RFSOC-based co-frequency direction finding positioning method and system

Abstract

The application discloses a same-frequency direction-finding positioning method and system based on RFSOC, and relates to the technical field of wireless communication. The method comprises the following steps: same-frequency positioning signals are transmitted by two transmitting ends with a preset fixed distance L1, and are received by two receiving ends with the same distance L1; then, the distance differences L2 and L3 between each receiving end and the two transmitting ends are calculated according to the signals received by the receiving ends; then, the motion trajectories of the two receiving ends are determined as a first hyperbola and a second hyperbola based on the distance differences; finally, the real-time coordinates and the position of the receiving device are solved by combining the trajectory equations of the two hyperbolas and the constraint condition that the distance between the two receiving ends is fixed as L1. The application solves the problem that the wireless positioning and direction-finding technology in the prior art generally depends on multiple geographically dispersed base stations, the system is complex to deploy, and the high-precision time synchronization between devices is required by solving the problem that a double-transmitting and double-receiving geometric model of a single station is constructed.

Description

Technical Field

[0001] This invention relates to the field of wireless communication technology, and in particular to a co-frequency direction finding and positioning method and system based on RFSOC. Background Technology

[0002] Wireless positioning and direction finding technology is a key supporting technology in fields such as wireless communication, electronic warfare, unmanned system navigation, and the Internet of Things. Its accuracy and real-time performance are crucial to the success of various applications. Currently, the mainstream wireless positioning and direction finding technologies in the industry mainly include methods based on principles such as Angle of Arrival (AOA), Time of Arrival (TOA), and Time Difference of Arrival (TDOA).

[0003] The AOA (Optical Direction Aspect) method measures the incident direction of electromagnetic wave signals using directional antennas or antenna arrays and determines the target position by the intersection of multiple direction lines. However, the AOA method has high requirements for antenna performance, typically requiring complex high-gain directional antennas, which limits the miniaturization and integration of the device. Furthermore, in non-line-of-sight (NLOS) environments such as urban buildings or complex terrain, multipath effects can cause severe angle measurement errors, leading to a significant decrease in positioning accuracy.

[0004] The Time-of-Age (TOA) and Time-of-Operation (TDOA) methods, based on signal propagation time, are also widely used. The TOA method directly measures the absolute time of flight of a signal from the transmitter to the receiver, and then converts this into distance. A fatal flaw of this method is that it requires all transmitting and receiving nodes in the system to maintain strict time synchronization at the nanosecond level, which is extremely costly and technically challenging to implement in distributed systems. The TDOA method locates a target by measuring the time difference between the arrival of a signal at receiving stations at different locations in space. A fixed time difference can define a hyperboloid with two receiving stations as foci, and the target location can be calculated by finding the intersections of multiple hyperboloids. Although TDOA technology relaxes the requirement for absolute time synchronization between the transmitter and receiver, its classic implementation still relies on at least three geographically dispersed, calibrated fixed base stations for collaborative measurement. This results in high system deployment and maintenance complexity, increased cost and power consumption, making it unsuitable for mobile or portable applications requiring flexible and rapid deployment.

[0005] Existing wireless positioning and direction finding technologies generally suffer from problems such as reliance on multiple base stations working together, complex system deployment, large equipment size and power consumption, stringent clock synchronization requirements, or weak multipath resistance. Therefore, the industry urgently needs a new technical solution that can simplify the system architecture, reduce the dependence on multi-station networking and high-precision time synchronization, and achieve accurate direction finding and positioning with higher integration and lower power consumption. Summary of the Invention

[0006] The purpose of this invention is to provide a co-frequency direction finding and positioning method and system based on RFSOC, aiming to solve the technical problems of existing wireless positioning and direction finding technologies, such as reliance on multiple base stations working together, complex system deployment, large equipment size and power consumption, and stringent clock synchronization requirements.

[0007] In a first aspect, embodiments of the present invention propose a co-frequency direction finding and positioning method based on RFSOC, the method comprising:

[0008] The first and second transmitting ends of the transmitting device transmit positioning signals at the same frequency, and the distance between the first and second transmitting ends is a preset fixed distance L1;

[0009] The positioning signal is received by the first receiving end and the second receiving end of the receiving device, and the distance between the first receiving end and the second receiving end is also a fixed distance L1;

[0010] Based on the positioning signal received by the first receiving end, calculate the distance difference L2 between the first receiving end and the first transmitting end and the second transmitting end respectively; and based on the positioning signal received by the second receiving end, calculate the distance difference L3 between the second receiving end and the first transmitting end and the second transmitting end respectively.

[0011] Based on the distance difference L2 and the fixed distance L1, the motion trajectory of the first receiving end is determined to be a first hyperbola; and based on the distance difference L3 and the fixed distance L1, the motion trajectory of the second receiving end is determined to be a second hyperbola.

[0012] By combining the trajectory equations of the first hyperbola and the second hyperbola, and taking into account the constraint that the first receiving end and the second receiving end maintain a fixed distance L1, the real-time coordinates of the receiving device are calculated, and the orientation of the receiving device relative to the transmitting device is determined accordingly.

[0013] Preferably, the transmitting device generates an intermediate frequency carrier signal carrying the positioning signal through the digital up-conversion (DUC) function of the RFSOC chip;

[0014] The receiving device processes the received signal through the digital down-conversion (DDC) function of the RFSOC chip; the transmitting and receiving devices operate in time-division duplex mode.

[0015] Preferably, the method for calculating the distance differences L2 and L3 includes:

[0016] The amplitude A of the transmitted signal from the transmitting device is obtained by calibration, and the amplitude Am of the superimposed signal is obtained by real-time sampling using the RF-ADC of the receiving device. The phase difference φ between the received signal and the transmitted signal is calculated using the phase difference calculation formula φ=2*arccos(Am / 2A). The corresponding distance difference is calculated based on the phase difference φ and the signal wavelength λ.

[0017] Preferably, the first hyperbola is a trajectory with the first transmitting end and the second transmitting end as its two foci, and the absolute value of the difference in distance from any point on the curve to the two foci is equal to the distance difference L2; the second hyperbola is a trajectory with the first transmitting end and the second transmitting end as its two foci, and the absolute value of the difference in distance from any point on the curve to the two foci is equal to the distance difference L3.

[0018] Preferably, in a coordinate system established with the straight line containing the first and second transmitting ends as the x-axis and the midpoint of the two transmitting ends as the origin, the equation parameters of the first hyperbola satisfy: focal length 2c = L1, real axis length 2a = |L2|; the equation parameters of the second hyperbola satisfy: focal length 2c = L1, real axis length 2a = |L3|.

[0019] Preferably, when the distance between the receiving device and the transmitting device meets a preset condition, it is assumed that the line segment connecting the first receiving end and the second receiving end is parallel to the line segment connecting the first transmitting end and the second transmitting end, thereby simplifying the calculation process of real-time coordinates.

[0020] Preferably, both the transmitting end of the transmitting device and the receiving end of the receiving device employ omnidirectional antennas.

[0021] Preferably, when there are multiple positioning nodes, different nodes use positioning signals of different frequency bands for identification and transmit them in a time-division manner through preset time slots.

[0022] Secondly, embodiments of the present invention propose a co-frequency direction finding and positioning system based on RFSOC, the system comprising:

[0023] The transmitting module is equipped with two transmitting ends spaced at a preset fixed distance L1, which are used to transmit positioning signals with the same frequency;

[0024] The receiving module, built on an RFSOC chip, is configured with two receivers spaced at a fixed distance L1 to receive positioning signals.

[0025] The processing module, integrated with the receiving module within the same RFSOC chip, includes:

[0026] The distance difference calculation unit is used to calculate the distance differences L2 and L3 from each receiver to the two transmitters based on the positioning signals received by the two receivers.

[0027] The trajectory determination unit is used to determine a first hyperbolic trajectory and a second hyperbolic trajectory for the two receiving ends based on the distance differences L2 and L3 and the fixed distance L1.

[0028] The positioning calculation unit is used to combine the first hyperbola and the second hyperbola, and calculate the position and orientation of the receiving module based on the constraint that the two receiving ends maintain a fixed distance L1.

[0029] Preferably, the RFSOC chip integrates a radio frequency digital-to-analog converter (RFADC) and a radio frequency digital-to-analog converter (RFDAC); the transmitting module generates radio frequency signals through the RFDAC, and the receiving module acquires radio frequency signals through the RFADC; the processing module further implements intermediate frequency carrier processing through the digital up-conversion (DUC) and digital down-conversion (DDC) functions of the RFSOC chip.

[0030] Beneficial effects:

[0031] This invention achieves high-precision single-station passive direction finding and positioning by constructing a unique direction-finding model with fixed spacing between dual transmitters and dual receivers, and using co-frequency signals to calculate hyperbolic trajectories. Its "single-station" characteristic overcomes the dependence on complex antennas in traditional AOA methods and the limitations of multi-base station networking in TDOA methods, thus greatly simplifying system deployment and maintenance costs. It is particularly suitable for mobile scenarios requiring rapid and flexible deployment, such as emergency communication and UAV navigation. Furthermore, this method is based on distance difference calculation, avoiding the stringent requirements of nanosecond-level high-precision time synchronization in traditional TOA methods, significantly reducing technical difficulty, hardware costs, and eliminating clock drift errors. By using an RFSOC chip as the core, the RF transceiver front-end and digital processing logic are highly integrated into a single chip, significantly reducing device size and power consumption, and enhancing signal integrity through simplified architecture. In summary, this invention transfers system complexity from external facilities to efficient on-chip algorithms, providing a novel technical path with low hardware requirements, flexible deployment, high integration, and accurate positioning. Attached Figure Description

[0032] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0033] Figure 1 This is a schematic diagram of the hardware architecture of the orientation finding and positioning system proposed in this embodiment of the invention;

[0034] Figure 2 This is a schematic diagram of the antenna transceiver plane proposed in an embodiment of the present invention;

[0035] Figure 3 This is a schematic diagram illustrating the definition of points A, B, and C as proposed in an embodiment of the present invention;

[0036] Figure 4 This is a schematic diagram of the trajectory of node C proposed in an embodiment of the present invention;

[0037] Figure 5 This is a schematic diagram of the trajectories of the two receiving nodes C and D proposed in this embodiment of the invention;

[0038] Figure 6 This is a schematic diagram of the receiving node direction finding and positioning proposed in an embodiment of the present invention;

[0039] Figure 7 This is a flowchart of a co-frequency direction finding and positioning method based on RFSOC proposed in an embodiment of the present invention;

[0040] Figure 8 This is a schematic diagram of the functional modules of a co-frequency direction finding and positioning device based on RFSOC proposed in an embodiment of the present invention;

[0041] Figure 9 This is a schematic diagram of the structure of the computer device proposed in the embodiments of the present invention. Detailed Implementation

[0042] To more clearly illustrate the technical solutions in the embodiments of the invention or the prior art, the invention will be briefly introduced below in conjunction with the accompanying drawings and descriptions of the embodiments or the prior art. Obviously, the following description of the structure of the drawings is only some embodiments of the invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. It should be noted that the description of these embodiments is for the purpose of helping to understand the invention, but does not constitute a limitation on the invention.

[0043] For the first aspect, please refer to... Figure 7 This embodiment provides a co-frequency direction finding and positioning method based on RFSOC. This method aims to solve the problems commonly found in existing direction finding and positioning systems, such as reliance on multiple base stations, complex deployment, large power consumption and size, and stringent clock synchronization requirements. It provides a highly integrated, low-power, and high-precision single-station direction finding and positioning solution. The executing entity of this method can be an electronic device integrating a transmitting and receiving device, such as a software-defined radio, a UAV payload, or a portable communication terminal.

[0044] See Figure 1This is a schematic diagram of the hardware architecture of the direction finding and positioning system described in this embodiment of the invention. Physically, the system mainly consists of a radio frequency (RF) section and a digital section, with its core being the Radio Frequency System on Chip (RFSOC) chip, which serves as the digital section. The RFSOC chip integrates high-performance radio frequency-to-data converters (RF-ADC and RF-DAC) and core Field Programmable Gate Array (FPGA) logic resources, enabling the entire process from direct sampling / generation of RF signals to complex baseband signal processing. Both the transmitting and receiving devices are built upon this RFSOC chip.

[0045] The radio frequency (RF) section includes at least two transmit links and two receive links. On the receive links, the signal received by the antenna passes sequentially through a bandpass filter (BPF), attenuator, low-noise amplifier (LNA), and a switchable segmented filter bank before being directly sampled by the RFADC of the RFSOC chip. On the transmit links, the signal generated by the RFDAC of the RFSOC chip passes through a power amplifier (PA) and a bandpass filter (BPF) before being transmitted through the antenna. This direct sampling architecture greatly simplifies the traditional superheterodyne structure, reduces the number of analog components, and improves system integration and stability. The following will be discussed in conjunction with the attached... Figures 2 to 6 The specific steps of the same-frequency direction finding and positioning method based on RFSOC provided in this embodiment are described in detail.

[0046] Step S1: The first and second transmitting ends of the transmitting device transmit positioning signals with the same frequency, and the distance between the first and second transmitting ends is a preset fixed distance L1.

[0047] In this step, positioning signals with identical frequencies are transmitted from the first transmitting end A and the second transmitting end B of the transmitting device. See also... Figure 2 and Figure 3 In the geometric model shown, the positions of the first transmitter A and the second transmitter B in physical space are fixed, and the distance between them is a preset, known fixed distance L1. These two transmitters can be regarded as positioning references.

[0048] Preferably, in order to maximize coverage and simplify the system's requirements for antenna directivity, both transmitters A and B of the transmitting device use omnidirectional antennas.

[0049] To achieve efficient signal generation and simultaneous transmission at the same frequency, this embodiment fully utilizes the powerful capabilities of the RFSOC chip. Specifically, the positioning signal itself is a low-data-rate baseband signal, for example, with a frequency below 10kHz. This baseband signal is digitally generated in the FPGA logic within the RFSOC chip. Subsequently, the transmitting device uses the digital up-conversion (DUC) function integrated into the RFSOC chip to mix this digital baseband signal with a digitally generated local oscillator (NCO) signal, thereby generating an intermediate frequency (IF) carrier signal carrying the positioning signal. Finally, this digital IF signal is sent to the RFDAC to be converted into an analog radio frequency (RF) signal and transmitted via the transmission link. Since the signals from both transmitters originate from the unified control and generation of the same RFSOC chip, it can be ensured that the signals they transmit are strictly consistent in frequency and have a definite phase relationship.

[0050] Step S2: The positioning signal is received by the first receiving end and the second receiving end of the receiving device, and the distance between the first receiving end and the second receiving end is also a fixed distance L1.

[0051] In this step, the first receiving end C and the second receiving end D of the receiving device synchronously receive the positioning signals transmitted by the transmitting ends A and B. Similar to the transmitting device, the physical distance between the two receiving ends C and D of the receiving device is also precisely designed to be the aforementioned fixed distance L1. Receiving ends C and D typically share an antenna with transmitting ends A and B, and the transmitting device and the receiving device operate in Time Division Duplex (TDD) mode.

[0052] Preferably, the receiving ends C and D of the receiving device also employ omnidirectional antennas to ensure stable signal reception from any direction.

[0053] Specifically, when the system is operating in the receive time slot, the mixed radio frequency signal received by the antennas of receivers C and D is transmitted via... Figure 1 The received signal, as shown, is fed into the RFADC of the RFSOC chip for high-speed, high-precision direct sampling and converted into a digital signal. Subsequently, the receiving device utilizes the digital down-conversion (DDC) function integrated into the RFSOC chip to process the sampled digital signal. The DDC module down-converts the broadband RF signal to baseband by digitally mixing, filtering, and decimating it with a digital local oscillator signal, thereby recovering the original positioning signal for subsequent processing. In this TDD mode, the transmitting and receiving devices alternately transmit and receive within a preset time slot, allowing the transceiver system to use the exact same frequency, significantly improving spectrum utilization.

[0054] Step S3: Based on the positioning signal received by the first receiving end, calculate the distance difference L2 between the first receiving end and the first transmitting end and the second transmitting end respectively; and based on the positioning signal received by the second receiving end, calculate the distance difference L3 between the second receiving end and the first transmitting end and the second transmitting end respectively.

[0055] In this step, the system needs to calculate a key geometric parameter—the distance difference—based on the received signal. Specifically, the processing module (integrated within the FPGA of the RFSOC chip) needs to perform the following calculations:

[0056] Based on the mixed signal received by the first receiver C (which includes signal components from the transmitter A and the transmitter B), the difference in propagation path length from the first receiver C to the first transmitter A and the second transmitter B is calculated and denoted as the distance difference L2, i.e., L2=|AC-BC|.

[0057] Similarly, based on the mixed signal received by the second receiver D, the difference in propagation path length from the second receiver D to the first transmitter A and the second transmitter B is calculated and denoted as the distance difference L3, i.e., L3=|AD-BD|.

[0058] Preferably, the specific method for calculating the distance differences L2 and L3 is as follows:

[0059] Since the signals emitted by transmitters A and B are continuous waves or periodic signals with the same frequency, at receiver C (or D), the signals from A and B will interfere and superimpose. The amplitude Am of the superimposed signal has a fixed mathematical relationship with the amplitude A of the original transmitted signal and the phase difference φ between the two signals. This embodiment utilizes this relationship to accurately deduce the phase difference.

[0060] First, a calibration is performed before system deployment or during operation to pre-determine the amplitude A of the transmitted signal from the transmitting device. At the receiving end, the RFSoC's RFADC samples the received superimposed signal to obtain its real-time amplitude value Am. Based on signal interference theory, the relationship between the phase difference φ and the amplitude can be derived as follows:

[0061] φ = 2*arccos(Am / 2A)

[0062] Using this formula, the processing module can accurately calculate the phase difference φ between the two signals arriving at the receiver based on the real-time sampling amplitude Am and the calibrated transmission amplitude A. After obtaining the phase difference, it can be converted into a physical distance difference L based on the electromagnetic wavelength λ (λ=c / f, where c is the speed of light and f is the signal frequency). For example, for receiver C, the distance difference L2 can be calculated using the phase difference φ_C. Similarly, the distance difference L3 for receiver D can be calculated. This method does not require high-precision timestamps; accurate calculation of the distance difference can be achieved solely through amplitude measurement.

[0063] Step S4: Based on the distance difference L2 and the fixed distance L1, determine the motion trajectory of the first receiving end as a first hyperbola; and based on the distance difference L3 and the fixed distance L1, determine the motion trajectory of the second receiving end as a second hyperbola.

[0064] In this step, the system uses the distance differences L2 and L3 calculated in the previous step, as well as the known transmitter spacing L1, to determine the geometric trajectories of the instantaneous positions of the two receivers. According to the geometric definition of a hyperbola: the locus of points in a plane whose absolute difference in distance to two fixed points (foci) is constant is a hyperbola.

[0065] Preferably, in the model of the present invention:

[0066] For the first receiver C, the absolute value of the difference in distances to the two fixed transmitters (foci) A and B is L2. Therefore, at any given time, point C must lie on a hyperbola with foci A and B and a distance difference of L2. This trajectory is called the first hyperbola. Similarly, for the second receiver D, the absolute value of the difference in distances to foci A and B is L3. Therefore, point D must lie on a hyperbola with foci A and B and a distance difference of L3. This trajectory is called the second hyperbola.

[0067] See Figure 4 This diagram illustrates the trajectory of a single receiving point (such as C). A and B are the foci, and the curve is a hyperbola formed by all possible positions of point C. See also... Figure 5 The figure illustrates the trajectory when two receiving points C and D exist simultaneously, each constrained by its own hyperbolic constraint.

[0068] Preferably, to facilitate mathematical description and equation solving, a Cartesian coordinate system is established. The line containing the first transmitter A and the second transmitter B is taken as the x-axis, and the midpoint of line segment AB is taken as the origin (0,0). Therefore, the coordinates of transmitter A are (-L1 / 2,0), and the coordinates of transmitter B are (L1 / 2,0). In this coordinate system:

[0069] The equation of the first hyperbola satisfies the following parameters: focal length 2c = L1, real axis length 2a = |L2|. Its standard equation can be written.

[0070] The equation of the second hyperbola satisfies the following parameters: focal length 2c = L1, real axis length 2a = |L3|. Its standard equation can also be written.

[0071] Step S5: Solve the trajectory equations of the first hyperbola and the second hyperbola simultaneously, and combine them with the constraint that the first receiving end and the second receiving end maintain a fixed distance L1, to calculate the real-time coordinates of the receiving device, and determine the orientation of the receiving device relative to the transmitting device accordingly.

[0072] In this step, the system will integrate all known information and constraints to ultimately calculate the precise position and orientation of the receiving device. At this point, the following equations and conditions are available:

[0073] The coordinates (x_C, y_C) of the first receiving end C satisfy the equation of the first hyperbola.

[0074] The coordinates (x_D, y_D) of the second receiver D satisfy the equation of the second hyperbola.

[0075] The distance between the first receiving end C and the second receiving end D is always L1.

[0076] Right now .

[0077] By simultaneously solving these three equations (two hyperbolic equations and one distance constraint equation), a system of equations can be formed. The processing module solves this system of equations using numerical calculations or analytical methods to obtain the unique and precise coordinates of receivers C and D. Once the coordinates of C and D are determined, the real-time coordinates of the receiving device (e.g., the coordinates of the midpoint of line segment CD) are also determined.

[0078] See Figure 6 After the coordinates of C and D are calculated, the azimuth angle (i.e., direction finding result) α of the receiving device relative to the transmitting device can also be easily calculated, for example, by calculating the angle between vector CD and the x-axis.

[0079] Preferably, to simplify calculations under specific conditions, an approximate assumption can be introduced. When the distance between the receiving device and the transmitting device is much greater than their respective internal fixed distance L1: wherein, when the distance between the receiving device and the transmitting device meets a preset condition, for example, this distance is at least 10 times the fixed distance L1, to ensure that the positioning error caused by the simplified calculation is within an acceptable range, the line segment connecting the first receiving end C and the second receiving end D can be approximated as parallel to the line segment connecting the first transmitting end A and the second transmitting end B (i.e., the x-axis). In this case, y_C = y_D, which greatly simplifies the solution process and allows for faster acquisition of approximate solutions for real-time coordinates, making it suitable for scenarios with extremely high computational efficiency requirements.

[0080] Preferably, the method of the present invention can be extended to multi-node cooperative positioning networks. When multiple such positioning nodes exist, to avoid mutual interference between signals, positioning signals of different frequency bands can be assigned to different nodes. Although the transmission and reception within each node are "on the same frequency," the different signal frequencies between nodes can serve as identification. Simultaneously, through an upper-level scheduling mechanism, a preset transmission time slot is allocated to each node, and each node operates using a time-division multiplexing method, thereby constructing an orderly and efficient multi-node cooperative direction-finding positioning network.

[0081] For the second aspect, please refer to... Figure 8 This invention also proposes a co-frequency direction finding and positioning system based on RFSOC, which is adapted to the co-frequency direction finding and positioning method described in the foregoing embodiments. This system aims to provide a direction finding and positioning solution with highly integrated hardware, simplified structure, low power consumption, and flexible deployment. The system is described in detail below with reference to specific embodiments. The system includes a transmitting module, a receiving module, and a processing module, wherein each module works collaboratively under the unified scheduling of the RFSOC chip to form an integrated high-performance direction finding and positioning platform.

[0082] The transmitting module's core function is to generate and transmit radio frequency (RF) signals for direction finding and positioning. Physically, this module includes two transmitters (corresponding to A and B in the aforementioned embodiments), such as two physically separate omnidirectional antennas precisely configured to be spaced a predetermined fixed distance L1 apart. This module transmits positioning signals at identical frequencies, establishing a stable geometric measurement reference for the receiver. Preferably, the signal generation chain of the transmitting module is entirely implemented based on an RFSOC chip. Specifically, the processing logic (FPGA) within the RFSOC chip first digitally generates a baseband positioning signal, then modulates this baseband signal to the required intermediate frequency (IF) using the chip's integrated digital up-conversion (DUC) function. Finally, this digital IF signal is fed into the chip's integrated radio frequency digital-to-analog converter (RFDAC) to convert it into an analog signal. This analog signal then passes through external RF front-end circuits such as a power amplifier (PA) and a bandpass filter (BPF) (see [link to relevant documentation]). Figure 1 After that, it is transmitted by two transmitting antennas. In this way, the transmitting module can use a single chip to generate two radio frequency signals with precisely controlled frequency and phase relationships, ensuring the accuracy of the positioning algorithm.

[0083] The receiving module's core function is to capture and digitize positioning signals in space for subsequent processing. This module is built on an RFSOC chip and physically has two receivers spaced at a fixed distance L1 (corresponding to C and D in the aforementioned embodiments), preferably using omnidirectional antennas. This module receives positioning signals transmitted from the transmitting module at the same frequency. Preferably, the signal processing link of the receiving module is also highly integrated within the RFSOC chip. Specifically, the radio frequency signals received by the two receiving antennas pass through external low-noise amplifiers (LNAs), filter banks, and other radio frequency front-end circuits (see...). Figure 1 After conditioning, the signal is directly fed into the radio frequency digital-to-analog converter (RFADC) integrated in the RFSOC chip for high-speed sampling, completing the analog-to-digital conversion. The sampled high-frequency digital signal is then fed into the chip-integrated digital down-conversion (DDC) module, where digital mixing and filtering operations demodulate the useful positioning signal from the high-frequency carrier, restoring it to a digital baseband signal. This direct sampling architecture based on RFSOC eliminates the need for traditional complex analog intermediate frequency circuits in the receiver module, greatly improving integration and reducing power consumption and size.

[0084] The processing module, the brain of the entire positioning system, is responsible for executing the core positioning algorithm. Crucially, the functional logic of this processing module and the receiving module (such as DDC) are seamlessly integrated within the FPGA resources of the same RFSOC chip, achieving zero-latency and high-bandwidth interaction between data acquisition and processing. The processing module is further divided into three collaborative logical units:

[0085] The distance difference calculation unit takes as input two digital baseband signals processed by the receiving module DDC. Its function is to calculate the distance differences L2 and L3 from each receiver (C and D) to the two transmitters (A and B) based on these two signals. As described in the previous embodiment, this unit analyzes the superimposed amplitude Am of the received signals and the calibrated amplitude A of the transmitted signals, uses the formula φ=2*arccos(Am / 2A) to inversely calculate the phase difference of the signals, and finally converts it into physical distance differences L2 and L3 based on the signal wavelength. All calculations are implemented in parallel hardware logic within the FPGA of the RFSOC chip, ensuring real-time computation.

[0086] The trajectory determination unit receives L2 and L3 from the distance difference calculation unit, along with a system-preset fixed distance L1, as input. Its core function is to determine a mathematically precise motion trajectory for each of the two receiving ends, C and D, based on the geometric definition of a hyperbola. Specifically, it determines the equation parameters of the first hyperbola (foci A and B, distance difference L2) and the second hyperbola (foci A and B, distance difference L3). For example, in a coordinate system with the midpoint of AB as the origin, it determines the a values ​​(|L2| / 2 and |L3| / 2) and c values ​​(L1 / 2) of the two hyperbolas, thus providing geometric constraints for the next step of positioning calculation.

[0087] The positioning and calculation unit is the executor of the final positioning. It receives two hyperbolic equations from the trajectory determination unit and combines them with the rigid constraint that the distance between the two receivers remains constant at a fixed value L1. Using a numerical iterative algorithm (such as Newton's method) or analytical algorithm implemented within the FPGA, this unit simultaneously solves the system of equations consisting of the two hyperbolic equations and a distance constraint equation, ultimately calculating the unique and precise coordinates (x_C, y_C) and (x_D, y_D) of receivers C and D. After obtaining the coordinates, this unit can further calculate the center position of the receiving module and its precise azimuth angle relative to the transmitting module, completing the entire direction finding and positioning process.

[0088] In summary, the system proposed in this embodiment of the invention highly integrates the functions of the three core modules of transmission, reception and processing into a single RFSOC chip, forming a compact, efficient and low-power single-station co-frequency direction finding and positioning system. It can effectively adapt to the methods described in the foregoing embodiments and provides strong technical support for various wireless positioning application scenarios that require flexible deployment.

[0089] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make various changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention.

[0090] Please see Figure 9 The third aspect of this application provides a co-frequency direction finding and positioning device based on RFSOC, including a memory and a processor connected in sequence. The memory is used to store a computer program, and the processor is used to read the computer program and execute the co-frequency direction finding and positioning method based on RFSOC as described in the first aspect of the application. Specifically, the memory may include, but is not limited to, random access memory (RAM), read-only memory (ROM), flash memory, first-in-first-out memory (FIFO), and / or last-in-first-out memory (FILO), etc.; the processor may be not limited to microprocessors of the STM32F105 series, ARM (Advanced RISC Machines), x86 architecture processors, or processors with integrated NPU (neural-network processing units).

[0091] The working process, working details and technical effects of the device provided in the third aspect of this embodiment can be found in the first aspect of the embodiment, and will not be repeated here.

[0092] This fourth aspect of the embodiment provides a computer-readable storage medium storing instructions containing the same-frequency direction finding and positioning method based on RFSOC according to the first aspect of the embodiment. Specifically, the computer-readable storage medium stores instructions that, when executed on a computer, perform the same-frequency direction finding and positioning method based on RFSOC as described in the first aspect. The computer-readable storage medium refers to a data storage medium, which may include, but is not limited to, floppy disks, optical disks, hard disks, flash memory, USB flash drives, and / or Memory Sticks. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices.

[0093] The working process, working details and technical effects of the computer-readable storage medium provided in the fourth aspect of this embodiment can be found in the first aspect of the embodiment, and will not be repeated here.

[0094] The fifth aspect of this embodiment provides a computer program product containing instructions that, when executed on a computer, cause the computer to perform the same-frequency direction finding and positioning method based on RFSOC as described in the first aspect of this embodiment. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices.

[0095] The embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0096] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., including several instructions to cause a repository code merging device to execute the methods of various embodiments or some parts of the embodiments.

[0097] Finally, it should be noted that the above are merely preferred embodiments of the invention and are not intended to limit the scope of protection of the invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the invention should be included within the scope of protection of the invention.

Claims

1. A co-frequency direction finding and positioning method based on RFSOC, characterized in that, The method includes: The first and second transmitting ends of the transmitting device transmit positioning signals at the same frequency, and the distance between the first and second transmitting ends is a preset fixed distance L1; The positioning signal is received by the first receiving end and the second receiving end of the receiving device, and the distance between the first receiving end and the second receiving end is also the fixed distance L1; Based on the positioning signal received by the first receiving end, calculate the distance difference L2 between the first receiving end and the first transmitting end and the second transmitting end respectively; and based on the positioning signal received by the second receiving end, calculate the distance difference L3 between the second receiving end and the first transmitting end and the second transmitting end respectively. Based on the distance difference L2 and the fixed distance L1, the motion trajectory of the first receiving end is determined to be a first hyperbola; and based on the distance difference L3 and the fixed distance L1, the motion trajectory of the second receiving end is determined to be a second hyperbola. By combining the trajectory equations of the first hyperbola and the second hyperbola, and taking into account the constraint that the first receiving end and the second receiving end maintain the fixed distance L1, the real-time coordinates of the receiving device are calculated, and the orientation of the receiving device relative to the transmitting device is determined accordingly. The methods for calculating the distance differences L2 and L3 include: The amplitude A of the transmitted signal from the transmitting device is obtained by calibration, and the amplitude Am of the superimposed signal is obtained by real-time sampling using the radio frequency digital-to-analog converter (RFADC) of the receiving device. The phase difference φ between the received signal and the transmitted signal is calculated using the phase difference calculation formula φ=2*arccos(Am / 2A). The corresponding distance difference is calculated based on the phase difference φ and the signal wavelength λ.

2. The method according to claim 1, characterized in that, The transmitting device generates an intermediate frequency carrier signal carrying the positioning signal through the digital up-conversion (DUC) function of the RFSOC chip. The receiving device processes the received signal through the digital down-conversion (DDC) function of the RFSOC chip; wherein the transmitting device and the receiving device operate in time-division duplex mode.

3. The same-frequency direction finding and positioning method according to claim 1, characterized in that, The first hyperbola is the trajectory with the first transmitting end and the second transmitting end as the two foci, and the absolute value of the difference in distance from any point on the curve to the two foci is equal to the distance difference L2; the second hyperbola is the trajectory with the first transmitting end and the second transmitting end as the two foci, and the absolute value of the difference in distance from any point on the curve to the two foci is equal to the distance difference L3.

4. The same-frequency direction finding and positioning method according to claim 3, characterized in that, In a coordinate system established with the straight line containing the first and second transmitters as the x-axis and the midpoint of the two transmitters as the origin, the equation parameters of the first hyperbola satisfy: focal length 2c = L1, real axis length 2a = |L2|; the equation parameters of the second hyperbola satisfy: focal length 2c = L1, real axis length 2a = |L3|.

5. The same-frequency direction finding and positioning method according to claim 1, characterized in that, When the distance between the receiving device and the transmitting device meets the preset conditions, it is assumed that the line segment connecting the first receiving end and the second receiving end is parallel to the line segment connecting the first transmitting end and the second transmitting end, thereby simplifying the calculation process of the real-time coordinates.

6. The same-frequency direction finding and positioning method according to claim 1, characterized in that, Both the transmitting end of the transmitting device and the receiving end of the receiving device employ omnidirectional antennas.

7. The same-frequency direction finding and positioning method according to claim 1, characterized in that, When there are multiple positioning nodes, different nodes use positioning signals of different frequency bands for identification and transmit them in a time-division manner through preset time slots.

8. A co-frequency direction finding and positioning system based on RFSOC, characterized in that, The system includes: The transmitting module is equipped with two transmitting ends spaced at a preset fixed distance L1, which are used to transmit positioning signals with the same frequency; The receiving module, built on an RFSOC chip, is configured with two receiving ends spaced at a fixed distance L1 for receiving the positioning signal; The processing module, integrated with the receiving module within the same RFSOC chip, includes: The distance difference calculation unit is used to calculate the distance differences L2 and L3 from each receiver to the two transmitters based on the positioning signals received by the two receivers. The trajectory determination unit is used to determine a first hyperbolic trajectory and a second hyperbolic trajectory for the two receiving ends based on the distance differences L2 and L3 and the fixed distance L1, respectively. The positioning calculation unit is used to combine the first hyperbola and the second hyperbola, and calculate the position and orientation of the receiving module based on the constraint of maintaining the fixed distance L1 between the two receiving ends. The specific configuration of the distance difference calculation unit is as follows: the amplitude A of the transmitted signal of the transmitting module is obtained by calibration, and the amplitude Am of the superimposed signal is obtained by real-time sampling using the radio frequency digital-to-analog converter (RFADC) of the receiving module. The phase difference φ between the received signal and the transmitted signal is calculated using the phase difference calculation formula φ=2*arccos(Am / 2A). The corresponding distance difference is calculated based on the phase difference φ and the signal wavelength λ.

9. The same-frequency direction finding and positioning system according to claim 8, characterized in that, The RFSOC chip integrates a radio frequency digital-to-analog converter (RFADC) and a radio frequency digital-to-analog converter (RFDAC); the transmitting module generates radio frequency signals through the RFDAC, and the receiving module acquires radio frequency signals through the RFADC; the processing module further implements intermediate frequency carrier processing through the digital up-conversion (DUC) and digital down-conversion (DDC) functions of the RFSOC chip.

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