Positioning tracking method and device based on LoRa signal, electronic equipment and storage medium

Abstract

The application provides a positioning and tracking method and device based on a LoRa signal, electronic equipment and a storage medium, the positioning and tracking method based on the LoRa signal comprises the following steps: acquiring a baseband signal at a LoRa signal receiving end; performing signal correction on the baseband signal to obtain a baseband corrected signal; extracting reflection signal phase information from the baseband corrected signal; and determining the moving track of a target according to the initial position of the target and the solving result of a tracking model, wherein the tracking model is constructed based on the reflection signal phase information. The carrier offset and clock drift of the LoRa signal are solved by performing signal correction on the baseband signal, the reflection signal phase is accurately extracted, the tracking model is constructed according to the extracted phase, the ghosting problem of object tracking in a dual-antenna sensing scene is solved, and accurate tracking is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wireless sensing, in particular to a positioning and tracking method and device based on LoRa signals, electronic equipment and storage medium. BACKGROUND

[0002] Position information is indispensable important information in our daily life, so target tracking, that is, continuously determining the position of the target, is of great significance. For example, in an industrial scene, the position of products on the assembly line can help workers monitor the working state of the transmission belt; in a museum, the position monitoring of precious cultural relics can also bring great convenience to management. The positioning method using wireless communication technology has attracted widespread attention in the industry, such as radio frequency identification technology for commodity positioning in industrial scenes, WiFi positioning technology for detecting personnel position and handwriting tracking, and handwriting tracking based on millimeter waves, but these positioning and tracking technologies based on wireless communication are based on short-distance communication and are not suitable for long-distance positioning and tracking scenes. In related technologies, LoRa signals are used as sensing carriers to position and track passive targets, which can realize long-distance positioning of passive targets. However, due to the carrier offset and clock drift of LoRa signals, the positioning is not accurate, and the tracked objects have ghosting problems, which cannot meet the user's demand. SUMMARY

[0003] The present application provides a positioning and tracking method and device based on LoRa signals, electronic equipment and storage medium, to solve the problem of inaccurate positioning and tracking objects with ghosting in the conventional positioning and tracking method using LoRa signals as sensing carriers.

[0004] The present application provides a positioning and tracking method based on LoRa signals, comprising:

[0005] Obtaining a baseband signal at a LoRa signal receiving end;

[0006] Signal correction is performed on the baseband signal to obtain a baseband corrected signal;

[0007] Extracting reflection signal phase information from the baseband corrected signal;

[0008] Determining the movement trajectory of the target according to the initial position of the target and the solution result of the tracking model, wherein the tracking model is constructed based on the reflection signal phase information.

[0009] According to the positioning and tracking method based on LoRa signals provided by the present application, the baseband signal received from the receiving end is decoded into a carrier signal and a backscattering signal by using the conjugate multiplication method.

[0010] The conjugate multiplication method is used to decode the baseband signal received from the receiving end into a carrier signal and a backscattering signal;

[0011] correcting the carrier frequency offset of the carrier signal received by the receiving end to obtain a carrier corrected signal;

[0012] correcting the sampling frequency offset of the backscatter signal to obtain a backscatter corrected signal.

[0013] According to the positioning and tracking method based on the LoRa signal provided by the application, the carrier frequency offset of the carrier signal received by the receiving end is corrected to obtain a carrier corrected signal, which comprises:

[0014] calculating the phase offset estimation of the carrier signal;

[0015] differential solving the phase offset estimation based on time to obtain a compensation amount;

[0016] compensating the carrier signal by the compensation amount to obtain a carrier corrected signal.

[0017] According to the positioning and tracking method based on the LoRa signal provided by the application, the sampling frequency offset of the backscatter signal is corrected to obtain a backscatter corrected signal, which comprises:

[0018] linearly transforming the backscatter signals at different sampling times to obtain a backscatter signal phase sequence;

[0019] calculating the quadratic term offset of the adjacent time phase in the backscatter signal phase sequence;

[0020] fitting the backscatter signal phase based on the quadratic term offset of the adjacent time phase to obtain a backscatter corrected signal.

[0021] According to the positioning and tracking method based on the LoRa signal provided by the application, the reflection signal phase information is extracted from the baseband corrected signal, which comprises:

[0022] clustering the sampling points according to the Euclidean distance on the I / Q plane to obtain the carrier signal and the backscatter signal;

[0023] When the target moves, the phase of the reflection signal is the difference between the backscatter corrected signal phase and the carrier corrected signal phase.

[0024] According to the positioning and tracking method based on the LoRa signal provided by the application, the tracking model is constructed based on the reflection signal phase information, which comprises:

[0025] calculating the phase change value according to the reflection signal phase information extracted at different times;

[0026] calculating the conversion relationship coefficient between the phase change value and the target moving distance;

[0027] According to the conversion relationship coefficient, a tracking model is constructed, and the tracking model comprises an elliptic equation set.

[0028] According to the present application, a positioning and tracking method based on a LoRa signal is provided.

[0029] Two intersection points of the double ellipse are obtained by solving the elliptic equation set.

[0030] The distances between the two intersection points and the initial position of the target are calculated respectively, and the intersection point corresponding to the distance less than the distance threshold is taken as the target arrival position.

[0031] The moving track of the target is obtained according to the target arrival positions calculated at different time points.

[0032] The present application also provides a positioning and tracking device based on a LoRa signal.

[0033] The acquisition module is configured to acquire a baseband signal at a LoRa signal receiving end.

[0034] The correction module is configured to correct the baseband signal to obtain a baseband corrected signal.

[0035] The extraction module is configured to extract reflection signal phase information from the baseband corrected signal.

[0036] The tracking module is configured to determine the moving track of the target according to the tracking model solving result and the initial position of the target, and the tracking model is constructed based on the reflection signal phase information.

[0037] The present application also provides an electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the positioning and tracking method based on the LoRa signal.

[0038] The present application also provides a non-transitory computer readable storage medium having a computer program stored thereon, wherein the computer program is executable on a processor to implement the positioning and tracking method based on the LoRa signal.

[0039] The application provides a LoRa signal-based positioning tracking method and device, electronic equipment and a storage medium. BRIEF DESCRIPTION OF DRAWINGS

[0040] In order to more clearly illustrate the technical solutions in the application or the prior art, the drawings needed in the embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor.

[0041] Figure 1 Fig. 1 is one of the flow diagrams of the LoRa signal-based positioning tracking method provided by the application;

[0042] Figure 2 Fig. 2 is another of the flow diagrams of the LoRa signal-based positioning tracking method provided by the application;

[0043] Figure 3 Fig. 3 is a schematic diagram of the binary amplitude shift keying modulation in backscattering provided by the application;

[0044] Figure 4 Fig. 4 is a chirp carrier offset diagram provided by the application;

[0045] Figure 5 Fig. 5 is a sampling frequency offset diagram provided by the application;

[0046] Figure 6 Fig. 6 is a third flow diagram of the LoRa signal-based positioning tracking method provided by the application;

[0047] Figure 7 Fig. 7 is a phase change diagram in an ideal case provided by the application;

[0048] Figure 8 Fig. 8 is a phase difference diagram when the cluster center is correctly identified provided by the application;

[0049] Figure 9 Fig. 9 is a phase difference diagram when the cluster center is incorrectly identified provided by the application;

[0050] Figure 10 Figure 4 is a flowchart of a positioning tracking method based on a LoRa signal according to an embodiment of the present application;

[0051] Figure 11 Figure 5 is a schematic diagram of a two-dimensional position tracking target according to an embodiment of the present application;

[0052] Figure 12 Figure 6 is a flowchart of a positioning tracking method based on a LoRa signal according to an embodiment of the present application;

[0053] Figure 13 Figure 7 is a structural diagram of a positioning tracking device based on a LoRa signal according to an embodiment of the present application;

[0054] Figure 14 Figure 8 is a structural diagram of an electronic device according to an embodiment of the present application. DETAILED DESCRIPTION

[0055] In order to make the objectives, technical solutions and advantages of the present application clearer, the technical solutions in the present application will be described clearly and completely below with reference to the drawings in the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0056] Figure 1 Figure 1 is a flowchart of a positioning tracking method based on a LoRa signal according to an embodiment of the present application, and the positioning tracking method based on a LoRa signal according to an embodiment of the present application includes: Figure 1

[0057] Step 101, acquiring a baseband signal at a LoRa signal receiving end;

[0058] In the present embodiment, LoRa refers to Long Range Radio, and the biggest feature of LoRa is that it can transmit farther than other wireless methods under the same power consumption condition, and can provide long-distance signal transmission, which helps long-distance wireless sensing capability.

[0059] Step 102, performing signal correction on the baseband signal to obtain a baseband corrected signal;

[0060] In the present embodiment, a quadratic fitting technique is used to eliminate sampling frequency offset, and the phase difference of the same point between two adjacent linear frequency modulation signals is used to eliminate carrier offset.

[0061] Step 103, extracting reflection signal phase information from the baseband corrected signal;

[0062] ​In the embodiment of the present application, the motion of the object is reflected on the phase change of the signal by using binary amplitude shift keying modulation technology, and the interference is eliminated by signal difference between adjacent high and low levels of binary amplitude shift keying, so as to realize phase extraction.

[0063] Step 104, determining the moving track of the target according to the initial position of the target and the solving result of the tracking model, wherein the tracking model is constructed based on the reflected signal phase information.

[0064] The initial position of the target is used to determine the reaching position of the target, so as to solve the ambiguity problem of two positioning points in the positioning and tracking process of the double receiver, that is, to solve the ghost problem in the tracking process.

[0065] The traditional positioning and tracking method of the passive target by using LoRa signal as a sensing carrier can realize long-distance positioning of the passive target, but due to the carrier offset and clock drift of the LoRa signal, it will lead to inaccurate positioning and ghost problem of the tracked object, which cannot meet the user demand.

[0066] The positioning and tracking method based on the LoRa signal provided in the embodiment of the present application acquires the baseband signal at the LoRa signal receiving end; the baseband signal is corrected to obtain a baseband corrected signal; the reflected signal phase information is extracted from the baseband corrected signal; the moving track of the target is determined according to the initial position of the target and the solving result of the tracking model, wherein the tracking model is constructed based on the reflected signal phase information, the carrier offset and clock drift of the LoRa signal are solved by correcting the baseband signal, the reflected signal phase is accurately extracted, and the tracking model is constructed according to the extracted phase, so as to solve the ghost problem of the object tracking in the double-antenna sensing scene and realize accurate tracking.

[0067] Based on any of the above embodiments, as Figure 2 shown, the baseband signal is corrected to obtain a baseband corrected signal, and the specific steps include:

[0068] Step 201, using the conjugate multiplication method to decode the carrier signal and the backscattering signal from the baseband signal received by the receiving end;

[0069] Step 202, correcting the carrier frequency offset of the carrier signal received by the receiving end to obtain a carrier corrected signal;

[0070] In the embodiment, the carrier signal received by the receiving end is corrected for carrier frequency offset to obtain a carrier corrected signal, including:

[0071] Step 2021, calculating the phase offset estimate of the carrier signal;

[0072] Step 2022, differentiating the phase offset estimation based on time to obtain a compensation amount;

[0073] Step 2023, compensating the carrier signal by the compensation amount to obtain a carrier corrected signal.

[0074] Step 203, sampling frequency offset correction is performed on the backscatter signal to obtain a backscatter corrected signal.

[0075] In the embodiment, the sampling frequency offset correction is performed on the backscatter signal to obtain a backscatter corrected signal, including:

[0076] Step 2031, linearly transforming the backscatter signals in different sampling time to obtain a backscatter signal phase sequence;

[0077] Step 2032, calculating a quadratic term offset of adjacent time phases in the backscatter signal phase sequence;

[0078] Step 2033, fitting the backscatter signal phase based on the quadratic term offset of the adjacent time phases to obtain a backscatter corrected signal.

[0079] LoRa signals can be successfully decoded even in the case of 20dB lower than the noise floor. A LoRa symbol is called a chirp, and in the duration of a chirp, its frequency increases linearly with time in the interval The time-domain signal can be expressed as:

[0080]

[0081] Where f0 is the starting frequency of the chirp, BW is the frequency modulation bandwidth, and SF is the spreading factor. When f0 is 0, the symbol is called up-chirp with linear frequency variation from low to high; when , the symbol is called down-chirp with linear frequency variation from high to low. A LoRa data packet contains a 10-up-chirp preamble and a 2.25-down-chirp synchronization code, and since there is a blank interval between LoRa data packets, the 12.25 symbols are used for packet positioning.

[0082] As Figure 3As shown, in the backscattering scenario, the data information is carried on the carrier wave by controlling the way the backscattering device reflects and absorbs the carrier wave collected from the environment using digital signals 1 and 0, reflecting the carrier wave in the '1' state and absorbing the carrier wave in the '0' state. This frequency modulation method is called binary amplitude keying frequency modulation. The receiving end realizes the decoding of the target by analyzing the amplitude and phase changes of the received signal. Specifically, each chirp is multiplied by the conjugate chirp signal corresponding thereto to obtain a quasi-sine signal, and the LoRa signal is removed to realize the demodulation frequency of the signal. The conjugate signal can be expressed as:

[0083]

[0084] (1) (2) The two expressions are multiplied to obtain a sine signal:

[0085]

[0086] If the accurate starting position of each chirp in the received signal can be found, the phase jump occurring in each chirp can be eliminated to obtain a single-frequency signal. We find that when f sin = 0, a zero-frequency signal without phase change is obtained. At this time, the amplitude modulation result of the binary amplitude keying frequency modulation on the chirp can produce a phase jump in the above generated sine signal. By tracking the phase jump and taking the reflected carrier signal phase as a reference, the phase offset of the target due to movement at the gateway can be tracked. Through the historical position information of the target, the accurate distance and direction of the target movement can be deduced.

[0087] However, in the actual environment, the carrier signal emitted by the LoRa node will produce a frequency offset at the node, as shown in Figure 4 This will disturb the LoRa baseband signal and cause random phase offset. In addition, the clock at the gateway is often not synchronized with the node, and its clock frequency is also not exactly the same as that of the node, which will also disturb the phase of the baseband signal, so it is necessary to estimate and correct these errors.

[0088] After removing the LoRa baseband using the conjugate multiplication method, a direct current signal is theoretically obtained, but due to the offset of the sampling frequency, the carrier frequency will be offset and a sine signal will be obtained. Assuming that the starting frequency of a LoRa chirp is f0, due to hardware errors, the actual starting frequency is often not equal to f0, but has a stable offset f c At this time, the LoRa signal expression should be expressed as:

[0089]

[0090] After removing the baseband, a sine signal is obtained To get the carrier frequency offset f c , define the estimator

[0091]

[0092] where N chirp is the number of up-chirps taken from the preamble part of the LoRa data packet, represents the phase at the lth sample point of the ith taken up-chirp after phase unwrapping. Taking the difference of these phases and averaging them, we can get an estimator of the phase offset After differentiating with respect to time, we get the carrier frequency offset f c :

[0093]

[0094] and compensate the demodulation result of the baseband signal with f c .

[0095] The sampling frequency offset is a problem that occurs between the gateway and the LoRa node transmitter, which is caused by the mismatch of sampling frequencies. The sampling frequency offset refers to the deviation between the real sampling frequency f′ s and the set sampling frequency f s , which makes a linear transformation to the sampling time sequence:

[0096] T * [n] = mT[n] + ΔT d (7)

[0097] Due to the sampling frequency offset, the starting point of the dth chirp occurs a time offset of ΔT d

[0098]

[0099] represents the residual time interval between the sampling points, which is shorter than the width between two sampling points. In the FFT result of a single chirp, the width of each FFT bin is

[0100]

[0101] When the FFT window slides h sampling points on a single chirp, the FFT peak will move h / 2 FFT bins. Therefore, if the LoRa data packet is accurately aligned by FFT, the λ / F s ​The residual cannot shift the position of the FFT peak of the LoRa data packet, but it will still significantly affect the phase of the signal. When f0 hops, a phase jump will occur, which will severely affect the phase quality. Applying formula (7) to the LoRa chirp signal yields the backscattered signal phase:

[0102]

[0103] After demodulation, the baseband signal retains a quadratic time offset, such as... Figure 5 As shown.

[0104] Quadratic term offset

[0105] Due to spectral leakage, the phase at the high-low frequency transition of the chirp signal is disturbed, and the error is a quadratic function of time in phase. By fitting the formula (11) through a fitting algorithm, the signal is corrected.

[0106] Based on any of the above embodiments, such as Figure 6 As shown, the specific steps for extracting the phase information of the reflected signal from the baseband corrected signal include:

[0107] Step 601: Cluster the sampling points according to the Euclidean distance on the I / Q plane to obtain the carrier signal and the backscattered signal;

[0108] Step 602: When the target moves, the phase of the reflected signal is the difference between the phase of the backscatter correction signal and the phase of the carrier correction signal.

[0109] Tracking backscattered targets relies on tracking the phase changes of the reflected signal. Using a single chirp as the sensing unit, the signal sampling points within a single sensing unit are clustered into two classes based on Euclidean distance in the I / Q plane. Ideally, such as... Figure 7 As shown, H s It is a signal that is not reflected by the device (carrier signal), including direct path signals and multipath reflected signals; H m It is a signal that has been backscattered.

[0110] When the target moves, the reflected signal H d The phase rotates, but the magnitude of the phase cannot be directly measured; it needs to be determined using the static component H. s H is solved as a reference value. d :

[0111] H d =H m -H s (12)

[0112] But due to the instability of the multipath in the environment, H s will change over time, which leads to the simultaneous change of the cluster centers of H s and H d , and the size of H d cannot be directly obtained.

[0113] Since H m and H s cannot be distinguished, H d will have two cases: as shown in FIGS. Figure 8 , 9 , H Figure 8 represents the correct alignment, and H Figure 9 is the wrong phase vector alignment. The sum of the two phase angles is equal to π, so if one of the phase angles θ can be kept within a certain range during perception, the range of the other angle can also be determined.

[0114] When the two θs are large enough, this ambiguity can be stably resolved. In order to distinguish them as much as possible, we take π / 2 as the critical condition, because the rotation angle of H d between two adjacent perception units is related to the distance of object movement, when the target moves at low speed, the rotation angle of H d will be much smaller than π / 2, so if the phase angle θ is less than π / 2, it is determined to be the true path.

[0115] If the speed of target movement is not limited, the phase changes of adjacent perception units can be correlated, assuming that the speed of target movement can be kept as continuous as possible, the difference between the two phase changes H d1 and H d2 of two perception units will not be too large. In this way, accurate estimation of H d can also be achieved under unstable channel conditions.

[0116] Based on any of the above embodiments, as shown in FIG. Figure 10 , a tracking model is constructed based on the phase information of the reflected signal, and the specific steps include:

[0117] Step 1001, calculating the phase change value according to the phase information of the reflected signal extracted at different times;

[0118] Step 1002, calculating the conversion relationship coefficient between the phase change value and the target movement distance;

[0119] Step 1003, constructing a tracking model according to the conversion relationship coefficient, and the tracking model includes an elliptic equation set.

[0120] In the process of target movement, a series of H d, denoted as H d,i , where i is the i-th sampling point. Two adjacent H... d The difference between them: H d,i H d,i+1 The difference between them represents the phase change at the receiver caused by the target's movement. The difference is denoted as ΔH. d,i =H d,i+1 -H d,i The system has two receivers, thus yielding two phase difference sequences: ΔH d,i,1 and ΔH d,i,2 The conversion coefficient between phase difference and distance is:

[0121] like Figure 11 As shown, points F1 and F3 are the locations of the two receivers, F2 is the location of the transmitter, P1 and P2 are the previous target location and the current predicted target location, respectively, the arrow direction indicates the target's movement direction, the focal length c represents 1 / 2 of the distance between the transmitter and receiver, and the value of a is related to the initial position. The initial position of the target is on the two ellipses, and then a can be obtained based on the target's position.

[0122] The movement of the target causes a change in phase, which is manifested as an increase or decrease in the sum of the distances from the target to the two receivers. We measured that the sum of the distances from the target to F1 and F3 increased by Δd1, while the sum of the distances to F1 and F2 increased by Δd2. The focal position and focal length c remain unchanged, but the major axis a changes. Assuming the target had not moved, the equations of the two ellipses are:

[0123]

[0124] After the target moves, the new system of elliptic equations is:

[0125]

[0126] The two new ellipses intersect at point P2, which is the current position of the target. Equation (14) is used as the updated formula and serves as the reference formula for the next calculation.

[0127] Based on any of the above embodiments, such as Figure 12 As shown, the target's trajectory is determined based on the solution results of the tracking model and the target's initial position. Specific steps include:

[0128] Step 1201: Solve the system of equations for the ellipse to obtain the two intersection points of the double ellipse;

[0129] Step 1202, respectively, calculate the distance between the two intersection points and the initial position of the target, and take the intersection point corresponding to the initial position of the target as the target arrival position.

[0130] Step 1203, according to the target arrival position calculated at different times, the moving track of the target is obtained.

[0131] When y1≤y2, let x=0, and:

[0132]

[0133] For an ellipse, the coordinate expression of all intersection points satisfying (14) and (15) is extremely complex and difficult to analyze. Under the condition that the equality of formula (15) is established, the intersection point group in the third quadrant within a certain range that satisfies formula (15) is obtained by using a large number of scattered points for approximation, and it is concluded that when the longitudinal coordinate of the tracking area in the third quadrant is greater than -2c, the two intersection points of the double ellipse will remain in two different quadrants. In this way, the movement of the target can be effectively tracked.

[0134] In order to verify its effectiveness, a commercial LoRa node (based on Semtech SX1276 chip) is used as the signal transmitting end, two USRP N210 software radio platforms are used as the signal receiving end, and three omnidirectional antennas are equipped. The LoRa signal works in the carrier frequency band of 902MHz, uses a bandwidth of 500KHz and a spreading factor of SF=11. Our backscattering device uses a target antenna of WISP 5.0 working in the 900MHz frequency band. In the experimental deployment, the distance between the two receiving ends and the transmitting end is kept at 2m. We use a two-dimensional sliding table to control the motion of WISP5.0, and perform linear motion at different distances. In the case of known initial position, we use the elliptic equation set to calculate the position information of the object, evaluate the distance and angle of motion, and evaluate the ghost elimination effect under different trajectories. Through the measurement of the signal phase, a tracking accuracy of 5cm within a range of 2m is achieved.

[0135] In the embodiment of the application, the binary amplitude shift keying frequency modulation method is used to sample the phase change of the baseband reflection signal caused by the target at the receiving end, and the moving track of the target on the plane is tracked according to the phase change and the initial position of the object. The carrier frequency offset and sampling frequency offset of the superimposed signal of the carrier signal and the backscattering signal are estimated and corrected using quadratic fitting technology. In the tracking model, the object position tracking problem is converted into an elliptical intersection mathematical problem, and the ambiguity problem caused by the positioning tracking based on two receivers is solved by using engineering mathematical analysis method.

[0136] The LoRa signal-based positioning and tracking device provided by the present application is described below, and the LoRa signal-based positioning and tracking device described below can be referred to each other corresponding to the LoRa signal-based positioning and tracking method described above.

[0137] Figure 13 The schematic diagram of the LoRa signal-based positioning and tracking device provided by the embodiment of the present application is shown in Figure 13 The LoRa signal-based positioning and tracking device provided by the embodiment of the present application comprises:

[0138] The acquisition module 1301 is configured to acquire a baseband signal at a LoRa signal receiving end.

[0139] The correction module 1302 is configured to correct the baseband signal to obtain a baseband corrected signal.

[0140] The extraction module 1303 is configured to extract reflection signal phase information from the baseband corrected signal.

[0141] The tracking module 1304 is configured to determine the moving track of the target according to the initial position of the target and the solving result of the tracking model, and the tracking model is constructed based on the reflection signal phase information.

[0142] The LoRa signal-based positioning and tracking device provided by the embodiment of the present application acquires a baseband signal at a LoRa signal receiving end, corrects the baseband signal to obtain a baseband corrected signal, extracts reflection signal phase information from the baseband corrected signal, and determines the moving track of the target according to the initial position of the target and the solving result of the tracking model, and the tracking model is constructed based on the reflection signal phase information, which solves the problems of carrier offset and clock drift of the LoRa signal, realizes accurate extraction of the reflection signal phase, and according to the extracted phase, the tracking model can be constructed to solve the ghost problem of object tracking in the dual-antenna sensing scene, and precise tracking is realized.

[0143] Figure 14 An example of the physical structure schematic diagram of an electronic device is shown in Figure 14As shown, the electronic device can include a processor 1410, a communications interface 1420, a memory 1430, and a communications bus 1440, wherein the processor 1410, the communications interface 1420, and the memory 1430 complete mutual communication through the communications bus 1440. The processor 1410 can invoke a logical instruction in the memory 1430 to execute a LoRa signal-based positioning tracking method, which includes: acquiring a baseband signal at a LoRa signal receiving end; performing signal correction on the baseband signal to obtain a baseband corrected signal; extracting reflection signal phase information from the baseband corrected signal; and determining a moving track of a target according to a tracking model solving result and an initial position of the target, the tracking model being constructed based on the reflection signal phase information.

[0144] In addition, the logical instruction in the memory 1430 described above can be implemented in the form of a software functional unit and sold or used as an independent product, and can be stored in a computer-readable storage medium. Based on such understanding, the technical solutions of the present application essentially or the part that contributes to the prior art or part of the technical solutions can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a plurality of instructions to make a computer device (which can be a personal computer, a server, or a network device, etc.) execute all or part of the steps of the methods described in various embodiments of the present application. The foregoing storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a magnetic disk or an optical disk, and various media that can store program codes.

[0145] On the other hand, the present application also provides a non-transitory computer-readable storage medium having a computer program stored thereon, the computer program being executed by a processor to implement a LoRa signal-based positioning tracking method provided by the above-mentioned methods, the method including: acquiring a baseband signal at a LoRa signal receiving end; performing signal correction on the baseband signal to obtain a baseband corrected signal; extracting reflection signal phase information from the baseband corrected signal; and determining a moving track of a target according to a tracking model solving result and an initial position of the target, the tracking model being constructed based on the reflection signal phase information.

[0146] The device embodiments described above are merely illustrative, wherein the units described as separate components can or can not be physically separate, and the components displayed as units can or can not be physical units, i.e., can be located in one place, or can be distributed to multiple network units. Part or all of the modules can be selected to achieve the purposes of the embodiments according to actual needs. Those skilled in the art can understand and implement without creative labor.

[0147] Through the description of the above embodiments, those skilled in the art can clearly understand that the embodiments can be realized by means of software and the necessary general hardware platform, and of course can also be realized by hardware. Based on such understanding, the above technical solutions can be embodied in the form of a software product, which can be stored in a computer readable storage medium, such as a ROM / RAM, a magnetic disk, an optical disk, etc., and includes a number of instructions to make a computer device (which can be a personal computer, a server, or a network device, etc.) execute the methods described in each embodiment or some parts of the embodiments.

[0148] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for positioning and tracking based on LoRa signals, characterized in that, The method comprises the following steps: acquiring a baseband signal at a LoRa signal receiving end; performing signal correction on the baseband signal to obtain a baseband corrected signal; extracting reflection signal phase information from the baseband corrected signal; determining a moving track of a target according to a solving result of a tracking model and an initial position of the target, and constructing the tracking model based on the reflection signal phase information; wherein the step of performing signal correction on the baseband signal to obtain a baseband corrected signal comprises: decoding a carrier signal and a backscatter signal from the baseband signal received from the receiving end by using a conjugate multiplication method; performing carrier frequency offset correction on the carrier signal received by the receiving end to obtain a carrier corrected signal; and performing sampling frequency offset correction on the backscatter signal to obtain a backscatter corrected signal; the step of constructing the tracking model based on the reflection signal phase information comprises: calculating a phase change value according to the reflection signal phase information extracted at different time instants; calculating a conversion relationship coefficient between the phase change value and a target moving distance; and constructing the tracking model according to the conversion relationship coefficient, wherein the tracking model comprises an elliptic equation set. 2.The LoRa signal based positioning tracking method of claim 1, wherein, the step of performing carrier frequency offset correction on the carrier signal received by the receiving end to obtain a carrier corrected signal comprises: calculating a phase offset estimation of the carrier signal; determining a compensation amount by differentiating the phase offset estimation based on time; compensating the carrier signal by using the compensation amount to obtain a carrier corrected signal. 3.The LoRa signal based positioning tracking method of claim 1, wherein, the step of performing sampling frequency offset correction on the backscatter signal to obtain a backscatter corrected signal comprises: performing linear transformation on the backscatter signal at different sampling time instants to obtain a backscatter signal phase sequence; calculating a quadratic term offset of adjacent time instant phases in the backscatter signal phase sequence; fitting the backscatter signal phase based on the quadratic term offset of the adjacent time instant phases to obtain a backscatter corrected signal. 4.The LoRa signal based positioning tracking method of claim 1, wherein, the step of extracting reflection signal phase information from the baseband corrected signal comprises: clustering sampling points according to Euclidean distances on an I / Q plane to obtain carrier signals and backscatter signals; when the target moves, the phase of the reflection signal is the difference between the backscatter corrected signal phase and the carrier corrected signal phase. 5.The LoRa signal based positioning tracking method of claim 1, wherein, the step of determining a moving track of a target according to a solving result of a tracking model and an initial position of the target comprises: solving the elliptic equation set to obtain two intersection points of a double ellipse; calculating distances between the two intersection points and the initial position of the target respectively, and taking the intersection point corresponding to a distance smaller than a distance threshold to the initial position of the target as a target arrival position; obtaining a moving track of the target according to the target arrival positions calculated at different time instants. 6.A LoRa signal based positioning and tracking device, characterized in that, The method comprises the following steps: an acquisition module, configured to acquire a baseband signal at a LoRa signal receiving end; a correction module, configured to perform signal correction on the baseband signal to obtain a baseband corrected signal; specifically configured to decode a carrier signal and a backscatter signal from the baseband signal received from the receiving end by using a conjugate multiplication method; and perform carrier frequency offset correction on the carrier signal received by the receiving end to obtain a carrier corrected signal; perform sampling frequency offset correction on the backscatter signal to obtain a backscatter corrected signal; an extraction module configured to extract reflection signal phase information from the baseband correction signal; a tracking module configured to determine a moving track of the target according to a tracking model solution result and an initial position of the target, and construct the tracking model based on the reflection signal phase information, specifically configured to calculate a phase change value according to the reflection signal phase information extracted at different time instants; calculate a conversion relationship coefficient between the phase change value and a target moving distance; and construct a tracking model according to the conversion relationship coefficient, the tracking model including an elliptic equation set.

7. An electronic device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, The processor implements the LoRa signal-based positioning and tracking method according to any one of claims 1 to 5 when executing the program.

8. A non-transitory computer-readable storage medium having stored thereon a computer program, characterized in that, The computer program implements the LoRa signal-based positioning and tracking method according to any one of claims 1 to 5 when executed by the processor.

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