High-precision positioning system based on millimeter wave backscattering system

Abstract

The invention relates to the technical field of radio positioning, and discloses a high-precision positioning system based on a millimeter wave backscattering system, and the system comprises a millimeter wave radar module which is provided with a plurality of millimeter wave radars which are respectively disposed at a plurality of non-coplanar positions in a three-dimensional space, and each millimeter wave radar works at a millimeter wave frequency band and employs a frequency modulation continuous wave technology, converting the millimeter wave signal into an intermediate frequency signal through down-conversion for distance measurement; the intermediate-frequency signal processing unit is used for filtering, amplifying and digitally processing the received intermediate-frequency signal so as to extract distance information of the target; the data fusion module is used for performing synchronous alignment on distance measurement data from the plurality of millimeter wave radars and performing data fusion through an extended Kalman filtering algorithm so as to estimate the three-dimensional position and speed of the target in real time; the millimeter wave reflection label is installed on a target and can reflect millimeter wave signals and transmit label ID information by adjusting an absorption switch and a reflection switch. According to the invention, high-precision real-time positioning of a target is realized through cooperative work of a plurality of millimeter-wave radars and the millimeter-wave reflection label capable of adjusting reflection.

Description

Technical Field

[0001] The present invention relates to the field of radio positioning technology, and in particular to a high-precision positioning system based on a millimeter wave backscattering system. Background Art

[0002] With the rapid development of the Internet of Things, smart manufacturing, autonomous driving, and smart logistics, the demand for high-precision, real-time positioning systems is growing. Existing positioning technologies such as the Global Positioning System (GPS) are not accurate enough indoors or in complex environments, and are susceptible to occlusion and multipath effects. Millimeter-wave radar is widely used in the field of high-precision positioning due to its high resolution, strong penetration ability, and anti-electromagnetic interference ability.

[0003] As a passive marker, backscatter tags can reflect radar signals without power supply, and have the advantages of low cost, small size, and easy maintenance. The existing multi-radar positioning system based on millimeter-wave radar has problems in radar layout, data fusion and real-time processing, such as complex layout, difficult data fusion, and insufficient real-time performance, which limits its wide promotion and application effect in practical applications. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a high-precision positioning system based on the millimeter wave backscattering system, which realizes real-time three-dimensional positioning of adjustable reflective millimeter wave reflective tags by rationally arranging multiple millimeter wave radars, using intermediate frequency signals for high-precision ranging, and combining the extended Kalman filter (EKF) algorithm. The system aims to solve the shortcomings of the existing positioning system in terms of accuracy, real-time performance, anti-interference ability and system robustness, and is suitable for a variety of application scenarios such as indoor positioning, autonomous driving, industrial automation and smart logistics.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] A high-precision positioning system based on a millimeter wave backscatter system, comprising:

[0007] The millimeter wave radar module has multiple millimeter wave radars, which are respectively arranged at multiple non-coplanar positions in three-dimensional space. Each millimeter wave radar operates in the millimeter wave frequency band and adopts frequency modulation continuous wave technology to convert the millimeter wave signal into an intermediate frequency signal through down-conversion for ranging;

[0008] An intermediate frequency signal processing unit is used to filter, amplify and digitize the received intermediate frequency signal to extract the distance information of the target;

[0009] The data fusion module is used to synchronize and align the distance measurement data from multiple millimeter-wave radars and perform data fusion through the extended Kalman filter algorithm to estimate the three-dimensional position and velocity of the target in real time;

[0010] Millimeter wave reflective tags, installed on the target, can reflect millimeter wave signals and transmit tag ID information by adjusting the absorption and reflection switches.

[0011] Furthermore, there are four millimeter-wave radars in total, and the four millimeter-wave radars adopt a tetrahedron layout.

[0012] Furthermore, the intermediate frequency signal processing unit includes a filter, an amplifier, an analog-to-digital converter and a fast Fourier transform module, wherein:

[0013] Filters are used to filter out noise and interference signals;

[0014] The amplifier is used to enhance the received intermediate frequency signal and improve the signal-to-noise ratio (SNR);

[0015] The analog-to-digital converter is used to convert the intermediate frequency signal from an analog signal to a digital signal;

[0016] The fast Fourier transform module is used to perform frequency domain analysis on the intermediate frequency signal and extract the distance information of the target.

[0017] Furthermore, the data fusion module fuses the measurement data of multiple millimeter-wave radars through an extended Kalman filter algorithm, wherein the state vector of the extended Kalman filter algorithm includes the position (x, y, z) and velocity (v x ,v y ,v z ), the state transfer model adopts a uniform motion model, and the observation model constructs a nonlinear observation equation based on the distance measurement of multiple millimeter-wave radar modules.

[0018] Furthermore, the millimeter wave reflective tag has a built-in switch capable of adjusting absorption and reflection. By controlling the switch state, the tag can dynamically adjust the reflection signal and transmit unique tag ID information.

[0019] Compared with the prior art, the beneficial technical effects of the present invention are:

[0020] 1. High-precision positioning: Utilizing multilateral measurements of multiple millimeter-wave radars, combined with high-precision ranging of intermediate frequency signals and data fusion of the extended Kalman filter algorithm, the three-dimensional positioning accuracy is significantly improved to meet the needs of high-precision applications.

[0021] 2. Strong anti-interference ability: Millimeter-wave radar has excellent anti-electromagnetic interference ability. Combined with intermediate frequency signal processing technology, the system can still work stably in complex electromagnetic environments, ensuring the reliability of positioning data.

[0022] 3. Good real-time performance: Through optimized signal processing flow and efficient extended Kalman filter algorithm, real-time positioning and tracking of targets can be achieved to adapt to dynamically changing application scenarios.

[0023] 4. Cost-effectiveness: By rationally selecting and deploying millimeter-wave radars, optimizing signal processing and data fusion algorithms, the overall system cost can be reduced, and market competitiveness and economic benefits can be improved.

[0024] 5. Wide range of applications: The positioning system is suitable for various application scenarios such as indoor positioning, autonomous driving, industrial automation, intelligent warehousing, etc., and has broad market application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Schematic diagram of the system architecture of the present invention. DETAILED DESCRIPTION

[0026] A preferred embodiment of the present invention is described in detail below with reference to the accompanying drawings.

[0027] 1. System architecture overview:

[0028] The high-precision positioning system based on the millimeter wave backscattering system of the present invention mainly includes the following components:

[0029] Millimeter wave radar module: Multiple millimeter wave radars are distributed in four non-coplanar positions in three-dimensional space, and target ranging is performed through intermediate frequency signals. In a preferred embodiment, there are four millimeter wave radars, and the present invention is introduced below using four millimeter wave radars as an example.

[0030] Intermediate frequency signal processing unit: filters, amplifies and digitizes the received intermediate frequency signal to extract the distance information of the target.

[0031] Data fusion module: Synchronizes and aligns the distance measurement data from four radars, and performs data fusion through the extended Kalman filter (EKF) algorithm to estimate the three-dimensional position and velocity of the target.

[0032] Millimeter wave reflective tag: installed on the target, it can reflect radar signals and transmit tag ID information by adjusting the absorption and reflection switches.

[0033] 2. The present invention is applicable to the following target application scenarios:

[0034] (1) Internet of Things (IoT) and Smart Home: With the popularity of smart home devices, the number of IoT devices is increasing, and how to accurately locate and identify devices has become the key. Traditional wireless communication and positioning technologies may face signal interference and accuracy issues.

[0035] (2) Industrial Automation and Logistics Management: In large-scale warehousing and production environments, it is necessary to accurately track the location of items in order to optimize warehouse management, production processes, and logistics scheduling.

[0036] (3) Asset management and anti-theft system: Asset management and anti-theft are important issues in large enterprises, shopping malls, airports, etc. Traditional barcode and RFID technologies face certain distance limitations and signal interference issues.

[0037] (4) Intelligent transportation and vehicle positioning: Intelligent transportation systems (ITS) need to accurately locate and identify vehicles, transportation facilities and other targets in order to conduct flow monitoring, autonomous driving navigation and traffic safety management.

[0038] 3. Module design details:

[0039] 3.1, millimeter wave radar module:

[0040] like Figure 1 As shown in the figure, the millimeter wave radar module operates in the millimeter wave frequency band of 60GHz. Each radar adopts frequency modulated continuous wave (FMCW) technology to convert high-frequency millimeter wave signals into intermediate frequency signals through down-conversion to achieve high-precision ranging. The four radars are arranged in a tetrahedron to ensure good geometric resolution between radars and avoid inaccurate positioning caused by coplanar arrangement.

[0041] 3.2, intermediate frequency signal processing unit:

[0042] The intermediate frequency signal processing unit includes filters, amplifiers, analog-to-digital converters (ADCs) and fast Fourier transform (FFT) modules. The filter is used to filter out noise and interference signals to ensure the purity of the intermediate frequency signal; the high-gain amplifier enhances the received intermediate frequency signal and improves the signal-to-noise ratio (SNR); the analog-to-digital converter converts the analog intermediate frequency signal into a digital signal for use by the subsequent digital signal processing module; the FFT module performs frequency domain analysis on the intermediate frequency signal, extracts distance information, calculates the frequency difference Δf and converts it into the target distance d.

[0043] 3.3, Data Fusion Module:

[0044] The data fusion module is responsible for time alignment and target matching of the distance measurement data from the four radars to ensure that the measurements at the same time correspond to the same target position. Through the extended Kalman filter (EKF) algorithm, this module fuses the multi-source measurement data to estimate the three-dimensional position and velocity of the target in real time. The state vector of the EKF algorithm includes the position (x, y, z) and velocity (v x ,v y ,v z), the state transfer model adopts a uniform motion model, and the observation model is based on the distance measurement of four radars to construct a nonlinear observation equation. The Jacobian matrix is ​​calculated to linearize the observation model to meet the needs of the EKF algorithm. Through the calculation of the Kalman gain and state update, the system can minimize the estimation error and provide accurate positioning results.

[0045] 3.4, millimeter wave reflection tag:

[0046] The millimeter wave reflective tag is installed on the target and can efficiently reflect the millimeter wave signal to ensure the signal strength received by the radar. The tag has a built-in adjustable absorption and reflection switch. By controlling the switch state, the tag can dynamically adjust the reflected signal and transmit unique ID information. This function not only supports the transmission of efficient reflected signals, but also facilitates the system to identify and distinguish different targets, improving the ability to locate multiple targets.

[0047] Example

[0048] The present invention can be applied to indoor high-precision positioning systems. A millimeter-wave radar module with high-precision intermediate frequency ranging capability is selected to ensure that it supports frequency modulated continuous wave (FMCW) technology and high-resolution distance measurement. According to the characteristics of the indoor environment, the specific installation positions of the four radars are determined to ensure coverage of the entire positioning area and optimize the geometric resolution. The positioning accuracy and real-time performance of the system are tested in an actual indoor environment. By comparing the actual position with the system estimated position, the high-precision positioning capability of the system is verified, and the system parameters are optimized according to the test results.

[0049] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention, and any reference numerals in the claims should not be regarded as limiting the claims involved.

[0050] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A high-precision positioning system based on a millimeter wave backscatter system, characterized in that: include: The millimeter wave radar module has multiple millimeter wave radars, which are respectively arranged at multiple non-coplanar positions in three-dimensional space. Each millimeter wave radar operates in the millimeter wave frequency band and adopts frequency modulation continuous wave technology to convert the millimeter wave signal into an intermediate frequency signal through down-conversion for ranging; An intermediate frequency signal processing unit is used to filter, amplify and digitize the received intermediate frequency signal to extract the distance information of the target; The data fusion module is used to synchronize and align the distance measurement data from multiple millimeter-wave radars and perform data fusion through the extended Kalman filter algorithm to estimate the three-dimensional position and velocity of the target in real time; Millimeter wave reflective tags, installed on the target, can reflect millimeter wave signals and transmit tag ID information by adjusting the absorption and reflection switches.

2. The high-precision positioning system based on the millimeter wave backscattering system according to claim 1 is characterized in that: There are four millimeter-wave radars in total, and the four millimeter-wave radars are arranged in a tetrahedron.

3. The high-precision positioning system based on the millimeter wave backscattering system according to claim 1 is characterized in that: The intermediate frequency signal processing unit includes a filter, an amplifier, an analog-to-digital converter and a fast Fourier transform module, wherein: Filters are used to filter out noise and interference signals; The amplifier is used to enhance the received intermediate frequency signal and improve the signal-to-noise ratio (SNR); The analog-to-digital converter is used to convert the intermediate frequency signal from an analog signal to a digital signal; The fast Fourier transform module is used to perform frequency domain analysis on the intermediate frequency signal and extract the distance information of the target.

4. The high-precision positioning system based on the millimeter wave backscattering system according to claim 1, characterized in that: The data fusion module fuses the measurement data of multiple millimeter-wave radars through an extended Kalman filter algorithm, wherein the state vector of the extended Kalman filter algorithm includes the position (x, y, z) and velocity (v x ,v y ,v z ), the state transfer model adopts a uniform motion model, and the observation model constructs a nonlinear observation equation based on the distance measurement of multiple millimeter-wave radar modules.

5. The high-precision positioning system based on the millimeter wave backscattering system according to claim 1, characterized in that: The millimeter wave reflective tag has a built-in switch that can adjust absorption and reflection. By controlling the switch state, the tag can dynamically adjust the reflection signal and transmit unique tag ID information.

Images