Low-cost uwb single-anchor mobile phone fusion positioning system

Abstract

The application provides a low-cost UWB single-anchor mobile phone fusion positioning system, which comprises a UWB anchor module, a smart phone and a UWB tag module, wherein the UWB anchor module is regarded as a UWB base station, and the position of the UWB anchor module is P BAS The UWB anchor module calculates and outputs distance information D between the UWB anchor module and the UWB tag module in real time, that is, the ranging is completed 1 , D 2 , D 3 The smart phone is connected with the UWB anchor module through a local area network, and the smart phone synchronously and in real time obtains the distance information D The application solves the problems of complicated deployment and high cost of the existing UWB indoor positioning, and is a low-cost, simple-to-deploy and long-term stable indoor UWB single-anchor fusion positioning system.

Description

Technical Field

[0001] This invention relates to the field of indoor positioning technology. Background Technology

[0002] Ultra-wideband (UWB) technology boasts strong anti-interference capabilities, high transmission rates, and security, leading to its widespread application in indoor positioning. However, practical challenges include high equipment costs, complex deployment, and difficult maintenance. Furthermore, standalone UWB positioning is susceptible to non-line-of-sight (NLoS) interference, affecting its accuracy indoors. To address these issues, numerous researchers have made progress. Some have combined UWB with other sensors, such as Bluetooth, WiFi, and inertial navigation devices, to achieve fusion positioning and improve accuracy. Others have optimized the layout of UWB anchor points to overcome the time-consuming and inaccurate mechanical measurements required for anchor point placement.

[0003] Publication No. 112729282A uses the least squares and gradient descent method to integrate UWB single anchor point ranging and pedestrian trajectory estimation, but it requires prior measurement of the anchor point's prior coordinates, and the positioning method used has relatively low accuracy.

[0004] Publication number 115235452A integrates UWB, IMU and visual information, which can achieve high positioning accuracy, but it still requires measuring the coordinates of UWB anchor points.

[0005] Publication No. 109451426 discloses a method for rapid layout of positioning anchor points in a UWB indoor positioning system. The method uses the geometric relationship between the distance measurement value and the anchor point to place the anchor point, thereby achieving rapid and accurate layout of anchor points in the UWB indoor positioning system. However, this invention does not involve fusion positioning.

[0006] Publication No. 109282811A discloses an indoor and outdoor positioning system and method that connects UWB with smartphones. It uses UWB, INS and GPS systems to achieve indoor and outdoor positioning. However, the UWB in the system requires at least three anchor points to achieve UWB positioning, which increases the hardware cost of the system and is not conducive to its widespread use.

[0007] Publication No. 113038362A provides a UWB positioning method and system, but this invention also requires at least two anchor points to achieve positioning.

[0008] Terminology Notes:

[0009] PDR: Pedestrian Tracking

[0010] UWB: Ultra Wideband Wireless

[0011] IMU (Inertial Measurement Unit)

[0012] NLoS: Non-line-of-sight

[0013] PF (Particle filter): Particle filtering algorithm Summary of the Invention

[0014] This invention addresses the problems of cumbersome and costly deployment of existing UWB indoor positioning systems by providing a low-cost, easy-to-deploy, and long-term stable indoor UWB single-anchor-point fusion positioning system.

[0015] Technical solution:

[0016] A low-cost UWB single-anchor-point mobile phone fusion positioning system includes a UWB anchor-point module 1 (i.e., a UWB base station), a smartphone 3, and a UWB tag module 4, wherein:

[0017] UWB anchor module 1 (considered a UWB base station, its location is P) BAS The distance information D between the device and the UWB tag module 4 is calculated and output in real time, thus completing the distance measurement.

[0018] Smartphone 3 and UWB anchor module 1 are connected via a local area network, and smartphone 3 synchronously obtains distance information D in real time. 1 D 2 D 3 .

[0019] The smartphone 3 includes a PDR pedestrian trajectory estimation module 31, a UWB anchor point position estimation module 32, a pedestrian ranging module 33, and a fusion positioning module 34, wherein:

[0020] The PDR pedestrian trajectory estimation module 31 includes a gait detection submodule 311, a heading angle estimation submodule 312, and a PDR positioning module submodule 313, wherein:

[0021] The magnetometer, accelerometer and gyroscope built into the mobile phone are connected to the step detection submodule 1. The step detection submodule 311 calculates and outputs the step length S using formula (1). L Provided to PDR positioning module submodule 313;

[0022] The heading angle estimation submodule 312 obtains the heading angle θ by performing complementary filtering on the output data of the accelerometer, gyroscope and magnetometer. This heading angle is then input to the PDR positioning module submodule 313 for position calculation.

[0023] The PDR positioning module submodule 313 calculates P using formula (2). 1 ,P 2 ,P 3 The traveler's flight path;

[0024]

[0025]

[0026] Equation (1) is the step size estimation formula, where S L It is stride length, f s where h is the walking frequency, h is the pedestrian's height, and k is the proportionality coefficient; (x t ,y t Let t be the coordinate position of the pedestrian at time t, and θ be the heading angle. The position coordinates at each time can be calculated according to formula (2).

[0027] The UWB anchor point position estimation module 32 is connected to the PDR pedestrian trajectory estimation module 31 to obtain three consecutive pedestrian positions P that are not on the same straight line. k (k=1,2,3)(Three consecutive different time points P) 1 P 2 P 3 ), and combined with ranging information D k (k=1,2,3)(Three consecutive different time points D) 1 D 2 D 3 The anchor point P of UWB anchor point module 1 (UWB base station) is calculated using equation (3). BAS :

[0028]

[0029] As shown above, the coordinates of the unknown UWB anchor point can be calculated using equation (3) and provided to the pedestrian ranging module 33.

[0030] Because the mobile phone PDR has high positioning accuracy at the initial moment, this characteristic is used to estimate the anchor point position in reverse.

[0031] The pedestrian ranging module 33 is connected to the UWB anchor point module 1; the UWB anchor point module 1 calculates and outputs the distance information D between itself and the UWB tag module 4 in real time based on the UWB anchor point coordinates output by the UWB anchor point position estimation module; the pedestrian ranging module regards the distance information D provided by the UWB anchor point module 1 as the distance information between the pedestrian and the UWB anchor point.

[0032] The fusion positioning module 34 optimizes the pedestrian trajectory output by the PDR pedestrian trajectory estimation module 31 to improve trajectory positioning.

[0033] Specifically, particle filtering is used to fuse the iterative PDR pedestrian trajectory estimation module 31 and the pedestrian ranging module 33;

[0034] More specifically, the system's state equation and observation equation are established. The state equation is established by the PDR pedestrian trajectory estimation module 31, and the observation equation is established by the pedestrian ranging module 33, as shown in equations (5) and (6) respectively.

[0035]

[0036] Z k =|P k -P BAS |+ν k (6)

[0037] In the formula ω k v k These represent the system's process noise and observation noise, respectively, and their parameters need to be adjusted based on the actual system and sensors. k This represents the observed value.

[0038] The optimal pedestrian trajectory is calculated by iterating as described above.

[0039] Technological innovation and beneficial effects of this invention:

[0040] In typical indoor positioning, three UWB anchor points are required, and the locations of these anchor points need to be known (which increases hardware and labor costs). However, in this invention, the anchor point locations are not obtained through manual measurement, but rather calculated using the initial position of the mobile phone's PDR (pedestrian trajectory estimation) module. These positions are then fused based on the PDR pedestrian trajectory estimation module 31, the UWB anchor point location estimation module 32, and the pedestrian ranging module 33. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the system scenario of the present invention;

[0042] Figure 2 System block diagram of UWB single-anchor-point mobile phone fusion positioning method;

[0043] Figure 3 This is a comparison chart of the system's trajectory results in the test case.

[0044] in,

[0045] UWB Anchor Module 1

[0046] Smartphone 3, PDR pedestrian trajectory estimation module 31, UWB anchor point position estimation module 32, pedestrian ranging module 33, fusion positioning module 34, gait detection submodule 311, heading angle estimation submodule 312, PDR positioning module submodule 313, UWB tag module 4. Detailed Implementation

[0047] The technical solutions provided in this application will be further described below with reference to specific embodiments and accompanying drawings. The advantages and features of this application will become clearer from the following description.

[0048] It should be noted that the embodiments of this application are preferred for implementation and are not intended to limit the application in any way. The technical features or combinations of technical features described in the embodiments of this application should not be considered isolated; they can be combined with each other to achieve better technical effects. The scope of the preferred embodiments of this application may also include other implementations, and this should be understood by those skilled in the art to which the embodiments of this application pertain.

[0049] Techniques, methods, and apparatus known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and apparatus should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limiting. Therefore, other examples of exemplary embodiments may have different values.

[0050] The accompanying drawings in this application are all in a very simplified form and use non-precise proportions, intended only to facilitate and clarify the illustration of the embodiments of this application, and are not intended to limit the implementation of this application. Any modifications to the structure, changes in the proportional relationships, or adjustments to the size, without affecting the effects and purposes achieved by this application, should fall within the scope of the technical content disclosed in this application. Furthermore, the same reference numerals appearing in the various drawings of this application represent the same features or components, and can be applied to different embodiments.

[0051] Figure 1 This is a schematic diagram of a UWB single-anchor-point mobile phone fusion positioning system scenario. The application scenario includes UWB anchor-point module 1, LAN interface module 2, smartphone 3, and UWB tag module 4.

[0052] UWB anchor module 1, which uses a microcontroller in hardware, is regarded as a UWB base station;

[0053] UWB anchor module 1 needs to be connected to the local area network through local area network interface module 2 to ensure the transmission of TCP data;

[0054] UWB tag module 4 is bound to smartphone 3, and the two are considered as one point;

[0055] The smartphone 3 has a built-in magnetometer, accelerometer, and gyroscope;

[0056] From UWB anchor module 1 (its position is P) BAS The distance information D between the device and the UWB tag module 4 is calculated and output in real time, thus completing the distance measurement.

[0057] Establish TCP protocol: Set up a TCP client on UWB anchor module 1 and a TCP server on smartphone 3 (mobile device); the person carries smartphone 3 and, while walking, UWB anchor module 1 and smartphone 3 are on the same local area network;

[0058] As shown above, smartphone 3 obtains the distance between itself and UWB anchor module 1 (i.e., UWB base station).

[0059] Distance information transmission: The distance between the UWB anchor module 1 and the UWB tag module 4 is calculated by bilateral ranging method, and then the distance information is transmitted to the mobile phone (smartphone 3) via TCP wireless transmission.

[0060] like Figure 2 As shown:

[0061] A low-cost UWB single-anchor mobile phone fusion positioning system, key components of which include a UWB anchor module 1 (i.e., a UWB base station), a smartphone 3, and a UWB tag module 4, wherein:

[0062] UWB anchor module 1 (considered a UWB base station, its location is P) BAS The distance information D between the device and the UWB tag module 4 is calculated and output in real time, thus completing the distance measurement.

[0063] Smartphone 3 and UWB anchor module 1 are connected via a local area network, and smartphone 3 synchronously obtains distance information D in real time. 1 D 2 D 3 .

[0064] Smartphone 3 includes a PDR pedestrian trajectory estimation module 31, a UWB anchor point position estimation module 32, a pedestrian ranging module 33, and a fusion positioning module 34, wherein:

[0065] The PDR pedestrian trajectory estimation module 31 includes a gait detection submodule 311, a heading angle estimation submodule 312, and a PDR positioning module submodule 313, wherein:

[0066] The magnetometer, accelerometer and gyroscope built into the mobile phone are connected to the step detection submodule 1. The step detection submodule 311 calculates and outputs the step length S using formula (1). L Provided to PDR positioning module submodule 313;

[0067] The heading angle estimation submodule 312 obtains the heading angle θ by performing complementary filtering on the output data from the accelerometer, gyroscope, and magnetometer. This heading angle is then input to the PDR positioning module submodule 313 for position calculation. The complementary filtering algorithm is existing technology in this field and includes two steps: sensor data reading and signal weighted summation.

[0068] First, sensor reading is the process of acquiring information from accelerometers, gyroscopes, and magnetometers;

[0069] Then, different weights are assigned to the information acquired by the accelerometer, gyroscope, and magnetometer, and finally, the summation yields the filtered heading angle θ. (In this field, the complementary filtering algorithm is a mature technology.)

[0070] The PDR positioning module submodule 313 calculates P using formula (2). 1 ,P 2 ,P 3 The traveler's flight path;

[0071]

[0072]

[0073] Equation (1) is the step size estimation formula, where S L It is stride length, f s Let be the walking frequency, h be the pedestrian's height, and k be the proportionality coefficient. (x t ,y t Let t be the coordinate position of the pedestrian at time t, and θ be the heading angle. The position coordinates at each time can be calculated according to formula (2).

[0074] The UWB anchor point position estimation module 32 is connected to the PDR pedestrian trajectory estimation module 31 to obtain three consecutive pedestrian positions P that are not on the same straight line. k (k=1,2,3)(Three consecutive different time points P) 1 P 2 P 3 ), and combined with ranging information D k (k=1,2,3)(Three consecutive different time points D) 1 D 2 D 3 The anchor point P of UWB anchor point module 1 (UWB base station) is calculated using equation (3). BAS :

[0075]

[0076] As shown above, the coordinates of the unknown UWB anchor point can be calculated using equation (3) and provided to the pedestrian ranging module 33.

[0077] Because the mobile phone PDR has high positioning accuracy at the initial moment, this invention uses this characteristic to estimate the anchor point position in reverse.

[0078] The pedestrian ranging module 33 is connected to the UWB anchor point module 1; the UWB anchor point module 1 calculates and outputs the distance information D between itself and the UWB tag module 4 in real time based on the UWB anchor point coordinates output by the UWB anchor point position estimation module; the pedestrian ranging module regards the distance information D provided by the UWB anchor point module 1 as the distance information between the pedestrian and the UWB anchor point.

[0079] The fusion positioning module 34 optimizes the pedestrian trajectory output by the PDR pedestrian trajectory estimation module 31 to improve trajectory positioning.

[0080] Specifically, particle filtering is used to fuse the iterative PDR pedestrian trajectory estimation module 31 and the pedestrian ranging module 33;

[0081] More specifically, the system's state equation and observation equation are established. The state equation is established by the PDR pedestrian trajectory estimation module 31, and the observation equation is established by the pedestrian ranging module 33, as shown in equations (5) and (6) respectively.

[0082]

[0083] Z k =|P k -P BAS |+ν k (6)

[0084] In the formula ω k v k These represent the system's process noise and observation noise, respectively, and their parameters need to be adjusted based on the actual system and sensors. k This represents the observed value.

[0085] The optimal pedestrian trajectory is calculated by iterating as described above.

[0086] The above technical solution eliminates the need to measure the UWB anchor point position in advance. The UWB anchor point position estimation module 32 on the smartphone 3 can estimate the UWB anchor point position in reverse. At the same time, TCP wireless transmission is used to obtain ranging information on the mobile phone in real time, so as to perform fusion positioning of the PDR pedestrian trajectory estimation module 31 and the pedestrian ranging module 33, thereby improving the positioning accuracy of the system.

[0087] Test case

[0088] An indoor scene

[0089] This invention can solve the problems of cumbersome indoor UWB deployment, difficult maintenance, and high hardware costs. It is suitable for low-cost indoor positioning locations where the accuracy requirements are not particularly high. Walking around a square with a side length of 8m for 4 circles, a distance of 128 meters, the cumulative deviation is 1.8 meters, which can meet general indoor positioning needs.

[0090] Figure 3 This example illustrates a comparison between the system-fused positioning result and the individual PDR trajectory. The red starting point in the figure is known, while the anchor point is unknown and needs to be obtained through the UWB anchor point estimation module 32. The black dashed line represents the actual trajectory of the pedestrian, and the purple solid line represents the trajectory obtained by the PDR pedestrian trajectory estimation module 31. This method is relatively accurate initially, but the offset error increases over time, making it difficult to meet requirements in practical applications. Therefore, the proposed method, specifically using particle filtering to fuse the pedestrian ranging module and the PDR pedestrian trajectory estimation module 31, yields the blue solid line trajectory in the figure. This trajectory remains close to the actual trajectory, meeting indoor positioning requirements.

[0091] The above description is merely a description of preferred embodiments of this application and is not intended to limit the scope of this application in any way. Any changes or modifications made by those skilled in the art based on the above-disclosed technical content should be considered as equivalent and valid embodiments and fall within the scope of protection of the technical solution of this application.

Claims

1. A low-cost UWB single-anchor mobile phone fusion positioning system, characterized in that, Includes a UWB anchor module (1), a smartphone (3), and a UWB tag module (4), wherein: The UWB anchor module (1) is regarded as a UWB base station, and its position is P BAS The UWB anchor module (1) calculates the distance information D between the UWB anchor module (1) and the UWB tag module (4) in real time, that is, the ranging is completed. The smart phone (3) is connected with the UWB anchor module (1) through a local area network, and the smart phone (3) synchronously and in real time obtains distance information D 1 , D 2 , D 3 ; The smartphone (3) includes a PDR pedestrian trajectory estimation module (31), a UWB anchor point position estimation module (32), a pedestrian ranging module (33), and a fusion positioning module (34), wherein: The PDR pedestrian trajectory estimation module (31) includes a gait detection submodule (311), a heading angle estimation submodule (312), and a PDR positioning module submodule (313), wherein: The built-in magnetometer, accelerometer and gyroscope of the mobile phone are connected with the step detection submodule (1), the step detection submodule (311) calculates the output step length through formula (1) , and provides the PDR positioning module submodule (313); The heading angle estimation submodule (312) is obtained by complementary filtering the output data of the accelerometer, the gyroscope, and the magnetometer to obtain a heading angle The heading angle is input to the PDR positioning module submodule (313) for position calculation. The PDR positioning module submodule (313) calculates P 1 ,P 2 ,P 3 ,derives the track of the pedestrian; （1） （2） Formula (1) is a step length estimation formula, wherein, is a step length, is a walking frequency, is a height of a pedestrian, is a proportional coefficient; is is a coordinate position of the pedestrian at a time, is a heading angle, and the position coordinate at each time can be calculated according to Formula (2). The UWB anchor point position estimation module (32) is connected with the PDR pedestrian trajectory estimation module (31), and obtains three continuous pedestrian positions not on the same straight line , i.e. three continuous positions P at different times 1 , P 2 , P 3 , and combines the ranging information , i.e. three continuous positions D at different times 1 , D 2 , D 3 , and the anchor point position of the UWB anchor point module 1 is calculated through formula (3) : （3） As shown above, the coordinates of the unknown UWB anchor point can be calculated by formula (3) and provided to the pedestrian ranging module (33). Because the mobile phone PDR has high positioning accuracy at the initial moment, this characteristic is used to estimate the anchor point position in reverse. The fusion positioning module (34) optimizes the pedestrian trajectory output by the PDR pedestrian trajectory estimation module (31) to improve trajectory positioning; Specifically, particle filtering is used to fuse the iterative PDR pedestrian trajectory estimation module (31) and the pedestrian ranging module (33). More specifically, the system's state equation and observation equation are established by the PDR pedestrian trajectory estimation module (31) and the observation equation is established by the pedestrian ranging module (33), as shown in equations (5) and (6) respectively. （5） （6） wherein , represent the process noise and the observation noise of the system, respectively, and need to be adjusted according to the actual system and the sensor; denotes the observation value; The optimal pedestrian trajectory is calculated by iterating as described above.

2. The system as described in claim 1, characterized in that, The pedestrian ranging module (33) is connected to the UWB anchor point module (1); the UWB anchor point module (1) calculates and outputs the distance information D between itself and the UWB tag module (4) in real time based on the UWB anchor point coordinates output by the UWB anchor point position estimation module; the pedestrian ranging module regards the distance information D provided by the UWB anchor point module (1) as the distance information between the pedestrian and the UWB anchor point.

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