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

Abstract

The invention relates to a position sensing method and device, computer equipment, a readable storage medium and a program product. The method is applied to a receiver, and comprises the following steps: processing a received receiving signal to obtain a direct link signal corresponding to a signal source; determining a reflected link signal from the received signal based on a serial interference cancellation strategy and the direct link signal; performing sensing parameter estimation on the reflection link signal to obtain position sensing data; and determining coordinate information of the target device based on the position sensing data. By adopting the method, the position sensing accuracy of the reflection and scattering equipment can be improved.

Description

Technical Field

[0001] The present application relates to the field of wireless communication technology, and in particular to a location sensing method, apparatus, computer equipment, readable storage medium and program product. Background Art

[0002] With the advancement of low-power and low-cost wireless technologies, wireless communication systems are developing rapidly in many fields such as Industry 4.0 and smart homes. Backscatter communication technology is a key technology for low-power wireless communication systems. In backscatter communication systems, data is transmitted by modulating and reflecting the received RF signals through backscattering devices.

[0003] In the related technologies, various wireless technologies have been used for indoor positioning, including Wireless Fidelity (WiFi), Ultra Wide Band (UWB), Bluetooth Low Energy (BLE), Radio Frequency Identification (RFID), etc. Since the reflection scattering communication system needs to use the weaker signal reflected by the target for perception and positioning, when the reflection scattering communication system is used outdoors and needs to realize long-distance target perception, the accuracy of the position perception of the reflection scattering device is low. Summary of the invention

[0004] Based on this, it is necessary to provide a position sensing method, device, computer equipment, readable storage medium and program product that can improve the accuracy of position sensing of reflection and scattering devices in response to the above technical problems.

[0005] In a first aspect, the present application provides a location awareness method, applied to a receiver, comprising:

[0006] Processing the received signal to obtain a direct link signal corresponding to the signal source;

[0007] determining a reflected link signal from the received signal based on a serial interference cancellation strategy and the direct link signal;

[0008] The sensing parameters of the reflected link signal are estimated to obtain position sensing data; and the coordinate information of the target device is determined based on the position sensing data.

[0009] In one embodiment, the receiver includes multiple antennas, and the processing of the received received signal to obtain the direct link signal corresponding to the signal source includes:

[0010] For each antenna receiving signal, preliminarily processing the receiving signal to obtain a first receiving signal;

[0011] Performing weighted processing on each of the first received signals to obtain a second received signal;

[0012] The second received signal is demodulated to obtain a direct link signal.

[0013] In one embodiment, the step of performing preliminary processing on the received signal of each antenna to obtain a first received signal includes:

[0014] For the received signal on each antenna, the received signal is frame synchronized to obtain the received signal after frame synchronization; the deviation of the received signal after frame synchronization is estimated to obtain the carrier frequency deviation value in the received signal; and the received signal after frame synchronization is processed based on the carrier frequency deviation value to obtain a first received signal.

[0015] In one embodiment, performing weighted processing on each of the first received signals to obtain a second received signal includes:

[0016] Performing channel estimation on the first received signal to obtain a channel gain value, and determining the channel gain value as a weighting coefficient;

[0017] Based on the weighting coefficients, each of the first received signals is weighted to obtain a second received signal.

[0018] In one embodiment, the received signal includes a first downlink linear frequency modulation signal, and the step of performing frame synchronization on the received signal to obtain a frame-synchronized received signal includes:

[0019] Performing low-pass filtering on the received signal to obtain a filtered received signal;

[0020] multiplying the filtered received signal by the first downlink linear frequency modulation signal to obtain a first calculation result;

[0021] The first calculation result is subjected to fast Fourier processing to obtain a plurality of starting frequencies of the received signal; if the number of consecutive identical starting frequencies reaches a preset number threshold, the received signal after frame synchronization is determined based on the preset number threshold.

[0022] In one embodiment, the second received signal includes a second downlink linear frequency modulation signal, and the demodulating the second received signal to obtain a direct link signal includes:

[0023] multiplying the second received signal by the second downlink linear frequency modulation signal to obtain a second calculation result;

[0024] Performing fast Fourier processing on the second calculation result to obtain multiple starting frequencies of the second received signal;

[0025] Each of the starting frequencies is mapped to a preset chip interval to determine a direct link signal.

[0026] In one embodiment, the estimating the sensing parameters of the reflected link signal to obtain the position sensing data includes:

[0027] Acquire a plurality of singular eigenvalues ​​in a signal covariance matrix of the reflection link signal;

[0028] Determine a singular eigenvector corresponding to a singular eigenvalue that meets a preset condition, determine a steering vector orthogonal to a preset noise eigenvector based on the singular eigenvector, and determine a two-dimensional spectrum peak search expression based on the steering vector;

[0029] The spectrum value of the preset coordinate position is calculated based on the two-dimensional spectrum peak search expression; the spectrum peak among the multiple spectrum values ​​is obtained through the spectrum peak search algorithm; and the position information of the spectrum peak is determined as the position perception data of the reflection link signal.

[0030] In one embodiment, the location sensing 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 determining the coordinate information of the target device based on the location sensing data includes:

[0031] The direction information, the distance information and the distance information of the direct link signal are calculated according to a preset location algorithm to obtain coordinate information of the backscatter device.

[0032] In a second aspect, the present application also provides a location sensing device, including:

[0033] A processing module, used for processing the received signal to obtain a direct link signal corresponding to the signal source;

[0034] A first determination module, configured to determine a reflected link signal from the received signal based on a serial interference cancellation strategy and the direct link signal;

[0035] The second determination module is used to estimate the perception parameters of the reflection link signal to obtain position perception data; and determine the coordinate information of the target device based on the position perception data.

[0036] In a third aspect, the present application further provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the following steps are implemented:

[0037] Processing the received signal to obtain a direct link signal corresponding to the signal source;

[0038] determining a reflected link signal from the received signal based on a serial interference cancellation strategy and the direct link signal;

[0039] The sensing parameters of the reflected link signal are estimated to obtain position sensing data; and the coordinate information of the target device is determined based on the position sensing data.

[0040] In a fourth aspect, 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 following steps are implemented:

[0041] Processing the received signal to obtain a direct link signal corresponding to the signal source;

[0042] determining a reflected link signal from the received signal based on a serial interference cancellation strategy and the direct link signal;

[0043] The sensing parameters of the reflected link signal are estimated to obtain position sensing data; and the coordinate information of the target device is determined based on the position sensing data.

[0044] In a fifth aspect, the present application further provides a computer program product, including a computer program, which implements the following steps when executed by a processor:

[0045] Processing the received signal to obtain a direct link signal corresponding to the signal source;

[0046] determining a reflected link signal from the received signal based on a serial interference cancellation strategy and the direct link signal;

[0047] The sensing parameters of the reflected link signal are estimated to obtain position sensing data; and the coordinate information of the target device is determined based on the position sensing data.

[0048] The above-mentioned position sensing method, device, computer equipment, readable storage medium and program product obtain a direct link signal by processing the received signal; eliminate the direct link signal in the received signal through a serial interference elimination strategy to obtain a reflected link signal; and obtain the coordinate information of the target device by performing position sensing on the reflected link signal to achieve accurate positioning of the target device at a long distance. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the drawings required for use in the embodiments of the present application or related technical descriptions will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0050] FIG1 is a schematic diagram of the structure of a position sensing system in one embodiment;

[0051] FIG2 is a frame structure of a chirp spread spectrum modulation signal in one embodiment;

[0052] FIG3 is a time-frequency diagram of a chirp spread spectrum modulation signal in one embodiment;

[0053] FIG4 is a schematic diagram of a flow chart of a location sensing method in one embodiment;

[0054] FIG5 is a schematic diagram of a received signal after frame synchronization in one embodiment;

[0055] FIG6 is a schematic diagram of the relative position relationship of various devices in a position sensing system according to an embodiment;

[0056] FIG7 is a time-frequency diagram of a received signal after short-time Fourier transformation in one embodiment;

[0057] FIG8 is a schematic diagram of an embodiment of an angle estimation error of a backscattering device using a MUSIC algorithm under different signal-to-noise ratio conditions;

[0058] FIG9 is a schematic diagram of using the MUSIC algorithm to estimate the coordinate error of a backscattering device under different signal-to-noise ratio conditions in one embodiment;

[0059] FIG10 is a block diagram of a location sensing device in one embodiment;

[0060] FIG. 11 is a diagram showing the internal structure of a computer device in one embodiment. DETAILED DESCRIPTION

[0061] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0062] The location sensing method provided in the embodiment of the present application can be applied to the location sensing system shown in FIG1. ​​The location 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 backscattering device.

[0063] The LoRa signal source can use a single antenna to send a chirp spread spectrum modulated signal. The chirp spread spectrum modulated signal uses CSS (Chirp Spread Spectrum) linear spread spectrum modulation. The frame structure of the chirp spread spectrum modulated signal sent by the transmitter is shown in Figure 2, which includes a preamble and a payload. The first part is a fixed N all-"1" signal used to eliminate the carrier frequency offset at the receiver end. The second part is composed of 12.25 fixed chirp symbols. The chirp symbol includes 10 consecutive upchirp symbols and 2.25 downchirp symbols. The load part is composed of M chirp symbols with random starting frequencies and linearly increasing frequencies over time. The upchirp symbol is a signal whose frequency increases linearly over time, and the downchirp symbol is a signal whose frequency decreases linearly over time. The LoRa signal source can be transmitted through the first communication channel h D Sending a chirp spread spectrum modulated signal to the receiver and transmitting the chirp spread spectrum modulated signal to the receiver through the second communication channel h f Send a chirp spread spectrum modulated signal to the target device.

[0064] As shown in FIG. 3 , FIG. 3 is a time-frequency diagram of a chirp spread spectrum modulation signal in an embodiment, wherein the horizontal axis represents time, the vertical axis represents frequency, and the frequency distribution of the signal is: , BW is the signal bandwidth. The frequency is swept linearly across the entire bandwidth, so it is highly resistant to interference and is also highly resistant to multipath and Doppler effects.

[0065] The backscattering 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 backscattering device uses binary phase shift keying (BPSK) modulation to control the change of the phase of the incident signal by inputting different binary data: when sending "0", the phase of the incident signal is reversed by 180°, and when sending "1", the phase of the incident signal is not changed. The backscattering device sends a square wave signal with a frequency of 1MHz. After bipolar coding mapping, bit "0" corresponds to "-1", and bit "1" corresponds to "1", that is, a ±1 sequence. The signal source reaches the receiver after backscattering.

[0066] The expression of the transmitted signal of the backscatter device can be:

[0067]

[0068] Among them, 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 modulation signal, τ 1 is the propagation time of the second communication channel, x BD (t) is a square wave signal with a frequency of 1Mhz, x BD The expression of (t) can be:

[0069]

[0070] Frequency band signal RF The expression of (t) can be:

[0071]

[0072] Among them, s(t) is the baseband signal of the signal source, f c is the carrier frequency.

[0073] The expression of the baseband signal of the signal source can be:

[0074]

[0075] in, is the starting frequency of the chirp spread spectrum modulation signal, is the slope of the chirp spread spectrum modulation signal. T is the symbol period, and SF is the spreading factor of the chirp spread spectrum modulation signal.

[0076] The receiver may include multiple antennas, and the antenna arrangement may be a uniform linear array. Each antenna may receive a chirp spread spectrum modulated signal sent by a signal source through a first communication channel and a chirp spread spectrum modulated signal sent by a backscattering device through a third communication channel. G The transmitted reflected link signal. Since the receiver uses multiple antennas for reception, the received reflected link signal contains the angle information of the backscattering device.

[0077] The steering vector in the receiver can be:

[0078]

[0079] Among them, M is the number of antenna elements, and the element spacing is , , λ is the carrier wavelength, θ is the incident angle of the received signal.

[0080] The received signal of the receiver includes at least a direct link signal, a reflected link signal and an interference signal.

[0081] The expression of the received signal can be:

[0082]

[0083] Among them, r direct is the direct link signal, r BD is the reflection link signal, n(t) is the interference signal

[0084] Direct link signal direct The expression can be:

[0085]

[0086] Among them, h D is the first communication channel, τ D is the propagation time of the direct link signal.

[0087] Reflected link signal r BD The expression can be:

[0088]

[0089] in, is the matrix dot product, h BD is the communication channel of the reflection link signal, τ 2 is the propagation time of the reflection link signal from the backscatter device to the receiver.

[0090] The first communication channel h D , the third communication channel h G and the communication channel h of the reflected link signal BD The expressions can be:

[0091] , ,

[0092] Among them, h 1 ,……,h M is the channel coefficient of the first communication channel; g 1 ,……,g M is the signal coefficient of the third communication channel.

[0093] Since the receiver and transmitter are separated, independent of each other and without clock synchronization, there is a certain deviation between the carrier frequencies of the receiver and the transmitter, resulting in a carrier frequency offset CFO in the received baseband signal. The specific expression of the received signal received by the receiver can be:

[0094]

[0095] Among them, fCFO is the frequency of the carrier frequency offset.

[0096] In an exemplary embodiment, as shown in FIG4 , a location awareness method is provided, which is described by taking the method applied to the receiver in FIG1 as an example, and includes the following steps 401 to 403. Among them:

[0097] Step 401: Process the received signal to obtain a direct link signal corresponding to the signal source.

[0098] The direct link signal may be a signal received by the receiver through the first communication channel. The reflected link signal may be a signal received by the receiver through the third communication channel. The interference signal may be a signal generated by interference from other influencing factors during the transmission process.

[0099] Specifically, the receiver can receive the received signal. Since the reflected link signal is a signal reflected by the backscattering device, the reflected link signal is relatively weaker than the direct link signal. The receiver can remove the reflected link signal of the 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.

[0100] Step 402: Determine a reflected link signal from a received signal based on a serial interference cancellation strategy and a direct link signal.

[0101] Specifically, the receiver can eliminate the direct link signal in the received signal through a serial interference elimination strategy to obtain a reflected link signal. A specific method for determining 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:

[0102]

[0103] Among them, y BD_k (t) is the reflected link signal received by the kth antenna, is the power reduction factor, n k (t) is the interference signal received by the kth antenna.

[0104] Step 403: Estimate the perception parameters of the reflected link signal to obtain position perception data; and determine the coordinate information of the target device based on the position perception data.

[0105] The location sensing data may represent the angle information and distance information of the backscattering device. The target device may be a backscattering device.

[0106] Specifically, the receiver can use a 2D-MUSIC (Multiple Signal Classification) algorithm to estimate the perception parameters of the reflected link signal and determine the angle information and distance information of the backscattering device. The receiver can obtain the coordinate information of the backscattering device based on the estimated angle information and distance information of the backscattering device.

[0107] The above-mentioned position sensing method obtains a direct link signal by processing the received signal; eliminates the direct link signal in the received signal through a serial interference elimination strategy to obtain a reflected link signal; obtains the coordinate information of the target device by performing position sensing on the reflected link signal, so as to achieve accurate positioning of the target device at a long distance, improve the accuracy of position sensing of the reflected scattering device, and at the same time realize signal transmission, thereby improving the utilization efficiency of the spectrum.

[0108] In an exemplary embodiment, processing a received signal to obtain a direct link signal corresponding to a signal source includes:

[0109] For the received signal of each antenna, the received signal is preliminarily processed to obtain a first received signal; each first received signal is weighted to obtain a second received signal; and the second received signal is demodulated to obtain a direct link signal.

[0110] The receiver includes multiple antennas.

[0111] Specifically, for the received signal of each antenna, based on the frame structure of the received signal, the receiver can perform frame synchronization on the received signal, and locate the leading part of the received signal according to the received signal after frame synchronization. When the receiver locates the leading part of the received signal, the start of the direct link signal frame is determined. Since the receiver and the transmitter are separated, the two are independent of each other and there is no clock synchronization, there is a certain deviation between the carrier frequencies of the receiver and the transmitter, and the baseband signal received by the receiver has a carrier frequency offset (Carrier Frequency Offset, CFO). The receiver can estimate the deviation of the carrier frequency to obtain a first received signal. The receiver can perform weighted summation processing on the first received signal corresponding to each antenna to obtain a second received signal. The receiver can obtain the starting frequency of the second received signal, and map the starting frequency to a preset code chip interval for demodulation processing to obtain a direct link signal.

[0112] In this embodiment, by performing weighted processing on each first received signal, multiple signals are combined into one signal and then demodulated to obtain a direct link signal, thereby improving the signal-to-noise ratio of the received signal and improving the accuracy of subsequent perception backscattering equipment.

[0113] In an exemplary embodiment, for a received signal of each antenna, preliminarily processing the received signal to obtain a first received signal includes:

[0114] For the received signal on each antenna, the received signal is frame synchronized to obtain the received signal after frame synchronization; the deviation of the received signal after frame synchronization is estimated to obtain the carrier frequency deviation value in the received signal, and the received signal after frame synchronization is processed based on the carrier frequency deviation value to obtain the first received signal.

[0115] Specifically, the receiver uses the characteristics of the chirped spread spectrum modulated signal preamble to perform frame synchronization on the received signal on each antenna. The receiver can locate the received signal through continuous identical starting frequencies and determine the received signal after frame synchronization. Since the receiver and transmitter are separated, the two are independent of each other and there is no clock synchronization, there is a certain deviation between the carrier frequencies of the receiver and the transmitter, and the baseband signal received by the receiver has a carrier frequency offset (CFO). As shown in Figure 2, the preamble part in the direct link signal contains an all-"1" part. The receiver can intercept the received signal corresponding to the all-"1" preamble, and the expression of the baseband signal received by the receiver can be:

[0116]

[0117] in, is the power attenuation factor; is the reflected link signal and the interference signal.

[0118] 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 an estimated value of CFO. The expression for estimating the carrier frequency offset can be:

[0119]

[0120] Among them, 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 subcarrier; R sym is the symbol rate, which is the number of symbols transmitted per second.

[0121] The receiver may eliminate the CFO in the received signal by using the frequency of the carrier frequency offset to obtain the first received signal. For example, the CFO may be eliminated by adjusting the frequency of the local oscillator. The specific elimination method is not limited here.

[0122] In this embodiment, by performing frame synchronization on the received signal and eliminating the CFO of the received signal after frame synchronization, a first received signal is obtained, thereby improving the accuracy of demodulating the received signal and improving the reliability of the data transmission process.

[0123] In an exemplary embodiment, weighted processing is performed on each first received signal to obtain a second received signal, including:

[0124] Channel estimation is performed on the first received signal to obtain a channel gain value, and the channel gain value is determined as a weighting coefficient; based on the weighting coefficient, each first received signal is weighted to obtain a second received signal.

[0125] Specifically, the receiver may perform signal estimation on the first received signal. For example, the receiver may perform channel estimation on the first received signal using a least squares (LS) channel estimation method. The expression of the channel estimation may be:

[0126]

[0127] in, is the channel gain value, y pre is the leading part of the first received signal, x pre It is a known preamble for the LoRa signal.

[0128] The receiver can use the weighting coefficient to perform weighted summation on the multi-path first received signals in a maximum combining ratio manner to obtain the second received signal. In addition, the receiver can eliminate interference signals in the signal transmission process by using minimum mean square error estimation or other estimation algorithms.

[0129] In this embodiment, the second received signal is obtained by performing channel estimation on the first received signal and performing weighted summation processing on each first received signal, and the multi-path signals are combined into one signal using the maximum combining ratio to increase the signal-to-noise ratio of the received signal and improve the accuracy of subsequent signal demodulation.

[0130] In an exemplary embodiment, performing frame synchronization on a received signal to obtain a frame-synchronized received signal includes:

[0131] The received signal is low-pass filtered to obtain a filtered received signal; the filtered received signal is multiplied by a first downlink linear frequency modulation signal to obtain a first calculation result; the first calculation result is fast Fourier processed to obtain multiple starting frequencies of the received signal; if the number of consecutive identical starting frequencies reaches a preset number threshold, the received signal after frame synchronization is determined based on the preset number threshold.

[0132] The received signal includes a first downlink linear frequency modulation signal (downchirp). The chirp symbol is a signal that sweeps from the lowest frequency to the highest frequency.

[0133] Specifically, the receiver can perform low-pass filtering on the received signal to obtain a received signal after filtering. The receiver multiplies the chirp symbol in the received signal after filtering by the downchirp signal to obtain a first calculation result, performs a fast Fourier transform on the first calculation result, and obtains 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, it determines that the received signal after frame synchronization is located. For example, as shown in Figure 5, Figure 5 is a received signal after frame synchronization in one 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 signal peak after FFT, if the starting frequencies corresponding to 10 consecutive FFT peaks are the same, the positions of the 10 FFT peaks 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 received signal after frame synchronization.

[0134] In this embodiment, the frame structure of the received signal is used to obtain the received signal after frame synchronization, so that the receiver can estimate the carrier frequency offset and synchronize and demodulate the direct link signal, thereby improving the system bit error rate and the positioning accuracy of the backscatter device.

[0135] In an exemplary embodiment, demodulating the second received signal to obtain a direct link signal includes:

[0136] The second received signal is multiplied by the second downlink linear frequency modulation signal to obtain a second calculation result; the second calculation result is fast Fourier processed to obtain multiple starting frequencies of the second received signal; each starting frequency is mapped to a preset code chip interval to determine a direct link signal.

[0137] The second received signal includes a second downlink linear frequency modulation signal (downchirp). The preset chip area can be 0~2 SF -1. SF is the spreading factor, which indicates the number of information bits contained in each symbol, that is, 1 symbol is spread to 2 SF Transmitted on one chip.

[0138] Specifically, the receiver can multiply the chirp symbol in the second received signal by downchirp to obtain a second calculation result, perform fast Fourier processing on the second settlement structure, and 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 be demodulated to obtain the information carried by the symbol. The receiver maps each starting frequency to 0~2 SF -1, obtain the mapped value, and compare the mapped value with the preset bit mapping table to obtain the direct link signal.

[0139] In this embodiment, the present application maps the starting frequency of each chirp symbol in the second received signal to 0~2 SF -1, realizes the demodulation of direct link signal and ensures the correct decoding of data.

[0140] In an exemplary embodiment, estimating a sensing parameter of a reflection link signal to obtain position sensing data includes:

[0141] Acquire multiple singular eigenvalues ​​in the signal covariance matrix of the reflection link signal; determine the singular eigenvectors corresponding to the singular eigenvalues ​​that meet the preset conditions, and determine the steering vector orthogonal to the preset noise eigenvector based on the singular eigenvector, and determine the two-dimensional spectrum peak search expression based on the steering vector; calculate the spectrum value of the preset coordinate position based on the two-dimensional spectrum peak search expression; obtain the spectrum peak among the multiple spectrum values ​​through the spectrum peak search algorithm; determine the position information of the spectrum peak as the position perception data of the reflection link signal.

[0142] The preset coordinate position is the angle and distance where the reflection scattering device may appear. The spectrum peak is the local maximum value.

[0143] Specifically, the receiver can calculate the signal covariance matrix of the reflected link signal, decompose the signal covariance matrix, and obtain multiple singular eigenvalues; sort the multiple singular eigenvalues, select the singular eigenvectors corresponding to the smaller singular eigenvalues; construct a steering vector orthogonal to the preset noise eigenvector, and use the steering vector as the denominator to determine the two-dimensional spectrum peak search expression. The receiver can calculate the angle and distance that the reflected scattering device may appear through the two-dimensional spectrum peak search expression to obtain the spectrum value of the preset coordinate position, and form a two-dimensional spectrum value matrix with multiple 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 reflected link signal.

[0144] In this embodiment, the reflection link signal is calculated to find the spectrum peak position, and the position perception data of the reflection link signal is determined based on the spectrum peak position, thereby realizing the perception of the reflection link signal, thereby improving the reliability of the reflection link signal detection at a longer distance.

[0145] In an exemplary embodiment, determining coordinate information of a target device based on location awareness data includes:

[0146] According to a preset location algorithm, the direction information, distance information and distance information of the direct link signal are calculated to obtain the coordinate information of the backscatter device.

[0147] The preset location algorithm may be a triangular geometric location relationship. The location sensing data includes direction information of the target device relative to the receiver and distance information of the reflected link signal, and the target device is a backscattering device.

[0148] Specifically, the receiver can obtain the distance L of the first communication channel between the signal source and the receiver through the direct link signal. 0 The receiver uses the target device's orientation information relative to the receiver. and distance information of reflected link signal , where L 1 is the distance of the first communication channel, L 2 is the distance of the second communication channel. As shown in FIG6 , FIG6 is a schematic diagram of the relative position relationship of each device in a position sensing system in an embodiment. The receiver can calculate the direction information, distance information and distance information of the direct link signal according to a preset position algorithm to obtain the coordinate information of the backscatter device. The specific calculation formula can be:

[0149]

[0150]

[0151]

[0152] Wherein, x is the abscissa of the plane where the backscattering device is located, and y is the ordinate of the plane where the backreflecting device is located.

[0153] In this embodiment, the coordinate information of the backscatter device is acquired through the position sensing data, thereby realizing the position sensing and coordinate estimation of the backscatter device and improving the accuracy of sensing the backscatter device.

[0154] In an exemplary embodiment, a simulation system is used to verify the location sensing method, 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 backscattering device is 60 m, the distance from the backscattering device to the receiver is 90 m, the relative angle between the backscattering device and the receiver is 29°, the number of receiver antennas is 4 and 16, and the number of experiments is set to 3000 times.

[0155] FIG7 is a time-frequency diagram of a received signal after short-time Fourier transform in one embodiment. It can be observed that the direct link signal is much stronger than the reflected link signal. Secondly, since the backscattering device transmits a square wave signal of a certain frequency, the direct link signal will be frequency-shifted on the spectrum, and the reflected link signal corresponding to the first harmonic is much larger than the other harmonics. The above received signal is frame synchronized to estimate the beginning of the chirped spread spectrum 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, so as to extract the starting frequency of the signal. As shown in FIG5, it can be clearly observed that the starting frequencies of N consecutive symbols in the preamble are the same. Two consecutive downchirp symbols can clearly distinguish the preamble part from the data part. The data part is modulated with 0~2 SF -1, so the starting frequency is a random value within the starting frequency interval, and the beginning of the frame can be easily determined.

[0156] Figure 8 shows the angle estimation error of the backscatter device using the MUSIC algorithm under different signal-to-noise ratio conditions. The horizontal axis is the received signal-to-noise ratio (SNR), and the vertical axis is the root mean square error (RMSE) of the angle estimation. The relative angle between the backscatter device and the receiver is 29 degrees. The solid line with circles represents the angle estimation error when the receiver has 4 antennas, and the solid line with crosses 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 there are 4 antennas, and the angle estimation error is stable at 0.3 degrees when there are 16 antennas.

[0157] Figure 9 shows the coordinate estimation error of the backscattering device using the MUSIC algorithm under different signal-to-noise ratio conditions. The horizontal axis is the signal-to-noise ratio of the reflected link signal reception, and the vertical axis is the coordinate estimation RMSE. The relative angle between the backscattering device and the receiver is 29 degrees. The solid line with a circle indicates that the receiver has 4 antennas, and the line with a cross indicates that 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 5m when there are 4 antennas, and the angle estimation error is stable at 0.7m when there are 16 antennas.

[0158] In this embodiment, a long-distance, low-cost, low-power location perception system using environmental LoRa signals is provided. The backscatter device transmits a square wave signal of a fixed frequency. The joint receiver can simultaneously recover the LoRa signal (direct link signal) and use the reflected link signal to perceive the location perception parameters of the backscatter device, thereby estimating the coordinates of the backscatter device.

[0159] It should be understood that, although the various steps in the flowcharts involved in the above-mentioned embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-mentioned embodiments can include multiple steps or multiple stages, and these steps or stages 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 to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0160] Based on the same inventive concept, the embodiment of the present application also provides a position sensing device for implementing the position sensing method involved above. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above method, so the specific limitations in one or more position sensing device embodiments provided below can refer to the limitations on the position sensing method above, and will not be repeated here.

[0161] In an exemplary embodiment, as shown in FIG10 , a position sensing device is provided. The position sensing device 100 includes: a processing module 1001, a first determining module 1002, and a second determining module 1003, wherein:

[0162] The processing module 1001 is used to process the received signal to obtain a direct link signal corresponding to the signal source;

[0163] A first determining module 1002 is configured to determine a reflected link signal from a received signal based on a serial interference cancellation strategy and a direct link signal;

[0164] The second determination module 1003 is used to estimate the perception parameters of the reflected link signal to obtain position perception data; and determine the coordinate information of the target device based on the position perception data.

[0165] In one embodiment, the receiver includes multiple antennas, and the processing module 1001 is specifically configured to perform preliminary processing on a received signal of each antenna to obtain a first received signal;

[0166] Performing weighted processing on each first received signal to obtain a second received signal;

[0167] The second received signal is demodulated to obtain a direct link signal.

[0168] In one embodiment, the processing module 1001 is specifically used to perform frame synchronization on the received signal on each antenna to obtain the received signal after frame synchronization; perform deviation estimation on the received signal after frame synchronization to obtain the carrier frequency deviation value in the received signal; and process the received signal after frame synchronization based on the carrier frequency deviation value to obtain a first received signal.

[0169] In one embodiment, 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;

[0170] Based on the weighting coefficients, each first received signal is weighted to obtain a second received signal.

[0171] In one embodiment, the received signal includes a plurality of first uplink linear frequency modulation signals and a first downlink linear frequency modulation signal, and the processing module 1001 is specifically configured to perform low-pass filtering on the received signal to obtain a filtered received signal;

[0172] Multiplying the filtered received signal by the first downlink linear frequency modulation signal to obtain a first calculation result;

[0173] The first calculation result is subjected to fast Fourier processing to obtain the starting frequency of each first uplink linear frequency modulation signal in the received signal; if the number of consecutive identical starting frequencies of each first uplink linear frequency modulation signal reaches a preset number threshold, the received signal after frame synchronization is determined based on the preset number threshold.

[0174] In one embodiment, the second received signal includes a plurality of second uplink linear frequency modulation signals and a second downlink linear frequency modulation signal, and the processing module 1001 is specifically configured to multiply the second received signal by the second downlink linear frequency modulation signal to obtain a second calculation result;

[0175] Performing fast Fourier processing on the second calculation result to obtain the starting frequency of each second uplink linear frequency modulation signal in the second received signal;

[0176] The starting frequency of each second uplink linear frequency modulation signal is mapped to a preset chip interval to determine a direct link signal.

[0177] In one embodiment, the second determination module 1003 is used to obtain multiple singular eigenvalues ​​in the signal covariance matrix of the reflection link signal;

[0178] Determine a singular eigenvector corresponding to a singular eigenvalue that meets a preset condition, determine a steering vector orthogonal to a preset noise eigenvector based on the singular eigenvector, and determine a two-dimensional spectrum peak search expression based on the steering vector;

[0179] The spectrum value of the preset coordinate position is calculated based on the two-dimensional spectrum peak search expression; the spectrum peak among the multiple spectrum values ​​is obtained through the spectrum peak search algorithm; and the position information of the spectrum peak is determined as the position perception data of the reflection link signal.

[0180] In one embodiment, the location sensing data includes direction information of the target device relative to the receiver and distance information of the reflected link signal, and the target device is a backscattering device. The second determination module 1003 is used to calculate the direction information, distance information and distance information of the direct link signal according to a preset location algorithm to obtain the coordinate information of the backscattering device.

[0181] Each module in the above-mentioned position sensing device can be implemented in whole or in part by software, hardware or a combination thereof. Each module can be embedded in or independent of a processor in a computer device in the form of hardware, or can be stored in a memory in a computer device in the form of software, so that the processor can call and execute the operations corresponding to each module above.

[0182] In an exemplary embodiment, a computer device is provided, which may be a terminal, and its internal structure diagram may be shown in FIG11. The computer device includes a processor, a memory, an input / output interface, a communication interface, a display unit, and an input device. The processor, the memory, and the input / output interface are connected via a system bus, and the communication interface, the display unit, and the input device are connected to the system bus via the input / output interface. 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 operation of the operating system and the computer program in the non-volatile storage medium. The input / output interface of the computer device is used to exchange information between the processor and an external device. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner may be implemented through WIFI, a mobile cellular network, near field communication (NFC) or other technologies. When the computer program is executed by the processor, a location perception method is implemented. The display unit of the computer device is used to form a visually visible picture, which may 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 covering the display screen, or a button, trackball or touchpad set on the computer device shell, or an external keyboard, touchpad or mouse.

[0183] Those skilled in the art will understand that the structure shown in FIG. 11 is merely a block diagram of a partial structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than shown in the figure, or combine certain components, or have a different arrangement of components.

[0184] In one embodiment, a computer device is provided, including a memory and a processor, wherein a computer program is stored in the memory, and the processor implements the steps in the above-mentioned method embodiments when executing the computer program.

[0185] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps in the above-mentioned method embodiments are implemented.

[0186] In one embodiment, a computer program product is provided, including a computer program, which implements the steps in the above method embodiments when executed by a processor.

[0187] A person of ordinary skill in the art can understand that all or part of the processes in the above-mentioned embodiment method can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the 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. 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), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. Non-relational databases may include distributed databases based on blockchains, etc., but are not limited to this. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, an artificial intelligence (AI) processor, etc., but are not limited to this.

[0188] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0189] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A location awareness method, characterized in that: Applied to a receiver, the method comprises: Processing the received signal to obtain a direct link signal corresponding to the signal source; determining a reflected link signal from the received signal based on a serial interference cancellation strategy and the direct link signal; The sensing parameters of the reflected link signal are estimated to obtain position sensing data; and the coordinate information of the target device is determined based on the position sensing data.

2. The method according to claim 1, characterized in that The receiver includes multiple antennas, and the received signals are processed to obtain direct link signals corresponding to the signal sources, including: For each antenna receiving signal, preliminarily processing the receiving signal to obtain a first receiving signal; Performing weighted processing on each of the first received signals to obtain a second received signal; The second received signal is demodulated to obtain a direct link signal.

3. The method according to claim 2, characterized in that The step of preliminarily processing the received signal of each antenna to obtain a first received signal includes: For the received signal on each antenna, the received signal is frame synchronized to obtain the received signal after frame synchronization; the deviation of the received signal after frame synchronization is estimated to obtain the carrier frequency deviation value in the received signal; and the received signal after frame synchronization is processed based on the carrier frequency deviation value to obtain a first received signal.

4. The method according to claim 2, characterized in that: The step of performing weighted processing on each of the first received signals to obtain a second received signal includes: Performing channel estimation on the first received signal to obtain a channel gain value, and determining the channel gain value as a weighting coefficient; Based on the weighting coefficients, each of the first received signals is weighted to obtain a second received signal.

5. The method according to claim 3, characterized in that: The received signal includes a first downlink linear frequency modulation signal, and the step of performing frame synchronization on the received signal to obtain a frame-synchronized received signal includes: Performing low-pass filtering on the received signal to obtain a filtered received signal; multiplying the filtered received signal by the first downlink linear frequency modulation signal to obtain a first calculation result; The first calculation result is subjected to fast Fourier processing to obtain a plurality of starting frequencies of the received signal; if the number of consecutive identical starting frequencies reaches a preset number threshold, the received signal after frame synchronization is determined based on the preset number threshold.

6. The method according to claim 2, characterized in that The second received signal includes a second downlink linear frequency modulation signal, and the demodulating the second received signal to obtain a direct link signal includes: multiplying the second received signal by the second downlink linear frequency modulation 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 received signal; Each of the starting frequencies is mapped to a preset chip interval to determine a direct link signal.

7. The method according to claim 1, characterized in that The estimating the sensing parameters of the reflection link signal to obtain the position sensing data includes: Acquire a plurality of singular eigenvalues ​​in a signal covariance matrix of the reflection link signal; Determine a singular eigenvector corresponding to a singular eigenvalue that meets a preset condition, determine a steering vector orthogonal to a preset noise eigenvector based on the singular eigenvector, and determine a two-dimensional spectrum peak search expression based on the steering vector; The spectrum value of the preset coordinate position is calculated based on the two-dimensional spectrum peak search expression; the spectrum peak among the multiple spectrum values ​​is obtained through the spectrum peak search algorithm; and the position information of the spectrum peak is determined as the position perception data of the reflection link signal.

8. The method according to claim 1, characterized in that The position sensing 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 determining the coordinate information of the target device based on the position sensing data includes: The direction information, the distance information and the distance information of the direct link signal are calculated according to a preset location algorithm to obtain coordinate information of the backscatter device.

9. A position sensing device, characterized in that: Applied to a receiver, the device comprises: A processing module, used for processing the received signal to obtain a direct link signal corresponding to the signal source; A first determination module, configured to determine a reflected link signal from the received signal based on a serial interference cancellation strategy and the direct link signal; The second determination module is used to estimate the perception parameters of the reflection link signal to obtain position perception data; and determine the coordinate information of the target device based on the position perception data.

10. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 8 are implemented.

11. 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 method according to any one of claims 1 to 8 are implemented.

12. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 8 are implemented.

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