A method and system for angle of arrival measurement suitable for low cost receivers

Abstract

The application relates to the technical field of communication, and particularly discloses a kind of angle of arrival measurement method and system suitable for low-cost receiver, the low-cost receiver has multiple radio frequency front ends and its shared analog-to-digital converter (ADC) and digital signal processor, wherein each radio frequency front end is connected with a corresponding antenna, the method comprises the following steps: receiving the signal of remote device through n antennas simultaneously, obtaining a reference antenna;Obtain the mixed signal of the jth antenna and the reference antenna, determine the phase of the mixed signal;Calculate the phase difference between the signal received by the reference antenna and the signal received by the jth antenna, generate a phase difference set;Determine the angle of arrival (AOA) of the signal sent by the remote device based on the phase difference set and the distance information between the n antennas.The application realizes low-power and low-cost AOA measurement, and reduces the cost of positioning.

Description

Technical Field

[0001] This invention relates to the field of communication technology, and more specifically to a method and system for measuring the angle of arrival of a low-cost receiver. Background Technology

[0002] Positioning requires measurements in two dimensions: distance and orientation. By combining the distance between the transmitter and receiver (or tag and anchor point) obtained from the distance measurement with the angle or AOA (angle of arrival) formed between the transmitter and receiver (tag and anchor point), the precise relative position of the remote device can be determined.

[0003] AOA measurement is a method for determining the propagation direction of radio frequency waves incident on an antenna. Its basic principle is to use a multi-antenna receiving system to calculate the angle of arrival of the signal by comparing the time difference or phase difference between the arrival times of the same signal at multiple antennas. This often requires the receiver to be able to process two or more signals simultaneously, which significantly increases the complexity, cost, and power consumption of the receiver. This is because parallel processing means the receiver has two or more complete receiving links (one receiving link includes an RF front-end, an ADC, and a baseband processor). The advantage of this is that the receiver can use multiple antennas to receive the same signal through different paths, achieving diversity gain and thus improving signal quality and reliability.

[0004] Low cost and low power consumption are crucial for ultra-wideband (UWB) receivers, as they directly impact the technology's viability, efficiency, and market acceptance. Many UWB applications, such as wearables, smartphones, and IoT devices, require efficient use of battery power. Low-power designs extend the battery life of these devices and improve user experience, making the approach of using receivers with two or more complete receive links for angle-of-arrival (AOA) measurements less than ideal.

[0005] In the method of obtaining incident angle information by measuring the phase difference between two signals, the phase difference between the two signals remains unchanged when the two antennas receive different versions of the same frame signal. Therefore, the phase difference between the two signals can also be obtained directly without parallel processing. Instead, the phase information of the two signals can be obtained separately and then subtracted. However, this implementation of a low-power receiver loses diversity gain, which will cause some loss to the system performance in the case of weak signals. Summary of the Invention

[0006] The purpose of this invention is to provide a method and system for measuring the angle of arrival suitable for low-cost receivers, thereby solving the aforementioned technical problems.

[0007] The objective of this invention can be achieved through the following technical solutions:

[0008] A method for measuring angle of arrival suitable for a low-cost receiver, the low-cost receiver having multiple radio frequency front-ends and a shared analog-to-digital converter (ADC) and digital signal processor, wherein each radio frequency front-end is connected to a corresponding antenna, the method comprising the following steps:

[0009] The signal transmitted by the remote device is received simultaneously through n antennas, where n is the preset number of antennas and n≥2. The i-th antenna is marked as the reference antenna, where i is a preset value.

[0010] The mixed signal AH = ACK + Aj from the j-th antenna and the reference antenna is obtained, where Aj represents the signal received by the j-th antenna and ACK represents the signal received by the reference antenna. The mixed signal AH is processed by an ADC, and the phase XW of the mixed signal is determined by a digital signal processor. AH ;

[0011] Switch to receiving the transmitted signal from the remote device through the j-th antenna, and obtain the signal XH received by the j-th antenna alone. j Signal XH j The signal XH is determined by the digital signal processor after passing through the ADC. j Phase XW j ;

[0012] Based on A j and XH j Having the same phase information, the signal ACK received by the reference antenna and the signal XH received by the j-th antenna can be calculated. j The phase difference ΔCZ between them CK，j =XW AH -XW j Generate the phase difference set ΔCZ={ΔCZ} CK，1 ΔCZ CK，2 , …, ΔCZ CK，n-1};

[0013] The angle of arrival (AOA) of the signal transmitted by the remote device is determined based on the phase difference set and the distance information between the n antennas.

[0014] As a further aspect of the present invention: the maximum ratio combining algorithm is used to obtain the mixed signal of the j-th antenna and the reference antenna.

[0015] As a further aspect of the present invention: the hybrid signal AH is obtained based on the synchronization field of the frame; the signal XH j Get the synchronization field or scrambled timestamp sequence based on the frame.

[0016] As a further aspect of the present invention, the operation of switching from multi-antenna reception to single-antenna reception is completed within the same data frame.

[0017] As a further aspect of the present invention: the operation of switching from multi-antenna reception to single-antenna reception is performed cyclically within the same data frame to obtain multiple measurement results; subsequent switching is implemented in the scrambling timestamp sequence portion of the frame.

[0018] As a further aspect of the present invention, the mixed signal is also used for time and frequency synchronization between the time and the transmitter.

[0019] As a further aspect of the present invention: during the process of acquiring the mixed signal, the analog gain of the signal received by the reference antenna and the signal received by the j-th antenna are different and are preset values.

[0020] As a further aspect of the present invention: the simulated gain is based on manual selection, and there are m different sets of the simulated gain, where m is a preset number.

[0021] As a further aspect of the present invention: the signal received by the n-channel antenna from the remote device is an impulse UWB signal.

[0022] As a further aspect of the present invention, the method further includes the following steps: obtaining the distance D between the receiver and the remote device, and determining the location information of the remote device based on the angle of arrival (AOA) of the signal transmitted by the remote device and the distance between the remote device and its parent device.

[0023] The distance D between the receiver and the remote device can be calculated by receiving the ultra-wideband (UWB) signal from the remote device, i.e., by utilizing the ranging function of the UWB signal. Ranging can be achieved using a mixture of signals received from multiple antennas and / or a single antenna, such as based on Time-of-Flight (ToF) or other ranging algorithms. Using the distance and angle-of-arrival (AOA) information, the position of the remote transmitter relative to the receiver can be determined. For example, assuming the receiver's coordinates are (x0, y0), the coordinates of the remote device can be calculated as (x1, y1), i.e., x1 = x0 + D * cos(AOA), y1 = y0 + sin(AOA).

[0024] A low-cost receiver system includes: multiple radio frequency (RF) front-ends and a shared analog-to-digital converter (ADC) and digital signal processor, wherein each RF front-end is connected to a corresponding antenna; the low-cost receiver is configured as follows:

[0025] The signal transmitted by the remote device is received simultaneously through n antennas, where n is the preset number of antennas and n≥2. The i-th antenna is marked as the reference antenna, where i is a preset value.

[0026] The mixed signal AH = ACK + Aj from the j-th antenna and the reference antenna is obtained, where Aj represents the signal received by the j-th antenna and ACK represents the signal received by the reference antenna. The mixed signal AH is processed by an ADC, and the phase XW of the mixed signal is determined by a digital signal processor. AH ;

[0027] Switch to receiving the transmitted signal from the remote device through the j-th antenna, and obtain the signal XH received by the j-th antenna alone. j Signal XH j The signal XH is determined by the digital signal processor after passing through the ADC. j Phase XW j ;

[0028] Based on A j and XH j Having the same phase information, the signal ACK received by the reference antenna and the signal XH received by the j-th antenna can be calculated. j The phase difference ΔCZ between them CK，j =XW AH -XW j Generate the phase difference set ΔCZ={ΔCZ} CK，1 ΔCZ CK，2 , …, ΔCZ CK，n-1};

[0029] The angle of arrival (AOA) of the signal transmitted by the remote device is determined based on the phase difference set and the distance information between the n antennas.

[0030] A low-cost receiver system includes: a positioning module: acquiring the distance D between the receiver and the remote device, and determining the location information of the remote device based on the angle of arrival (AOA) of the signal transmitted by the remote device and the distance between the receiver and the remote device.

[0031] The distance D between the receiver and the remote device can be calculated by receiving the ultra-wideband (UWB) signal from the remote device, i.e., by utilizing the ranging function of the UWB signal. Ranging can be achieved using a mixture of signals received from multiple antennas and / or a single antenna, such as based on Time-of-Flight (ToF) or other ranging algorithms. Using the distance and angle-of-arrival (AOA) information, the position of the remote transmitter relative to the receiver can be determined. For example, assuming the receiver's coordinates are (x0, y0), the coordinates of the remote device can be calculated as (x1, y1), i.e., x1 = x0 + D * cos(AOA), y1 = y0 + sin(AOA).

[0032] A low-cost receiver system for remote devices using pulse ultra-wideband (UWB) signals.

[0033] The beneficial effects of this invention compared to the prior art are as follows:

[0034] 1) Because this invention requires only a small number of RF front-ends and can share a single ADC and baseband processing module, it eliminates the hardware investment and power consumption overhead associated with multi-path parallel receiving links. Therefore, the entire system has lower cost, smaller hardware size, and lower power consumption, making it particularly suitable for power-sensitive or space-constrained terminal device applications.

[0035] 2) In weak signal and long-distance transmission situations, the strength of the received signal is often limited. By employing the Maximum Ratio Combining (MRC) equal-division combinatorial algorithm at the analog end, the signals received by each antenna can be coherently superimposed as much as possible, thereby enhancing the overall signal strength, improving the signal-to-noise ratio (SNR), and improving anti-interference performance. Stable reception in weak signal environments can be achieved without adding additional digital front-ends and ADCs.

[0036] 3) This invention first obtains the phase of the mixed signal after the reference antenna is combined with other antennas, then switches to single-antenna reception mode to measure the phase of the independently received signal of the corresponding antenna. The phase difference between different antennas is obtained by subtracting the two phase differences to calculate the AOA. This method effectively avoids the need to allocate a complete reception channel to each antenna, which simplifies the hardware architecture and enables accurate estimation of the phase difference between multiple antennas.

[0037] 4) UWB frames have predictable and detectable known pulse or code sequences in parts such as the synchronization field (SYNC) and scrambling timestamp sequence (STS). This invention utilizes these known sequences to simultaneously complete the time and frequency synchronization of the receiver and transmitter, as well as the acquisition of signals required for phase measurement, avoiding additional calibration or synchronization links and improving system integration and working efficiency.

[0038] 5) This invention allows for different combinations of analog gain when the reference antenna is combined with other antennas, and even multiple different gain options are available, which can be flexibly switched during the measurement process. This not only allows for rapid adaptation to different interference environments, antenna characteristics or link conditions, but also enables better extraction of phase information and enhanced receiving sensitivity, further improving the accuracy of AOA measurement.

[0039] 6) Based on the existing AOA measurement accuracy, combined with Time of Flight (ToF) or other ranging methods, the precise coordinates of the target remote device can be obtained quickly. This invention has great application value in fields with high requirements for positioning accuracy, device miniaturization and low power consumption, such as indoor positioning, asset tracking, smart home, and robot navigation.

[0040] In summary, this invention cleverly combines multiple antenna signals at the analog end with one or more single-antenna reception measurements, achieving reliable angle of arrival (AOA) extraction even under adverse conditions such as weak signals and multipath propagation. This significantly reduces system hardware complexity and power consumption, while also significantly improving positioning performance and stability. Attached Figure Description

[0041] The invention will now be further described with reference to the accompanying drawings.

[0042] Figure 1 This is a flowchart illustrating an angle-of-arrival measurement method for a low-cost receiver according to the present invention.

[0043] Figure 2 This is a schematic diagram of the frame structure. Detailed Implementation

[0044] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0045] Please see Figure 1 As shown, this invention provides a method for measuring the angle of arrival (Angle of Arrival) using a low-cost receiver. The low-cost receiver has multiple radio frequency (RF) front-ends and a shared analog-to-digital converter (ADC) and digital signal processor (DSP). Each RF front-end is connected to a corresponding antenna. The method includes the following steps:

[0046] The signal transmitted by the remote device is received simultaneously through n antennas, where n is the preset number of antennas and n≥2. The i-th antenna is marked as the reference antenna, where i is a preset value.

[0047] In a preferred embodiment of the present invention, the signal received by the n antennas from the remote device is an impulse UWB signal.

[0048] Assuming there are 3 antennas in the system, 3 antennas A1, A2, and A3 are deployed at the receiving end, and they are ensured to have appropriate geometric spacing (such as being arranged at a known distance on the same horizontal line or forming an array). Among them, A1 is used as the reference antenna (i=1), which is responsible for providing a reference in generating the mixed signal and subsequent phase difference calculation. The impulse signal transmitted by the remote device arrives at A1, A2, and A3 respectively, and each antenna receives the signal and sends it to its respective analog front end.

[0049] The mixed signal AH = ACK + Aj from the j-th antenna and the reference antenna is obtained, where Aj represents the signal received by the j-th antenna and ACK represents the signal received by the reference antenna. The mixed signal AH is processed by an ADC, and the phase XW of the mixed signal is determined by a digital signal processor. AH ;

[0050] In a preferred embodiment of the present invention, a maximum ratio combining algorithm is used to obtain the mixed signal of the j-th antenna and the reference antenna;

[0051] In another preferred embodiment of the present invention, during the process of acquiring the mixed signal, the analog gain of the signal received by the reference antenna and the signal received by the j-th antenna are different and are preset values;

[0052] In a preferred embodiment, the simulated gain is based on manual selection, and there are m different simulated gains, where m is a preset number.

[0053] Suppose that at time t, the signal received by A1 is ACK(t), the signal received by A2 is A2(t), and the signal received by A3 is A3(t). At this time, for the signal Aj(t) of the j-th antenna (j=2 or 3), we want to combine it with the reference antenna signal ACK(t) and then input it into the ADC for phase measurement.

[0054] First, both antenna signals A1 and A2 are simultaneously output at the analog end. For example, when j=2, A1 outputs ACK(t) and A2 outputs A2(t). Both outputs may have their own analog gains (such as LNA gain, adjustable attenuator, etc.). These can be manually configured or automatically controlled before mixing. Afterward, MRC usually needs to estimate the channel gain, signal-to-noise ratio (SNR), etc. of each signal to determine the weighting coefficients w1 and w2 of each signal. Assume that at this moment, the receiver obtains w1 and w2 through prior measurements or estimations (e.g., w1 and w2 are divided into...). (For 0, 8 and 0.2 respectively), in analog circuits, signal weighting and superposition can be achieved through power dividers / phase shifters / adjustable amplifiers, etc. AH(t) is the mixed signal obtained after merging. In actual hardware, this process can be implemented using analog phase shifting and weighting networks or integrated RF front-end chips. The merged AH(t) is input to a single ADC for sampling and sent to the baseband processing module. In the baseband, phase estimation is performed on the sampled digital signal. Since there is a known sequence in the frame structure (such as the SYNC field), high-precision phase estimation can be obtained by using correlation algorithms or matched filtering.

[0055] In another preferred embodiment of the present invention, the hybrid signal AH is obtained based on the synchronization field of the frame; the signal XH j Obtained based on the frame's synchronization field or scrambled timestamp sequence;

[0056] It is understood that the operation of switching from multi-antenna reception to single-antenna reception is completed within the same data frame;

[0057] It is worth noting that the operation of switching from multi-antenna reception to single-antenna reception is performed cyclically within the same data frame to obtain multiple measurement results; subsequent switching is implemented in the scrambling timestamp sequence part of the frame;

[0058] It should be noted that when the UWB data packet arrives, all three antennas (A1, A2, A3) receive the pulse sequence. During the first half of the frame (i.e., the SYNC field), the analog signals from the reference antenna A1 and the j-th antenna (A2 or A3) are combined using maximum ratio combining (MRC) or other weighted superposition to form a mixed signal AH(t). Since the SYNC field has a long and known preamble sequence, it is easier to perform phase estimation by observing the signal during this period, and sufficient correlation gain can also be guaranteed. The combined AH(t) is sampled and output through a single ADC. At the baseband processing module, based on the known sequence within the SYNC field, conventional methods such as matched filtering or correlation detection can be used to estimate the phase of the combined signal AH. After sampling the mixed signal, the system commands the receiver to switch to single-antenna mode, retaining only the signal input ADC of the j-th antenna (A2 or A3). The SYNC field typically lasts for a certain length, or multiple observations can be performed during the STS period, providing a time window for subsequent single-antenna signal phase acquisition. The preferred approach is to use one (or a combination of) the following two methods to complete the single-antenna signal phase estimation:

[0059] 1) Reuse the SYNC field: Perform phase measurement on the single-antenna signal XHⱼ during the remaining SYNC time or repeated chip in the same frame;

[0060] 2) Using the STS field: If the SYNC field period is insufficient to complete multi-antenna rotation measurement or more measurement opportunities are needed, phase estimation of the j-th antenna can be performed in the STS field after the frame. The STS field contains a pseudo-random pulse sequence, which is also suitable for correlation matching to obtain high-precision phase information.

[0061] In another preferred embodiment of the present invention, the mixed signal is further used for time and frequency synchronization between the time and the transmitter;

[0062] In UWB systems, it is necessary to accurately locate the start position or key symbol boundary of the data frame at the receiver. By performing relevant detection (such as matching the SYNC preamble or STS sequence) in the mixed signal AH, the precise arrival time of the received signal can be determined, and a synchronization trigger signal can be generated for alignment of ADC sampling, baseband demodulation, and subsequent phase measurements. Since the mixed signal usually has a higher signal-to-noise ratio (achieving diversity gain through maximum ratio combining), the arrival of the preamble can be detected more reliably even in weak signal or long-distance scenarios, thereby improving the accuracy and robustness of time synchronization. In wireless communication, the frequencies of the receiver's local oscillator (LO) and the transmitter often have slight deviations, resulting in incomplete carrier frequency synchronization. When the deviation is large, frequency offset estimation and compensation are required. Coherent demodulation using the mixed signal AH allows estimation of the instantaneous phase or phase rotation rate on known sequences such as SYNC or STS, thereby inferring and correcting the frequency offset. Similarly, since the AH has a better signal-to-noise ratio, it can improve the accuracy of frequency offset estimation and reduce the impact of errors on subsequent phase measurements and data demodulation.

[0063] Switch to receiving the transmitted signal from the remote device through the j-th antenna, and obtain the signal XH received by the j-th antenna alone. j Signal XH j The signal XH is determined by the digital signal processor after passing through the ADC. j Phase XW j ;

[0064] Based on A j and XH j Having the same phase information, the signal ACK received by the reference antenna and the signal XH received by the j-th antenna can be calculated. j The phase difference ΔCZ between them CK，j =XW AH -XW j Generate the phase difference set ΔCZ={ΔCZ} CK，1 ΔCZ CK，2 , …, ΔCZ CK，n-1};

[0065] The angle of arrival (AOA) of the signal transmitted by the remote device is determined based on the phase difference set and the distance information between the n antennas.

[0066] In a preferred embodiment of the present invention, the method further includes the following steps: calculating the distance D between the receiver and the remote device by receiving the signal from the remote device, and determining the location information of the remote device based on the angle of arrival (AOA) of the signal transmitted by the remote device and the distance between the remote device and its parent remote device. For example, assuming the coordinates of the receiver are (x0, y0), the coordinates of the remote device can be calculated as (x1, y1), i.e., x1 = x0 + D * cos(AOA), y1 = y0 + sin(AOA).

[0067] It is worth noting that when the receiver's lateral and longitudinal coordinates are known, the target device's lateral and longitudinal coordinates can be derived by multiplying the distance values ​​by the cosine and sine functions of the angle of arrival, respectively, and then adding the results to the receiver's lateral and longitudinal coordinates. In this process, obtaining a richer set of phase differences through multiple antennas can further improve the accuracy of the angle of arrival estimation using beamforming algorithms, resulting in a more stable final positioning result. Even in complex environments such as weak signals and multipath reflections, this method can effectively suppress interference and maintain high-precision coordinate calculations. Therefore, in applications such as indoor navigation, wearable devices, and object tracking, this solution can provide terminals with more reliable and flexible positioning support.

[0068] A low-cost receiver system includes: multiple radio frequency (RF) front-ends and a shared analog-to-digital converter (ADC) and digital signal processor, wherein each RF front-end is connected to a corresponding antenna; the low-cost receiver is configured as follows:

[0069] The signal transmitted by the remote device is received simultaneously through n antennas, where n is the preset number of antennas and n≥2. The i-th antenna is marked as the reference antenna, where i is a preset value.

[0070] The mixed signal AH = ACK + Aj from the j-th antenna and the reference antenna is obtained, where Aj represents the signal received by the j-th antenna and ACK represents the signal received by the reference antenna. The mixed signal AH is processed by an ADC, and the phase XW of the mixed signal is determined by a digital signal processor. AH ;

[0071] Switch to receiving the transmitted signal from the remote device through the j-th antenna, and obtain the signal XH received by the j-th antenna alone. j Signal XH j The signal XH is determined by the digital signal processor after passing through the ADC. j Phase XW j ;

[0072] Based on the fact that Aj and XHj have the same phase information, the signal ACK received by the reference antenna and the signal XHj received by the j-th antenna can be calculated.j The phase difference ΔCZ between them CK，j =XW AH -XW j Generate the phase difference set ΔCZ={ΔCZ} CK，1 ΔCZ CK，2 , …, ΔCZ CK，n-1};

[0073] The angle of arrival (AOA) of the signal transmitted by the remote device is determined based on the phase difference set and the distance information between the n antennas.

[0074] A low-cost receiver system includes: a positioning module: acquiring the distance D between the receiver and a remote device, and determining the location information of the remote device based on the angle of arrival (AOA) of the signal transmitted by the remote device and the distance between the receiver and the remote device. For example, the coordinates of the remote device are (x1, y1), x1 = x0 + D * cos(AOA), y1 = y0 + sin(AOA), and (x0, y0) represent the coordinates of the receiver.

[0075] A low-cost receiver system for remote devices using pulse ultra-wideband (UWB) signals.

[0076] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should still fall within the patent coverage of this invention.

Claims

1. A method for measuring the angle of arrival (Angle of Arrival) of a low-cost receiver, the low-cost receiver having multiple radio frequency (RF) front-ends and a shared analog-to-digital converter (ADC) and digital signal processor (DSP), wherein each RF front-end is connected to a corresponding antenna, characterized in that, The method includes the following steps: The signal transmitted by the remote device is received simultaneously through n antennas, where n is the preset number of antennas and n≥2. The i-th antenna is marked as the reference antenna, where i is a preset value. The mixed signal AH = ACK + Aj from the j-th antenna and the reference antenna is obtained, where Aj represents the signal received by the j-th antenna and ACK represents the signal received by the reference antenna. The mixed signal AH is processed by an ADC, and the phase XW of the mixed signal is determined by a digital signal processor. AH ; Switch to receiving the transmitted signal from the remote device through the j-th antenna, and obtain the signal XH received by the j-th antenna alone. j Signal XH j The signal XH is determined by the digital signal processor after passing through the ADC. j Phase XW j ; Based on A j and XH j Having the same phase information, the signal ACK received by the reference antenna and the signal XH received by the j-th antenna can be calculated. j The phase difference ΔCZ between them CK，j =XW AH -XW j Generate the phase difference set ΔCZ={ΔCZ} CK，1 ΔCZ CK，2 , …, ΔCZ CK，n-1 }; The angle of arrival (AOA) of the signal transmitted by the remote device is determined based on the phase difference set and the distance information between the n antennas.

2. The method for measuring the angle of arrival of a low-cost receiver according to claim 1, characterized in that, The maximum ratio combining algorithm is used to obtain the mixed signal of the j-th antenna and the reference antenna.

3. The method for measuring the angle of arrival of a low-cost receiver according to claim 1, characterized in that, The hybrid signal AH is obtained based on the frame's synchronization field; the signal XH j Get the synchronization field or scrambled timestamp sequence based on the frame.

4. The angle of arrival measurement method for a low-cost receiver according to claim 3, characterized in that, The operation of switching from multi-antenna reception to single-antenna reception is completed within the same data frame.

5. The angle of arrival measurement method for a low-cost receiver according to claim 4, wherein the operation of switching from multi-antenna reception to single-antenna reception is performed cyclically within the same data frame to obtain multiple measurement results; subsequent switching is implemented in the scrambling timestamp sequence portion of the frame.

6. The method for measuring the angle of arrival of a low-cost receiver according to claim 1, characterized in that, The mixed signal is also used for time and frequency synchronization between the time and the transmitter.

7. The method for measuring the angle of arrival of a low-cost receiver according to claim 1, characterized in that, During the acquisition of the mixed signal, the analog gain of the signal received by the reference antenna and the signal received by the j-th antenna are different and are preset values.

8. The method for measuring the angle of arrival of a low-cost receiver according to claim 7, characterized in that, The simulated gain is based on manual selection, and there are m different simulated gains, where m is a preset number.

9. The method for measuring the angle of arrival of a low-cost receiver according to claim 1, characterized in that, The signal received by the n-channel antenna from the remote device is an impulse UWB signal.

10. The method for measuring the angle of arrival of a low-cost receiver according to claim 1, characterized in that, The method further includes the following steps: obtaining the distance D between the receiver and the remote device, and determining the location information of the remote device based on the angle of arrival (AOA) of the signal transmitted by the remote device and the distance between the remote device and its parent device.

11. A low-cost receiver system, characterized in that, include: Multiple radio frequency (RF) front-ends and their shared analog-to-digital converter (ADC) and digital signal processor, wherein each RF front-end is connected to a corresponding antenna; this low-cost receiver is configured as follows: The signal transmitted by the remote device is received simultaneously by two or more of the n antennas, where n is the preset number of antennas and n≥2. The i-th antenna is marked as the reference antenna, where i is a preset value. The mixed signal AH = ACK + Aj from the j-th antenna and the reference antenna is obtained, where Aj represents the signal received by the j-th antenna and ACK represents the signal received by the reference antenna. The mixed signal AH is processed by an ADC, and the phase XW of the mixed signal is determined by a digital signal processor. AH ; Switch to receiving the transmitted signal from the remote device through the j-th antenna, and obtain the signal XH received by the j-th antenna alone. j Signal XH j The signal XH is determined by the digital signal processor after passing through the ADC. j Phase XW j ; Based on A j and XH j Having the same phase information, the signal ACK received by the reference antenna and the signal XH received by the j-th antenna can be calculated. j The phase difference ΔCZ between them CK，j =XW AH -XW j Generate the phase difference set ΔCZ={ΔCZ} CK，1 ΔCZ CK，2 , …, ΔCZ CK，n-1 }; The angle of arrival (AOA) of the signal transmitted by the remote device is determined based on the phase difference set and the distance information between the n antennas.

12. A low-cost receiver system according to claim 11, characterized in that, Includes: a positioning module: acquiring the distance D between the receiver and the remote device, and determining the location information of the remote device based on the angle of arrival (AOA) of the signal transmitted by the remote device and the distance between the receiver and the remote device.

13. A low-cost receiver system according to claim 11, characterized in that, The signal from the remote device is a pulse ultra-wideband signal.

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