A dual-antenna-based unambiguous cooperative node position detection method and system

Abstract

The present application provides a dual-antenna-based unambiguous collaborative node azimuth detection method and system, which relates to the field of anchor-free collaborative positioning. The method includes: receiving signals transmitted by collaborative nodes through static antennas and mobile antennas to obtain stationary antenna data and rotating antenna data; calculating a channel ratio based on the wireless channel value of the stationary antenna data and the wireless channel value of the rotating antenna data; spatially filtering the channel ratio based on a circular SAR model to obtain a spatial spectrum; extracting peak points in the spatial spectrum to obtain an azimuth angle estimate of the collaborative node, thereby achieving unambiguous multi-collaborative node azimuth detection. Utilizing the present invention, a dual-antenna configuration can be used to achieve high-precision, unambiguous, low-complexity, and clock-free multi-collaborative node azimuth detection, implement anchor-free collaborative positioning, and help deploy multi-functional integrated radio frequency sensor network nodes to meet the multi-scenario perception and information fusion needs of military and civilian fields.

Description

Technical Field

[0001] The present application relates to the field of anchor-free collaborative positioning, and in particular to a dual-antenna-based unambiguous collaborative node orientation detection method and system. Background Art

[0002] In recent years, anchor-free collaborative positioning technology, which estimates the relative position of nodes solely through wireless measurements and information sharing between nodes and their neighbors, has gradually attracted attention due to its potential for widespread application in complex environments. It has become a research hotspot in fields such as intelligent transportation, industrial automation, emergency rescue, smart cities, environmental monitoring, and national defense and security. In a two-dimensional plane, distance and azimuth are the two elements that uniquely establish a relative position. Therefore, accurately estimating the direction of the incident wave from neighboring collaborative nodes is a key aspect of anchor-free collaborative positioning research. Passive direction-finding technology is currently developing rapidly both domestically and internationally. However, traditional passive direction-finding systems require at least three antennas to form an array to receive signals to achieve high angular resolution, and phase ambiguity must also be considered, which makes the system structure complex and costly. Summary of the Invention

[0003] The purpose of the present invention is to provide a dual-antenna-based unambiguous collaborative node direction detection method and system in order to solve the problems of complex system construction and high construction cost caused by the need to configure antenna arrays and strict clock synchronization in existing passive direction-finding solutions in collaborative positioning, which makes the system structure complex and the cost high.

[0004] The above-mentioned purpose of this application is achieved through the following technical solutions:

[0005] S1: Receive the signals transmitted by the cooperative node through the static antenna and the mobile antenna to obtain the static antenna data and the rotating antenna data;

[0006] S2: Wireless channel value based on rotating antenna data and the wireless channel value with the stationary antenna data , calculate the channel ratio;

[0007] S3: Based on the circular SAR model, the channel ratio is spatially filtered to obtain a spatial spectrum. The peak points in the spatial spectrum are extracted to obtain the azimuth angle estimation value of the cooperative node, realizing unambiguous azimuth detection of multiple cooperative nodes.

[0008] Optionally, step S2 includes:

[0009] The static antenna and the mobile antenna receive signals simultaneously, and the time steps of the static antenna data and the rotating antenna data are the same;

[0010]

[0011] in, represents the cumulative phase;

[0012] Calculate the wireless channel ratio using the following formula:

[0013]

[0014] in, Relatively constant over a short period of time.

[0015] Optionally, step S3 includes:

[0016] Substitute the channel ratio into the circular SAR formula, adjust the weight to enhance the signal strength in the direction of the cooperative node, and perform spatial filtering.

[0017] A dual-antenna-based unambiguous cooperative node position detection system, comprising: an antenna unit, a radio frequency front-end module, and an FPGA signal processing unit;

[0018] The antenna unit includes: a stationary antenna and a rotating antenna;

[0019] The radio frequency front-end module is used to transmit and receive radio frequency signals;

[0020] The antenna unit is used to receive signals transmitted by the cooperative node and obtain static antenna data and rotating antenna data;

[0021] The FPGA signal processing unit is used to calculate the wireless channel value based on the rotating antenna data and the wireless channel value with the stationary antenna data , calculate the channel ratio;

[0022] The FPGA signal processing unit is also used to perform spatial filtering on the channel ratio based on the circular SAR model to obtain a spatial spectrum; extract the peak points in the spatial spectrum to obtain the azimuth estimation value of the collaborative node, thereby realizing unambiguous multi-collaborative node azimuth detection.

[0023] Optionally, the antenna unit is connected to an FPGA signal processing unit;

[0024] The radio frequency front-end module is connected to the FPGA signal processing unit.

[0025] Optionally, the antenna unit adopts a 2-transmit 2-receive omnidirectional broadband antenna with a frequency range of 600MHz to 6000MHz.

[0026] Optionally, the FPGA signal processing unit adopts a heterogeneous architecture ZYNQMP FPGA.

[0027] A computer-readable storage medium stores instructions. When the instructions are executed, an unambiguous cooperative node position detection method based on dual antennas is executed.

[0028] The beneficial effects of the technical solution provided by this application are:

[0029] Based on a circular synthetic aperture radar (SAR) model, this invention employs a rotating antenna to receive data, combined with a stationary antenna to construct a wireless channel ratio and perform spatial filtering. This method constructs a high-precision, unambiguous, low-complexity, and clock-synchronization-free multi-cooperative node direction detection method without anchor point assistance, further reducing system complexity and construction costs. Using dual antennas, one stationary and one moving, this method achieves unambiguous multi-cooperative node direction detection without the need for antenna arrays and clock synchronization, reducing system complexity and construction costs. This method has applications in intelligent transportation, unmanned aerial vehicle systems, industrial automation, emergency rescue, smart cities, and environmental monitoring. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The present application will be further described below with reference to the accompanying drawings and embodiments, in which:

[0031] Figure 1 It is a diagram of the unambiguous collaborative node position detection model in an embodiment of the present application;

[0032] Figure 2 This is an overall block diagram of the anchor-free collaborative positioning system in an embodiment of the present application;

[0033] Figure 3 is a flow chart in an embodiment of the present application;

[0034] Figure 4 This is a diagram of a single-target experiment scene in an embodiment of the present application;

[0035] Figure 5 This is a diagram showing the experimental results of a single target direction finding scenario in an embodiment of the present application;

[0036] Figure 6 This is a multi-target experimental scene diagram in an embodiment of the present application;

[0037] Figure 7 This is a diagram of the experimental results of a multi-target direction finding scenario in an embodiment of the present application. DETAILED DESCRIPTION

[0038] In order to have a clearer understanding of the technical features, purposes and effects of this application, the specific implementation methods of this application are now described in detail with reference to the accompanying drawings.

[0039] The embodiments of the present application provide a dual-antenna-based unambiguous collaborative node position detection method.

[0040] Please refer to Figure 1 , Figure 1 This is an unambiguous cooperative node position detection model diagram of an unambiguous cooperative node position detection method based on dual antennas in an embodiment of the present application, including:

[0041] S1: Receive the signals transmitted by the cooperative node through the static antenna and the mobile antenna to obtain the static antenna data and the rotating antenna data;

[0042] S2: Wireless channel value based on rotating antenna data and the wireless channel value with the stationary antenna data , calculate the channel ratio;

[0043] S3: Based on the circular SAR model, the channel ratio is spatially filtered to obtain a spatial spectrum. The peak points in the spatial spectrum are extracted to obtain the azimuth angle estimation value of the cooperative node, realizing unambiguous azimuth detection of multiple cooperative nodes.

[0044] Specifically, the system uses an embedded radio transceiver platform as its hardware foundation, utilizing dual antennas—one static and one dynamic—to receive data. The ratio of the two wireless channels is calculated to eliminate phase differences between the independent transceivers, while also adjusting the weights. By deploying a circular SAR model on the platform and supplementing it with appropriate accessories, unambiguous collaborative node position detection can be implemented.

[0045] Specifically, based on a circular synthetic aperture radar (SAR) model, a rotating antenna is used to receive data, and a stationary antenna is combined to form a wireless channel ratio and perform spatial filtering.

[0046] Step S2 includes:

[0047] The static antenna and the mobile antenna receive signals simultaneously, and the time steps of the static antenna data and the rotating antenna data are the same;

[0048]

[0049] in, represents the cumulative phase;

[0050] Calculate the wireless channel ratio using the following formula:

[0051]

[0052] in, Relatively constant over a short period of time.

[0053] In one embodiment, the unambiguous cooperative node position detection model diagram based on dual antennas is as follows: Figure 1As shown in the figure, the transmission and reception are completed on independent devices. The receiving device consists of a stationary antenna and a mobile antenna. The mobile antenna moves along a circle with a radius of r, similar to a circular synthetic aperture radar. Since the transmission and reception work on SAR used the same reference clock, the wireless channel value of the mobile antenna is measured. It has nothing to do with frequency, that is, However, SAR is actually performed between independent transmitters and receivers, and the measured wireless channel Due to position changes, carrier and sampling frequency offsets between the transmitter and receiver, and phase noise, there will be To eliminate this accumulated phase ,like Figure 1 As shown, one stationary antenna and one mobile antenna are used for reception.

[0054] It is relatively constant in a short time, so the wireless channel ratio is It is a constant multiple of the mobile channel, and there is no phase accumulation caused by frequency deviation and noise, so it is used Substituting this into the SAR formula and adjusting the weights to enhance the signal strength in the incoming wave direction, spatial filtering is achieved. This effectively yields the result of a wireless receiver performing SAR analysis on the incoming wave signal without frequency offset and signal noise accumulation. This enables unambiguous collaborative node direction detection based on dual antennas, reducing system complexity and construction costs without requiring clock synchronization. The technical solution of this application can identify multiple incoming wave directions, as evidenced by the presence of corresponding peaks in the spatial spectrum after data processing for each incoming wave direction.

[0055] Step S3 includes:

[0056] Substitute the channel ratio into the circular SAR formula, adjust the weight to enhance the signal strength in the direction of the cooperative node, and perform spatial filtering.

[0057] A dual-antenna-based unambiguous cooperative node position detection system, comprising: an antenna unit, a radio frequency front-end module, and an FPGA signal processing unit;

[0058] The antenna unit includes: a stationary antenna and a rotating antenna;

[0059] The radio frequency front-end module is used to transmit and receive radio frequency signals;

[0060] The antenna unit is used to receive signals transmitted by the cooperative node and obtain static antenna data and rotating antenna data;

[0061] The FPGA signal processing unit is used to calculate the wireless channel value based on the rotating antenna data and the wireless channel value with the stationary antenna data , calculate the channel ratio;

[0062] The FPGA signal processing unit is also used to perform spatial filtering on the channel ratio based on the circular SAR model to obtain a spatial spectrum; extract the peak points in the spatial spectrum to obtain the azimuth estimation value of the collaborative node, thereby realizing unambiguous multi-collaborative node azimuth detection.

[0063] The antenna unit is connected to the FPGA signal processing unit;

[0064] The radio frequency front-end module is connected to the FPGA signal processing unit.

[0065] The antenna unit adopts a 2-transmit 2-receive omnidirectional broadband antenna with a frequency range of 600MHz to 6000MHz.

[0066] In one embodiment, the overall block diagram of the anchor-free collaborative positioning system used in the present invention is as follows. Figure 2 The system is generally divided into three parts: the antenna unit, the RF front-end module, and the FPGA signal processing unit. The antenna unit uses a dual-transmitter, dual-receiver omnidirectional broadband antenna with a frequency range of 600MHz to 6000MHz. The RF front-end module primarily performs signal up / down conversion, digital-to-analog conversion, and RF signal transmission and reception. The FPGA signal processing unit primarily implements the corresponding signal generation, reception, and processing algorithms.

[0067] The FPGA signal processing unit adopts a heterogeneous architecture ZYNQMP FPGA.

[0068] In one embodiment, co-location RF sensors are typically deployed on outdoor mobile platforms such as unmanned vehicles and drones, placing certain demands on sensor size and power consumption. Therefore, the present invention designs a RF front-end solution based on the ADRV9009 integrated RF transceiver chip. This chip includes four independent communication links: two receive and two transmit, enabling ultra-wideband RF signal transmission and reception from 75MHz to 6000MHz. The core control unit utilizes a Xilinx ZYNQMP heterogeneous FPGA, comprised of resource-rich FPGA programmable logic (PL) and four ARM architecture 53 hard-core processing systems (PS). Most digital signal processing (DSP) tasks, such as filtering, sequence acquisition and tracking, direction of arrival angle calculation, and range estimation, are performed in the core control unit.

[0069] In one embodiment, Figure 3A dual-antenna implementation scheme for unambiguous cooperative node position detection is presented. The embedded radio transceiver platform acquires the cooperative node's transmitted signal, which is converted from analog to digital by the ADC in the RF front-end. This signal is then fed into the FPGA for subsequent signal processing. On the FPGA digital side, after low-pass filtering, the ratio of the two wireless channels is calculated to eliminate phase differences between the independent transceivers. Weights are adjusted, and the channel ratio is spatially filtered using the circular SAR formula. Finally, the peak points in the resulting spatial spectrum are extracted to detect the cooperative node's position in line-of-sight scenarios.

[0070] Example 1:

[0071] Select and Figure 1 The experimental scenario consistent with the model shown in the figure is used to verify the single target direction finding. Figure 4 As shown, the positioning system is deployed in a darkroom with low external multipath interference. The transmitting and receiving antennas use directional and omnidirectional antennas, respectively, with a transmit power of 26 dBm. The rotating antenna and RF sensor on the receiving end are mounted on a device that enables seamless, continuous, and high-precision electronic rotation of 360 degrees horizontally. The antenna's rotation radius is 0.28 meters, and the stationary antenna is placed close to the rotating platform.

[0072] by Figure 4 The coordinate system shown in the figure is used as a reference. The target Tx azimuth angle is set to 90°, 80.54°, and 62.8° by moving the transmitting antenna position. The receiving turntable drives the rotating antenna to move. The current angular position of the rotating antenna is recorded every 10° movement and the data received by the rotating antenna and the stationary antenna at this time are saved. A total of 36 sets of data are saved. The azimuth angle of the collaborative node is estimated by analyzing the received data.

[0073] Use MATLAB to analyze the data received by the antenna and draw a multipath profile diagram. Figure 5 As shown in the figure, the horizontal axis is the spatial angle, and the vertical axis represents the power spectrum amplitude. (a), (b), and (c) respectively show the results of azimuth detection of Amplitude Modulated (AM) and Frequency Modulated (FM) signals when the actual incoming wave directions are 90°, 80.54°, and 62.8°. The angle corresponding to the peak in each sub-figure is the measured incoming wave direction, from which the error table can be obtained, as shown in Table 1:

[0074] Table 1

[0075]

[0076] In the experimental result graph, there is only one obvious beam in each sub-graph, and its amplitude is significantly different from the amplitudes of other side lobes. The angle corresponding to the beam and the actual direction of the incoming wave are both within 1.8°, and the experimental results are relatively ideal.

[0077] Example 2:

[0078] Next, we conduct experimental verification in a multi-objective scenario. Figure 6 As shown, in Figure 4 On the basis, a metal plate was placed to create a reflection path, and the waveforms were verified to be FM signals and sinusoidal signals, both with a carrier frequency of 2.56GHz. The signals reached the receiving end along the direct path and the reflected path with azimuth angles of 116.00° and 132.78° respectively. The other parameters and experimental conditions were the same as those in Example 1. The experimental results are shown in Figure 2. Figure 7 As shown:

[0079] Figure 7 There are two obvious peaks in each subgraph, corresponding to the azimuth angles of the signal reaching the receiver via the two paths. By observing the angles corresponding to the peaks, we can obtain the error table shown in Table 2:

[0080] Table 2

[0081]

[0082] The error between the estimated direction of arrival and the actual azimuth angle is within 1.5°, which once again proves that the invention can detect multiple directions of arrival. The results of Examples 1 and 2 are all single measurement results. As the number of measurements increases, the angle estimation error will be lower, basically within 1°.

[0083] The present application also discloses a computer-readable storage medium storing a plurality of instructions suitable for loading by a processor to execute the above-mentioned method for unambiguous cooperative node position detection based on dual antennas.

[0084] The above are merely exemplary embodiments of the present disclosure and are not intended to limit the scope of the present disclosure. In other words, any equivalent changes and modifications made according to the teachings of the present disclosure are still within the scope of the present disclosure.

[0085] This application is intended to cover any variations, uses, or adaptations of the present disclosure that follow the general principles of the present disclosure and include common knowledge or customary techniques in the art not described herein. The description and examples are to be considered as exemplary only, and the scope and spirit of the present disclosure are to be defined by the claims.

Claims

1. A dual-antenna unambiguous cooperative node position detection method, characterized in that: The method comprises the following steps: S1: Receive the signals transmitted by the cooperative node through the static antenna and the mobile antenna to obtain the static antenna data and the rotating antenna data; S2: Wireless channel value based on rotating antenna data and the wireless channel value with the stationary antenna data Calculate channel ratio; Step S2 includes: The static antenna and the mobile antenna receive signals simultaneously, and the time steps of the static antenna data and the rotating antenna data are the same; in, represents the cumulative phase; Calculate the wireless channel ratio using the following formula: Among them, h2(t)=h2 is relatively constant in a short period of time; S3: Based on the circular SAR model, the channel ratio is spatially filtered to obtain a spatial spectrum. The peak points in the spatial spectrum are extracted to obtain the azimuth angle estimation value of the cooperative node, realizing unambiguous azimuth detection of multiple cooperative nodes.

2. The method for unambiguous cooperative node position detection based on dual antennas according to claim 1, characterized in that: Step S3 includes: Substitute the channel ratio into the circular SAR formula, adjust the weight to enhance the signal strength in the direction of the cooperative node, and perform spatial filtering.

3. A dual-antenna-based unambiguous cooperative node position detection system, used to implement the dual-antenna-based unambiguous cooperative node position detection method according to any one of claims 1 to 2, characterized in that: The system includes: an antenna unit, a radio frequency front-end module and an FPGA signal processing unit; The antenna unit includes: a stationary antenna and a rotating antenna; The radio frequency front-end module is used to transmit and receive radio frequency signals; The antenna unit is used to receive signals transmitted by the cooperative node and obtain static antenna data and rotating antenna data; The FPGA signal processing unit is used to calculate the wireless channel value based on the rotating antenna data and the wireless channel value with the stationary antenna data Calculate channel ratio; The FPGA signal processing unit is also used to perform spatial filtering on the channel ratio based on the circular SAR model to obtain a spatial spectrum; extract the peak points in the spatial spectrum to obtain the azimuth estimation value of the collaborative node, thereby realizing unambiguous multi-collaborative node azimuth detection.

4. The dual-antenna unambiguous cooperative node position detection system according to claim 3, characterized in that: The antenna unit is connected to the FPGA signal processing unit; The radio frequency front-end module is connected to the FPGA signal processing unit.

5. The dual-antenna-based unambiguous cooperative node position detection system according to claim 3, characterized in that: The antenna unit adopts a 2-transmit 2-receive omnidirectional broadband antenna with a frequency range of 600MHz to 6000MHz.

6. The dual-antenna-based unambiguous cooperative node position detection system according to claim 3, characterized in that: The FPGA signal processing unit adopts a heterogeneous architecture ZYNQMP FPGA.

7. A computer-readable storage medium, characterized in that The computer-readable storage medium stores instructions, and when the instructions are executed by a computer, the method according to any one of claims 1 to 2 is executed.

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