LoRa positioning system and method based on layered fusion of RSSI and TDOA

Abstract

The invention discloses a LoRa positioning system and method based on RSSI and TDOA hierarchical fusion, the system is a base station system composed of at least four base stations, each base station in the base station system is configured with an RSSI module and a TDOA module, and the base stations determine radio wave intensity signals and time difference signals based on acquired signals; the RSSI module executes an RSSI algorithm according to the electric wave intensity signal, and the TDOA module executes a TDOA algorithm according to the time difference signal. The method has the advantages of high positioning efficiency, high positioning precision, low manufacturing cost, wide application range, portability and the like.

Description

Technical Field

[0001] The present application belongs to the field of wireless positioning technology, and in particular, relates to a LoRa positioning system and method based on hierarchical fusion of RSSI and TDOA. Background Art

[0002] Wireless positioning is a technology that relies on known base stations to receive signals from transmitters at unknown locations for analysis and calculation to derive their locations. With the development of the times, people's requirements for positioning are no longer limited to aviation positioning, navigation positioning, etc., but are also used in daily life, such as car positioning, navigation routes, etc. There are many mature wireless positioning systems today, such as the Global Positioning System (GPS), the Global Navigation Satellite System (GLONASS), Beidou, etc. All of the above systems use multiple satellites to achieve triangulation of the target. GPS is currently the most widely used navigation and positioning system with a recognized high positioning accuracy. Even though GPS has achieved a high accuracy of use, it still has its drawbacks in many cases, such as the inability to measure in tunnels, indoors, and in places with dense buildings, high latency in places with poor signals, and transparent and easy exposure of location information. Therefore, more ground base stations need to be deployed to solve regional positioning problems.

[0003] Today's wireless positioning technology also has many types, which can be divided into non-range measurement and range measurement based on whether distance measurement is performed during positioning. The base station collects the radio waves emitted by the transmitter and generates different positioning algorithms based on different signal measurement values. The most commonly used range measurement positioning algorithms are based on the time of arrival (TOA), the time difference of arrival (TDOA), the angle of arrival (AOA), and the received signal strength (RSSI) of the base station. These range measurement positioning technologies measure different parameters and obtain the target position through geometric calculation. In real life, due to the existence of various complex environments, such as mountains, forests, high-rise buildings, etc., these positioning algorithms cannot meet people's positioning requirements alone. Summary of the invention

[0004] The present application provides a LoRa positioning system and method based on RSSI and TDOA hierarchical fusion, which is used to solve the above problems or at least partially solve the above problems.

[0005] In the first aspect, a LoRa positioning system based on hierarchical fusion of RSSI and TDOA is disclosed, wherein the system is a base station system composed of at least four base stations, each base station in the base station system is configured with an RSSI module and a TDOA module, and the base station determines the radio wave strength signal and the time difference signal based on the acquired signal; the RSSI module executes the RSSI algorithm according to the radio wave strength signal, and the TDOA module executes the TDOA algorithm according to the time difference signal.

[0006] Preferably, the base station is equipped with a base station positioning module, and the base station positioning module acquires the coordinate information of the base station based on GNSS positioning.

[0007] In a second aspect, a LoRa positioning method based on hierarchical fusion of RSSI and TDOA is disclosed. Based on the LoRa positioning system based on hierarchical fusion of RSSI and TDOA as described above, the method includes:

[0008] Step S1: The base station system receives a signal transmitted by the transmitting module of the device to be located, and the base station system includes at least four base stations; each base station in the base station system determines the radio wave strength signal and the time difference signal based on the signal, and each base station in the base station system is configured with an RSSI module and a TDOA module;

[0009] Step S2: Screening the radio wave strength signals of each base station, retaining the radio wave strength signals obtained by several base stations with the largest signal stability values; each base station that retains the radio wave strength signals uses the configured RSSI module to calculate based on their respective radio wave strength signals to determine the preliminary positioning range of the device to be located; the RSSI module is used to execute the RSSI algorithm;

[0010] Step S3: sending the time difference signals obtained by each base station that retains the strong and weak signals of the radio waves to the base stations within the preliminary positioning range, so that each base station within the preliminary positioning range obtains the time difference signals of all base stations that retain the strong and weak signals of the radio waves; each base station within the preliminary positioning range uses the TDOA module configured therein to calculate the received time difference signal to determine the re-positioning of the device to be positioned; the TDOA module is used to execute the TDOA algorithm;

[0011] Step S4: Determine the position of the device to be located based on the preliminary positioning range and re-positioning of the device to be located.

[0012] Preferably, the transmitting module is a LoRa mobile transmitting module.

[0013] Preferably, the signal stability value is determined based on signal strength and signal-to-noise ratio.

[0014] Preferably, determining the position of the device to be located based on the preliminary positioning range and re-positioning of the device to be located includes:

[0015] If the relocated position is within the initial positioning range, the weight corresponding to the relocated position is set to 0.8, and the weight of the initial positioning range is set to 0.2. The position of the device to be located is determined based on the initial positioning range, relocation, and the weights corresponding to the initial positioning range and relocation of the device to be located.

[0016] If the re-positioned position is not within the preliminary positioning range, the weight corresponding to the re-positioned position is set to 0.5, and the weight of the preliminary positioning range is set to 0.5. The position of the device to be positioned is determined based on the preliminary positioning range, re-positioning, and the weights corresponding to the preliminary positioning range and re-positioning of the device to be positioned.

[0017] In a third aspect, an electronic device is disclosed, the electronic device comprising:

[0018] at least one processor; and

[0019] a memory communicatively connected to the at least one processor; wherein,

[0020] The memory stores instructions that can be executed by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to perform the method described above.

[0021] In a fourth aspect, a non-transitory computer-readable storage medium storing computer instructions is disclosed, wherein the computer instructions are used to cause the computer to execute the method as described above.

[0022] This application has the following technical effects:

[0023] This application uses TDOA and RSSI algorithms for fusion. The RSSI unit and TDOA unit built into the base station positioning module are used to obtain the signal information transmitted by the LoRa mobile transmission module in the base station coverage area. The final positioning result is calculated through layered fusion calculations and finally sent back to the terminal device by the communication module. The positioning efficiency is high and the positioning accuracy is high. It is not only low in cost, but also has a wide range of adaptability and is easy to carry.

[0024] This application aims at the drawbacks of traditional GNSS positioning methods, such as the inability to locate in tunnels, indoors and places with dense buildings, high positioning delay in places with poor GNSS signals, and transparent and easy exposure of location information. Through the RSSI unit and TDOA unit built into the Lora base station positioning module, the signal information transmitted by the LoRa mobile transmission module in the base station coverage area is obtained, and the final positioning result is calculated through layered fusion calculation, and finally sent back to the terminal device by the communication module. It has technical advantages such as high positioning efficiency, high positioning accuracy, low cost, wide adaptability, and easy to carry. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a flowchart of the LoRa positioning method based on RSSI and TDOA hierarchical fusion;

[0026] Figure 2 Schematic diagram of the principle of LoRa positioning method based on RSSI and TDOA hierarchical fusion

[0027] Figure 3 It is a schematic diagram of base stations involved in the LoRa positioning method based on RSSI and TDOA hierarchical fusion;

[0028] Figure 4 This is another flowchart of the LoRa positioning method based on hierarchical fusion of RSSI and TDOA. DETAILED DESCRIPTION

[0029] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0030] The present application provides a LoRa positioning system based on RSSI and TDOA hierarchical fusion, wherein the system is a base station system composed of at least four base stations, wherein:

[0031] Each base station in the base station system is configured with an RSSI module and a TDOA module. The base station determines the radio wave strength signal and the time difference signal based on the acquired signal; the RSSI module executes the RSSI algorithm according to the radio wave strength signal, and the TDOA module executes the TDOA algorithm according to the time difference signal.

[0032] like Figure 1-Figure 2 As shown, the present application provides a LoRa positioning method based on RSSI and TDOA hierarchical fusion, based on the LoRa positioning system based on RSSI and TDOA hierarchical fusion as described above, the method includes:

[0033] Step S1: The base station system receives a signal transmitted by the transmitting module of the device to be located, and the base station system includes at least four base stations; each base station in the base station system determines the radio wave strength signal and the time difference signal based on the signal, and each base station in the base station system is configured with an RSSI module and a TDOA module;

[0034] Step S2: Screening the radio wave strength signals of each base station, retaining the radio wave strength signals obtained by several base stations with the largest signal stability values; each base station that retains the radio wave strength signals uses the configured RSSI module to calculate based on their respective radio wave strength signals to determine the preliminary positioning range of the device to be located; the RSSI module is used to execute the RSSI algorithm;

[0035] Step S3: sending the time difference signals obtained by each base station that retains the strong and weak signals of the radio waves to the base stations within the preliminary positioning range, so that each base station within the preliminary positioning range obtains the time difference signals of all base stations that retain the strong and weak signals of the radio waves; each base station within the preliminary positioning range uses the TDOA module configured therein to calculate the received time difference signal to determine the re-positioning of the device to be positioned; the TDOA module is used to execute the TDOA algorithm;

[0036] Step S4: Determine the position of the device to be located based on the preliminary positioning range and re-positioning of the device to be located.

[0037] Furthermore, the transmitting module is a LoRa mobile transmitting module.

[0038] The signal stability value is determined based on signal strength and signal-to-noise ratio.

[0039] The determining the position of the device to be located based on the preliminary positioning range and the re-positioning of the device to be located includes:

[0040] If the relocated position is within the initial positioning range, the weight corresponding to the relocated position is set to 0.8, and the weight of the initial positioning range is set to 0.2. The position of the device to be located is determined based on the initial positioning range, relocation, and the weights corresponding to the initial positioning range and relocation of the device to be located.

[0041] If the re-positioned position is not within the preliminary positioning range, the weight corresponding to the re-positioned position is set to 0.5, and the weight of the preliminary positioning range is set to 0.5. The position of the device to be positioned is determined based on the preliminary positioning range, re-positioning, and the weights corresponding to the preliminary positioning range and re-positioning of the device to be positioned.

[0042] Furthermore, the base stations are pre-built and the coordinate information is set, and the base stations are all equipped with a base station positioning module, and the base station positioning module obtains the coordinate information of the base station based on GNSS positioning.

[0043] When the RSSI module executes the RSSI algorithm, other required data is determined based on the signal acquired by the base station. When the TDOA module is used to execute the TDOA algorithm, other required data is determined based on the signal acquired by the base station.

[0044] like Figure 3-Figure 4 As shown, the present invention provides a specific embodiment of a LoRa positioning system and method based on hierarchical fusion of RSSI and TDOA.

[0045] R1, R2, R3, R4, and R5 represent RSSI signal measurement values; T1, T2, T3, and T4 represent TDOA signal measurement values.

[0046] According to an embodiment of the present invention, a LoRa positioning system based on hierarchical fusion of RSSI and TDOA includes a LoRa mobile transmission module and a base station positioning module, wherein the base station positioning module includes an RSSI unit and a TDOA unit, wherein the LoRa mobile transmission module is used to transmit signal information required by the base station positioning module.

[0047] Among them, there are at least four positioning base stations.

[0048] It also includes a processing module and a communication module. The processing module acquires the signal and performs layered fusion operations, and finally transmits it to the server through the communication module.

[0049] To construct a base station group, according to the algorithm of the present invention, at least four base stations need to be constructed to form a base station group, and a LoRa mobile module is equipped to transmit signals at any time.

[0050] This method is based on the existing RSSI and TDOA algorithms, and relies on different signals received by the base station to implement operations within the base station. First, multiple base stations receive RSSI signal values, and obtain preliminary calculation values ​​through the strength of the radio waves. At this time, data analysis is performed to filter out sudden changes and signals with large fluctuations. After obtaining the initial positioning range, the base station receiving time difference signals within the initial positioning range of the target is called to perform TDOA operations, and the final calculated position is obtained through weighted data analysis with the RSSI estimated value.

[0051] In addition, data screening is to receive data from multiple base stations and use algorithms to filter out the fluctuation signal with the largest difference in the data. High-quality mathematical algorithms can effectively improve positioning accuracy. First, analyze the signal value of RSSI, filter out a fluctuation value from the same batch of measured signal estimates, and then retain the remaining signal estimates to obtain preliminary positioning. The second step is to filter out the base station with the largest fluctuation signal after filtering the signal and then use TDOA to start positioning calculations. The third step is to integrate the positioning information of RSSI and TDOA.

[0052] A LoRa positioning method based on RSSI and TDOA hierarchical fusion, comprising the following steps:

[0053] Build a base station in advance and set coordinate information;

[0054] Get the signal of the LoRa mobile transmitter module in the coverage area of ​​the positioning base station.

[0055] The following steps are also included:

[0056] The base station positioning module obtains coordinate information based on GNSS positioning;

[0057] Obtain the signal information transmitted by the LoRa mobile transmission module in the coverage area of ​​the base station positioning module;

[0058] The RSSI signal is first screened to remove abnormal base station signal values, and then integrated with the positioning obtained by the TDOA signal;

[0059] Uploaded to the terminal by the communication module.

[0060] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application is described in detail with reference to the above embodiments, a person skilled in the art should understand that the technical solutions described in the above embodiments can still be modified, or some or all of the technical features can be replaced by equivalents, and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A LoRa positioning system based on RSSI and TDOA hierarchical fusion, characterized in that: The system is a base station system composed of at least four base stations, each base station in the base station system is configured with an RSSI module and a TDOA module, and the base station determines the radio wave strength signal and the time difference signal based on the acquired signal; the RSSI module executes the RSSI algorithm according to the radio wave strength signal, and the TDOA module executes the TDOA algorithm according to the time difference signal.

2. The system according to claim 1, characterized in that The base station is equipped with a base station positioning module, and the base station positioning module obtains the coordinate information of the base station based on GNSS positioning.

3. A LoRa positioning method based on hierarchical fusion of RSSI and TDOA, based on the LoRa positioning system based on hierarchical fusion of RSSI and TDOA as claimed in any one of claims 1-2, characterized in that: The method comprises: Step S1: The base station system receives a signal transmitted by the transmitting module of the device to be located, and the base station system includes at least four base stations; each base station in the base station system determines the radio wave strength signal and the time difference signal based on the signal, and each base station in the base station system is configured with an RSSI module and a TDOA module; Step S2: Screening the radio wave strength signals of each base station, retaining the radio wave strength signals obtained by several base stations with the largest signal stability values; each base station that retains the radio wave strength signals uses the configured RSSI module to calculate based on their respective radio wave strength signals to determine the preliminary positioning range of the device to be located; the RSSI module is used to execute the RSSI algorithm; Step S3: sending the time difference signals obtained by each base station that retains the strong and weak signals of the radio waves to the base stations within the preliminary positioning range, so that each base station within the preliminary positioning range obtains the time difference signals of all base stations that retain the strong and weak signals of the radio waves; each base station within the preliminary positioning range uses the TDOA module configured therein to calculate the received time difference signal to determine the re-positioning of the device to be positioned; the TDOA module is used to execute the TDOA algorithm; Step S4: Determine the position of the device to be located based on the preliminary positioning range and re-positioning of the device to be located.

4. The method according to claim 3, characterized in that The transmitting module is a LoRa mobile transmitting module.

5. The method according to claim 3, characterized in that The signal stability value is determined based on signal strength and signal-to-noise ratio.

6. The method according to claim 3, characterized in that The determining the position of the device to be located based on the preliminary positioning range and the re-positioning of the device to be located includes: If the relocated position is within the initial positioning range, the weight corresponding to the relocated position is set to 0.8, and the weight of the initial positioning range is set to 0.

2. The position of the device to be located is determined based on the initial positioning range, relocation, and the weights corresponding to the initial positioning range and relocation of the device to be located. If the re-positioned position is not within the preliminary positioning range, the weight corresponding to the re-positioned position is set to 0.5, and the weight of the preliminary positioning range is set to 0.

5. The position of the device to be positioned is determined based on the preliminary positioning range, re-positioning, and the weights corresponding to the preliminary positioning range and re-positioning of the device to be positioned.

7. A computer-readable storage medium, wherein a plurality of instructions are stored in the storage medium; the plurality of instructions are used for a processor to load and execute the method as claimed in any one of claims 3 to 6.

8. An electronic device, characterized in that: The electronic device comprises: A processor, which is used to execute multiple instructions; A memory for storing a plurality of instructions; The plurality of instructions are used to be stored by the memory, and loaded and executed by the processor according to any one of claims 3 to 6.

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