Radar signal detection method and device, equipment and storage medium

Abstract

The embodiment of the invention discloses a radar signal detection method, device and equipment and a storage medium, which are used for solving the problem of low detection accuracy of a traditional radar system under the condition of large difference between strong and weak signals. The method provided by the embodiment of the invention comprises the following steps: receiving a plurality of radar signals reflected from the same distance point in each sensing period; determining a target amplitude threshold value corresponding to each sensing period; determining an over-threshold probability of the distance point in each sensing period by comparing the amplitudes of the plurality of radar signals at the same distance point in each sensing period with a target amplitude threshold; and determining the radar signal target power of the distance point according to the over-threshold probability of the distance point of each sensing period in the plurality of sensing periods and the target amplitude threshold value corresponding to each sensing period. And each sensing period corresponds to different amplitude thresholds, so that saturation of over-strong signals and missing detection of over-weak signals can be avoided, the radar signal power is more accurate, and the capability and reliability of detecting weak signals and strong signals are remarkably improved.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of wireless communication technology, and in particular, to radar signal detection methods, devices, equipment, and storage media. Background Art

[0002] In the field of wireless radar, the radar sensing process involves the conversion and processing of analog signals, in which the analog-to-digital converter (ADC) plays a vital role. The ADC converts the received reflected signal into a digital signal for subsequent digital signal processing.

[0003] In the case of limited resources, in order to save computing resources, ADC usually uses a 1-bit comparator. If the received signal is higher than the threshold, it outputs 1, otherwise it outputs 0. However, when facing application scenarios with large differences in strong and weak signals, ADC has the problem that too strong signals are easily saturated and too weak signals are difficult to detect, which will affect the accuracy and reliability of radar signal detection. Summary of the invention

[0004] Based on the above problems, the embodiments of the present application provide a radar signal detection method, apparatus, device and storage medium, the purpose of which is to enable the radar to detect weak signals and strong signals more accurately and reliably.

[0005] In a first aspect, an embodiment of the present application provides a radar signal detection method, which is applied to a radar, wherein the radar performs signal detection in multiple sensing cycles, and the method includes:

[0006] receiving a plurality of radar signals reflected from a same distance point in each of the sensing cycles;

[0007] Determine a target amplitude threshold corresponding to each of the sensing cycles;

[0008] Determine the threshold-crossing probability of the distance point in each sensing cycle by comparing the amplitudes of the multiple radar signals at the same distance point in each sensing cycle with the target amplitude threshold; the threshold-crossing probability of the distance point represents the probability that the amplitudes of the multiple radar signals at the distance point exceed the target amplitude threshold;

[0009] The radar signal target power of the distance point is determined according to the threshold-crossing probability of the distance point in each of the sensing cycles within the plurality of sensing cycles and the target amplitude threshold corresponding to each of the sensing cycles.

[0010] In one embodiment, determining the target amplitude threshold corresponding to each sensing cycle includes:

[0011] Obtaining an initial amplitude threshold corresponding to each of the sensing cycles;

[0012] Calculate a threshold range corresponding to each of the initial amplitude thresholds based on a preset compensation coefficient;

[0013] The target amplitude threshold corresponding to each of the sensing cycles is determined according to the threshold range corresponding to each of the initial amplitude thresholds and the overlap rate of each of the threshold ranges.

[0014] In one embodiment, determining the radar signal target power of the distance point according to the threshold crossing probability of the distance point in each of the sensing cycles within the plurality of sensing cycles and the target amplitude threshold corresponding to each of the sensing cycles includes:

[0015] Power estimation is performed according to the threshold crossing probability of the distance point in each sensing cycle and the target amplitude threshold corresponding to each sensing cycle, to determine the estimated power of the radar signal of the distance point in each sensing cycle;

[0016] A weighted average calculation is performed based on the estimated power of the radar signal at the distance point in each of the sensing cycles and the threshold-crossing probability of the distance point in each of the sensing cycles to determine the target power of the radar signal at the distance point.

[0017] In one embodiment, the performing power estimation according to the threshold crossing probability of the distance point in each sensing cycle and the target amplitude threshold corresponding to each sensing cycle to determine the estimated power of the radar signal of the distance point in each sensing cycle includes:

[0018] Solving an amplitude estimation equation according to the threshold crossing probability of the distance point in each sensing cycle to obtain the radar signal amplitude of the distance point in each sensing cycle;

[0019] A power conversion equation is solved according to the radar signal amplitude of the distance point in each sensing cycle to obtain the estimated power of the radar signal at the distance point in each sensing cycle.

[0020] In one embodiment, the performing power estimation according to the threshold crossing probability of the distance point in each sensing cycle and the target amplitude threshold corresponding to each sensing cycle to determine the estimated power of the radar signal of the distance point in each sensing cycle includes:

[0021] Based on the target amplitude threshold corresponding to each sensing cycle and the threshold crossing probability of each distance point, an interpolation calculation is performed using a preset calibration mapping table to obtain the estimated power of the radar signal at the distance point in each sensing cycle.

[0022] In one embodiment, solving the amplitude estimation equation according to the threshold crossing probability of the distance point in each sensing cycle to obtain the radar signal amplitude of the distance point in each sensing cycle includes:

[0023] The threshold crossing probability of each distance point in each sensing cycle is input into the amplitude estimation equation. Obtaining the radar signal amplitude of the distance point in each sensing cycle;

[0024] Among them, L j is the radar signal amplitude of the distance point in the jth sensing cycle, u is the target amplitude threshold corresponding to the jth sensing cycle, σ is the noise standard deviation, erf -1 () is the inverse function of the Gaussian error function, p j is the threshold crossing probability of the distance point in the jth sensing cycle.

[0025] In one embodiment, the determining the radar signal target power of the distance point by performing weighted average calculation according to the estimated power of the radar signal of the distance point in each of the sensing cycles in the plurality of sensing cycles and the threshold crossing probability of the distance point in each of the sensing cycles includes:

[0026] Inputting the estimated power of the distance point in each sensing cycle and the threshold crossing probability of the distance point in each sensing cycle into a weighted average equation to obtain the radar signal target power of the distance point;

[0027] The weighted average equation includes:

[0028] Where, cm is the radar signal target power at the distance point, N is the number of sensing cycles, and p j is the threshold crossing probability of the distance point in the jth sensing cycle, m j Estimate the power of the radar signal at the distance point in the jth sensing cycle.

[0029] In a second aspect, an embodiment of the present application further provides a radar signal detection device, which is applied to a radar, wherein the radar performs signal detection in multiple sensing cycles, and the radar signal detection device includes:

[0030] A receiving unit, used for receiving a plurality of radar signals reflected from a same distance point in each sensing cycle;

[0031] A determination unit, used to determine a target amplitude threshold corresponding to each of the sensing cycles;

[0032] The determination unit is further configured to determine the threshold crossing probability of the distance point in each sensing cycle by comparing the amplitudes of the multiple radar signals at the same distance point in each sensing cycle with the target amplitude threshold; the threshold crossing probability of the distance point represents the probability that the amplitudes of the multiple radar signals at the distance point exceed the target amplitude threshold;

[0033] The determination unit is also used to determine the radar signal target power of the distance point according to the threshold-crossing probability of the distance point in each of the sensing cycles within the multiple sensing cycles and the target amplitude threshold corresponding to each of the sensing cycles.

[0034] In a third aspect, an embodiment of the present application further provides a radar device, including: a signal receiver and a signal processor;

[0035] The signal receiver is used to receive multiple radar signals reflected from the same distance point in each sensing cycle;

[0036] The signal processor is configured to execute the steps of any one of the above radar signal detection methods.

[0037] In a fourth aspect, an embodiment of the present application further provides a computer-readable storage medium having a computer program stored thereon, wherein when the computer program is executed by a processor, the steps of any one of the above-mentioned radar signal detection methods are implemented.

[0038] It can be seen from the above technical solutions that the embodiments of the present application have the following advantages:

[0039] By receiving multiple radar signals from the same distance point in multiple sensing cycles, and comparing the signal amplitude in each sensing cycle with the target amplitude threshold, the over-threshold probability is determined, and each sensing cycle corresponds to a different amplitude threshold, which can avoid saturation of over-strong signals and missed detection of over-weak signals, and improve the sensitivity and accuracy of radar signal detection. According to the over-threshold probability and target amplitude threshold of multiple sensing cycles, the target power of the radar signal at the distance point is determined. In this way, the over-threshold probability and target amplitude threshold of multiple sensing cycles are combined, so that the target power of the radar signal at the determined distance point is more comprehensive and accurate, which solves the problem of low detection accuracy of traditional radar systems when there is a large difference between strong and weak signals, and significantly improves the detection capability and reliability of weak and strong signals. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0041] Figure 1 A schematic diagram of a perception frame and super frame structure provided in an embodiment of the present application;

[0042] Figure 2A schematic diagram of a radar signal detection method provided in an embodiment of the present application;

[0043] Figure 3 A schematic diagram of a radar signal detection device provided in an embodiment of the present application;

[0044] Figure 4 A schematic diagram of the structure of a radar device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0045] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0046] In radar signal detection, perception refers to the process by which the radar system detects and analyzes target objects in the environment by transmitting and receiving signals. At present, the demand for high-precision radar perception and detection is increasing in the fields of healthcare, high-risk chemical industry, tunnels and pipe galleries, construction sites, intelligent robots, drones, public security, procuratorial and judicial fields, especially in the Internet of Things industry, which has higher requirements for perception and monitoring of indoor and outdoor environments. Although multi-bit ADC can achieve high-precision radar perception, it has high material cost (multiple comparators) and R&D cost, especially when high sampling frequency is required.

[0047] The radar involved in the embodiments of the present application may be a pulse radar (such as Impulse-Radio Ultra-Wide Band (IR-UWB)), a continuous wave radar, a pulse compression radar and a frequency agile radar, which can be set as needed and are not limited in the embodiments of the present application. In common application scenarios such as health monitoring, life presence detection, and fall detection, the requirements for radar sensing frequency are relatively low, and 20 frames per second (FPS) are sufficient. For IR-UWB radar, a sensing frame usually takes one to several milliseconds, and the specific duration depends on the firmware and hardware design. In this application context, the applicant has found through in-depth research that when the sensing frequency is set to 20FPS, radar sensing will be repeated every 50 milliseconds, but the sensing only lasts for 5 milliseconds in each sensing cycle, and the remaining 45 milliseconds are in standby mode. Therefore, the applicant found that such a design has a huge vacuum period, which is not effectively utilized, resulting in a waste of computing resources and time.

[0048] The radar completes detection by transmitting radar signals and receiving the radar signals reflected from the environment. The ADC is used to convert the reflected radar signals into digital signals that are easier to process subsequently (such as Fourier transform, etc.). In order to save computing resources, 1-bit comparators are usually adopted by the ADC. However, the comparison range of 1-bit comparators is limited, and all strong signals are "truncated" to a maximum value. That is, a very strong signal and a slightly stronger signal both output 1 in a 1-bit ADC, resulting in the saturation of over-strong signals. In addition, for weak signals, if the signal amplitude is close to or lower than the reference threshold, it is easily submerged by noise, and it is difficult for the ADC to distinguish the signal from the noise, resulting in inaccurate detection. Therefore, the above limitations pose great challenges to the radar system in processing strong and weak signals, and the processing capabilities for over-strong signals and over-weak signals are limited, thus leading to a smaller reception range of the radar. In view of the above situation, the applicant has proposed the radar signal detection method of this application.

[0049] Please refer to the following Figure 1 , Figure 1 which shows the structure of the sensing frames and superframes in a time series. By reasonably utilizing the idle period, multiple sensing frames corresponding to different target amplitude thresholds are set and cascaded in chronological order, so as to perform multiple sensing operations within a superframe, which can reduce the waste of time and computing resources. At the same time, it can also increase the reception range of the IR-UWB radar, enabling it to reliably detect weak signals and strong signals.

[0050] Radar sensing is performed periodically as shown in Figure 1 . For example, the sensing of a superframe is performed every 50 milliseconds (ms, millisecond). Similarly, it can also be set to perform 20 superframe senses per second. In a superframe, there can be N sensing frames, where N is an integer greater than or equal to 0. Each sensing frame can include two operations. One is to set the threshold, that is, to set the target amplitude threshold according to the initial amplitude threshold (i.e., the "set the first threshold" and "set the second threshold" in each sensing frame in Figure 1 ). All the hardware of the radar system is ready for sensing within a few microseconds (μs, microsecond), and then the radar device can perform sensing. The other is to perform sensing, that is, the process of detecting and analyzing the target objects in the environment by transmitting and receiving signals. Or it is also possible not to set the target amplitude threshold within the sensing period, but to set the target amplitude thresholds of each sensing frame in advance, and then perform the radar sensing of each sensing frame in sequence according to the structure of the sensing frames and superframes shown in Figure 1 .

[0051] The N sensing frames are cascaded in chronological order, and each sensing frame is correspondingly set with a target amplitude threshold. The upper limit of N is determined by the following equation: N*τ < T, where τ is the duration of the sensing frame and T is the superframe interval. Please refer to Figure 1 , Figure 1 Here τ is 5ms, T is 50ms, and N is 3.

[0052] The various embodiments of the present application are described in further detail below in conjunction with the accompanying drawings.

[0053] The present application embodiment provides a radar signal detection method, such as Figure 2 As shown, the method includes steps S201-S204.

[0054] S201: receiving multiple radar signals reflected from the same distance point in each sensing cycle.

[0055] It can be understood that the aforementioned perception frame can be understood as a perception cycle, so the super frame can be understood as a collection of multiple consecutive perception cycles in a time period. Multiple radar signals will be emitted in each perception cycle, and multiple radar signals reflected from the same distance point will also be received. Of course, the radar signals received in each perception cycle can also come from different distance points. For the convenience of description, the radar signal detection method provided in the embodiment of the present application will be described below based on the dimension of detecting the radar signal at the same distance point. It can be understood that in actual applications, radar signals reflected from multiple distance points are detected in each perception cycle. The detection of radar signals at other distance points in the same perception frame can be performed by executing the same method steps as S201, S203-204, and finally obtaining the radar signal target power at each distance point.

[0056] S202: Determine a target amplitude threshold corresponding to each sensing cycle.

[0057] In the embodiment of the present application, before the radar starts sensing, the target amplitude threshold corresponding to each sensing cycle can be pre-set, and then Figure 1 The structure of the sensing frame and super frame shown in the figure performs radar sensing in each sensing cycle in turn. Alternatively, the target amplitude threshold corresponding to each sensing cycle can be determined according to the execution order of each sensing cycle. For example, Figure 1 During the duration of the first sensing cycle shown in FIG. 1 , the first target amplitude threshold (i.e. Figure 1 ), and then perform radar perception in the first perception cycle; then, in the second perception cycle, determine the target amplitude threshold of the second perception frame (i.e. Figure 1 ), and perform radar perception in the second perception cycle.

[0058] Specifically, the duration of determining the target amplitude threshold corresponding to each sensing cycle may be 0.5 ms, and the duration of radar sensing in each sensing cycle may be 4.5 ms. Figure 1The time nodes and time periods (such as 0.5ms, 4.5ms, t=50ms, etc.) shown in are only examples, and the time nodes and time periods such as duration are not limited. In this way, by reasonably utilizing the vacuum period of the super frame, designing different perception frames corresponding to different thresholds and performing multiple perceptions, the effective detection distance range of the radar is increased, and the radar can robustly detect the vital signs of human signals.

[0059] S203: Determine the threshold crossing probability of the distance point in each sensing cycle by comparing the amplitudes of multiple radar signals at the same distance point in each sensing cycle with the target amplitude threshold.

[0060] In an embodiment of the present application, each perception cycle will have a corresponding output result. A frame of output after radar perception is performed in each perception cycle is usually a one-dimensional vector. The one-dimensional vector can be the threshold-crossing probability of the distance point in each perception cycle. The threshold-crossing probability of the distance point represents the probability that the amplitudes of multiple radar signals at the distance point exceed the target amplitude threshold.

[0061] In order to optimize the radar's signal processing process and improve detection accuracy, the radar usually divides the detection range into multiple distance points, each distance point represents a distance interval. For example, the radar's detection range is 200 meters, which is divided into a distance point every 1 meter, so there are a total of 200 distance points (from 1 meter to 200 meters). In general, if there is no object that can reflect the radar signal within a distance interval, the probability of crossing the threshold at this distance point will approach zero. If there is an object that can reflect the radar signal within the distance interval, the probability of crossing the threshold at this distance point will be processed according to the strength of the reflected signal, and the final value is a non-zero value.

[0062] The distance between each distance point can be determined according to the sampling rate of the ADC, for example, according to the ADC sampling rate (assuming f s =10MHz=10×10 6 times / second) and the electromagnetic wave speed c≈3×10 8 m / s, input into the following formula:

[0063]

[0064] The distance resolution of ADC is obtained as ΔR=15 meters, and then the distance between each distance point is set according to the distance resolution ΔR.

[0065] Those skilled in the art should understand that due to design cost issues, the ADC used in the radar is a 1-bit analog-to-digital converter. For the received radar signal, it only displays whether it exceeds or does not exceed the target amplitude threshold, that is, if it exceeds the target amplitude threshold, it outputs 1, and if it does not exceed the target amplitude threshold, it outputs 0. The ADC does not directly indicate the strength of the signal. It can be understood that in a pulse radar, each time a pulse signal is sent out by the radar, after receiving the reflected signal, the radar counts the number of 0s and 1s to obtain the number of times the amplitude of multiple radar signals at a certain distance point exceeds the target amplitude threshold. In traditional methods, the number of times the threshold is crossed will be directly used by other programs, but in complex environments, the strength and distribution of signals may vary greatly, and using only the number of times the threshold is crossed may not accurately reflect changes in the environment. For example, some interference signals in a strong interference environment also exceed the threshold, which may lead to a decrease in detection accuracy. Therefore, in an embodiment of the present application, the amplitudes of multiple radar signals at the distance point in each sensing cycle can be compared with the target amplitude threshold to determine the number of times the amplitude of the radar signal at the distance point exceeds the target amplitude threshold. Then, based on the total number of radar transmission pulses and the number of times the distance point crosses the threshold, the probability of the amplitude of the radar signal at the distance point exceeding the target amplitude threshold in each sensing cycle can be determined.

[0066] Specifically, the radar signals reflected from multiple distance points can be detected, each sensing cycle corresponds to a target amplitude threshold, and the output result of each sensing cycle can be uniformly expressed as x = [r1, r2, ..., r M ], where x is the cumulative result set of different distance points within the same sensing cycle, i.e., the same target amplitude threshold, M is the number of distance points to be measured (M is greater than 0), r i represents the number of times the i-th distance point crosses the threshold (i is an integer greater than 1 and less than or equal to M). Assuming there are k sensing cycles, k one-dimensional vectors [x1, x2, …, x k ], where k is an integer greater than 0. k one-dimensional vectors are transformed according to the total number of radar pulses transmitted r max Normalization is performed, and the specific normalization process can be: [pr1, pr2, ..., pr k ]=[x1,x2,…,x k ] / r max , where pr k It represents the probability that the amplitude of the radar signal at each distance point in the kth sensing cycle exceeds the target amplitude threshold.

[0067] In this way, the threshold probability pr jProvide a relative value to reflect the frequency of the signal exceeding the threshold. Even in the case of large fluctuations in signal strength, the over-threshold probability can still provide a consistent detection standard, indirectly reflecting the overall characteristics and distribution of the radar signal. And if the interference signal exceeds the threshold by chance later, the over-threshold probability can reflect the low frequency of such abnormal situation and reduce the false alarm rate.

[0068] S204: Determine the radar signal target power of the distance point according to the threshold crossing probability of the distance point in each sensing cycle within multiple sensing cycles and the target amplitude threshold corresponding to each sensing cycle.

[0069] The aforementioned specification mentioned that each perception cycle will have a corresponding output result. Furthermore, in the embodiment of the present application, the threshold-crossing probability calculated using the output results of N perception frames and the N target amplitude thresholds corresponding to the N perception frames can be combined into the output result of a super frame to finally obtain the target radar signal power of the distance point. For each distance point, the product between the threshold-crossing probability of the distance point of each perception cycle and the target amplitude threshold corresponding to each perception cycle can be calculated, and then the product results calculated for each perception cycle of the distance point are sorted, and the median is selected as the radar signal target power of the distance point. Alternatively, different weights can be assigned to each perception cycle, and then the weighted average of each product result is calculated using the weight, and the weighted average finally calculated is determined as the radar signal target power of the distance point.

[0070] In the embodiment of the present application, by designing a super frame including multiple sensing cycles, and setting different target amplitude thresholds for each sensing cycle, it is possible to avoid ADC saturation of overly strong signals and missed detection of overly weak signals in scenarios where the difference between strong and weak signals is large, thereby improving the radar's receiving range. Then, the reflected signal at each distance point in each sensing cycle is compared with the target amplitude threshold to obtain the threshold-crossing probability of the distance point; by combining the threshold-crossing probability of the distance point in each sensing cycle in multiple sensing cycles and the target amplitude threshold corresponding to each sensing cycle, the radar signal target power at the distance point is determined, thereby solving the problem of low detection accuracy of traditional radar systems in situations where the difference between strong and weak signals is large, and significantly improving the ability and reliability of detecting weak and strong signals.

[0071] In order to avoid saturation of over-strong signals and missed detection of over-weak signals due to the use of a single threshold, in one embodiment, a target amplitude threshold corresponding to each perception cycle is determined, including: obtaining an initial amplitude threshold corresponding to each perception cycle; calculating a threshold range corresponding to each initial amplitude threshold based on a preset compensation coefficient; and determining the target amplitude threshold corresponding to each perception cycle according to the threshold range corresponding to each initial amplitude threshold and the overlap rate of each threshold range.

[0072] In an embodiment of the present application, in order to avoid inaccurate signal detection due to factors such as environmental changes, equipment drift or signal interference, a preset compensation coefficient can be set, and each initial amplitude threshold can be compensated for to obtain a threshold range corresponding to each initial amplitude threshold. Then, based on the overlap rate of the threshold range corresponding to each initial amplitude threshold (the overlap rate represents the similarity or overlap between the threshold ranges), the target amplitude threshold corresponding to each perception cycle is re-determined.

[0073] Specifically, reference may be made to Table 1, which shows an example of determining the threshold range corresponding to the initial amplitude threshold. It should be noted that each initial amplitude threshold corresponds to each perception cycle one by one. In Table 2, by using 5 initial amplitude thresholds (such as -41dBm, -43dBm, -46dBm, -50dBm, -55dBm), the coverage range of 5 single initial amplitude thresholds is expanded by 20dB, i.e., -60 to -40dBm, using a preset compensation coefficient. In this example, if the overlap rate of the threshold range corresponding to adjacent initial amplitude thresholds meets the preset overlap rate index, then the 5 initial amplitude thresholds can be directly used as the target amplitude threshold. Exemplarily, the overlap rate can be calculated by the following formula: overlap rate = length of overlapping range / length of smaller range. In practical applications, it can also be directly determined based on historical data or experimental data.

[0074] Table 1

[0075] Initial amplitude threshold Preset compensation coefficient Threshold Range -55dBm + / -5dB -60~-50dBm -50dBm + / -3dB -53~-47dBm -46dBm + / -2dB -48~-44dBm -43dBm + / -2dB -45~-41dBm -41dBm + / -1dB -42~-40dBm

[0076] It should be noted that in the embodiments of the present application, in order to generally illustrate the concept, the threshold is directly expressed in dBm. In the absence of additional noise interference, the threshold range of a single threshold value usually decreases as the initial amplitude threshold increases. It can be understood that in high amplitude areas such as -41dBm, the signal strength is large, so the relative change amplitude is small, so the preset compensation coefficient and threshold range can be set smaller. In low amplitude areas such as -55dBm, the signal strength is weak, easily affected by noise and interference, and the fluctuation amplitude of the signal is large, so the preset compensation coefficient and threshold range should be set larger accordingly. In addition, the preset compensation coefficient is usually calculated based on the Gaussian distribution of the signal and noise. After obtaining the threshold range corresponding to different initial amplitude thresholds, the threshold range is re-determined according to the overlap rate between each threshold range, so that each threshold range can be seamlessly cascaded, and finally the target amplitude threshold of each sensing cycle is determined, which can effectively balance the sensitivity of signal detection, improve the detection accuracy and reliability of the system, and also further expand the receiving range of the radar signal.

[0077] Furthermore, if the above five initial amplitude thresholds "-43dBm, -46dBm, -50dBm, -55dBm" are not changed, and "-41dBm" is changed to "-39dBm", and the preset compensation coefficient corresponding to -39dBm is still + / -1dB, then the threshold range corresponding to -39dBm is -40 to -38dBm, which has no overlap with the threshold range -45 to -41dBm corresponding to -43dBm, and the overlap rate is 0. At this time, the threshold range of -39dBm can be reset according to the preset overlap rate indicator, for example, -40 to -38dBm is modified to a threshold range (-42dBm to -38dBm) that can overlap with -45 to -41dBm, and the median -40dBm of -42dBm to -38dBm is selected as the target amplitude threshold of the sensing cycle.

[0078] It should be noted that all the powers used above refer to pulse power, not average power. Pulse power refers to the power of a single pulse, that is, the instantaneous power during the pulse period, and average power refers to the average power over a longer period of time. Since the pulse signal has no power output during the non-pulse period, the average power will be lower than the pulse power. If the average power is to be used to calculate the target power of the radar signal at the distance point, the duty cycle of the pulse can be calculated based on the pulse width and the pulse repetition frequency (PRF, Pulse Repetition Frequency). Specifically, Duty Cycle = pulse width / (1 / pulse repetition frequency PRF). If the calculated duty cycle of the Duty Cycle is 0.1%, it means that the pulse only occupies 0.1% of the entire cycle. Next, the average power is calculated, and the average power = instantaneous power of the pulse * pulse repetition frequency PRF * duty cycle Duty Cycle. In this way, the average power can be obtained to calculate the target power of the radar signal. If it is a long-term radar signal detection, the average power calculation can be used; if it is used for radar signal detection in a short period of time, the pulse power can be used for calculation.

[0079] In the traditional method, when a single threshold is used, although the radar may receive a wide range of signal power, due to the limitation of the single threshold, the calculated effective radar signal target power is usually limited to a certain range, and it is impossible to fully and accurately detect the signal power of all ranges. In contrast, the embodiment of the present application uses multiple sensing cycles and multiple target amplitude thresholds to determine the target power of the radar signal, effectively avoiding the problem of signal saturation due to excessive strength or signal being too weak to be detected due to a single threshold, and significantly improving the radar receiving range and the accuracy of calculating the radar signal target power.

[0080] In order to reduce the influence of errors or uncertainties that may be caused in signal processing, in one embodiment, the target power of the radar signal at the distance point is determined according to the threshold-crossing probability of the distance point in each sensing cycle within multiple sensing cycles and the target amplitude threshold corresponding to each sensing cycle, including: performing power estimation according to the threshold-crossing probability of the distance point in each sensing cycle and the target amplitude threshold corresponding to each sensing cycle, and determining the estimated power of the radar signal at the distance point in each sensing cycle; performing weighted average calculation according to the estimated power of the radar signal at the distance point in each sensing cycle within multiple sensing cycles and the threshold-crossing probability of the distance point in each sensing cycle, and determining the target power of the radar signal at the distance point.

[0081] For a specific distance point within each sensing cycle, the threshold crossing probability is calculated using the number of threshold crossings obtained by sampling within the cycle, and then the power estimation is performed based on the threshold crossing probability within each sensing cycle and the preset target amplitude threshold. In a feasible embodiment, the prior distribution P(θ) of the signal power can be defined first, and P(θ) represents the probability distribution of the radar signal target power before the signal received by the radar is processed. The prior distribution P(θ) is combined with the result of signal processing using Bayes' theorem to obtain the posterior distribution P(θ|D), and the radar signal estimated power E[θ|D] is calculated based on the posterior distribution, E[θ|D]=∫θP(θ|D)dθ. Alternatively, the radar signal estimated power can be directly calculated based on the Gaussian distribution law of the radar signal. After obtaining the radar signal estimated power of each sensing cycle within multiple sensing cycles, a weighted average calculation is performed. The weighted average can comprehensively consider the data within multiple cycles by assigning different weights according to the importance of the data within different sensing cycles, thereby further reducing the error or uncertainty caused by the data of a single sensing cycle.

[0082] In order to improve the detection accuracy and reliability of the radar system for the target signal, in one embodiment, power estimation is performed based on the threshold-crossing probability of the distance point in each sensing cycle and the target amplitude threshold corresponding to each sensing cycle, and the estimated power of the radar signal at the distance point in each sensing cycle is determined, including: solving the amplitude estimation equation based on the threshold-crossing probability of the distance point in each sensing cycle to obtain the radar signal amplitude of the distance point in each sensing cycle; solving the power conversion equation based on the radar signal amplitude of the distance point in each sensing cycle to obtain the radar signal estimated power of the distance point in each sensing cycle.

[0083] In the embodiment of the present application, an amplitude estimation equation is established to quantify the amplitude of the radar signal by using the number of times exceeding the threshold. The load resistance of the radar receiving circuit and the amplitude of the radar reflection signal at the distance point in each sensing frame are then input into the power conversion equation:

[0084]

[0085] The estimated power of the reflected signal at the distance point in each sensing frame is obtained through the power conversion equation; where m i,j is the estimated power of the radar reflection signal at the i-th distance point in the j-th sensing frame, and R is the load resistance of the radar receiving circuit.

[0086] In addition to the radar signal estimated power calculated by using the amplitude estimation equation and the power conversion equation, the radar signal estimated power can also be calculated by using a preset calibration mapping table. Specifically, in one embodiment, power estimation is performed based on the threshold-crossing probability of the distance point in each sensing cycle and the target amplitude threshold corresponding to each sensing cycle, and the radar signal estimated power of the distance point in each sensing cycle is determined, including: based on the target amplitude threshold corresponding to each sensing cycle and the threshold-crossing probability of each distance point, interpolation calculation is performed using a preset calibration mapping table to obtain the radar signal estimated power of the distance point in each sensing cycle.

[0087] Refer to Table 2, which only lists some of the mapping relationships between target amplitude thresholds, threshold crossing probabilities, and radar signal estimated power. It can be understood that the calibration mapping table is a power-probability pair of a specific threshold, and N calibration mapping tables can be formulated for N thresholds. In order to ensure the reliability of calculating the estimated amplitude of the radar signal, the threshold crossing probability can be limited to a certain range, such as setting the effective threshold crossing probability range to [p min , p max The effective threshold probability range can be optimized according to the actual product specifications. The general principle for setting the threshold probability range can be [max(50 / r max , 0.05), min(1-50 / r max , 0.95)]. For example, if r max ≥1000, the range is [0.05, 0.95]. This setting ensures that at least 50 (5%) signals are received that exceed the threshold, and at least 50 (5%) signals are received that are below the threshold, to ensure the reliability of the estimated power of the radar signal.

[0088] Table 2

[0089]

[0090] Taking Table 2 as an example, if the target amplitude threshold corresponding to the current sensing period is -50dBm, the over-threshold probability is 0.7, and the over-threshold probability 0.7 is between 0.50 (corresponding to the estimated radar signal power of -50dBm) and 0.80 (corresponding to the estimated radar signal power of -46dBm), the linear interpolation method can be used to estimate the corresponding radar signal power. Substituting it into the following linear interpolation formula, the estimated radar signal power is -47.3333dBm.

[0091] Linear interpolation formula:

[0092]

[0093] Among them, P is the estimated power of the radar signal, P1 and P2 are the estimated powers of two radar signals known by the preset calibration mapping table, the over-threshold probability corresponding to P1 is Q1, the over-threshold probability corresponding to P2 is Q2, and Q is the over-threshold probability of the distance point in the current sensing cycle.

[0094] In one embodiment, solving the amplitude estimation equation according to the threshold crossing probability of the distance point in each sensing cycle to obtain the radar signal amplitude of the distance point in each sensing cycle includes:

[0095] The threshold crossing probability of each distance point in each sensing cycle is input into the amplitude estimation equation Get the radar signal amplitude at each distance point in each sensing cycle;

[0096] Among them, L j is the radar signal amplitude of the distance point in the jth sensing cycle, u is the target amplitude threshold corresponding to the jth sensing cycle, σ is the noise standard deviation, erf -1 () is the inverse function of the Gaussian error function, p j is the threshold crossing probability of the distance point in the jth perception cycle.

[0097] The above amplitude calculation formula is for a specific distance point. If you want to calculate the estimated power of the radar signal at multiple distance points, the amplitude estimation equation can be Then the amplitude of the reflected signal at the distance point in each sensing cycle is obtained; where L i,j is the amplitude of the radar signal at the i-th distance point in the j-th sensing cycle, p i,j is the threshold crossing probability of the i-th distance point in the j-th perception cycle.

[0098] In order to improve the accuracy of calculating the target power of the radar signal, in one embodiment, a weighted average calculation is performed based on the estimated power of the radar signal at the distance point in each sensing cycle in multiple sensing cycles and the threshold crossing probability of the distance point in each sensing cycle to determine the target power of the radar signal at the distance point, including:

[0099] The estimated power of the distance point in each sensing cycle and the threshold-crossing probability of the distance point in each sensing cycle are input into the weighted average equation to obtain the radar signal target power of the distance point;

[0100] The weighted average equation includes:

[0101]

[0102] Where cm is the radar signal target power at the distance point, N is the number of sensing cycles, and p j is the threshold crossing probability of the distance point in the jth sensing cycle, m j Estimate the power of the radar signal at the distance point in the jth sensing cycle.

[0103] The above weighted average equation is a calculation equation for a specific distance point. If you want to calculate the radar signal target power at multiple distance points, the weighted average equation can be:

[0104]

[0105] Among them, cm i is the radar signal target power at the i-th distance point, p i,j is the threshold crossing probability of the i-th distance point in the j-th sensing cycle, m i,j Estimate the power of the radar signal at the i-th distance point in the j-th sensing cycle.

[0106] Based on the above description, in actual application, when applying the radar signal detection method provided by the embodiment of the present application, it is only necessary to set the initial amplitude threshold and determine the target amplitude threshold in advance, so that the radar can have a larger receiving range during the perception process of the entire super frame. Please refer to Table 3, which shows the radar signal target power obtained by using the radar signal detection method provided by the embodiment of the present application, where r max =3000. According to Table 3, the calculated radar signal target power has a variation range within 0.1 dB of the actual signal power. max When the value is smaller, the variation range may be larger than 0.1 dB. In addition, when setting the initial amplitude threshold, if a lower initial amplitude threshold is also set, such as -65 dBm, then the deviation at -60 dBm will be smaller, for example, the variation range will become -59.9 to -60.0.

[0107] Table 3

[0108] Actual signal power (dBm) Radar signal target power variation range (dBm) -60 -59.7～-59.8 -55 -55.0 -53 -52.9～-53.0 -50 -50.0 -48 -48.0 -45 -45.0 -40 -40.1

[0109] In order to implement the radar signal detection method of the embodiment of the present application, the embodiment of the present application also provides a radar signal detection device, which is applied to a radar, and the radar performs signal detection in multiple sensing cycles, such as Figure 3 As shown, the radar signal detection device 300 includes:

[0110] The receiving unit 301 is used to receive multiple radar signals reflected from the same distance point in each sensing cycle;

[0111] A determination unit 302, configured to determine a target amplitude threshold corresponding to each of the sensing cycles;

[0112] The determination unit 302 is further configured to determine the threshold crossing probability of the distance point in each of the sensing cycles by comparing the amplitudes of the multiple radar signals at the same distance point in each of the sensing cycles with the target amplitude threshold; the threshold crossing probability of the distance point represents the probability that the amplitudes of the multiple radar signals at the distance point exceed the target amplitude threshold;

[0113] The determination unit 302 is further used to determine the radar signal target power of the distance point according to the threshold-crossing probability of the distance point in each of the sensing cycles within the plurality of sensing cycles and the target amplitude threshold corresponding to each of the sensing cycles.

[0114] In one embodiment, the device further includes an acquisition unit. The acquisition unit is used to acquire the initial amplitude threshold corresponding to each of the perception cycles; the device further includes a processing unit. The processing unit is used to calculate the threshold range corresponding to each of the initial amplitude thresholds based on a preset compensation coefficient; the determination unit 302 is further used to determine the target amplitude threshold corresponding to each of the perception cycles according to the threshold range corresponding to each of the initial amplitude thresholds and the overlap rate of each of the threshold ranges.

[0115] In one embodiment, the determination unit 302 is further used to perform power estimation based on the threshold-crossing probability of the distance point in each sensing cycle and the target amplitude threshold corresponding to each sensing cycle, and determine the radar signal estimated power of the distance point in each sensing cycle; the determination unit 302 is further used to perform weighted average calculation based on the radar signal estimated power of the distance point in each sensing cycle in multiple sensing cycles and the threshold-crossing probability of the distance point in each sensing cycle, and determine the radar signal target power of the distance point.

[0116] In one embodiment, the processing unit is further used to solve the amplitude estimation equation according to the threshold-crossing probability of the distance point in each of the sensing cycles to obtain the radar signal amplitude of the distance point in each of the sensing cycles; the processing unit is further used to solve the power conversion equation according to the radar signal amplitude of the distance point in each of the sensing cycles to obtain the estimated radar signal power of the distance point in each of the sensing cycles.

[0117] In one embodiment, the processing unit is further used to perform interpolation calculations based on a preset calibration mapping table based on a target amplitude threshold corresponding to each of the sensing cycles and a threshold-crossing probability of each of the distance points, to obtain an estimated power of the radar signal at the distance point within each of the sensing cycles.

[0118] In one embodiment, the processing unit is further configured to input the threshold crossing probability of each distance point in each sensing cycle into the amplitude estimation equation: Obtain the radar signal amplitude of the distance point in each sensing cycle; wherein, L j is the radar signal amplitude of the distance point in the jth sensing cycle, u is the target amplitude threshold corresponding to the jth sensing cycle, σ is the noise standard deviation, erf -1 () is the inverse function of the Gaussian error function, p j is the threshold crossing probability of the distance point in the jth sensing cycle.

[0119] In one embodiment, the processing unit is further used to input the estimated power of the distance point in each sensing cycle and the threshold crossing probability of the distance point in each sensing cycle into a weighted average equation to obtain the radar signal target power of the distance point; the weighted average equation includes:

[0120]

[0121] Where, cm is the radar signal target power at the distance point, N is the number of sensing cycles, and p j is the threshold crossing probability of the distance point in the jth sensing cycle, m j Estimate the power of the radar signal at the distance point in the jth sensing cycle.

[0122] It should be noted that: the above embodiment provides a radar signal detection device, and only uses the division of the above program modules as an example to illustrate when performing radar signal detection. In actual applications, the above processing can be assigned to different program modules as needed, that is, the internal structure of the device is divided into different program modules to complete all or part of the above-described processing. In addition, the radar signal detection device and the radar signal detection method embodiment provided in the above embodiment belong to the same concept, and the specific implementation process is detailed in the method embodiment, which will not be repeated here.

[0123] Based on the hardware implementation of the above program module, and in order to implement a radar signal detection method provided in an embodiment of the present application, an embodiment of the present application further provides a radar device, such as Figure 4 As shown, the radar device 400 includes: a signal receiver 401 and a signal processor 402;

[0124] The signal receiver 401 is used to receive multiple radar signals reflected from the same distance point in each sensing cycle;

[0125] The signal processor 402 is configured to execute the steps of any one of the above radar signal detection methods.

[0126] The radar device in the present application may be a pulse radar (such as pulse radio ultra-wideband IR-UWB) or a continuous wave radar. The specific radar may be selected as needed and is not limited in the embodiments of the present application.

[0127] An embodiment of the present application further provides a computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, the steps of any one of the above-mentioned radar signal detection methods are implemented.

[0128] An embodiment of the present application further provides a computer program product having a computer program / instruction stored thereon, which, when executed by a processor, is used to implement the steps of any one of the above-mentioned radar signal detection methods.

[0129] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0130] In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0131] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0132] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0133] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program code.

Claims

1. A radar signal detection method, characterized in that: Applied to a radar, the radar performs signal detection in multiple sensing cycles, and the method includes: receiving a plurality of radar signals reflected from a same distance point in each of the sensing cycles; Determine a target amplitude threshold corresponding to each of the sensing cycles; Determine the threshold-crossing probability of the distance point in each sensing cycle by comparing the amplitudes of the multiple radar signals at the same distance point in each sensing cycle with the target amplitude threshold; the threshold-crossing probability of the distance point represents the probability that the amplitudes of the multiple radar signals at the distance point exceed the target amplitude threshold; The radar signal target power of the distance point is determined according to the threshold-crossing probability of the distance point in each of the sensing cycles within the plurality of sensing cycles and the target amplitude threshold corresponding to each of the sensing cycles.

2. The radar signal detection method according to claim 1, characterized in that: The determining of the target amplitude threshold corresponding to each sensing cycle includes: Obtaining an initial amplitude threshold corresponding to each of the sensing cycles; Calculate a threshold range corresponding to each of the initial amplitude thresholds based on a preset compensation coefficient; The target amplitude threshold corresponding to each of the sensing cycles is determined according to the threshold range corresponding to each of the initial amplitude thresholds and the overlap rate of each of the threshold ranges.

3. The radar signal detection method according to claim 1, characterized in that: The determining the radar signal target power of the distance point according to the threshold crossing probability of the distance point in each of the sensing cycles within the plurality of sensing cycles and the target amplitude threshold corresponding to each of the sensing cycles comprises: Power estimation is performed according to the threshold crossing probability of the distance point in each sensing cycle and the target amplitude threshold corresponding to each sensing cycle, to determine the estimated power of the radar signal of the distance point in each sensing cycle; A weighted average calculation is performed based on the estimated power of the radar signal at the distance point in each of the sensing cycles and the threshold-crossing probability of the distance point in each of the sensing cycles to determine the target power of the radar signal at the distance point.

4. The radar signal detection method according to claim 3, characterized in that: The performing power estimation according to the threshold crossing probability of the distance point in each sensing cycle and the target amplitude threshold corresponding to each sensing cycle, and determining the estimated power of the radar signal of the distance point in each sensing cycle, includes: Solving an amplitude estimation equation according to the threshold crossing probability of the distance point in each sensing cycle to obtain the radar signal amplitude of the distance point in each sensing cycle; A power conversion equation is solved according to the radar signal amplitude of the distance point in each sensing cycle to obtain the estimated power of the radar signal at the distance point in each sensing cycle.

5. The radar signal detection method according to claim 3, characterized in that: The performing power estimation according to the threshold crossing probability of the distance point in each sensing cycle and the target amplitude threshold corresponding to each sensing cycle, and determining the estimated power of the radar signal of the distance point in each sensing cycle, includes: Based on the target amplitude threshold corresponding to each sensing cycle and the threshold crossing probability of each distance point, an interpolation calculation is performed using a preset calibration mapping table to obtain the estimated power of the radar signal at the distance point in each sensing cycle.

6. The radar signal detection method according to claim 4, characterized in that: Solving the amplitude estimation equation according to the threshold crossing probability of the distance point in each sensing cycle to obtain the radar signal amplitude of the distance point in each sensing cycle includes: The threshold crossing probability of each distance point in each sensing cycle is input into the amplitude estimation equation. Obtaining the radar signal amplitude of the distance point in each sensing cycle; Among them, L j is the radar signal amplitude of the distance point in the jth sensing cycle, u is the target amplitude threshold corresponding to the jth sensing cycle, σ is the noise standard deviation, erf -1 () is the inverse function of the Gaussian error function, p j is the threshold crossing probability of the distance point in the jth sensing cycle.

7. The radar signal detection method according to claim 3, characterized in that: The step of performing weighted average calculation based on the estimated power of the radar signal at the distance point in each of the sensing cycles and the threshold crossing probability of the distance point in each of the sensing cycles to determine the target power of the radar signal at the distance point comprises: Inputting the estimated power of the distance point in each sensing cycle and the threshold crossing probability of the distance point in each sensing cycle into a weighted average equation to obtain the radar signal target power of the distance point; The weighted average equation includes: Where, cm is the radar signal target power at the distance point, N is the number of sensing cycles, and p j is the threshold crossing probability of the distance point in the jth sensing cycle, m j Estimate the power of the radar signal at the distance point in the jth sensing cycle.

8. A radar signal detection device, characterized in that: Applied to a radar, the radar performs signal detection in multiple sensing cycles, and the radar signal detection device includes: A receiving unit, used for receiving a plurality of radar signals reflected from a same distance point in each sensing cycle; A determination unit, used to determine a target amplitude threshold corresponding to each of the sensing cycles; The determination unit is further configured to determine the threshold crossing probability of the distance point in each sensing cycle by comparing the amplitudes of the multiple radar signals at the same distance point in each sensing cycle with the target amplitude threshold; the threshold crossing probability of the distance point represents the probability that the amplitudes of the multiple radar signals at the distance point exceed the target amplitude threshold; The determination unit is also used to determine the radar signal target power of the distance point according to the threshold-crossing probability of the distance point in each of the sensing cycles within the multiple sensing cycles and the target amplitude threshold corresponding to each of the sensing cycles.

9. A radar device, characterized in that: include: Signal receiver and signal processor; The signal receiver is used to receive multiple radar signals reflected from the same distance point in each sensing cycle; The signal processor is configured to execute the steps of the radar signal detection method according to any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the radar signal detection method according to any one of claims 1 to 7 are implemented.

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