A direction-finding sensor device based on a single receiver and an ultra-wideband antenna array.

Abstract

This invention discloses a direction-finding sensor device based on a single-receiver ultra-wideband antenna array. The device includes an MCU microcontroller, an IMU sensor, a barometric altimeter, an ultra-wideband receiver, and a multi-input single-output (MIMO) delay overlay network. The MIMO delay overlay network has a delay line module. The output of the MIMO delay overlay network is connected to the input of the ultra-wideband receiver via a first data bus. The ultra-wideband receiver is interconnected with the MCU microcontroller via a second data bus. The MCU microcontroller is interconnected with the barometric altimeter via an SPI bus. The output of the IMU sensor is connected to the input of the MCU microcontroller via a third data bus. This invention can improve the positioning accuracy of ultra-wideband direction-finding information by using a delay line of a given length to perform group delay on ultra-wideband pulse signals. As a direction-finding sensor device based on a single-receiver ultra-wideband antenna array, this invention can be widely used in the field of ultra-wideband positioning technology.

Description

Technical Field

[0001] This invention relates to the field of ultra-wideband positioning technology, and in particular to an ultra-wideband antenna array direction-finding sensor device based on a single receiver. Background Technology

[0002] Location information acquisition is one of the fundamental technologies for realizing the Internet of Things (IoT). Ultra-wideband (UWB) signals, as a high-precision positioning signal, have many advantages such as high time resolution, strong penetration, insensitivity to channel fading, low signal energy spectral density, and low system complexity. They can be widely used in various indoor and outdoor environments without satellite navigation for locating personnel, materials, and vehicles. By utilizing the time phase difference of the source signals received by each antenna in an UWB antenna array, source direction estimation can be performed based on TDoA or PDoA theories, which can be used to solve the direction positioning problem in GNSS-denied environments. However, to meet the requirement of simultaneously processing signals received by multiple antennas in the antenna array, existing technologies use a one-to-one receiver-antenna pairing scheme, using multiple receivers to process the corresponding antenna signals. This results in problems such as low clock synchronization accuracy among the receivers. This affects the positioning accuracy on the one hand, and increases material costs on the other. Summary of the Invention

[0003] To address the aforementioned technical problems, the present invention aims to provide a single-receiver-based ultra-wideband antenna array direction-finding sensor device. This device can solve the signal peak aliasing and correspondence problems by using a delay line of a given length to perform group delay on the ultra-wideband pulse signal, thereby improving the positioning accuracy of ultra-wideband direction-finding information.

[0004] The first technical solution adopted in this invention is: a direction-finding sensor device based on a single receiver ultra-wideband antenna array, comprising an MCU microcontroller, an IMU sensor, a barometric altimeter, an ultra-wideband receiver, and a multi-input single-output delay superposition network. The multi-input single-output delay superposition network has a delay line module. The output of the multi-input single-output delay superposition network is connected to the input of the ultra-wideband receiver through a first data bus. The ultra-wideband receiver is interconnected with the MCU microcontroller through a second data bus. The MCU microcontroller is interconnected with the barometric altimeter through an SPI bus. The output of the IMU sensor is connected to the input of the MCU microcontroller through a third data bus.

[0005] Furthermore, it also includes:

[0006] The multi-input single-output delay superposition network is used to acquire the antenna received signal and perform compensation processing on the antenna received signal to obtain an ultra-wideband pulse sequence signal.

[0007] The ultra-wideband receiver is used to acquire and detect ultra-wideband pulse sequence signals, and output valid data packets of ultra-wideband pulse sequence signals.

[0008] The IMU sensor and the barometric altimeter are used to measure the attitude of the ultra-wideband direction finding device and obtain the coordinate transformation relationship from the antenna array body coordinate system to the inertial coordinate system.

[0009] The MCU microcontroller is used to calculate the arrival time difference and phase difference of the effective data packets of the ultra-wideband pulse sequence signal according to the coordinate transformation relationship, so as to realize the ultra-wideband direction finding information positioning.

[0010] Furthermore, the multiple-input single-output delay overlay network includes N antennas, N-1 delay line modules, and N-1 combiners. The output of the first antenna is connected to the first input of the first combiner, the output of the first combiner is connected to the input of the ultra-wideband receiver, the output of the first delay line module is connected to the second input of the first combiner, the output of the second antenna is connected to the first input of the second combiner, the output of the second delay line module is connected to the second input of the second combiner, the output of the second combiner is connected to the input of the first delay line module, the output of the (N-1)th antenna is connected to the first input of the (N-1)th combiner, the output of the (N-1)th delay line module is connected to the second input of the (N-1)th combiner, the output of the (N-1)th combiner is connected to the input of the (N-2)th delay line module, and the output of the Nth antenna is connected to the input of the (N-1)th delay line module.

[0011] Furthermore, it also includes the delay time d of the antenna signal from the first antenna to the ultra-wideband receiver. T1 The delay between the first antenna and the first combiner is d. s1 The delay time d of the antenna signal from the second antenna to the ultra-wideband receiver T2 The delay d between the second antenna and the second combiner s2 The delay d between the second combiner and the first combiner s2' In addition to the sum of the delay d1 of the first delay line module, the delay d of the antenna signal from the Nth antenna to the ultra-wideband receiver. TN for Where N>1.

[0012] Furthermore, it also includes equal-length serpentine wiring between N antennas, N-1 delay line modules, and N-1 combiners, so that the delay between the N-1th antenna and the N-1th combiner is equal, and the delay between adjacent combiners is equal.

[0013] The beneficial effects of the device of this invention are as follows: By introducing delay lines into a multi-input single-output delay superposition network, and by using delay lines of a given length to perform group delay on ultra-wideband pulse signals, different delay networks are designed for different antennas. The corresponding ultra-wideband pulses are controlled within non-overlapping delay regions, and the delayed pulse signals are superimposed to form a pulse sequence, thereby solving the peak aliasing and correspondence problems. The time difference of arrival at each antenna is calculated by extracting the position difference of each pulse peak in the pulse sequence and the fixed delay of each region. The phase difference of arrival at each antenna is calculated by extracting the phase difference of each pulse peak in the pulse sequence and the fixed delay phase difference of each region, ultimately improving the positioning accuracy of ultra-wideband direction finding information. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of an ultra-wideband antenna array direction-finding sensor device based on a single receiver according to the present invention;

[0015] Figure 2 This is a schematic diagram of the structure of the multi-input single-output delay superposition network provided by the present invention;

[0016] Figure 3 This is a schematic diagram of received channel impulse response (CIR) data provided in a specific embodiment of the present invention.

[0017] Reference numerals in the attached diagram: 1. First delay line; 2. Second delay line; 3. Third delay line; 4. First combiner; 5. Second combiner; 6. Third combiner; 7. Ultra-wideband receiver; 8. Microcontroller unit (MCU); 9. IMU sensor; 10. Barometric altimeter sensor; 11. First data bus; 12. Second data bus; 13. Third data bus; 14. SPI bus; 15. Multiple-input single-output delay overlay network; 16. First antenna; 17. Second antenna; 18. Third antenna; 19. Fourth antenna. Detailed Implementation

[0018] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. The step numbers in the following embodiments are only for ease of explanation and do not limit the order of the steps. The execution order of each step in the embodiments can be adapted according to the understanding of those skilled in the art.

[0019] First, it's important to note that current technology employs a receiver-antenna one-to-one pairing scheme, using multiple receivers to process the corresponding antenna signals. Ideally, assuming all receivers have the same timing start point and clock frequency, the time difference can be obtained by subtracting the timestamps of the peak CIR signals received by the antennas, and the phase difference can be obtained by subtracting the phase values ​​of the peak CIR signals. However, in practical engineering applications, achieving high-precision alignment of timing start points and clock frequency synchronization is difficult. For example, if the timing start points of two ultra-wideband receivers are not aligned, their peak timestamps will have different starting points, resulting in a time difference that includes alignment errors. When multiple ultra-wideband receivers have misaligned timing start points, the time difference will be contaminated by alignment errors. To improve the clock frequency consistency of multiple ultra-wideband receivers, a single clock source is typically used to drive multiple ultra-fastband receivers, employing equal-length wiring. However, due to PCB manufacturing errors, differences in parasitic inductance and capacitance, even small frequency and phase differences can introduce significant errors in the timing and phase measurements of each module.

[0020] Delay lines, by increasing the transmission line length, achieve a certain transmission delay, making them suitable for high-frequency signal delays. A multi-delay line network can be constructed by designing delay lines of varying lengths, allowing ultra-wideband pulse signals received from multiple antennas to be combined into a single ultra-wideband pulse sequence signal through appropriate delays and superposition.

[0021] Based on this, embodiments of the present invention employ a single receiver to receive and process the CIR signal received by the antenna array, thereby avoiding the timing start alignment and clock frequency synchronization problems of multiple receivers. However, if a single receiver simultaneously receives antenna signals, aliasing will occur, making it impossible to identify peak points and their corresponding receiving antennas. Considering the pulse waveform characteristics of ultra-wideband signals, the present invention uses a delay line of a given length to perform group delay on the ultra-wideband pulse signal, designs different delay networks corresponding to different antennas, controls the corresponding ultra-wideband pulses to be in mutually non-overlapping delay regions, and superimposes the delayed pulse signals to form a pulse sequence, thereby solving the peak aliasing and correspondence problems. Given a certain antenna, the pulse received by that antenna, after passing through the delay superposition network, will only appear in a given region of the pulse sequence, and the delay between each region is fixed, so the antenna can be matched by the position of the pulse. The time difference reaching each antenna is calculated by extracting the position difference of each pulse peak in the pulse sequence and the fixed delay of each region; the phase difference reaching each antenna is calculated by extracting the phase difference of each pulse peak in the pulse sequence and the fixed delay phase difference of each region. For a certain multi-input single-output delay superposition network, the fixed delay of each delay line network can be obtained through sensor calibration and stored in the MCU for real-time calculation.

[0022] Reference Figure 1This invention provides a direction-finding sensor device based on a single receiver ultra-wideband antenna array. The device includes an MCU microcontroller 8, an IMU sensor 9, a barometric altimeter 10, an ultra-wideband receiver 7, and a multi-input single-output delay superposition network 15. The multi-input single-output delay superposition network has a delay line module. The output of the multi-input single-output delay superposition network is connected to the input of the ultra-wideband receiver via a first data bus 11. The ultra-wideband receiver is interconnected with the MCU microcontroller via a second data bus 12. The MCU microcontroller is interconnected with the barometric altimeter via an SPI bus 14. The output of the IMU sensor is connected to the input of the MCU microcontroller via a third data bus 13. Wherein:

[0023] The multi-input single-output delay superposition network is used to acquire the antenna received signal and perform compensation processing on the antenna received signal to obtain an ultra-wideband pulse sequence signal.

[0024] Among them, the multi-input single-output delay superposition network performs group delay on the ultra-wideband pulse signal that presents a pulse waveform, controls the corresponding ultra-wideband pulse received by each antenna to be in a delay region that does not overlap with each other, and superimposes the delayed pulse signals to form an ultra-wideband pulse sequence signal with non-overlapping CIR peaks.

[0025] Specifically, the multiple-input single-output delay overlay network includes N antennas, N-1 delay line modules, and N-1 combiners. The output of the first antenna is connected to the first input of the first combiner, the output of the first combiner is connected to the input of the ultra-wideband receiver, the output of the first delay line module is connected to the second input of the first combiner, the output of the second antenna is connected to the first input of the second combiner, the output of the second delay line module is connected to the second input of the second combiner, the output of the second combiner is connected to the input of the first delay line module, the output of the (N-1)th antenna is connected to the first input of the (N-1)th combiner, the output of the (N-1)th delay line module is connected to the second input of the (N-1)th combiner, the output of the (N-1)th combiner is connected to the input of the (N-2)th delay line module, and the output of the Nth antenna is connected to the input of the (N-1)th delay line module.

[0026] Furthermore, in combination Figure 2The multi-delay-line network comprises four antennas, three delay lines, and three combiners. The delay lines include a first delay line 1, a second delay line 2, and a third delay line 3. The combiners include a first combiner 4, a second combiner 5, and a third combiner 6. The antennas include a first antenna 16, a second antenna 17, a third antenna 18, and a fourth antenna 19. The output and one input of the second combiner are connected to the first delay line and the second antenna, respectively, forming a delay superposition network unit. Similarly, the second delay line, the third combiner, and the third antenna form a delay superposition network unit, with the other input of the second combiner connected to it. The fourth antenna is connected to the third combiner via the third delay line. The two inputs of the first combiner are connected to the first antenna and the first delay line, respectively, and its output is connected to a single ultra-wideband receiver. All connections between the antennas, combiners, and delay lines employ an equal-length serpentine wiring design.

[0027] In this embodiment, the multiple-input single-output delay overlay network is constructed by connecting multiple delay line networks through combiners, including N antenna input terminals, N-1 delay line modules, and N-1 combiners. The output terminal and one of the input terminals of the combiner are connected to the delay line and the antenna respectively to form a delay overlay network unit, and the other input terminal of the combiner is connected to another delay overlay network unit. Furthermore, the Nth antenna is connected to the N-1th combiner through the N-1th delay line. The two input terminals of the first combiner are connected to the first antenna and the first delay line respectively, and the output terminal is connected to a single ultra-wideband receiver. Therefore, the N antenna input terminals, N-1 delay line modules, and N-1 combiners form a multiple-input single-output delay overlay network composed of N-2 delay overlay network units.

[0028] In the multi-path delay line network, the connections between the antenna and the combiner, the antenna and the delay line module, and the combiner and the delay line module all adopt an equal-length serpentine wiring design.

[0029] Additionally, in this embodiment of the invention, the delay time d from the first antenna to the ultra-wideband receiver is also included. T1 The delay between the first antenna and the first combiner is d. s1 The delay time d of the antenna signal from the second antenna to the ultra-wideband receiver T2 The delay d between the second antenna and the second combiner s2 The delay d between the second combiner and the first combiner s2' In addition to the sum of the delay d1 of the first delay line module, the delay d of the antenna signal from the Nth antenna to the ultra-wideband receiver. TN for Where N>1.

[0030] In some specific embodiments, the delay time d from the antenna signal to the ultra-wideband receiver is...T1 The delay d caused by the equal-length serpentine wiring between the first antenna and the first combiner s1 , that is, d T1 =d s1 The delay time d of the antenna signal from the second antenna to the ultra-wideband receiver. T2 Including the delay d caused by the equal-length serpentine wiring between the second antenna and the second combiner. s2 The delay d caused by the equal-length serpentine wiring between the second combiner and the first combiner s2' The delay d1 of the first delay line, i.e., d T2 =d s2 +d s2' +d1; the delay time d from the third antenna to the ultra-wideband receiver. T3 Including the delay d caused by the equal-length serpentine wiring between the third antenna and the third combiner. s3 The delay d2 of the second delay line, and the delay d caused by the equal-length serpentine wiring between the third combiner and the second combiner. s3' The delay d caused by the equal-length serpentine wiring between the second combiner and the first combiner s2' The delay d1 of the first delay line, i.e., d T3 =d s3 +d s3' +d2+d s2' +d1; Similarly, the delay time d from the fourth antenna to the ultra-wideband receiver. T4 =d s4 +d3+d s4' +d s3' +d2+d s2' +d1. Using equal-length serpentine wiring, d... s1 =d s2 =d s3 =d s4 , and d s2' =d s3' =d s4' This ensures that the time difference between the arrival of signals from adjacent antennas at the ultra-wideband receiver is the same, thus obtaining... Figure 3 The distribution of CIR data shown indicates that the four antenna signals have different delay times d. T1 d T2 d T3 and d T4 The data is then received by an ultra-wideband receiver, and the CIR data peak gradually decreases.

[0031] The ultra-wideband receiver is used to acquire and detect ultra-wideband pulse sequence signals, and output valid data packets of ultra-wideband pulse sequence signals.

[0032] The IMU sensor and the barometric altimeter are used to measure the attitude of the ultra-wideband direction finding device and obtain the coordinate transformation relationship from the antenna array body coordinate system to the inertial coordinate system.

[0033] Specifically, the IMU sensor and barometric altimeter are used to measure the attitude of the ultra-wideband direction-finding device, obtaining the coordinate transformation relationship from the antenna array body coordinate system to the inertial coordinate system, providing support for spatial direction finding and pose estimation in the inertial frame. They are also used to calibrate the fixed delay of the delay line network.

[0034] The MCU microcontroller is used to calculate the arrival time difference and phase difference of the effective data packets of the ultra-wideband pulse sequence signal according to the coordinate transformation relationship, so as to realize the ultra-wideband direction finding information positioning.

[0035] Specifically, the microcontroller (MCU) is used to control the ultra-wideband receiver to extract the CIR (Channel Impulse Response) signal. The MCU is also used to receive attitude information from the IMU sensor and altitude information from the barometric altimeter.

[0036] Furthermore, it should be noted that methods for determining the direction of signal source using ultra-wideband antenna arrays often employ TDoA or PDoA algorithms. TDOA is a positioning method that infers the relative position of the target object to each reference base station by solving a system of nonlinear hyperbolic equations based on the distance difference between each reference base station and the target object. The distance difference is calculated using time of flight and time difference. PDOA converts the phase difference between two identical antennas at the base station, spaced less than half a wavelength apart, into a distance difference, and then combines this with the time of flight (TOF) to obtain the coordinates of the signal source.

[0037] In summary, this invention has designed and implemented a multi-input single-output (MIMO) ultra-wideband signal delay superposition network, using a single receiver to receive signals acquired by an antenna array. Then, source direction estimation is performed based on TDoA or PDoA theory, avoiding problems such as low clock synchronization accuracy associated with multiple receiver modules, thus improving positioning accuracy and reducing material costs.

[0038] The above is a detailed description of the preferred embodiments of the present invention. However, the present invention is not limited to the embodiments described. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention. All such equivalent modifications or substitutions are included within the scope defined by the claims of this application.

Claims

1. A direction-finding sensor device based on a single receiver ultra-wideband antenna array, characterized in that, The system includes an MCU microcontroller, an IMU sensor, a barometric altimeter, an ultra-wideband receiver, and a multi-input single-output delay overlay network. The multi-input single-output delay overlay network has a delay line module. The output of the multi-input single-output delay overlay network is connected to the input of the ultra-wideband receiver via a first data bus. The ultra-wideband receiver is interconnected with the MCU microcontroller via a second data bus. The MCU microcontroller is interconnected with the barometric altimeter via an SPI bus. The output of the IMU sensor is connected to the input of the MCU microcontroller via a third data bus. Wherein: The multi-input single-output delay superposition network is used to acquire the antenna received signal and perform compensation processing on the antenna received signal to obtain an ultra-wideband pulse sequence signal. The multi-input single-output delay overlay network includes N antennas, N-1 delay line modules, and N-1 combiners. The output of the first antenna is connected to the first input of the first combiner, the output of the first combiner is connected to the input of the ultra-wideband receiver, the output of the first delay line module is connected to the second input of the first combiner, the output of the second antenna is connected to the first input of the second combiner, the output of the second delay line module is connected to the second input of the second combiner, the output of the second combiner is connected to the input of the first delay line module, the output of the (N-1)th antenna is connected to the first input of the (N-1)th combiner, the output of the (N-1)th delay line module is connected to the second input of the (N-1)th combiner, the output of the (N-1)th combiner is connected to the input of the (N-2)th delay line module, and the output of the Nth antenna is connected to the input of the (N-1)th delay line module. The ultra-wideband receiver is used to acquire and detect ultra-wideband pulse sequence signals, and output valid data packets of ultra-wideband pulse sequence signals. The IMU sensor and the barometric altimeter are used to measure the attitude of the ultra-wideband direction finding device and obtain the coordinate transformation relationship from the antenna array body coordinate system to the inertial coordinate system. The MCU microcontroller is used to calculate the arrival time difference and phase difference of the effective data packets of the ultra-wideband pulse sequence signal according to the coordinate transformation relationship, so as to realize the ultra-wideband direction finding information positioning.

2. The ultra-wideband antenna array direction-finding sensor device based on a single receiver according to claim 1, characterized in that, This also includes the delay time of the antenna signal from the first antenna to the ultra-wideband receiver. The delay between the first antenna and the first combiner The delay time of the antenna signal from the second antenna to the ultra-wideband receiver Delay between the second antenna and the second combiner Delay between the second combiner and the first combiner And the delay of the first delay line module The sum of the time delays from the Nth antenna to the ultra-wideband receiver. for ,in .

3. The ultra-wideband antenna array direction-finding sensor device based on a single receiver according to claim 2, characterized in that, It also includes N antennas, N-1 delay line modules, and N-1 combiners connected by equal-length serpentine wiring, so that the delay between directly connected antennas and combiners is equal, and the delay between adjacent combiners is equal.

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