Position sensing method and apparatus, computer device, readable storage medium and program product

Abstract

The present application relates to a position sensing method and apparatus, a computer device, a readable storage medium, and a program product. The method is applied to a receiver. The method comprises: processing a received reception signal to obtain a direct link signal corresponding to a signal source; on the basis of a serial interference cancellation policy and the direct link signal, determining a reflected link signal from the reception signal; performing sensing parameter estimation on the reflected link signal to obtain position sensing data; and determining coordinate information of a target device on the basis of the position sensing data. The present method can improve the accuracy of position sensing of reflection and scattering devices.

Description

Position awareness method and device, computer device, readable storage medium and program product

[0001] The present application claims priority to the Chinese patent application No. 2024112930109, filed on September 14, 2024, and entitled "Position awareness method and device, computer device, readable storage medium and program product", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] The present application relates to the technical field of wireless communication, and in particular to a position awareness method, device, computer device, readable storage medium and program product. BACKGROUND

[0003] With the progress of low-power and low-cost wireless technology, wireless communication systems are rapidly developing in many fields such as industry 4.0 and smart home. Backscatter communication technology is a key technology of low-power wireless communication system, which transmits data by modulating and reflecting the received radio frequency signal through a backscatter device in a backscatter communication system.

[0004] In related technologies, various wireless technologies have been used for indoor positioning, including Wireless Fidelity (WiFi), Ultra Wide Band (UWB), Bluetooth Low Energe (BLE), Radio Frequency Identification (RFID), etc. Since the reflection scattering communication system needs to use the weak signal reflected by the target for awareness positioning, when the reflection scattering communication system is applied outdoors and needs to realize long-distance target awareness, the accuracy of the reflection scattering device position awareness is low. SUMMARY

[0005] Therefore, it is necessary to provide a position awareness method, device, computer device, readable storage medium and program product capable of improving the accuracy of reflection scattering device position awareness to solve the above technical problems.

[0006] In a first aspect, the present application provides a position awareness method applied to a receiver, comprising:

[0007] processing a received receive signal to obtain a direct link signal corresponding to a signal source;

[0008] determining a reflection link signal from the receive signal based on a serial interference cancellation strategy and the direct link signal;

[0009] The reflection link signal is subjected to perceptual parameter estimation to obtain position perception data, and coordinate information of the target device is determined based on the position perception data.

[0010] In one of the embodiments, the receiver comprises a plurality of antennas, and the processing of the received receiving signal to obtain the direct link signal corresponding to the signal source comprises:

[0011] The receiving signal of each antenna is subjected to preliminary processing to obtain a first receiving signal;

[0012] The first receiving signals are subjected to weighted processing to obtain a second receiving signal;

[0013] The second receiving signal is subjected to demodulation processing to obtain the direct link signal.

[0014] In one of the embodiments, the preliminary processing of the receiving signal of each antenna to obtain a first receiving signal comprises:

[0015] The receiving signal of each antenna is subjected to frame synchronization to obtain a frame-synchronized receiving signal, the frame-synchronized receiving signal is subjected to bias estimation to obtain a carrier frequency bias value in the receiving signal, and the frame-synchronized receiving signal is processed based on the carrier frequency bias value to obtain a first receiving signal.

[0016] In one of the embodiments, the weighted processing of the first receiving signals to obtain a second receiving signal comprises:

[0017] The first receiving signal is subjected to channel estimation to obtain a channel gain value, and the channel gain value is determined as a weighting coefficient;

[0018] The first receiving signals are subjected to weighted processing based on the weighting coefficient to obtain a second receiving signal.

[0019] In one of the embodiments, the receiving signal comprises a first downlink chirp signal, and the frame synchronization of the receiving signal to obtain a frame-synchronized receiving signal comprises:

[0020] The receiving signal is subjected to low-pass filtering processing to obtain a filtered receiving signal;

[0021] The filtered receiving signal is multiplied by the first downlink chirp signal to obtain a first calculation result;

[0022] performing fast Fourier transform on the first calculation result to obtain a plurality of starting frequencies of the received signal; and determining a frame-synchronized received signal based on a preset number threshold if a number of continuous identical starting frequencies reaches the preset number threshold.

[0023] In one of the embodiments, the second received signal comprises a second downlink chirp signal, and the demodulation of the second received signal to obtain the direct link signal comprises:

[0024] multiplying the second received signal by the second downlink chirp signal to obtain a second calculation result;

[0025] performing fast Fourier transform on the second calculation result to obtain a plurality of starting frequencies of the second received signal;

[0026] mapping each of the starting frequencies to a preset chip interval to determine the direct link signal.

[0027] In one of the embodiments, the sensing parameter estimation of the reflected link signal to obtain the position sensing data comprises:

[0028] obtaining a plurality of singular eigenvalues in a signal covariance matrix of the reflected link signal;

[0029] determining a singular eigenvector corresponding to the singular eigenvalue satisfying a preset condition, determining a steering vector orthogonal to a preset noise eigenvector based on the singular eigenvector, and determining a two-dimensional spectrum peak search expression based on the steering vector;

[0030] calculating spectrum values of preset coordinate positions based on the two-dimensional spectrum peak search expression, obtaining a spectrum peak in a plurality of the spectrum values through a spectrum peak search algorithm, and determining position information of the spectrum peak as the position sensing data of the reflected link signal.

[0031] In one of the embodiments, the position sensing data comprises direction information of the target device relative to the receiver and distance information of the reflected link signal, the target device is a backscattering device, and the determination of coordinate information of the target device based on the position sensing data comprises:

[0032] calculating the direction information, the distance information and distance information of the direct link signal according to a preset position algorithm to obtain coordinate information of the backscattering device.

[0033] In a second aspect, the application further provides a position sensing device, comprising:

[0034] a processing module configured to process a received received signal to obtain a direct link signal corresponding to a signal source.

[0035] a first determining module, configured to determine a reflected link signal from the received signal based on a serial interference cancellation strategy and the direct link signal;

[0036] a second determining module, configured to perform sensing parameter estimation on the reflected link signal to obtain position sensing data, and determine coordinate information of the target device based on the position sensing data.

[0037] In a third aspect, the present application provides a computer device, comprising a memory and a processor, wherein the memory stores a computer program, and the processor implements the following steps when executing the computer program:

[0038] processing the received received signal to obtain a direct link signal corresponding to a signal source;

[0039] determining a reflected link signal from the received signal based on a serial interference cancellation strategy and the direct link signal;

[0040] performing sensing parameter estimation on the reflected link signal to obtain position sensing data, and determining coordinate information of the target device based on the position sensing data.

[0041] In a fourth aspect, the present application provides a computer readable storage medium, which stores a computer program, and the computer program implements the following steps when executed by a processor:

[0042] processing the received received signal to obtain a direct link signal corresponding to a signal source;

[0043] determining a reflected link signal from the received signal based on a serial interference cancellation strategy and the direct link signal;

[0044] performing sensing parameter estimation on the reflected link signal to obtain position sensing data, and determining coordinate information of the target device based on the position sensing data.

[0045] In a fifth aspect, the present application provides a computer program product, comprising a computer program, and the computer program implements the following steps when executed by a processor:

[0046] processing the received received signal to obtain a direct link signal corresponding to a signal source;

[0047] determining a reflected link signal from the received signal based on a serial interference cancellation strategy and the direct link signal;

[0048] performing sensing parameter estimation on the reflected link signal to obtain position sensing data, and determining coordinate information of the target device based on the position sensing data.

[0049] The position sensing method, device, computer device, readable storage medium and program product can obtain the coordinate information of the target device by processing the received signal to obtain the direct link signal, eliminating the direct link signal in the received signal by using the serial interference cancellation strategy to obtain the reflected link signal, and performing position sensing on the reflected link signal. BRIEF DESCRIPTION OF DRAWINGS

[0050] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the related art, the drawings needed to be used in the description of the embodiments of the present application or the related art will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other related drawings can be obtained by those skilled in the art without creative labor.

[0051] FIG. 1 is a structural schematic diagram of a position sensing system in an embodiment;

[0052] FIG. 2 is a frame structure of a chirp spread spectrum modulated signal in an embodiment;

[0053] FIG. 3 is a time-frequency diagram of a chirp spread spectrum modulated signal in an embodiment;

[0054] FIG. 4 is a flowchart of a position sensing method in an embodiment;

[0055] FIG. 5 is a schematic diagram of a received signal after frame synchronization in an embodiment;

[0056] FIG. 6 is a schematic diagram of the relative position relationship of devices in a position sensing system in an embodiment;

[0057] FIG. 7 is a time-frequency diagram of a received signal after short-time Fourier transform in an embodiment;

[0058] FIG. 8 is a schematic diagram of the angle estimation error of a backscattering device under different signal-to-noise ratio conditions using the MUSIC algorithm in an embodiment;

[0059] FIG. 9 is a schematic diagram of the coordinate estimation error of a backscattering device under different signal-to-noise ratio conditions using the MUSIC algorithm in an embodiment;

[0060] FIG. 10 is a structural block diagram of a position sensing device in an embodiment;

[0061] FIG. 11 is an internal structure diagram of a computer device in an embodiment. DETAILED DESCRIPTION

[0062] In order to make the purposes, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not used to limit the present application.

[0063] The position sensing method provided by the embodiments of the present application can be applied to a position sensing system as shown in FIG. 1. The position sensing system includes a transmitter, a receiver and a target device. The transmitter can be a long range radio (LoRa) signal source, the receiver can be a joint receiver, and the target device can be a backscatter device.

[0064] The LoRa signal source can send a chirp spread spectrum modulation signal using a single antenna. The chirp spread spectrum modulation signal uses CSS (Chirp Spread Spectrum) linear spread spectrum modulation. The frame structure of the chirp spread spectrum modulation signal sent by the transmitting end is shown in FIG. 2, which includes a preamble and a payload. The first part is a fixed N all-“1” signal used to eliminate carrier frequency offset at the receiver end. The second part is composed of 12.25 chirp symbols, which include 10 consecutive upchirp symbols and 2.25 downchirp symbols. The payload part is composed of M chirp symbols with random starting frequencies and linearly increasing frequencies over time. The upchirp symbol is a signal with a linearly increasing frequency over time, and the downchirp symbol is a signal with a linearly decreasing frequency over time. The LoRa signal source can send the chirp spread spectrum modulation signal to the receiver through a first communication channel h D The chirp spread spectrum modulation signal is sent to the receiver through a second communication channel h f The chirp spread spectrum modulation signal is sent to the target device.

[0065] As shown in FIG. 3, which is a time-frequency diagram of the chirp spread spectrum modulation signal in an embodiment, the horizontal axis represents time, and the vertical axis represents frequency. The frequency distribution of the signal is BW is the signal bandwidth. The frequency linearly sweeps through the entire bandwidth, so the anti-interference is very strong, and the resistance to multipath and Doppler effect is also very strong.

[0066] The backscatter device can be a single-antenna device that backscatters the chirp spread spectrum modulated signal and sends the reflected link signal to the receiver through the third communication channel. The backscatter device uses a binary phase shift keying (BPSK) modulation method to control the phase change of the incident signal by inputting different binary data: when "0" is sent, the phase of the incident signal is reversed by 180°, and when "1" is sent, the phase of the incident signal is not changed. The backscatter device sends a square wave signal with a frequency of 1 MHz, which is mapped through bipolar coding: bit "0" corresponds to "-1", and bit "1" corresponds to "1", i.e., a ±1 sequence. The signal source reaches the receiver through backscattering.

[0067] The expression of the transmitted signal of the backscatter device can be: BD (t)=h f (t-τ1)·x RF (t) BD (t)

[0068] where y BD (t) is the reflected link signal, h f is the second communication channel, s RF (t) is the frequency band signal of the chirp spread spectrum modulated signal, τ1 is the propagation time of the second communication channel, x BD (t) is a square wave signal with a frequency of 1 MHz, and the expression of x BD (t) can be:

[0069] The expression of the frequency band signal s RF (t) can be:

[0070] where s(t) is the baseband signal of the signal source, and f c is the carrier frequency.

[0071] The expression of the baseband signal of the signal source can be:

[0072] where f0 is the starting frequency of the chirp spread spectrum modulated signal, is the slope of the chirp spread spectrum modulated signal, T is the symbol period, and SF is the spreading factor of the chirp spread spectrum modulated signal.

[0073] The receiver can include multiple antennas, and the arrangement of the antennas can be a uniform linear array. Each antenna can receive the chirp spread spectrum modulated signal sent by the signal source through the first communication channel and the reflected link signal sent by the backscatter device through the third communication channel h GThe transmitted reflected link signal. Since the receiver employs multiple antennas for reception, the received reflected link signal contains angle information of the backscatter device.

[0074] The steering vector in the receiver can be:

[0075] where M is the number of antenna elements, the element spacing is λ is the carrier wavelength, and θ is the angle of incidence of the received signal.

[0076] The received signal of the receiver includes at least the direct link signal, the reflected link signal and the interference signal.

[0077] The expression of the received signal can be: y RF (t) = r direct + r BD + n(t)

[0078] where r direct is the direct link signal, r BD is the reflected link signal, and n(t) is the interference signal

[0079] The expression of the direct link signal r direct can be: r direct = ae h D · s RF (t-τ D )

[0080] where h D is the first communication channel, and τ D is the propagation time of the direct link signal.

[0081] The expression of the reflected link signal r BD can be: r BD = ae h BD · s RF (t-τ1-τ2)· x BD (t-τ2)

[0082] where ⊙ is the matrix dot product, h BD is the communication channel of the reflected link signal, and τ2 is the propagation time of the reflected link signal from the backscatter device to the receiver.

[0083] The expressions of the first communication channel h D , the third communication channel h G and the communication channel h BD of the reflected link signal can be respectively:

[0084] where h1, …, h Mchannel coefficients of the first communication channel; g1,..., g M signal coefficients of the third communication channel.

[0085] Since the receiver and the transmitter are separated, both are independent and there is no clock synchronization, there is a certain deviation in the carrier frequency of the receiver and the transmitter, so that the received baseband signal has a carrier frequency offset CFO, and the specific expression of the received signal received by the receiver can be:

[0086] wherein f CFO is the frequency of the carrier frequency offset.

[0087] In an exemplary embodiment, as shown in FIG. 4, a position-aware method is provided, which is applied to the receiver in FIG. 1 as an example, and includes the following steps 401 to 403. Among them:

[0088] Step 401, processing the received received signal to obtain a direct link signal corresponding to the signal source.

[0089] Among them, the direct link signal can be a signal received by the receiver through the first communication channel. The reflected link signal can be a signal received by the receiver through the third communication channel. The interference signal can be a signal generated by the signal being disturbed by other influencing factors during transmission.

[0090] In some embodiments, the receiver can receive the received signal, and since the reflected link signal is a signal reflected by the backscattering device, the signal of the reflected link signal is relatively weak compared with the direct link signal. The receiver can eliminate the reflected link signal of the received received signal as an interference signal based on the direct link communication demodulation algorithm, and eliminate the interference signal to obtain the direct link signal corresponding to the signal source.

[0091] Step 402, determining the reflected link signal from the received signal based on the serial interference cancellation strategy and the direct link signal.

[0092] In some embodiments, the receiver can eliminate the direct link signal in the received signal to obtain the reflected link signal through the serial interference cancellation strategy. The specific way to determine the reflected link signal can be to determine the difference between the received signal and the direct link signal as the reflected link signal. The expression of the reflected link signal received by the kth antenna in the receiver can be:

[0093] wherein y BD_k (t) is the reflected link signal received by the kth antenna, is a power attenuation factor, n k (t) is the interference signal received by the kth antenna.

[0094] In step 403, the reflection link signal is subjected to sensing parameter estimation to obtain position sensing data, and coordinate information of the target device is determined based on the position sensing data.

[0095] The position sensing data can represent angle information and distance information of the backscattering device. The target device can be the backscattering device.

[0096] In some embodiments, the receiver can employ a two-dimensional multiple signal classification (2D-MUSIC) algorithm to perform sensing parameter estimation on the reflection link signal, to determine the angle information and distance information of the backscattering device. The receiver can obtain the coordinate information of the backscattering device according to the estimated angle information and distance information of the backscattering device.

[0097] The above position sensing method can obtain the direct link signal by processing the received signal, eliminate the direct link signal in the received signal by a serial interference cancellation strategy to obtain the reflection link signal, and obtain the coordinate information of the target device by position sensing on the reflection link signal, so as to realize accurate positioning of the target device at a long distance, improve the accuracy of position sensing of the backscattering device, and also realize signal transmission and improve the utilization efficiency of the spectrum.

[0098] In an exemplary embodiment, the received received signal is processed to obtain a direct link signal corresponding to a signal source, including:

[0099] The received signal is subjected to preliminary processing to obtain a first received signal for each antenna, the first received signals are subjected to weighting processing to obtain a second received signal, and the second received signal is subjected to demodulation processing to obtain the direct link signal.

[0100] The receiver includes a plurality of antennas.

[0101] In some embodiments, for each antenna's received signal, the receiver can perform frame synchronization on the received signal based on a frame structure of the received signal, locate a preamble portion of the received signal according to the frame-synchronized received signal, and determine a start of a direct link signal frame when the receiver locates the preamble portion of the received signal. Since the receiver and the transmitter are separated, independent of each other and without clock synchronization, there is a certain deviation in the carrier frequencies of the receiver and the transmitter, and there is a carrier frequency offset (CFO) in the baseband signal received by the receiver. The receiver can estimate the deviation in the carrier frequencies to obtain a first received signal. The receiver can perform weighted sum processing on the first received signal corresponding to each antenna to obtain a second received signal. The receiver can obtain a starting frequency of the second received signal and map the starting frequency to a preset chip interval for demodulation processing to obtain the direct link signal.

[0102] In this embodiment, the multiple signals are combined into one signal for demodulation processing to obtain the direct link signal by performing weighted processing on the first received signals, which improves the signal-to-noise ratio of the received signal and improves the accuracy of the subsequent sensing backscatter device.

[0103] In an exemplary embodiment, for each antenna's received signal, the received signal is preliminarily processed to obtain a first received signal, including:

[0104] For each antenna's received signal, the received signal is frame-synchronized to obtain a frame-synchronized received signal, the frame-synchronized received signal is estimated for deviation to obtain a carrier frequency deviation value in the received signal, and the frame-synchronized received signal is processed based on the carrier frequency deviation value to obtain the first received signal.

[0105] In some embodiments, the receiver performs frame synchronization on the received signal on each antenna using the characteristics of the preamble of the chirp spread spectrum modulation signal. The receiver can locate the frame-synchronized received signal by receiving signals with the same starting frequency in succession. Since the receiver and the transmitter are separated, independent of each other and without clock synchronization, there is a certain deviation in the carrier frequencies of the receiver and the transmitter, and there is a carrier frequency offset (CFO) in the baseband signal received by the receiver. As shown in FIG. 2, the preamble portion in the direct link signal includes an all-“1” portion, and the receiver can obtain the received signal corresponding to the all-“1” preamble. The expression of the baseband signal received by the receiver can be:

[0106] wherein, is a power attenuation factor; n'(t) is a reflected link signal and an interference signal.

[0107] The receiver can calculate the product of the square sum of the received signal and the complex exponential function, and then perform a modulo operation on the result to obtain the estimation value of the CFO. The expression for estimating the carrier frequency offset can be:

[0108] where f s is the sampling frequency, N is the number of sampling points, y(k) is the complex value of the received signal on the kth subcarrier; R sym is the symbol rate, i.e., the number of symbols transmitted per second.

[0109] The receiver can eliminate the CFO in the received signal by the frequency of the carrier frequency offset to obtain the first received signal. For example, the CFO can be eliminated by adjusting the frequency of the local oscillator, and the specific elimination method is not limited herein.

[0110] In this embodiment, the frame synchronization is performed on the received signal, and the CFO of the received signal after the frame synchronization is eliminated to obtain the first received signal, thereby improving the accuracy of demodulating the received signal and improving the reliability in the data transmission process.

[0111] In an exemplary embodiment, the first received signals are weighted to obtain the second received signal, including:

[0112] The channel estimation is performed on the first received signal to obtain the channel gain value, and the channel gain value is determined as the weighting coefficient. Based on the weighting coefficient, the first received signals are weighted to obtain the second received signal.

[0113] In some embodiments, the receiver can perform signal estimation on the first received signal. For example, the receiver can use the least squares (LS) channel estimation method to perform channel estimation on the first received signal. The expression of the channel estimation can be:

[0114] where, is the channel gain value, y pre is the preamble part of the first received signal, x pre is the known preamble of the lora signal.

[0115] The receiver can use the maximum combining ratio to weight and sum the first received signals of multiple paths using the weighting coefficient to obtain the second received signal. In addition, the receiver can eliminate the interference signal in the signal transmission process by using the least mean square error estimation or other estimation algorithms.

[0116] In the embodiment, the first received signals are subjected to channel estimation, and weighted summation processing is performed on each first received signal to obtain a second received signal, and the multiple signals are combined into one signal by using a maximum combination ratio to increase the signal-to-noise ratio of the received signal and improve the accuracy of subsequent signal demodulation.

[0117] In an exemplary embodiment, frame synchronization is performed on the received signal to obtain a frame-synchronized received signal, including:

[0118] The received signal is subjected to low-pass filtering processing to obtain a filtered received signal, the filtered received signal is multiplied by the first downchirp signal to obtain a first calculation result, the first calculation result is subjected to fast Fourier processing to obtain multiple starting frequencies of the received signal, and if the number of consecutive identical starting frequencies reaches a preset number threshold, the frame-synchronized received signal is determined based on the preset number threshold.

[0119] The received signal includes a first downchirp signal (downchirp). The chirp symbol is a signal sweeping from the lowest frequency to the highest frequency.

[0120] In some embodiments, the receiver can perform low-pass filtering processing on the received signal to obtain a filtered received signal. The receiver multiplies the chirp symbol in the filtered received signal with the downchirp signal to obtain a first calculation result, and performs fast Fourier transformation on the first calculation result to obtain the starting frequency of each chirp symbol in the received signal. If the receiver detects that the number of consecutive identical starting frequencies reaches a preset number, the receiver determines that the frame-synchronized received signal is located. For example, as shown in FIG. 5, FIG. 5 is a frame-synchronized received signal in an embodiment. Since the preamble of the received signal contains 10 consecutive chirp symbols with the same starting frequency, by detecting the frequency value corresponding to the FFT peak value, if the starting frequencies corresponding to the consecutive 10 FFT peak values are the same, the positions of the 10 FFT peak values can be determined as the positions of the preamble signal, and based on this, the signal after the preamble signal can be determined as the frame-synchronized received signal.

[0121] In the embodiment, the frame-synchronized received signal is obtained through the frame structure of the received signal, so that the receiver can estimate the carrier frequency offset and synchronize and demodulate the direct link signal, thereby improving the bit error rate of the system and the positioning accuracy of the backscatter device.

[0122] In an exemplary embodiment, the second received signal is subjected to demodulation processing to obtain a direct link signal, including:

[0123] The second received signal is multiplied by the second down chirp signal to obtain a second calculation result; the second calculation result is subjected to fast Fourier processing to obtain a plurality of starting frequencies of the second received signal; and each starting frequency is mapped to a preset chip interval to determine the direct link signal.

[0124] The second received signal includes a down chirp. The preset chip interval can be 0-2 SF -1. SF is a spreading factor, and SF represents the number of information bits contained in each symbol, i.e., 1 symbol is spread to 2 SF chips for transmission.

[0125] In some embodiments, the receiver can multiply the chirp symbol in the second received signal with the down chirp to obtain a second calculation result, and subject the second calculation result to fast Fourier processing to obtain the starting frequency of each chirp symbol in the payload part of the second received signal. The starting frequencies of different chirp symbols can demodulate the information carried by the symbol. The receiver maps each starting frequency to 0-2 SF -1 to obtain a mapped value, compares the mapped value with a preset bit mapping table, and obtains the direct link signal.

[0126] In this embodiment, the starting frequencies of each chirp symbol in the second received signal are obtained, and the starting frequencies are mapped to 0-2 SF -1, which realizes demodulation of the direct link signal and ensures correct decoding of data.

[0127] In an exemplary embodiment, a sensing parameter estimation is performed on the reflection link signal to obtain position sensing data, including:

[0128] A plurality of singular eigenvalues in a signal covariance matrix of the reflection link signal are obtained; a singular eigenvector corresponding to a singular eigenvalue satisfying a preset condition is determined, and a steering vector orthogonal to a preset noise eigenvector is determined based on the singular eigenvector, and a two-dimensional spectrum peak search expression is determined based on the steering vector; a spectrum value of a preset coordinate position is calculated based on the two-dimensional spectrum peak search expression; a spectrum peak in a plurality of spectrum values is obtained through a spectrum peak search algorithm; and position information of the spectrum peak is determined as the position sensing data of the reflection link signal.

[0129] The preset coordinate position is an angle and a distance that the reflection scattering device can appear. The spectrum peak is a local maximum value.

[0130] In some embodiments, the receiver can calculate a signal covariance matrix of the reflection link signal, decompose the signal covariance matrix to obtain a plurality of singular eigenvalues, sort the plurality of singular eigenvalues, and select a singular eigenvector corresponding to a smaller singular eigenvalue; construct a steering vector orthogonal to a preset noise eigenvector, and determine a two-dimensional spectrum peak search expression with the steering vector as a denominator. The receiver can calculate the angle and distance that the reflection scattering device can appear through the two-dimensional spectrum peak search expression, obtain the spectrum value of the preset coordinate position, form a two-dimensional spectrum value matrix with the plurality of spectrum values, select the position corresponding to the spectrum peak in the two-dimensional spectrum value matrix, and determine the angle and distance corresponding to the position of the spectrum peak according to the position of the spectrum peak. The angle and distance corresponding to the spectrum peak are determined as the position perception data of the reflection link signal.

[0131] In the embodiment, the position perception data of the reflection link signal is determined based on the spectrum peak position, the spectrum peak position is found by calculating the reflection link signal, and the perception of the reflection link signal is realized, so that the reliability of the detection of the reflection link signal is improved in a long distance.

[0132] In an exemplary embodiment, the coordinate information of the target device is determined based on the position perception data, including:

[0133] The direction information, the distance information, and the distance information of the direct link signal are calculated according to a preset position algorithm to obtain the coordinate information of the backscattering device.

[0134] The preset position algorithm can be a triangular geometric position relationship. The position perception data includes the direction information of the target device relative to the receiver and the distance information of the reflection link signal, and the target device is the backscattering device.

[0135] In some embodiments, the receiver can obtain the distance L0 of the first communication channel between the signal source and the receiver through the direct link signal. The receiver calculates the distance L1 of the first communication channel and the distance L2 of the second communication channel based on the direction information of the target device relative to the receiver and the distance information of the reflection link signal Wherein L1 is the distance of the first communication channel, and L2 is the distance of the second communication channel. As shown in FIG. 6, FIG. 6 is a schematic diagram of the relative position relationship of the devices in the position perception system in an embodiment. The receiver can calculate the direction information, the distance information, and the distance information of the direct link signal according to a preset position algorithm to obtain the coordinate information of the backscattering device. In some embodiments, the calculation formula can be:

[0136] Wherein x is the horizontal coordinate of the plane where the backscattering device is located, and y is the vertical coordinate of the plane where the backscattering device is located.

[0137] In the embodiment, the coordinate information of the backscatter device is acquired through the position-aware data, the position awareness and coordinate estimation of the backscatter device are realized, and the accuracy of the backscatter device awareness is improved.

[0138] In an exemplary embodiment, the position-aware method is verified by using an analog system, and the parameters are set as follows: the system carrier frequency is 433 MHz, the bandwidth is 500 kHz, the spreading factor is SF=7, the distance between the transmitter and the receiver is 120 m, the distance between the transmitter and the backscatter device is 60 m, the distance between the backscatter device and the receiver is 90 m, the relative angle between the backscatter device and the receiver is 29°, the number of receiver antennas is 4 and 16, and the number of experiments is set to 3000.

[0139] FIG. 7 is a time-frequency diagram after short-time Fourier transform of the received signal in an embodiment. It can be observed that the direct link signal is much stronger than the reflected link signal. Secondly, since the backscatter device transmits a square wave signal of a certain frequency, the direct link signal will be frequency-shifted in the frequency spectrum. The reflected link signal corresponding to the first harmonic is much larger than other harmonics. Frame synchronization is performed on the above-mentioned received signal to estimate the start of the chirp spread signal frame. First, the received signal is low-pass filtered to reduce the influence of interference and noise on the direct link signal. Then, the signal is multiplied by the downchirp signal to eliminate the influence of the sweep signal, facilitating the extraction of the starting frequency. As shown in FIG. 5, it can be clearly observed that the starting frequencies of the continuous N symbols in the preamble are the same. The continuous two downchirp symbols can clearly distinguish the preamble part and the data part. The data part is modulated with random information of 0-2 SF -1, so the starting frequency is a random value in the starting frequency interval, and the start of the frame can be easily determined.

[0140] FIG. 8 shows the angle estimation error of the backscatter device under different signal-to-noise ratios using the MUSIC algorithm. The abscissa is the received signal-to-noise ratio (SNR), and the ordinate is the root mean square error (RMSE) of angle estimation. The relative angle between the backscatter device and the receiver is 29 degrees. The solid line with a circle represents the angle estimation error when the receiver has 4 antennas, and the solid line with a cross represents the angle estimation error when the receiver has 16 antennas. The signal-to-noise ratio is set to vary in the range of -20:5:20 (dB). It can be observed that the angle estimation error is stable at 2.2 degrees when the receiver has 4 antennas, and the angle estimation error is stable at 0.3 degrees when the receiver has 16 antennas.

[0141] Figure 9 shows the coordinate estimation error of the backscatter device under different signal-to-noise ratio conditions using the MUSIC algorithm. The horizontal axis is the signal-to-noise ratio of the reflected link signal received, and the vertical axis is the coordinate estimation RMSE. The relative angle between the backscatter device and the receiver is 29 degrees. The solid line with a circle represents a receiver with 4 antennas, and the solid line with a cross represents a receiver with 16 antennas. The signal-to-noise ratio is set to vary in the range of -20:5:20 (dB). It can be observed that the angle estimation error is stable at 5m for 4 antennas and 0.7m for 16 antennas.

[0142] In this embodiment, a long-distance, low-cost, and low-power location-aware system is provided using environmental LoRa signals. The backscatter device transmits a fixed frequency square wave signal, and the joint receiver can simultaneously recover the LoRa signal (direct link signal) and use the reflected link signal to perceive the location-aware parameters of the backscatter device, thereby estimating the coordinates of the backscatter device.

[0143] It should be understood that although the steps in the flowcharts involved in the above-described embodiments are shown in sequence according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified herein, the execution of these steps is not strictly limited in sequence, and these steps can be executed in other orders. Moreover, at least some of the steps in the flowcharts involved in the above-described embodiments can include multiple steps or stages, which are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily sequential, but can be alternately or alternately executed with at least some of the other steps or steps or stages in other steps.

[0144] Based on the same inventive concept, the embodiments of the present application also provide a location-aware device for implementing the above-mentioned location-aware method. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme described in the above method, so the specific limitations in one or more location-aware device embodiments provided below can refer to the limitations of the location-aware method described above, which will not be repeated here.

[0145] In an exemplary embodiment, as shown in Figure 10, a location-aware device is provided, and the location-aware device 100 includes a processing module 1001, a first determination module 1002, and a second determination module 1003, wherein:

[0146] The processing module 1001 is configured to process the received received signal to obtain a direct link signal corresponding to a signal source;

[0147] The first determination module 1002 is configured to determine, based on a serial interference cancellation strategy and the direct link signal, the reflection link signal from the received signal.

[0148] The second determination module 1003 is configured to perform sensing parameter estimation on the reflection link signal to obtain position sensing data, and determine coordinate information of the target device based on the position sensing data.

[0149] In one of the embodiments, the receiver includes a plurality of antennas, and the processing module 1001 is specifically configured to perform preliminary processing on the received signal of each antenna to obtain a first received signal.

[0150] The first received signals are weighted to obtain a second received signal.

[0151] The second received signal is demodulated to obtain the direct link signal.

[0152] In one of the embodiments, the processing module 1001 is specifically configured to perform frame synchronization on the received signal of each antenna to obtain a frame-synchronized received signal, perform bias estimation on the frame-synchronized received signal to obtain a carrier frequency bias value in the received signal, and perform processing on the frame-synchronized received signal based on the carrier frequency bias value to obtain the first received signal.

[0153] In one of the embodiments, the processing module 1001 is specifically configured to perform channel estimation on the first received signal to obtain a channel gain value, and determine the channel gain value as a weighting coefficient.

[0154] The first received signals are weighted based on the weighting coefficient to obtain the second received signal.

[0155] In one of the embodiments, the received signal includes a plurality of first uplink chirp signals and a first downlink chirp signal, and the processing module 1001 is specifically configured to perform low-pass filtering processing on the received signal to obtain a filtered received signal.

[0156] The filtered received signal is multiplied by the first downlink chirp signal to obtain a first calculation result.

[0157] The first calculation result is subjected to fast Fourier processing to obtain a starting frequency of each first uplink chirp signal in the received signal; and if a number of continuous identical starting frequencies of the first uplink chirp signals reaches a preset number threshold, the frame-synchronized received signal is determined based on the preset number threshold.

[0158] In one of the embodiments, the second received signal includes a plurality of second uplink chirp signals and a second downlink chirp signal, and the processing module 1001 is specifically configured to multiply the second received signal by the second downlink chirp signal to obtain a second calculation result.

[0159] The second calculation result is subjected to fast Fourier transform to obtain a starting frequency of each second uplink chirp signal in the second received signal.

[0160] The starting frequency of each second uplink chirp signal is mapped to a preset chip interval to determine the direct link signal.

[0161] In one of the embodiments, the second determining module 1003 is configured to obtain a plurality of singular eigenvalues in a signal covariance matrix of the reflected link signal.

[0162] The singular eigenvector corresponding to the singular eigenvalue satisfying the preset condition is determined, and a steering vector orthogonal to a preset noise eigenvector is determined based on the singular eigenvector, and a two-dimensional spectrum peak search expression is determined based on the steering vector.

[0163] The spectrum value of the preset coordinate position is calculated based on the two-dimensional spectrum peak search expression, the spectrum peak in the plurality of spectrum values is obtained through a spectrum peak search algorithm, and the position information of the spectrum peak is determined as the position perception data of the reflected link signal.

[0164] In one of the embodiments, the position perception data includes direction information of the target device relative to the receiver and distance information of the reflected link signal, the target device is a backscattering device, and the second determining module 1003 is configured to calculate the direction information, the distance information and the distance information of the direct link signal according to a preset position algorithm to obtain coordinate information of the backscattering device.

[0165] Each of the above position perception devices can be realized by software, hardware and a combination thereof in whole or in part. Each of the above modules can be embedded in or independent of a processor in a computer device in a hardware form, or can be stored in a memory in the computer device in a software form, so as to be called and executed by a processor to perform the operations corresponding to each of the above modules.

[0166] In an example embodiment, a computer device is provided, which can be a terminal, and an internal structure diagram of the computer device can be as shown in FIG. 11. The computer device includes a processor, a memory, an input / output interface, a communication interface, a display unit and an input device. Among them, the processor, the memory and the input / output interface are connected through a system bus, and the communication interface, the display unit and the input device are connected to the system bus through the input / output interface. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operating system and the computer program in the non-volatile storage medium to run. The input / output interface of the computer device is used to exchange information between the processor and external devices. The communication interface of the computer device is used to communicate with external terminals in a wired or wireless manner, and the wireless manner can be achieved through WIFI, mobile cellular network, near field communication (NFC) or other technologies. The computer program is executed by the processor to implement a position sensing method. The display unit of the computer device is used to form a visually visible picture, which can be a display screen, a projection device or a virtual reality imaging device. The display screen can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device can be a touch layer overlaid on the display screen, or a key, trackball or touchpad arranged on the shell of the computer device, or an external keyboard, touchpad or mouse, etc.

[0167] Those skilled in the art can understand that the structure shown in FIG. 11 is only a block diagram of part of the structure related to the scheme of the present application, and does not constitute a limitation on the computer device to which the scheme of the present application is applied. A specific computer device can include more or fewer components than those shown in the figure, or combine certain components, or have a different component arrangement.

[0168] In an example embodiment, a computer device is provided, which includes a memory and a processor, and the memory stores a computer program. The processor executes the computer program to implement the steps in the above method embodiments.

[0169] In an example embodiment, a computer readable storage medium is provided, which stores a computer program. The computer program is executed by a processor to implement the steps in the above method embodiments.

[0170] In an example embodiment, a computer program product is provided, which includes a computer program. The computer program is executed by a processor to implement the steps in the above method embodiments.

[0171] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a non-volatile computer readable storage medium, and when executed, can include the processes of the above-mentioned embodiment methods. Any reference to memory, database or other medium used in the embodiments provided in the present application can include at least one of non-volatile memory and volatile memory. The non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magneto resistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. The volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration but not limitation, the RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc. The database involved in the embodiments provided in the present application can include at least one of a relational database and a non-relational database. The non-relational database can include a distributed database based on a block chain, etc., without being limited thereto. The processor involved in the embodiments provided in the present application can be a general-purpose processor, a central processing unit, a graphics processing unit, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, an artificial intelligence (AI) processor, etc., without being limited thereto.

[0172] The technical features of the above embodiments can be combined in any manner. To make the description concise, not all possible combinations of the technical features in the above embodiments are described, but as long as the combinations of the technical features do not exist contradictions, they should be considered as the scope of the present application.

[0173] The above-described embodiments are merely illustrative of several embodiments of the present application, and the description is relatively specific and detailed, but should not be understood as a limitation on the scope of the patent. It should be noted that for those skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are all within the scope of the present application. Therefore, the scope of protection of the present application should be subject to the appended claims.

Claims

1. A position sensing method applied to a receiver, the method comprising: processing a received receive signal to obtain a direct link signal corresponding to a signal source; determining a reflected link signal from the receive signal based on a serial interference cancellation strategy and the direct link signal; performing sensing parameter estimation on the reflected link signal to obtain position sensing data, and determining coordinate information of a target device based on the position sensing data.

2. The method of claim 1, wherein, The receiver comprises a plurality of antennas, and the processing the received receive signal to obtain a direct link signal corresponding to a signal source comprises: performing preliminary processing on the receive signal of each antenna to obtain a first receive signal; performing weighted processing on each first receive signal to obtain a second receive signal; performing demodulation processing on the second receive signal to obtain a direct link signal.

3. The method of claim 2, wherein, The performing preliminary processing on the receive signal of each antenna to obtain a first receive signal comprises: performing frame synchronization on the receive signal of each antenna to obtain a frame-synchronized receive signal, performing bias estimation on the frame-synchronized receive signal to obtain a carrier frequency bias value in the receive signal, and performing processing on the frame-synchronized receive signal based on the carrier frequency bias value to obtain a first receive signal.

4. The method of claim 2, wherein, The performing weighted processing on each first receive signal to obtain a second receive signal comprises: performing channel estimation on the first receive signal to obtain a channel gain value, and determining the channel gain value as a weighting coefficient; performing weighted processing on each first receive signal based on the weighting coefficient to obtain a second receive signal.

5. The method of claim 3, wherein, The receive signal comprises a first downlink chirp signal, and the performing frame synchronization on the receive signal to obtain a frame-synchronized receive signal comprises: performing low-pass filtering processing on the receive signal to obtain a filtered receive signal; multiplying the filtered receive signal by the first downlink chirp signal to obtain a first calculation result; performing fast Fourier processing on the first calculation result to obtain a plurality of starting frequencies of the receive signal; and if a number of continuous identical starting frequencies reaches a preset number threshold, determining a frame-synchronized receive signal based on the preset number threshold.

6. The method of claim 2, wherein, The second receive signal comprises a second downlink chirp signal, and the performing demodulation processing on the second receive signal to obtain a direct link signal comprises: multiplying the second receive signal by the second downlink chirp signal to obtain a second calculation result; performing fast Fourier processing on the second calculation result to obtain a plurality of starting frequencies in the second receive signal; mapping each starting frequency to a preset chip interval to determine a direct link signal.

7. The method of claim 1, wherein, The performing sensing parameter estimation on the reflected link signal to obtain position sensing data comprises: obtaining a plurality of singular eigenvalues in a signal covariance matrix of the reflected link signal; determine a singular eigenvector corresponding to a singular eigenvalue satisfying a preset condition, determine a steering vector orthogonal to a preset noise eigenvector based on the singular eigenvector, and determine a two-dimensional spectral peak search expression based on the steering vector; calculate spectral values of preset coordinate positions based on the two-dimensional spectral peak search expression, obtain spectral peaks in the spectral values by a spectral peak search algorithm, and determine position information of the spectral peaks as position sensing data of the reflection link signal.

8. The method of claim 1, wherein, The position sensing data includes direction information of the target device relative to the receiver and distance information of the reflection link signal, the target device is a backscattering device, and the coordinate information of the target device is determined based on the position sensing data, including: calculating the direction information, the distance information, and distance information of the direct link signal according to a preset position algorithm to obtain coordinate information of the backscattering device.

9. The method of claim 1, wherein, The reflection link signal includes a plurality of harmonic components generated by modulating a back wave signal by the target device, and the sensing parameter estimation on the reflection link signal includes sensing parameter estimation based on a first harmonic component in the plurality of harmonic components.

10. The method of claim 1, wherein, The reflection link signal is generated by modulating and reflecting an incident radio frequency signal by the target device using a binary phase shift keying modulation method.

11. A position sensing device applied to a receiver, the device comprising: a processing module configured to process a received signal to obtain a direct link signal corresponding to a signal source; a first determining module configured to determine a reflection link signal from the received signal based on a serial interference cancellation strategy and the direct link signal; a second determining module configured to perform sensing parameter estimation on the reflection link signal to obtain position sensing data, and determine coordinate information of a target device based on the position sensing data.

12. A computer device comprising a memory and a processor, the memory storing a computer program, wherein, The processor implements the steps of the method of any one of claims 1 to 10 when executing the computer program.

13. A computer readable storage medium having stored thereon a computer program, wherein, The computer program, when executed by the processor, implements the steps of the method of any one of claims 1 to 10.

14. A computer program product comprising a computer program, wherein, The computer program, when executed by the processor, implements the steps of the method of any one of claims 1 to 10. The computer program, when executed by the processor, implements the steps of the method of any one of claims 1 to 10.

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