AOA Indoor Positioning Simulation System and Positioning Method Based on UWB System

Abstract

The present invention discloses an AOA indoor positioning simulation system and a positioning method based on the UWB system. The system includes a transmitting module, a channel module, an antenna receiving module, a radio frequency module, an ADC module, and a baseband processing module that are connected in sequence. By extracting the initial phases of the UWB signals received by two receiving antennas respectively, the present invention can calculate the angles between the UWB signals and the receiving antennas, and further calculate the position of the receiving end in the indoor environment. Using this platform, the influence of system indexes such as the signal-to-noise ratio of the channel, the sampling frequency and quantization bit width of the ADC module on the positioning accuracy can be tested, which can provide references for the designers of UWB systems when designing system indexes, and can also help them evaluate the positioning accuracy that can be achieved by the systems they design.

Description

Technical Field

[0001] The present invention belongs to the field of indoor positioning simulation, and particularly relates to an AOA indoor positioning simulation system and method based on the UWB system. An indoor positioning simulation platform built by MATLAB / SIMULINK can test the influence of various indexes of the system on the positioning accuracy. Background Art

[0002] Since the emergence of positioning technologies represented by GPS, people's lives have undergone great changes. However, due to the limitations of the technical principles, traditional indoor positioning technologies cannot meet the positioning requirements in indoor environments. Since the 21st century, with the rapid development of society, the practicality and necessity of indoor positioning technologies in some specific scenarios have become increasingly prominent, and the application prospects are very broad. The commonly used indoor positioning technologies mainly include the following several types: ultrasonic positioning technology, infrared positioning technology, UWB-based positioning technology, and radio frequency identification positioning technology.

[0003] Among them, the UWB technology has the advantages of high positioning accuracy, low transmission power, and strong penetration ability. AOA (Angle of Arrival) is one of the basic algorithms of indoor positioning systems. The AOA algorithm calculates the arrival angle of the UWB signal by calculating the phase difference of the signals received by the antennas, so as to realize the positioning of the target to be measured. However, compared with other indoor positioning technologies, the test cost of the UWB technology is relatively high. Therefore, by using a simulation platform, the performance of the UWB system can be more conveniently evaluated, so as to achieve the purpose of reducing costs.

[0004] Since 2002, the UWB technology has been opened to the civilian field and has obtained rapid development. Successively, standard channel models such as IEEE.802.15.3a and IEEE.802.15.4a have emerged. In addition to the establishment of standard channel models, UWB antennas have also obtained rapid development, and UWB positioning algorithms have emerged in an endless stream. However, until now, there are still few system-level UWB indoor positioning simulation models. Summary of the Invention

[0005] The purpose of the present invention is to overcome the deficiencies of the prior art and provide an AOA indoor positioning simulation system based on the UWB system that can calculate the angle between the UWB signal and the receiving antenna by extracting the initial phases of the UWB signals received by two receiving antennas respectively, and then calculate the position of the receiving end in the room, and provide a positioning method.

[0006] The purpose of the present invention is achieved by the following technical solutions: The AOA indoor positioning simulation system based on the UWB system includes a transmitting module, a channel module, an antenna receiving module, a radio frequency module, an ADC module, and a baseband processing module that are connected in sequence.

[0007] The signal transmission module is used for the up-conversion of analog signals; the transmission module consists of a signal source and an up-conversion local oscillator module. The signal source generates UWB pulse signals, which are then mixed with the local oscillator signals to obtain modulated UWB pulse signals and sent into the channel module.

[0008] The channel module consists of an additive white Gaussian noise channel sub-module and a multipath simulation sub-module; the additive white Gaussian noise channel sub-module is used to simulate the influence of noise generated in the channel, and the multipath simulation sub-module is composed of 8 delay modules and an energy attenuation module, which is used to simulate the influence of multipath; after the modulated UWB pulse signal enters the multipath simulation sub-module, it passes through the 8 delay modules and the energy attenuation module in the channel, becoming multipath signals with different delays and amplitudes, and then passes through the additive white Gaussian noise channel sub-module, outputting an energy signal containing noise with multiple different delay paths and entering the antenna receiving module.

[0009] The antenna receiving module is used to simulate the receiving function of the antenna. The antenna receiving module consists of two parallel delays and an antenna pattern.

[0010] The RF module is used for the down-conversion of signals, including two RF sub-modules, and the two RF sub-modules respectively perform quadrature demodulation processing on the two signals output by the antenna receiving module;

[0011] There are two local oscillator modules inside the RF sub-module, and the frequencies of the local oscillator signals output by them are the same as those of the local oscillator signals of the transmission module, with a phase difference of 90 degrees; the two local oscillator signals are respectively mixed with the two signals input from the antenna receiving module, and after filtering processing respectively, four baseband signals carrying phase information are obtained; the internal RF module has adjustable local oscillator amplitude ratios and phase differences.

[0012] The ADC module is used for analog-to-digital conversion of the 4 signals output by the RF module, converting them into digital signals.

[0013] The baseband processing module is used to simulate the baseband processing part of the positioning algorithm; the specific implementation method is: analyze the 4 signals output by the ADC module, extract the phase difference from them, and finally extract the angle.

[0014] The first step of the baseband processing program is to use the first-path extraction algorithm to extract the first paths of the four output signals; the second step is to extract the larger value of the amplitude in the first paths as the effective value; the third step is to calculate the phase according to the effective value extracted in the second step and calculate the average value of all measured phases; the fourth step is to calculate the angle between the transmitting base station and the antenna according to the average value of the calculated phases, realizing the function of indoor positioning.

[0015] Another object of the present invention is to provide a UWB-based AOA indoor positioning method, which is implemented by using the above positioning simulation system; the method includes the following steps:

[0016] Step 1: Define the angles of the transmitting base station and the receiving antenna to be simulated, modify the time difference between the two antennas in the antenna module for receiving UWB signals, and the frequency of the transmitted signal. The relationship between the antenna reception difference and the angle is d*sin(θ) = Δτ*c, where d represents the distance between the two antennas, θ represents the incident angle of the UWB signal reaching the antenna, c represents the speed of light, and Δτ represents the time difference between the two receiving antennas for receiving signals.

[0017] Step 2: Define the parameters of each module of the simulation system; the specific parameters to be defined are as follows: the initial phase of the local oscillator signal of the transmitting module, the signal-to-noise ratio of the channel module, the antenna pattern of the antenna receiving module, the IQ phase difference and IQ amplitude ratio of the radio frequency module, the sampling frequency and quantization bit width of the ADC module.

[0018] Step 3: The simulation system starts to run: the transmitting module generates a UWB initial signal, denoted as p(t), which is mixed with the carrier signal cos(ωt) generated by the local oscillator module to obtain a transmitted signal p(t)cos(ωt), and then sent to the channel module; where ω is the angular velocity of the carrier signal.

[0019] Step 4: After the transmitted signal p(t)cos(ωt) enters the channel module, the influence of noise and multipath is added. Since in the subsequent process, only the influence of the first path is considered whether it is the extraction of the phase difference or the extraction of the angle, only the first path of the signal is considered here; assume that after passing through the channel module, the delay of the first path of the signal is τ, and the attenuation ratio is α. Ignoring the influence of noise, the first path of the signal output by the channel module is expressed as:

[0020] α*p(t - τ)*cos(ω(t - τ))

[0021] Step 5: After the signal output by the channel module enters the antenna receiving module, assume that the UWB signal arrives at antenna 1 first, then the signal received by antenna 1 is the first path of the signal output by the channel module, which is expressed as:

[0022] α*p(t - τ)*cos(ω(t - τ))

[0023] The time difference of the receiving antenna is Δτ, so the signal received by antenna 2 is expressed as:

[0024] α*p(t - τ - Δτ)*cos(ω(t - τ - Δτ))

[0025] Assume that at the current time difference, the attenuation amplitude of the antenna pattern module is β; then the two signals output by the antenna module are respectively expressed as:

[0026] α*β*p(t-τ)*cos(ω(t-τ))

[0027] α*β*p(t-τ-Δτ)*cos(ω(t-τ-Δτ))

[0028] remember The two signals output by the antenna module are expressed as:

[0029]

[0030]

[0031] Step 6: After the first path of the signal output by the antenna module enters the RF module, it is mixed with two local oscillator signals sin(ωt) and cos(ωt) with a phase difference of 90°, and then filtered and amplified. The first paths of the four output signals are expressed as follows:

[0032]

[0033]

[0034]

[0035]

[0036] Step 7: The first path of the four-way signal output by the RF module enters the ADC module and is processed by the sampling module and the quantization module. Suppose the currently set sampling frequency is f S , the quantization bit width is B, then the first path of the four signals output by the ADC module are expressed as:

[0037]

[0038]

[0039]

[0040]

[0041] Step 8: After the four-way signals output by the ADC module enter the baseband processing program, they are first processed by the first path extraction module. Then, the value with the largest first path effect is selected as the effective point for phase extraction; the average values ​​of the phases extracted here are respectively The extracted phase difference is expressed as The final output angle is expressed as

[0042]

[0043] The beneficial effects of the present invention are as follows: The UWB-based AOA indoor positioning simulation system provided by the present invention can calculate the angle between the UWB signal and the receiving antenna by extracting the initial phases of the UWB signals received by two receiving antennas respectively, and then calculate the position of the receiving end in the room. Using this platform, it is possible to test the influence of system indicators such as the signal-to-noise ratio of the channel, the sampling frequency and quantization bit width of the ADC module on the positioning accuracy, which can provide reference for the designers of UWB systems when designing system indicators, and can also help them evaluate the positioning accuracy that can be achieved by the systems they design.

[0044] In addition, this simulation system is not limited to the simulation of indoor positioning. By changing the channel module, it can also be applied to UWB simulation systems for various scenarios such as outdoor positioning. At the same time, by modifying the algorithm part of this simulation model, it can also simulate other indoor positioning algorithms such as RSSI (Received Signal Strength Indicator) and TDOA (Time Difference of Arrival). By modifying the algorithm of the first path extraction part, it is also possible to test the influence of different first path extraction algorithms on the positioning accuracy. Brief Description of the Drawings

[0045] Figure 1 It is the schematic diagram of the UWB-based AOA indoor positioning simulation system involved in the present invention;

[0046] Figure 2 It is the overall block diagram and implementation flowchart of the UWB simulation system involved in the present invention;

[0047] Figure 3 It is the system structure diagram of the simulation of the present invention on Simulink;

[0048] Figure 4 It is the internal structure diagram of the transmitting module involved in the present invention;

[0049] Figure 5 It is the internal structure diagram of the channel module involved in the present invention;

[0050] Figure 6 It is the internal structure diagram of the antenna receiving module involved in the present invention;

[0051] Figure 7 It is the internal structure diagram of the RF module involved in the present invention;

[0052] Figure 8 It is the internal structure diagram of the ADC module involved in the present invention;

[0053] Figure 9 It is the implementation flowchart of the baseband processing program involved in the present invention;

[0054] Figure 10 It is the basic UWB signal involved in the implementation process of the present invention;

[0055] Figure 11 is the output signal of the transmitting module involved in the implementation process of the present invention;

[0056] Figure 12 is the output signal of the channel module involved in the implementation process of the present invention;

[0057] Figure 13 is the output signal of the antenna receiving module involved in the implementation process of the present invention;

[0058] Figure 14 is the output signal of the radio frequency module involved in the implementation process of the present invention;

[0059] Figure 15 is the output signal of the ADC module involved in the implementation process of the present invention. Detailed implementation manners

[0060] The basic principle of the AOA (Angle of Arrival) indoor positioning algorithm based on UWB (Ultra-Wideband) is shown in Figure 1 as follows. Since the positions of the receiving antennas are different, the time for the UWB signal transmitted by the transmitting base station to reach the dual antennas is different. The time difference will cause the phases of the received UWB signals to be different. By extracting the initial phases of the UWB signals received by the two receiving antennas respectively, the angle between the UWB signal and the receiving antennas can be deduced, and then the position of the receiving end in the room can be deduced. The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0061] As Figure 2 shown, an AOA indoor positioning simulation system based on the UWB (Ultra-Wideband) system of the present invention includes a transmitting module, a channel module, an antenna receiving module, a radio frequency module, an ADC module, and a baseband processing module connected in sequence. The transmitting module, the channel module, the antenna receiving module, the radio frequency module, the ADC module, and the baseband processing module are all simulated on Simulink, and the system structure is as Figure 3 shown.

[0062] The signal transmitting module is used to simulate the up-conversion of the signal; the structure of the transmitting module is as Figure 4 shown, and it is composed of a signal source and an up-conversion local oscillator module. The signal source generates a UWB (Ultra-Wideband) pulse signal, and then mixes it with the local oscillator signal to obtain a modulated UWB pulse signal and sends it into the channel module. The transmission period of the UWB signal generated by the transmitting module and the frequency of the local oscillator signal are both adjustable, and can be used to simulate the influence of the period of the UWB signal and the frequency of the local oscillator signal on the angle measurement accuracy.

[0063] The channel module is used to simulate the influence of channel noise and multipath, and its structure is as Figure 5As shown in the figure; the channel module consists of a Gaussian white noise channel sub-module and a multipath simulation sub-module; the Gaussian white noise channel sub-module is used to simulate the influence of noise generated in the channel, and the multipath simulation sub-module is composed of an 8-path delay module and an energy attenuation module, which is used to simulate the influence of multipath; after the modulated UWB pulse signal enters the multipath simulation sub-module, it passes through the 8-path delay module and the energy attenuation module in the channel and becomes a multipath signal with different delays and amplitudes. The multipath signal is divided into two clusters, with 4 signals in each cluster (the second cluster has a relative delay compared to the first cluster, so a relative delay module and a relative attenuation module are added for simulation). Then, after the two clusters of signals are superimposed and passed through the additive Gaussian white noise channel sub-module, an energy signal containing noise with multiple different delay paths is output and enters the antenna receiving module. By adjusting the signal-to-noise ratio and multipath influence parameters of the channel module, the influence of noise and multipath problems on the accuracy of the UWB system can be tested.

[0064] The described antenna receiving module is used to simulate the receiving function of the antenna, and its structure is as Figure 6 shown. The antenna receiving module consists of two parallel delays and an antenna pattern, which is used to simulate the time difference of the UWB signal arriving at two antennas and the influence of the antenna pattern. By adjusting the delays of the two delay modules, it can simulate the UWB signal arriving at the receiving antenna from different angles. By adjusting the parameters of the antenna pattern module, the antenna pattern characteristics of different receiving antennas can be simulated. The output signal of the antenna receiving module is two UWB signals with different delays and enters the RF module.

[0065] The described RF module is used to simulate the down-conversion of the signal. Since the antenna receiving module outputs two signals, the RF module also requires two RF sub-modules to process the two signals respectively. The internal structure diagram of the RF sub-module is as Figure 7 shown. The two RF sub-modules perform quadrature demodulation processing on the two signals output by the antenna receiving module respectively to facilitate subsequent phase extraction work;

[0066] There are two local oscillator modules inside the RF sub-module. The output local oscillator signal has the same frequency as the local oscillator signal of the transmitting module and a phase difference of 90 degrees. The two local oscillator signals are mixed with the two signals input from the antenna receiving module respectively, and after filtering processing respectively, four baseband signals carrying phase information are obtained. The RF module has adjustable local oscillator amplitude ratios and phase differences inside. Therefore, in addition to realizing the demodulation function, this module can also simulate the influence of in-phase and quadrature amplitude imbalance and in-phase and quadrature phase imbalance on the positioning accuracy. The output signal of the RF module is 4 analog signals carrying phase information and is sent to the ADC module.

[0067] The internal structure of the described ADC module is as Figure 8As shown, the ADC module is used to perform analog-to-digital conversion on the 4-channel signals output by the RF module and convert them into digital signals. Therefore, the ADC module has 4-channel inputs and outputs respectively. The specific implementation process of the ADC is sampling - quantization - holding. Since the quantization function is integrated in the sampling module provided in SIMULINK, only the sampling module and the quantization module are used in the ADC module. By adjusting parameters such as the ADC sampling frequency and quantization bit width inside the ADC module, the influence of the ADC sampling frequency and quantization bit width on the measured angle can be tested.

[0068] The baseband processing module is used for the baseband processing part of the analog positioning algorithm; the specific implementation method is as follows: analyze the 4-channel signals output by the ADC module, extract the phase difference from them, and finally extract the angle, which is implemented by a MATLAB program;

[0069] The processing flow of the baseband processing module is as Figure 9 shown. The first step of the baseband processing program is to extract the first path of the four-channel output signals using the first path extraction algorithm; in this embodiment, the double sliding window measurement algorithm is used to extract the first path of the four-channel output signals. This algorithm has the advantages of simple principle and high detection accuracy. In addition, by modifying the first path extraction algorithm in this part, the influence of different first path extraction algorithms on the positioning accuracy can also be tested. The second step is to extract the larger value in the first path as the effective value; due to the influence of noise, using the smaller value in the first path to extract the phase will result in poor positioning accuracy. Therefore, the present invention uses the larger value in the first path for first path extraction to ensure the positioning accuracy. The third step is to calculate the phase according to the effective value extracted in the second step and calculate the average value of all measured phases; the fourth step is to calculate the angle between the transmitting base station and the antenna according to the average value of the calculated phases to realize the function of indoor positioning.

[0070] A method for indoor positioning based on AOA of UWB system according to the present invention is implemented using the above positioning simulation system; it includes the following steps:

[0071] Step 1: Define the angles between the transmitting base station and the receiving antenna to be simulated, modify the time difference between the two antennas in the antenna module for receiving UWB signals, and the frequency of the transmitted signal; according to Figure 1 the schematic diagram, the relationship between the antenna reception difference and the angle is d*sin(θ) = Δτ*c, where d represents the distance between the two antennas, θ represents the incident angle of the UWB signal reaching the antenna, c represents the speed of light, and Δτ represents the time difference between the receiving antennas for receiving signals. In this embodiment, assume that the angle to be tested currently is 20°, the frequency of the transmitted signal is 6.5 GHz, and according to the antenna distance being half of a half wavelength, the time difference Δτ can be obtained as 0.0263 nanoseconds.

[0072] Step 2: Define the parameters of each module of the simulation system. The specific parameters to be defined are as follows: the initial phase of the local oscillator signal of the transmitting module, the signal-to-noise ratio of the channel module, the antenna pattern of the antenna receiving module, the IQ phase difference and IQ amplitude ratio of the RF module, the sampling frequency and quantization bit width of the ADC module;

[0073] Step 3: After all the parameters of the simulation system are determined, the simulation system starts to run: The transmitting module generates a UWB initial signal, denoted as p(t), which is mixed with the carrier signal cos(ωt) generated by the local oscillator module to obtain the transmitted signal p(t)cos(ωt), and then sent to the channel module. Here, ω is the angular velocity of the carrier signal. In this implementation process, the UWB signal p(t) is set as shown in Figure 10 and the signal output after mixing with the 6.5 GHz local oscillator signal is shown in Figure 11 .

[0074] Step 4: After the transmitted signal p(t)cos(ωt) enters the channel module, the influence of noise and multipath is added. Since in the subsequent process, whether it is the extraction of the phase difference or the extraction of the angle, only the influence of the first path is considered (because the first path must be directly transmitted from the target to be measured to the receiving antenna, and other paths may be reflected from other places), so only the first path of the signal is considered here. Let the delay of the first path of the signal after passing through the channel module be τ, and the attenuation ratio be α. Ignoring the influence of noise, the first path of the signal output by the channel module is expressed as:

[0075] α*p(t - τ)*cos(ω(t - τ));

[0076] If two clusters are considered and there are four multipaths in each cluster, the signal output by the channel module is shown in Figure 12 .

[0077] Step 5: After the signal output by the channel module enters the antenna receiving module, assuming that the UWB signal arrives at antenna 1 first, the signal received by antenna 1 is the signal output by the channel module, and its first path is expressed as:

[0078] α*p(t - τ)*cos(ω(t - τ))

[0079] As known from Step 1, the time difference of the receiving antenna is Δτ. Therefore, the signal received by antenna 2 is expressed as:

[0080] α*p(t - τ - Δτ)*cos(ω(t - τ - Δτ))

[0081] Assume that at the current time difference (i.e., at the currently set angle), the attenuation amplitude of the antenna pattern module is β. Then the two signals output by the antenna module are respectively expressed as:

[0082] α * β * p(t - τ) * cos(ω(t - τ))

[0083] α * β * p(t - τ - Δτ) * cos(ω(t - τ - Δτ))

[0084] Denote Then the two signals output by the antenna module are respectively expressed as:

[0085]

[0086]

[0087] According to Step 1, it is known that the set antenna reception time difference is 0.0263 nanoseconds. Assuming the signal-to-noise ratio is 20 dB, the output waveform diagram of the antenna module is shown in Figure 13 as follows.

[0088] Step 6: After the first path of the signal output by the antenna module enters the RF module, it is mixed with the local oscillator signals sin(ωt) and cos(ωt) with a phase difference of 90° respectively. The first paths of the signals are respectively expressed as:

[0089]

[0090]

[0091]

[0092]

[0093] It can be equivalently expressed as:

[0094]

[0095]

[0096]

[0097]

[0098] After filtering and amplification processing to eliminate high-order harmonics, the first paths of the four output signals are respectively expressed as:

[0099]

[0100]

[0101]

[0102]

[0103] Assume that the amplitude ratio of the current radio frequency module is 1 and the quadrature phase imbalance is 0, then the output signal of the radio frequency module is as Figure 14 shown.

[0104] Step 7: After the first paths of the four signals output by the radio frequency module enter the ADC module, they are processed by the sampling module and the quantization module. Assume that the currently set sampling frequency is f S , and the quantization bit width is B. Then the first paths of the four signals output by the ADC module are respectively expressed as:

[0105]

[0106]

[0107]

[0108]

[0109] Assume that the current ADC module sampling frequency is 10 GHz and the quantization bit width is 12 bit. Then the output signal of the ADC module is shown in Figure 15 shown.

[0110] Step 8: After the four signals output by the ADC module enter the baseband processing program, they are first processed by the first path extraction module. Then, a value with a greater effect of the first path is selected as the effective point for phase extraction; assume that the average values of the phases extracted here are respectively Then the extracted phase difference is expressed as Then the finally output angle is expressed as:

[0111]

[0112] Under the parameters set in this embodiment, the finally measured angle is 20.06° and the error is 0.06°.

[0113] Those of ordinary skill in the art will realize that the embodiments described herein are for helping readers understand the principles of the present invention and should be understood that the protection scope of the present invention is not limited to such specific statements and embodiments. Those of ordinary skill in the art can make various other specific deformations and combinations that do not depart from the essence of the present invention based on these technical revelations disclosed in the present invention, and these deformations and combinations are still within the protection scope of the present invention.

Claims

1. An AOA indoor positioning simulation system based on the UWB system, characterized in that It includes a transmitting module, a channel module, an antenna receiving module, a radio frequency module, an ADC module, and a baseband processing module connected in sequence; The transmitting module is used for the up-conversion of analog signals; the transmitting module consists of a signal source and an up-conversion local oscillator module. The signal source generates a UWB pulse signal, which is then mixed with the local oscillator signal to obtain a modulated UWB pulse signal and sent into the channel module; The channel module is used for simulating the noise effect and the multipath effect of the channel; The channel module consists of a Gaussian white noise channel sub-module and a multipath simulation sub-module; the Gaussian white noise channel sub-module is used for simulating the effect of noise generation in the channel, and the multipath simulation sub-module is composed of 8 delay modules and an energy attenuation module, which is used for simulating the multipath effect; after the modulated UWB pulse signal enters the multipath simulation sub-module and passes through the 8 delay modules and the energy attenuation module in the channel, it becomes a multipath signal with different delays and different amplitudes, and then passes through the additive Gaussian white noise channel sub-module, and outputs an energy signal containing noise with multiple different delay paths and enters the antenna receiving module; The antenna receiving module is used for simulating the receiving function of the antenna, and the antenna receiving module consists of two parallel delays and an antenna pattern; The radio frequency module is used for simulating the down-conversion of signals, including two radio frequency sub-modules, and the two radio frequency sub-modules respectively perform quadrature demodulation processing on the two signals output by the antenna receiving module; There are two local oscillator modules inside the radio frequency sub-module, and the frequencies of the local oscillator signals output by them are the same as the frequency of the local oscillator signal of the transmitting module, and the phases differ by 90 degrees; the two local oscillator signals are respectively mixed with the two signals input from the antenna receiving module, and after filtering processing respectively, four baseband signals carrying phase information are obtained.

2. The AOA indoor positioning simulation system based on the UWB system according to claim 1, characterized in that, The ADC module is used for analog-to-digital conversion of the 4 signals output by the radio frequency module and converts them into digital signals.

3. The AOA indoor positioning simulation system based on the UWB system according to claim 2, characterized in that, The baseband processing module is used for simulating the baseband processing part of the positioning algorithm; the specific implementation method is: analyzing the 4 signals output by the ADC module, extracting the phase difference from them, and finally extracting the angle; The first step of the baseband processing program is to use the first path extraction algorithm to extract the first path of the four output signals; the second step is to extract the larger value of the amplitude in the first path as the effective value; the third step is to calculate the phase according to the effective value extracted in the second step and calculate the average value of all measured phases; the fourth step is to calculate the angle between the transmitting base station and the antenna according to the average value of the calculated phases to realize the function of indoor positioning.

4. The AOA indoor positioning method based on the UWB system is implemented by using the positioning simulation system described in any one of claims 1 to 3; characterized in that, It includes the following steps: Step 1: Define the angles between the transmitting base station and the receiving antenna to be simulated, modify the time difference between the two antennas receiving UWB signals in the antenna module, and the frequency of the transmitted signal. The relationship between the antenna receiving difference and the angle is d*sin(θ) = Δτ*c, where d represents the distance between the two antennas, θ represents the incident angle of the UWB signal reaching the antenna, c represents the speed of light, and Δτ represents the time difference of the receiving antenna receiving the signal; Step 2: Define the parameters of each module of the simulation system; the specific parameters that need to be defined are as follows: the initial phase of the local oscillator signal of the transmitting module, the signal-to-noise ratio of the channel module, the antenna pattern of the antenna receiving module, the IQ phase difference and IQ amplitude ratio of the RF module, and the sampling frequency and quantization bit width of the ADC module; Step 3: The simulation system starts running: the transmitting module generates the UWB initial signal, denoted as p(t), and after mixing with the carrier signal cos(ωt) generated by the local oscillator module, the transmitting signal p(t)cos(ωt) is obtained and sent to the channel module; where ω is the angular velocity of the carrier signal; Step 4: After the transmitted signal p(t)cos(ωt) enters the channel module, the influence of noise and multipath is added. Since in the subsequent process, whether it is the extraction of phase difference or angle, only the influence of the first path is considered, so only the first path of the signal is considered here; suppose that after passing through the channel module, the first path delay of the signal is τ, the attenuation ratio is α, and the influence of noise is ignored, then the first path of the signal output by the channel module is expressed as: α*p(t-τ)*cos(ω(t-τ)); Step 5: After the signal output by the channel module enters the antenna receiving module, assuming that the UWB signal reaches antenna 1 first, the signal received by antenna 1 is the first path of the signal output by the channel module, which is expressed as: α*p(t-τ)*cos(ω(t-τ)) The time difference of the receiving antenna is Δτ, so the signal received by antenna two is expressed as: α*p(t-τ-Δτ)*cos(ω(t-τ-Δτ)) Assume that under the current time difference, the attenuation amplitude of the antenna pattern module is β; then the two signals output by the antenna module are expressed as: α*β*p(t-τ)*cos(ω(t-τ)) α*β*p(t-τ-Δτ)*cos(ω(t-τ-Δτ)) Record The two signals output by the antenna module are respectively represented as: Step 6: After the first path of the signal output by the antenna module enters the RF module, it is mixed with two local oscillator signals sin(ωt) and cos(ωt) with a phase difference of 90°, and then filtered and amplified. The first paths of the four output signals are expressed as follows: Step 7: After the first paths of the four signals output by the RF module enter the ADC module, they are processed by the sampling module and the quantization module. Let the currently set sampling frequency be f S , and the quantization bit width be B. Then the first paths of the four signals output by the ADC module are respectively expressed as: Step 8: After the four-way signals output by the ADC module enter the baseband processing program, they are first processed by the first path extraction module; After that, select a value with a larger leading diameter as the effective point for phase extraction; assume that the average values of the phases extracted here are respectively Then the extracted phase difference is expressed as Then the finally output angle is expressed as

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