences by fast Fourier transform (FFT); It is specifically structured as follows.

[0210]

[0217] Optionally, the processing module 1902: performing phase compensation on the intermediate frequency signal sequence or the second frequency modulated continuous wave sequence based on the intervals between frequency domain positions of the N frequency modulated continuous waves before processing the intermediate frequency signal sequence by FFT; The present invention may be configured as follows.

[0211]

[0218] It should be understood that all the relevant contents of the steps in the foregoing method embodiments may be cited in the functional descriptions of the corresponding functional modules, and details will not be described here.

[0212]

[0219] In specific implementation, the device provided in this embodiment of the present application may have multiple product forms, some possible product forms are described below.

[0213]

[0220] Please refer to Fig. 20. An embodiment of the present application further provides a communication device. The device includes at least one processor 2001 and an interface circuit 2002. The interface circuit 2002 is configured to receive a signal from another device other than the device, send a signal to the processor 2001, or transmit a signal from the processor 2001 to another communication device other than the device. The processor 2001 is configured to implement a method performed by the first device or the second device by using a logic circuit or by executing code instructions.

[0214]

[0221] It should be understood that the processor referred to in this embodiment of the present application may be implemented by hardware or software. When the processor is implemented by using hardware, the processor may be a logic circuit, an integrated circuit, etc. When the processor is implemented by using software, the processor may be a general-purpose processor and is implemented by reading software code stored in a memory.

[0215]

[0222] For example, a processor may be a Central Processing Unit (CPU) or may be another general purpose processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or another programmable logic device, a discrete gate or transistor logic device, a discrete hardware component, etc. A general purpose processor may be a microprocessor, or the processor may be any conventional processor, etc.

[0216]

[0223] It can be understood that the memory referred to in the embodiments of the present application may be a volatile memory or a non-volatile memory, or may include a volatile memory and a non-volatile memory. The non-volatile memory may be a Read-Only Memory (ROM), a Programmable Read-Only Memory (PROM), an Erasable Programmable Read-Only Memory (EPROM), an Electrically Erasable Programmable Read-Only Memory (EEPROM), or a Flash memory. The volatile memory may be a Random Access Memory (RAM) used as an external cache. By way of example and not limitation, many forms of RAM may be used, such as static random access memory (Static RAM, SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (Synchronous DRAM, SDRAM), Double Data Rate Synchronous Dynamic Random Access Memory (Double Data Rate SDRAM, DDR SDRAM), Enhanced Synchronous Dynamic Random Access Memory (Enhanced SDRAM, ESDRAM), Synchlink Dynamic Random Access Memory (Synchlink DRAM, SLDRAM), and Direct Rambus Random Access Memory (Direct Rambus RAM, DR RAM).

[0217]

[0224] It should be noted that the memory (storage module) may be integrated into the processor when the processor is a general purpose processor, a DSP, an ASIC, an FPGA, or another programmable logic device, a discrete gate or transistor logic device, or a discrete hardware component.

[0218]

[0225] It should be noted that memory as described herein is intended to include, without being limited to, these and any other suitable types of memory.

[0219]

[0226] Based on the same technical concept, an embodiment of the present application further provides a computer-readable storage medium including a program or instruction, which, when executed on a computer, executes the method executed by the first device or the second device.

[0220]

[0227] Based on the same technical concept, an embodiment of the present application further provides a computer program product, which includes instructions, which, when executed on a computer, perform a method executed by the first device or the second device.

[0221]

[0228] Based on the same technical concept, an embodiment of the present application further provides a radar system including the aforementioned signal transmitting device and / or signal receiving device.

[0222]

[0229] Based on the same technical concept, the embodiment of the present application further provides a terminal device, including the aforementioned signal transmitting device and / or signal receiving device. The terminal device may be a vehicle, an unmanned aerial vehicle, a helicopter, an aircraft, a ship, an intelligent transportation device, a smart home device, etc. The specific form of the terminal device is not limited in the embodiment of the present application.

Claims

1. 1. A method of signal transmission comprising: generating a first frequency modulated continuous wave sequence; and transmitting the first frequency modulated continuous wave sequence, the first frequency modulated continuous wave sequence including N frequency modulated continuous waves, where N is a positive integer greater than or equal to 1; wherein a product of a time domain position and a corresponding frequency domain position in a first frequency modulated continuous wave of the N frequency modulated continuous waves satisfies a first condition.

2. 2. The method of claim 1, wherein the first condition is associated with a position of a first frequency modulated continuous wave of the N frequency modulated continuous waves.

3. The method of claim 1 or 2, wherein the frequency domain location comprises a start frequency and / or a center frequency, and the time domain location comprises a start time and / or a center time.

4. 4. The method of claim 1, wherein the first condition is: [0010] n is a sequence number of a frequency modulated continuous wave among the N frequency modulated continuous waves, n=0, 1, 2,..., N-1; T n is the time domain position of the frequency modulated continuous wave having sequence number n among the N frequency modulated continuous waves; f n is the frequency domain position of the frequency modulated continuous wave having sequence number n among the N frequency modulated continuous waves; and α and β are pre-set frequency hopping parameters.

5. 5. The method of claim 4, wherein the frequency domain positions of the N frequency modulated continuous waves are equally distributed in the frequency domain, and the interval between the frequency domain positions of two adjacent frequency modulated continuous waves of the N frequency modulated continuous waves is a fixed value x 0 That is, the method.

6. The method according to claim 5, [0025] and T 0 is the time domain position of the frequency modulated continuous wave having sequence number 0 among the N frequency modulated continuous waves; f c is the frequency domain position of the frequency modulated continuous wave having sequence number 0 among the N frequency modulated continuous waves; T c is the frequency modulated continuous wave duration of each of a plurality of frequency modulated continuous waves, and the N frequency modulated continuous waves have the same duration.

7. The method according to claim 4, [0030] and T 0 is the time domain position of the frequency modulated continuous wave having sequence number 0 among the N frequency modulated continuous waves; f c is the frequency domain position of the frequency modulated continuous wave having sequence number 0 among the N frequency modulated continuous waves; T c is the frequency modulated continuous wave duration of each of N frequency modulated continuous waves, and the N frequency modulated continuous waves have the same duration.

8. 1. A method of receiving a signal, comprising: receiving a second frequency modulated continuous wave sequence, the second frequency modulated continuous wave sequence being a signal formed after the first frequency modulated continuous wave sequence is transmitted by a first device, propagates through space, and is reflected by a target; determining information about the target based on the second frequency modulated continuous wave sequence and the first frequency modulated continuous wave sequence, the information including range and / or velocity; wherein the first frequency modulated continuous wave sequence includes N frequency modulated continuous waves, N being a positive integer greater than or equal to 1, and a product of a time domain position and a corresponding frequency domain position in a first frequency modulated continuous wave of the N frequency modulated continuous waves satisfies a first condition.

9. 9. The method of claim 8, wherein the first condition is associated with a position of a first frequency modulated continuous wave of the N frequency modulated continuous waves.

10. 10. The method of claim 8 or 9, wherein the frequency domain location comprises a start frequency and / or a centre frequency, and the time domain location comprises a start time and / or a centre time.

11. 11. The method of claim 8, wherein the first condition is: [0045] n is a sequence number of a frequency modulated continuous wave among the N frequency modulated continuous waves, n=0, 1, 2,..., N-1; T n is the time domain position of the frequency modulated continuous wave having sequence number n among the N frequency modulated continuous waves; f n is the frequency domain position of the frequency modulated continuous wave having sequence number n among the N frequency modulated continuous waves; and α and β are pre-set frequency hopping parameters.

12. 12. The method of claim 11, wherein the frequency domain positions of the N frequency modulated continuous waves are equally distributed in the frequency domain, and the spacing between the frequency domain positions of two adjacent frequency modulated continuous waves of the N frequency modulated continuous waves is a fixed value x 0 That is, the method.

13. The method of claim 12, [0050] and T 0 is the time domain position of the frequency modulated continuous wave having sequence number 0 among the N frequency modulated continuous waves; f c is the frequency domain position of the frequency modulated continuous wave having sequence number 0 among the N frequency modulated continuous waves; T c is the frequency modulated continuous wave duration of each of a plurality of frequency modulated continuous waves, and the N frequency modulated continuous waves have the same duration.

14. The method of claim 11, [006] and T 0 is the time domain position of the frequency modulated continuous wave having sequence number 0 among the N frequency modulated continuous waves; f c is the frequency domain position of the frequency modulated continuous wave having sequence number 0 among the N frequency modulated continuous waves; T c is the frequency modulated continuous wave duration of each of N frequency modulated continuous waves, and the N frequency modulated continuous waves have the same duration.

15. 15. The method of claim 8, wherein determining a velocity of the target based on the second frequency modulated continuous wave sequence and the first frequency modulated continuous wave sequence comprises: determining an intermediate frequency signal sequence based on the second frequency modulated continuous wave sequence and the first frequency modulated continuous wave sequence; and processing said intermediate frequency signal sequence by a Fast Fourier Transform (FFT); A method comprising:

16. 16. The method of claim 15, prior to processing the intermediate frequency signal sequence by FFT, the method further comprising: performing phase compensation on the intermediate frequency signal sequence or the second frequency modulated continuous wave sequence based on the spacing between frequency domain positions of the N frequency modulated continuous waves; The method includes:

17. 1. A signal transmitting device comprising: a processing unit configured to generate a first frequency modulated continuous wave sequence; and a transmitting unit configured to transmit the first frequency modulated continuous wave sequence, the first frequency modulated continuous wave sequence including N frequency modulated continuous waves, N being a positive integer greater than or equal to 1; wherein a product of a time domain position and a corresponding frequency domain position in a first frequency modulated continuous wave of the N frequency modulated continuous waves satisfies a first condition.

18. 20. The apparatus of claim 17, wherein the first condition is associated with a position of a first frequency modulated continuous wave of the N frequency modulated continuous waves.

19. 19. An apparatus according to claim 17 or 18, wherein the frequency domain location comprises a start frequency and / or a centre frequency, and the time domain location comprises a start time and / or a centre time.

20. 20. The apparatus of claim 17, wherein the first condition is: [0070] n is a sequence number of a frequency modulated continuous wave among the N frequency modulated continuous waves, n=0, 1, 2,..., N-1; T n is the time domain position of the frequency modulated continuous wave having sequence number n among the N frequency modulated continuous waves; f n is a frequency domain position of a frequency modulated continuous wave having sequence number n among the N frequency modulated continuous waves; and α and β are preset frequency hopping parameters.

21. 21. The apparatus according to claim 20, wherein the frequency domain positions of the N frequency modulated continuous waves are equally distributed in the frequency domain, and the spacing between the frequency domain positions of two adjacent frequency modulated continuous waves of the N frequency modulated continuous waves is a fixed value x 0 That is, the device.

22. 22. The apparatus of claim 21, [0080] and T 0 is the time domain position of the frequency modulated continuous wave having sequence number 0 among the N frequency modulated continuous waves; f c is the frequency domain position of the frequency modulated continuous wave having sequence number 0 among the N frequency modulated continuous waves; T c is the frequency modulated continuous wave duration of each of a plurality of frequency modulated continuous waves, and the N frequency modulated continuous waves have the same duration.

23. 21. The apparatus of claim 20, [0097] and T 0 is the time domain position of the frequency modulated continuous wave having sequence number 0 among the N frequency modulated continuous waves; f c is the frequency domain position of the frequency modulated continuous wave having sequence number 0 among the N frequency modulated continuous waves; T c is the frequency modulated continuous wave duration of each of N frequency modulated continuous waves, the durations of the N frequency modulated continuous waves being the same.

24. 1. A signal receiving device comprising: a receiving unit configured to receive a second frequency modulated continuous wave sequence, the second frequency modulated continuous wave sequence being a signal formed after the first frequency modulated continuous wave sequence is transmitted by a first device, propagates through space, and is reflected by a target; and a processing unit configured to determine information about the target based on the second frequency modulated continuous wave sequence and the first frequency modulated continuous wave sequence, the information including velocity and / or distance; wherein the first frequency modulated continuous wave sequence includes N frequency modulated continuous waves, N being a positive integer greater than or equal to 1, and a product of a time domain position and a corresponding frequency domain position in a first frequency modulated continuous wave of the N frequency modulated continuous waves satisfies a first condition.

25. 25. The apparatus of claim 24, wherein the first condition is associated with a position of a first frequency modulated continuous wave of the N frequency modulated continuous waves.

26. 26. Apparatus according to claim 24 or 25, wherein the frequency domain location comprises a start frequency and / or a centre frequency and the time domain location comprises a start time and / or a centre time.

27. 27. The apparatus of any one of claims 24 to 26, wherein the first condition is: [0010] n is a sequence number of a frequency modulated continuous wave among the N frequency modulated continuous waves, n=0, 1, 2,..., N-1; T n is the time domain position of the frequency modulated continuous wave having sequence number n among the N frequency modulated continuous waves; f n is a frequency domain position of a frequency modulated continuous wave having sequence number n among the N frequency modulated continuous waves; and α and β are preset frequency hopping parameters.

28. 28. The apparatus according to claim 27, wherein the frequency domain locations of the N frequency modulated continuous waves are equally distributed in the frequency domain, and the spacing between the frequency domain locations of two adjacent frequency modulated continuous waves of the N frequency modulated continuous waves is a fixed value x 0 That is, the device.

29. 29. The apparatus of claim 28, ##EQU00011## and T 0 is the time domain position of the frequency modulated continuous wave having sequence number 0 among the N frequency modulated continuous waves; f c is the frequency domain position of the frequency modulated continuous wave having sequence number 0 among the N frequency modulated continuous waves; T c is the frequency modulated continuous wave duration of each of a plurality of frequency modulated continuous waves, and the N frequency modulated continuous waves have the same duration.

30. 28. The apparatus of claim 27, ##EQU00012## and T 0 is the time domain position of the frequency modulated continuous wave having sequence number 0 among the N frequency modulated continuous waves; f c is the frequency domain position of the frequency modulated continuous wave having sequence number 0 among the N frequency modulated continuous waves; T c is the frequency modulated continuous wave duration of each of N frequency modulated continuous waves, the durations of the N frequency modulated continuous waves being the same.

31. 31. An apparatus according to any one of claims 24 to 30, wherein the processing unit comprises: determining an intermediate frequency signal sequence based on the second frequency modulated continuous wave sequence and the first frequency modulated continuous wave sequence; and processing said intermediate frequency signal sequence by a fast Fourier transform (FFT); The apparatus is specifically configured to:

32. 32. The apparatus of claim 31, wherein the processing module comprises: performing phase compensation on the intermediate frequency signal sequence or the second frequency modulated continuous wave sequence based on the spacing between frequency domain positions of the N frequency modulated continuous waves before processing the intermediate frequency signal sequence with an FFT; The apparatus, further configured as follows.

33. A terminal device comprising an apparatus according to any one of claims 17 to 23 and / or an apparatus according to any one of claims 24 to 32.

34. 17. A computer readable storage medium configured to store instructions that, when executed, perform a method according to any one of claims 1 to 16.

35. 17. A computer program product having instructions stored therein which, when run on a computer, enable the computer to carry out a method according to any one of claims 1 to 16.

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