Urban rail vehicle positioning methods, devices and equipment

Abstract

This application provides a method, apparatus, and device for locating urban rail vehicles. The method includes: establishing a virtual line-of-sight link between a first rail vehicle and a second rail vehicle based on multiple elements included in a RIS (Radio Frequency Array); acquiring the received signal received by the processor in response to the transmitted signal at the current moment based on the virtual line-of-sight link; determining the Doppler frequency shift at the current moment based on the frequency of the received signal and the frequency of the transmitted signal; correcting the travel direction of the first rail vehicle based on the Doppler frequency shift to determine the horizontal and vertical correction speeds of the first rail vehicle; and determining the second location of the first rail vehicle at the current moment based on the first location, the horizontal correction speed, the vertical correction speed, and the time difference between the current moment and the previous moment. The solution of this application addresses the problem of poor positioning performance for urban rail vehicles under line-of-sight link congestion.

Description

Technical Field

[0001] This application relates to the field of rail transit technology, and in particular to a method, device and equipment for positioning urban rail vehicles. Background Technology

[0002] With the rapid development of urbanization, urban rail transit is playing an increasingly significant role in daily travel.

[0003] Because urban rail vehicles often operate in indoor environments such as underground locations and tunnels, they cannot use satellite positioning systems such as GPS or BeiDou. Therefore, urban rail vehicle positioning mainly relies on trackside equipment and onboard Automatic Train Protection (ATP) equipment. Currently, urban rail vehicle positioning solutions primarily achieve positioning through line-of-sight links.

[0004] However, in complex track scenarios such as curves, there may be line-of-sight link blockages, resulting in poor positioning performance for urban rail vehicles. Summary of the Invention

[0005] This application provides a method, apparatus, and equipment for locating urban rail vehicles to solve the problem of poor positioning performance of urban rail vehicles under line-of-sight link congestion.

[0006] In a first aspect, this application provides a method for locating urban rail vehicles, applied to a processor located in a first rail vehicle, wherein both the first and second rail vehicles travel on a preset track, the method comprising:

[0007] Based on the multiple elements included in the reconfigurable smart surface RIS, a virtual line-of-sight link is established between the first rail vehicle and the second rail vehicle. The virtual line-of-sight link is a link for a signal to travel from the second rail vehicle through the multiple elements to the first rail vehicle.

[0008] Based on the virtual line-of-sight link, the received signal received by the processor in response to the transmitted signal at the current moment is obtained, wherein the transmitted signal is the signal transmitted by the signal transmitting device in the second rail vehicle;

[0009] The Doppler frequency shift at the current moment is determined based on the frequency of the received signal and the frequency of the transmitted signal;

[0010] Based on the speed indicated by the first sensor of the first rail vehicle at the current time, the speed indicated by the second sensor of the second rail vehicle at the current time, and the Doppler frequency shift, the travel direction of the first rail vehicle is corrected to determine the horizontal corrected speed of the first rail vehicle on the x-axis and the vertical corrected speed on the y-axis at the current time.

[0011] The second positioning position of the first track vehicle at the current moment is determined based on the first positioning position of the first track vehicle at the previous moment, the horizontal correction speed, the vertical correction speed, and the time difference between the current moment and the previous moment.

[0012] In one possible implementation, establishing a virtual line-of-sight link between the first and second rail vehicles based on multiple elements included in the reconfigurable smart surface RIS includes:

[0013] Obtain the quantity of the plurality of elements and the distance between any two adjacent elements among the plurality of elements;

[0014] Based on the number of the plurality of elements and the distance between any two adjacent elements, a RIS-assisted received signal model is established.

[0015] The RIS phase shift parameter is determined based on the received signal model. The RIS phase shift parameter is used to indicate the phase of the signals reflected by the plurality of elements, so that the signals reflected by the plurality of elements are in a constructive interference relationship.

[0016] The virtual line-of-sight link is established based on the RIS phase shift parameters.

[0017] In one possible implementation, establishing a RIS-assisted received signal model based on the number of the plurality of elements and the distance between any two adjacent elements includes:

[0018] Obtain first channel information of the channel from the plurality of elements to the first rail vehicle at the current time, and second channel information of the channel from the second rail vehicle to the plurality of elements at the current time;

[0019] Determine a first functional relationship between the control matrix of the plurality of elements at the current time and the phase shift parameter of each element;

[0020] The received signal model is established based on the first channel information, the second channel information, and the first functional relationship.

[0021] In one possible implementation, determining the RIS phase shift parameters based on the received signal model includes:

[0022] Based on the received signal model, a second functional relationship is determined between the received signal power at the current moment and the phase shift parameters of each element;

[0023] Based on the second functional relationship, the RIS phase shift parameter is determined, wherein the RIS phase shift parameter is the phase shift parameter that maximizes the received signal power.

[0024] In one possible implementation, the step of correcting the travel direction of the first rail vehicle based on the first sensor-indicated speed of the first rail vehicle at the current moment, the second sensor-indicated speed of the second rail vehicle at the current moment, and the Doppler frequency shift, to determine the horizontal correction speed of the first rail vehicle on the x-axis and the vertical correction speed on the y-axis at the current moment, includes:

[0025] Based on the Doppler frequency shift, the frequency of the transmitted signal, the velocity indicated by the first sensor, the velocity indicated by the second sensor, and the first angle between the direction of the velocity indicated by the second sensor and the transmission direction of the transmitted signal, a second angle between the direction of the velocity indicated by the first sensor and the transmission direction of the received signal is determined.

[0026] Based on the second included angle, the travel direction of the first rail vehicle is corrected to determine the horizontal correction speed and the vertical correction speed.

[0027] In one possible implementation, the step of correcting the travel direction of the first rail vehicle based on the second included angle, and determining the horizontal correction speed and the vertical correction speed, includes:

[0028] Based on the second included angle and the estimated value of the angle from RIS to the first rail vehicle at the previous moment, the third included angle between the direction of the speed indicated by the first sensor and the x-axis is determined.

[0029] The horizontal correction speed and the vertical correction speed are determined based on the magnitude of the speed indicated by the first sensor and the third included angle.

[0030] In one possible implementation, determining the second positioning position of the first rail vehicle at the current moment based on the first positioning position of the first rail vehicle at the previous moment, the horizontal correction speed, the vertical correction speed, and the time difference between the current moment and the previous moment includes:

[0031] Determine the state transition matrix from the previous moment to the current moment based on the time difference;

[0032] Based on the state transition matrix, the first positioning position is predicted using a particle filter to obtain multiple sampling positions of the first track vehicle at the current time.

[0033] For any sampling position, the signal transmission duration corresponding to the sampling position is determined based on the first element of the RIS. The signal transmission duration is the time between the transmission of the signal transmitting device in the second rail vehicle and the receipt of the corresponding signal by the second rail vehicle at the corresponding sampling position.

[0034] The second positioning position is determined based on the plurality of sampling positions and the signal transmission duration corresponding to each sampling position.

[0035] In one possible implementation, determining the second positioning position based on the plurality of sampling positions and the signal transmission duration corresponding to each sampling position includes:

[0036] The weight corresponding to each sampling position is determined based on the signal transmission duration corresponding to each sampling position.

[0037] The second positioning position is obtained by performing a weighted average of the multiple sampling positions according to the weights corresponding to each sampling position.

[0038] Secondly, this application provides a positioning device for urban rail vehicles, the device comprising:

[0039] A module is established to establish a virtual line-of-sight link between a first track vehicle and a second track vehicle based on multiple elements included in the RIS. Both the first track vehicle and the second track vehicle travel on a preset track. The virtual line-of-sight link is a link between the second track vehicle and the first track vehicle through the multiple elements.

[0040] The acquisition module is used to acquire, based on the virtual line-of-sight link, the received signal received by the processor in the first rail vehicle in response to the transmitted signal at the current moment, wherein the transmitted signal is the signal transmitted by the signal transmitting device in the second rail vehicle;

[0041] The first determining module is used to determine the Doppler frequency shift at the current moment based on the frequency of the received signal and the frequency of the transmitted signal;

[0042] The processing module is used to perform correction processing on the travel direction of the first rail vehicle based on the first sensor indicated speed of the first rail vehicle at the current time, the second sensor indicated speed of the second rail vehicle at the current time, and the Doppler frequency shift, and to determine the horizontal correction speed of the first rail vehicle on the x-axis and the vertical correction speed on the y-axis at the current time.

[0043] The second determining module is used to determine the positioning position of the first rail vehicle at the current moment based on the first positioning position of the first rail vehicle at the previous moment, the horizontal correction speed, the vertical correction speed, and the time difference between the current moment and the previous moment.

[0044] In one possible implementation, the establishment module is specifically used for:

[0045] Obtain the quantity of the plurality of elements and the distance between any two adjacent elements among the plurality of elements;

[0046] Based on the number of the plurality of elements and the distance between any two adjacent elements, a RIS-assisted received signal model is established.

[0047] The RIS phase shift parameter is determined based on the received signal model. The RIS phase shift parameter is used to indicate the phase of the signals reflected by the plurality of elements, so that the signals reflected by the plurality of elements are in a constructive interference relationship.

[0048] The virtual line-of-sight link is established based on the RIS phase shift parameters.

[0049] In one possible implementation, the establishment module is specifically used for:

[0050] Obtain first channel information of the channel from the plurality of elements to the first rail vehicle at the current time, and second channel information of the channel from the second rail vehicle to the plurality of elements at the current time;

[0051] Determine a first functional relationship between the control matrix of the plurality of elements at the current time and the phase shift parameter of each element;

[0052] The received signal model is established based on the first channel information, the second channel information, and the first functional relationship.

[0053] In one possible implementation, the establishment module is specifically used for:

[0054] Based on the received signal model, a second functional relationship is determined between the received signal power at the current moment and the phase shift parameters of each element;

[0055] Based on the second functional relationship, the RIS phase shift parameter is determined, wherein the RIS phase shift parameter is the phase shift parameter that maximizes the received signal power.

[0056] In one possible implementation, the processing module is specifically used for:

[0057] Based on the Doppler frequency shift, the frequency of the transmitted signal, the velocity indicated by the first sensor, the velocity indicated by the second sensor, and the first angle between the direction of the velocity indicated by the second sensor and the transmission direction of the transmitted signal, a second angle between the direction of the velocity indicated by the first sensor and the transmission direction of the received signal is determined.

[0058] Based on the second included angle, the travel direction of the first rail vehicle is corrected to determine the horizontal correction speed and the vertical correction speed.

[0059] In one possible implementation, the processing module is specifically used for:

[0060] Based on the second included angle and the estimated value of the angle from RIS to the first rail vehicle at the previous moment, the third included angle between the direction of the speed indicated by the first sensor and the x-axis is determined.

[0061] The horizontal correction speed and the vertical correction speed are determined based on the magnitude of the speed indicated by the first sensor and the third included angle.

[0062] In one possible implementation, the second determining module is specifically used for:

[0063] Determine the state transition matrix from the previous moment to the current moment based on the time difference;

[0064] Based on the state transition matrix, the first positioning position is predicted using a particle filter to obtain multiple sampling positions of the first track vehicle at the current time.

[0065] For any sampling position, the signal transmission duration corresponding to the sampling position is determined based on the first element of the RIS. The signal transmission duration is the time between the transmission of the signal transmitting device in the second rail vehicle and the receipt of the corresponding signal by the second rail vehicle at the corresponding sampling position.

[0066] The second positioning position is determined based on the plurality of sampling positions and the signal transmission duration corresponding to each sampling position.

[0067] In one possible implementation, the second determining module is specifically used for:

[0068] The weight corresponding to each sampling position is determined based on the signal transmission duration corresponding to each sampling position.

[0069] The second positioning position is obtained by performing a weighted average of the multiple sampling positions according to the weights corresponding to each sampling position.

[0070] Thirdly, this application also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the urban rail vehicle positioning method as described in any of the first aspects.

[0071] Fourthly, this application also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the urban rail vehicle positioning method as described in any of the first aspects.

[0072] Fifthly, this application also provides a computer program product, including a computer program that, when executed by a processor, implements the urban rail vehicle positioning method as described in any of the first aspects.

[0073] The urban rail vehicle positioning method, apparatus, and equipment provided in this application first establish a virtual line-of-sight link between a first rail vehicle and a second rail vehicle based on multiple elements included in the RIS (Radio Router System). This virtual line-of-sight link is a link between the signal from the second rail vehicle and the first rail vehicle through multiple elements. Then, based on the virtual line-of-sight link, the received signal received by the processor for the transmitted signal at the current moment is obtained. This transmitted signal is the signal transmitted by the signal transmitting device in the second rail vehicle. The Doppler frequency shift at the current moment is determined according to the frequency of the received signal and the frequency of the transmitted signal. Based on the first sensor indicated speed of the first rail vehicle at the current moment, the second sensor indicated speed of the second rail vehicle at the current moment, and the Doppler frequency shift, the travel direction of the first rail vehicle is corrected to determine the horizontal correction speed of the first rail vehicle on the x-axis and the vertical correction speed on the y-axis at the current moment. Finally, based on the first positioning position of the first rail vehicle at the previous moment, the horizontal correction speed, the vertical correction speed, and the time difference between the current moment and the previous moment, the second positioning position of the first rail vehicle at the current moment is determined. The solution proposed in this application improves the characteristics of the wireless signal propagation environment by intelligently reflecting signals through multiple elements included in the RIS. A virtual line-of-sight link is established based on multiple elements in the RIS, which solves the problems of signal attenuation and signal heterogeneity caused by the lack of line-of-sight propagation paths in complex environments, and effectively improves the positioning accuracy of rail vehicles in the absence of line-of-sight links. Attached Figure Description

[0074] To more clearly illustrate the technical solutions in this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0075] Figure 1 This is a schematic diagram illustrating an application scenario provided in the embodiments of this application;

[0076] Figure 2 A flowchart illustrating the urban rail vehicle positioning method provided in this application embodiment;

[0077] Figure 3 This is a schematic diagram of rail vehicle positioning in an uplink scenario provided in an embodiment of this application;

[0078] Figure 4 This is a schematic diagram of rail vehicle positioning in a downlink scenario provided in an embodiment of this application;

[0079] Figure 5 This is a schematic diagram of signal reflection provided in an embodiment of this application;

[0080] Figure 6 A schematic diagram illustrating the process of establishing a virtual line-of-sight link, provided for an embodiment of this application;

[0081] Figure 7 A schematic diagram illustrating the process of correcting the travel direction of a first rail vehicle using Doppler frequency shift, as provided in an embodiment of this application.

[0082] Figure 8 A flowchart illustrating the process of determining the second positioning position of the first rail vehicle, provided in an embodiment of this application;

[0083] Figure 9 This is a schematic diagram of the structure of the urban rail vehicle positioning device provided in the embodiments of this application;

[0084] Figure 10 This is a schematic diagram of the physical structure of an electronic device provided in an embodiment of this application. Detailed Implementation

[0085] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0086] With the rapid development of urbanization, urban rail transit is playing an increasingly significant role in daily travel.

[0087] Since urban rail vehicles often operate in indoor environments such as underground and tunnels, they cannot use satellite positioning systems such as GPS or Beidou. Therefore, subway train positioning mainly relies on trackside equipment and onboard ATP equipment.

[0088] Onboard equipment includes transponder receivers, odometers, and Doppler radar. When a train passes over a transponder mounted on the trackside, the onboard transponder antenna emits electromagnetic energy to the ground transponder. The ground transponder then converts this energy into power, activating its internal electronic unit to transmit its stored location information to the train. The odometer is mounted on the train's axles. The train calculates its distance traveled by integrating its speed in real time. Due to significant errors in speed sensors, the train needs to use the trackside transponder to correct its positioning information. However, this positioning method leads to a decrease in positioning performance when the train cannot obtain the absolute position information transmitted by the equipment.

[0089] In recent years, many positioning technologies for urban rail vehicles have been proposed, among which vehicle-to-vehicle communication, as a development trend of the next generation of train control systems, has received widespread attention. Existing technologies can be broadly classified into three categories based on different positioning performance requirements:

[0090] (1) Positioning technology based on wireless signals, such as using time of arrival (TOA), time difference of arrival (TDOA), or received signal strength (RSS) for positioning;

[0091] (2) Positioning technology based on track circuits;

[0092] (3) Machine vision-based positioning technologies, such as stereo vision positioning technology that integrates visible light communication, Simultaneous Localization and Mapping (SLAM) technology, and track QR code beacon recognition and positioning technology.

[0093] Most of these methods rely on cooperative communication in wireless sensor networks (such as multilateral positioning and vehicle-to-everything (V2X)) or have high computational complexity. Machine vision, in particular, requires a large amount of training data to effectively improve positioning accuracy, placing high demands on both hardware and software. The algorithms may fail when the necessary infrastructure is lacking. Furthermore, complex underground and tunnel environments increase the probability of line-of-sight link congestion, leading to signal attenuation, multipath effects, and channel heterogeneity. Additionally, when a train travels on a curve, the odometer cannot correct the train's direction of travel and cannot decompose speed, resulting in errors in the train's position coordinates.

[0094] In summary, current urban rail vehicle positioning solutions suffer from performance degradation when the line-of-sight link is obstructed, and the odometer cannot correct train orientation at curves, nor can it decompose speed, thus failing to accurately locate urban rail vehicles. Therefore, this application provides an urban rail vehicle positioning solution that can accurately locate urban rail vehicles even when the line-of-sight link is blocked.

[0095] First, combine Figure 1 An applicable application scenario of the embodiments of this application will be introduced.

[0096] Figure 1 This is a schematic diagram of an application scenario provided in the embodiments of this application, such as... Figure 1 As shown, it includes a first rail vehicle 11 and a second rail vehicle 12, both of which travel on a preset track 13.

[0097] exist Figure 1 The example shown depicts a counter-clockwise direction of travel. It is understood that the direction of travel for the rail vehicle in various embodiments of this application may also be clockwise or other possible directions. Figure 1 The driving direction shown in the example is just one example.

[0098] Both the first rail vehicle 11 and the second rail vehicle 12 are equipped with devices for vehicle positioning. Figure 1 (Not shown in the image), for example, it includes a signal transmitting device, a signal receiving device, a processor, a speed sensor, etc. The signal transmitting device can be used to transmit signals, the signal receiving device can be used to receive signals, the speed sensor can be used to acquire the speed of the rail vehicle, the processor can be used to determine the position of the rail vehicle based on relevant data from other devices, and so on.

[0099] The following is based on Figure 1 Example application scenarios, combined with Figure 2 The solutions of the embodiments of this application will be described.

[0100] Figure 2 This is a flowchart illustrating the urban rail vehicle positioning method provided in an embodiment of this application. The method is applied to a processor located in a first rail vehicle. Both the first and second rail vehicles travel on a preset track. Figure 2 As shown, the method includes:

[0101] S21, based on the multiple elements included in the RIS, establishes a virtual line-of-sight link between the first and second rail vehicles. The virtual line-of-sight link is the link between the signal from the second rail vehicle through multiple elements to the first rail vehicle.

[0102] Both the first and second rail vehicles travel on a preset track. The first rail vehicle can be either in front of or behind the second rail vehicle; this embodiment does not limit this. When the first and second rail vehicles encounter a line-of-sight link blockage, for example in… Figure 1 In this case, the line-of-sight link between the first and second rail vehicles is blocked. At this time, the original line-of-sight link-based positioning method suffers from problems such as signal attenuation, multipath effect and channel heterogeneity.

[0103] Based on this, embodiments of this application configure multiple elements in the RIS in areas where line-of-sight link congestion may occur, for example... Figure 1 Element 14. In some embodiments, these multiple elements may be composed of diodes, which have the ability to reflect signals.

[0104] The processor can establish a virtual line-of-sight link between the first and second rail vehicles based on multiple elements included in the RIS. This virtual line-of-sight link is a link between the second rail vehicle and the first rail vehicle, where signals are reflected from the second rail vehicle through multiple elements. After the virtual line-of-sight link is established, transmitted signals from the second rail vehicle can reach the first rail vehicle through this virtual line-of-sight link.

[0105] In one possible implementation, the RIS phase shift parameters can be determined by the positions of multiple elements, as well as the approximate positions of the first and second rail vehicles. The RIS phase shift parameters are used to indicate the transmission angle of the transmitted signal and the reflection angle of the elements. Then, a virtual line-of-sight link is established based on the RIS phase shift parameters.

[0106] In one possible implementation, the RIS phase shift parameter can be determined by the distance between adjacent elements, and then a virtual line-of-sight link can be established based on the RIS phase shift parameter.

[0107] S22, based on the virtual line-of-sight link, obtains the received signal received by the processor for the transmitted signal at the current moment. The transmitted signal is the signal transmitted by the signal transmitting device in the second rail vehicle.

[0108] After establishing a virtual line-of-sight link between the first and second rail vehicles, even if there is a line-of-sight link blockage between the first and second rail vehicles, signals emitted from the signal transmitter in the second rail vehicle can still be transmitted to the first rail vehicle through the virtual line-of-sight link.

[0109] Therefore, the signal transmitter in the second rail vehicle transmits a signal to the first rail vehicle; this transmitted signal is the transmitted signal. The signal received by the processor in the first rail vehicle is the received signal, which is the signal received at the current moment in response to the transmitted signal. Due to objective reasons such as interference, the transmitted signal and the received signal are not exactly the same.

[0110] S23, determine the Doppler frequency shift at the current moment based on the frequency of the received signal and the frequency of the transmitted signal.

[0111] The frequency of the received signal can be measured using appropriate equipment, and the frequency of the transmitted signal is known. Based on the frequencies of the received and transmitted signals, the Doppler frequency shift at the current moment can be calculated, as shown in equation (1):

[0112] Δf(t)=f′(t)-f (1)

[0113] Where Δf(t) is the Doppler frequency shift at time t, which is also the Doppler frequency shift at the current time; f′(t) is the frequency of the received signal; f represents the frequency of the transmitted signal, f=c / λ, where λ is the wavelength of the transmitted signal.

[0114] S24. Based on the speed indicated by the first sensor of the first rail vehicle at the current moment, the speed indicated by the second sensor of the second rail vehicle at the current moment, and the Doppler frequency shift, the travel direction of the first rail vehicle is corrected to determine the horizontal corrected speed of the first rail vehicle on the x-axis and the vertical corrected speed on the y-axis at the current moment.

[0115] The first sensor indicated speed refers to the speed of the first rail vehicle at the current moment, as obtained from the speed sensor, including both the magnitude and direction of the speed. After obtaining the first sensor indicated speed, the speed sensor in the first rail vehicle can send it to the processor in the first rail vehicle.

[0116] The second sensor indicated speed refers to the speed at which the second rail vehicle obtains its speed from the speed sensor at the current moment, including both the magnitude and direction of the speed. After obtaining the second sensor indicated speed, the speed sensor in the second rail vehicle can send it to the processor in the first rail vehicle.

[0117] After obtaining the indicated speeds from the first and second sensors, the processor performs a correction process on the travel direction of the first rail vehicle based on the indicated speeds from the first and second sensors and the Doppler frequency shift, thereby determining the horizontal correction speed of the first rail vehicle on the x-axis and the vertical correction speed on the y-axis at the current moment.

[0118] S25. Based on the first positioning position of the first rail vehicle at the previous moment, its horizontal correction speed, vertical correction speed, and the time difference between the current moment and the previous moment, determine the second positioning position of the first rail vehicle at the current moment.

[0119] The first positioning position is the positioning position of the first rail vehicle at the previous moment, which is the optimal estimate determined based on multiple first sampling positions of the first rail vehicle at the previous moment. After determining the horizontal and vertical correction speeds, the distance traveled by the first rail vehicle within the time difference between the current moment and the previous moment can be determined based on the horizontal and vertical correction speeds and the time difference between the current moment and the previous moment. Based on the first positioning position of the first rail vehicle at the previous moment and the distance traveled by the first rail vehicle within the time difference, the second positioning position of the first rail vehicle at the current moment can be determined.

[0120] The solutions of the embodiments of this application are described below with reference to specific examples.

[0121] Figure 3 This is a schematic diagram of rail vehicle positioning in an uplink scenario provided in an embodiment of this application. Figure 4 This is a schematic diagram of rail vehicle positioning in a downlink scenario provided in an embodiment of this application. Figure 3 As shown, the uplink scenario refers to a second rail vehicle following behind the first rail vehicle, moving in the direction of the first rail vehicle's travel path. Signals are transmitted from the second rail vehicle to the first rail vehicle through multiple elements of the RIS. For example... Figure 4 As shown, the downlink scenario refers to the second rail vehicle being in front of the first rail vehicle, with the first rail vehicle moving toward the travel path of the second rail vehicle, and signals being sent from the second rail vehicle to the first rail vehicle through multiple elements of the RIS.

[0122] The positioning process is similar in both uplink and downlink scenarios. The solutions described in the embodiments of this application are applicable to both uplink and downlink scenarios. Figure 3 and Figure 4 For example, due to the presence of a curve, the line-of-sight link between the first and second rail vehicles is blocked, making it impossible to use the line-of-sight link for positioning.

[0123] Figure 5 This is a schematic diagram of signal reflection provided in an embodiment of this application, such as... Figure 5As shown, RIS consists of K elements, namely the 1st element, the 2nd element, ..., the Kth element. Among them, let... Indicates the transmitted signal (i.e. Figure 5 The angle between the incident signal (in the image) and the x-axis, expressed as θ. t Indicates the received signal (i.e.) Figure 5 The angle between the reflected signal (in the image) and the x-axis.

[0124] The following is based on Figures 3 to 5 The following examples, in conjunction with the accompanying drawings, will further illustrate the solutions of the embodiments of this application.

[0125] Figure 6 This is a schematic diagram of the process for establishing a virtual line-of-sight link provided in an embodiment of this application, such as... Figure 6 As shown, it includes:

[0126] S61, get the number of multiple elements and the distance between any two adjacent elements.

[0127] like Figure 5 As shown, the number of elements is K, where K is a positive integer. The distance between any two adjacent elements is d, where d is a positive number.

[0128] S62 establishes a RIS-assisted received signal model based on the number of multiple elements and the distance between pairs of adjacent elements.

[0129] Specifically, firstly, the first channel information of the channels from multiple elements to the first rail vehicle at the current time, and the second channel information of the channels from the second rail vehicle to the multiple elements at the current time are obtained.

[0130] Let the current time be t, the number of elements be K (where K is a positive integer), and the distance between any two adjacent elements be d. Then, the first channel information can be obtained based on the following formula (2):

[0131]

[0132]

[0133] Where H1(t) represents the first channel information; λ is the wavelength of the transmitted signal; θ t The angle between RIS and the first orbital vehicle at time t represents the current time; k represents the k-th element, k = 1, 2, ..., K; the superscript T indicates that the matrix is ​​transposed.

[0134] The second channel information can be obtained based on the following formula (3):

[0135]

[0136] Where H2(t) represents the second channel information; λ represents the wavelength of the transmitted signal; Let t represent the angle between the second orbital vehicle and RIS at time t, which is the current time; k represents the k-th element, k = 1, 2, ..., K; the superscript T indicates that the matrix is ​​transposed.

[0137] exist Figure 3 and Figure 4 The examples are H1(t) and H2(t). Then, the first functional relationship between the control matrix of multiple elements at the current time and the phase shift parameters of each element is determined, as shown in Equation (4):

[0138]

[0139] Where, Φ t Φ is the control matrix with multiple elements at the current time. t =∈C K×K K represents the number of elements, and C represents a complex matrix; α k,t Let represent the phase shift parameter of the k-th element at time t; k represents the k-th element, k = 1, 2, ..., K; diag represents the diagonal matrix.

[0140] After determining the first functional relationship, the received signal model can be established based on the first channel information, the second channel information, and the first functional relationship. The received signal model is shown in the following example (5):

[0141]

[0142] Where y(t) is the received signal model, that is, the received signal at time t, which is the current time; P tr R represents the power of the transmitted signal; R(t) is the path loss of the virtual line-of-sight link constructed by RIS at time t, which can be obtained according to the 3rd Generation Partnership Project (3GPP) Urban-micro (UMi) model. λ is the wavelength of the transmitted signal, l1(t) is the distance from the first element of RIS to the first orbital vehicle at time t, l2(t) is the distance from the second orbital vehicle to the first element of RIS at time t; H1(t) is the first channel information; H2(t) is the second channel information; Φ t This is a control matrix with multiple elements at the current time; s(t) represents the transmitted signal at time t; It has a mean of 0 and a variance of Gaussian white noise. The entire system is based on the first element of the RIS.

[0143] S63, determine the RIS phase shift parameter based on the received signal model. The RIS phase shift parameter is used to indicate the phase of the signals reflected by multiple elements, so that the signals reflected by multiple elements form a constructive interference relationship.

[0144] First, based on the received signal model, the second functional relationship between the received signal power at the current moment and the phase shift parameters of each element is determined. Based on the above equation (5), we can obtain:

[0145]

[0146] Among them, P r (t) represents the power of the received signal at time t; the symbol |·| represents the modulo operation; P tr R(t) represents the power of the transmitted signal; R(t) is the path loss of the virtual line-of-sight link constructed by RIS at time t; H1(t) is the first channel information; H2(t) is the second channel information; Φ t This is the control matrix for multiple elements at the current time.

[0147] After determining the second functional relationship, the RIS phase shift parameter can be determined based on the second functional relationship. The RIS phase shift parameter is the phase shift parameter that makes the received signal power take the maximum value. The signals reflected by multiple elements indicated by the RIS phase shift parameter have a constructive interference relationship.

[0148] In the absence of a line-of-sight link, a virtual line-of-sight link is constructed between the first and second rail vehicles using a RIS (Receiving Signal-to-Survey) architecture. The power P of the received signal... r A larger value for P(t) indicates a higher signal strength and higher data transmission quality; therefore, P should be set as high as possible. r Maximize (t).

[0149] According to equation (5) above, at time t, maxP r (t) is equivalent to:

[0150]

[0151] Among them, P r (t) represents the power of the received signal at time t; maxP r (t) represents that P r (t) takes the maximum value; time t is the current time.

[0152] Using the estimated angle from RIS to the first orbital vehicle at time t-1 Instead of θ t ,in:

[0153]

[0154] Where t-1 is the time before the current time; This is the optimal estimate of the position coordinates of the first track vehicle at time t-1. Adjust the phase shift parameter α. k,t for The power P of the received signal can be increased r (t) is approximately at its maximum. At this time, the signals reflected by each element of the RIS received by the first track vehicle are in phase and form a constructive interference relationship between the signals. That is, the RIS phase shift parameter, then For the launch angle, For receiving angle.

[0155] S64 establishes a virtual line-of-sight link based on RIS phase shift parameters.

[0156] After determining the transmission and reception angles, the signals reflected by each element of the RIS received by the first orbital vehicle are in phase, and a constructive interference relationship is formed between the signals, thus completing the construction of the virtual line-of-sight link.

[0157] The above embodiments describe the process of establishing a virtual line-of-sight link. The process of determining the correction speed of the first rail vehicle is described below with reference to the accompanying drawings.

[0158] Figure 7 This is a schematic diagram of the process for correcting the travel direction of the first rail vehicle using Doppler frequency shift, as provided in an embodiment of this application. Figure 7 As shown, it includes:

[0159] S71, based on the Doppler frequency shift, the frequency of the transmitted signal, the speed indicated by the first sensor, the speed indicated by the second sensor, and the first angle between the direction of the speed indicated by the second sensor and the transmission direction of the transmitted signal, determine the second angle between the direction of the speed indicated by the first sensor and the transmission direction of the transmitted signal.

[0160] The second sensor indicated speed refers to the speed at which the second rail vehicle obtains its speed from the speed sensor at the current moment, including both the magnitude and direction of the speed. After obtaining the second sensor indicated speed, the speed sensor in the second rail vehicle can send it to the processor in the first rail vehicle.

[0161] After the processor acquires the speed indicated by the second sensor, the wavelength of the received signal can be determined based on the magnitude of the speed indicated by the second sensor and the first angle between the direction of the speed indicated by the second sensor and the transmission direction of the transmitted signal. This process can be described by the following formula (9):

[0162]

[0163] Where λ′(t) is the wavelength of the received signal; c is the speed of light; v s,t θ represents the magnitude of the speed of the second rail vehicle obtained from the speed sensor at time t, which is also the magnitude of the speed indicated by the second sensor. Time t is the current time. 2,t Let θ represent the angle between the direction of travel of the second rail vehicle and the direction of transmission of the transmitted signal at time t. The direction of travel of the second rail vehicle is also the direction in which the second sensor indicates the velocity. Therefore, θ 2,t That is, the first angle between the direction of the velocity indicated by the second sensor and the transmission direction of the transmitted signal; λ is the wavelength of the transmitted signal.

[0164] The first sensor indicated speed refers to the speed of the first rail vehicle at the current moment, as obtained from the speed sensor, including both the magnitude and direction of the speed. After obtaining the first sensor indicated speed, the speed sensor in the first rail vehicle can send it to the processor in the first rail vehicle.

[0165] After determining the wavelength of the received signal, the functional relationship between the frequency of the received signal and the second angle can be determined based on the wavelength of the received signal and the magnitude of the speed indicated by the first sensor. The second angle is the angle between the direction of the speed indicated by the first sensor and the transmission direction of the received signal. This process can be referred to in the following formula (10):

[0166]

[0167] Where f′(t) is the frequency of the received signal; c is the speed of light; v l,t θ represents the speed of the first rail vehicle at time t, as obtained from the speed sensor, which is also the speed indicated by the first sensor. Time t is the current time. 1,t Let θ represent the angle between the direction of travel of the first rail vehicle at time t and the direction of transmission of the received signal. The direction of travel of the first rail vehicle is also the direction in which the first sensor indicates the velocity. Therefore, θ 1,t That is, the second angle between the direction of the velocity indicated by the first sensor and the transmission direction of the received signal; λ′(t) is the wavelength of the received signal; f represents the frequency of the transmitted signal, f=c / λ, where λ is the wavelength of the transmitted signal.

[0168] According to equations (1) and (10):

[0169]

[0170] Where Δf(t) is the Doppler frequency shift at time t, which is also the Doppler frequency shift at the current time; f′(t) is the frequency of the received signal; f represents the frequency of the transmitted signal, f=c / λ, where λ is the wavelength of the transmitted signal; v l,t This indicates the magnitude of the velocity indicated by the first sensor; v s,tθ represents the magnitude of the velocity indicated by the second sensor. 1,t Indicates the second included angle; θ 2,t denoted by ; c represents the first included angle; is the speed of light.

[0171] Since the frequency of the received signal is known, and the frequency of the transmitted signal is also known, the second included angle θ can be obtained based on equation (11). 1,t The value of is shown in equation (12) below:

[0172]

[0173] Where, θ 1,t Indicates the second included angle; θ 2,t The first included angle is represented by c; the speed of light is c; Δf is the Doppler frequency shift at time t; v l,t This indicates the magnitude of the velocity indicated by the first sensor; v s,t The value indicates the magnitude of the speed indicated by the second sensor; f represents the frequency of the transmitted signal, f = c / λ, where λ is the wavelength of the transmitted signal.

[0174] S72, based on the second included angle, corrects the travel direction of the first rail vehicle and determines the horizontal correction speed and the vertical correction speed.

[0175] After determining the second included angle, the third included angle between the direction of the velocity indicated by the first sensor and the x-axis is first determined based on the second included angle and the estimated angle between RIS and the first track vehicle at the previous moment. The third included angle θ is... 3,t Equal to or approximately equal to Or the third included angle θ 3,t Equal to or approximately equal to θ is the estimated angle from RIS to the first orbital vehicle at time t-1, where t-1 is the previous time. 1,t This is the second included angle.

[0176] Then, based on the magnitude of the velocity indicated by the first sensor and the third included angle, the horizontal correction velocity and the vertical correction velocity are determined. This process can be referred to in the following equations (13) and (14):

[0177] v lx,t =v l,t cosθ 3,t (13)

[0178] v ly,t =v l,t sinθ 3,t (14)

[0179] Among them, v lx,t v is the horizontal correction speed of the first rail vehicle on the x-axis; ly,tv is the vertical correction velocity of the first rail vehicle on the y-axis; l,t θ represents the magnitude of the velocity indicated by the first sensor. 3,t It is the third included angle.

[0180] The above embodiments introduced a scheme for determining the corrected speed of the first rail vehicle at the current moment. The following will combine... Figure 8 This paper introduces a scheme for positioning the first rail vehicle based on the correction speed.

[0181] Figure 8 This is a flowchart illustrating the process of determining the second positioning position of the first rail vehicle according to an embodiment of this application, as shown below. Figure 8 As shown, it includes:

[0182] S81, determine the state transition matrix from the previous moment to the current moment based on the time difference.

[0183] Let Δt be the time difference between the current moment and the previous moment, then the state transition matrix A is:

[0184]

[0185] S82, based on the state transition matrix, the first positioning position is predicted using a particle filter to obtain multiple sampling positions of the first track vehicle at the current moment.

[0186] The system state equations are constructed as follows:

[0187] x(t)=Ax(t-1)+Gω=[x t v lx,t y t v ly,t ] T (16)

[0188] Where x(t) represents the true state of the first track vehicle at time t, which is also the true state of the first track vehicle at the current time; x(t-1) represents the true state of the first track vehicle at time t-1, which is also the true state of the first track vehicle at the previous time; A is the state transition matrix; x t Let y represent the coordinate position of the first track vehicle in the two-dimensional Cartesian coordinate system at time t along the x-axis. t v represents the coordinate position of the first track vehicle along the y-axis in a two-dimensional Cartesian coordinate system at time t; lx,t For horizontal correction speed, v ly,t The vertical correction velocity is represented by ω; ω represents Gaussian noise with zero mean and covariance matrix Q; G is the noise driving matrix of the Gaussian noise ω.

[0189] Using the state transition matrix A, the state x(t) of the vehicle at time t is predicted I times based on the particle filter, resulting in I predicted particles. These I predicted particles represent the multiple sampling positions of the first track vehicle at the current time.

[0190]

[0191] Where i = 1, 2, ..., I, I is a positive integer; This represents the x-coordinate of the sampling position of the first orbital vehicle at the current moment in the i-th prediction. Let represent the ordinate of the sampling position of the first orbital vehicle at the current moment in the i-th prediction. Let be the sampling position for the i-th prediction; This represents the optimal state estimate at time t-1 calculated by the particle filter, which is the first positioning position of the first track vehicle at the previous time. This represents the state of the first track vehicle in the i-th prediction.

[0192] The particle filter is a recursive filter that uses the Monte Carlo method. The initial system state x(0) of the first orbital vehicle is the true position information obtained from the ground transponder. The particle filter uses x(0) to deduce the optimal estimate of the system state x(1) at the next moment. Then As a calculation of the true value The optimal estimate of the system state at each moment is obtained recursively until the first orbital vehicle reads the latest position information sent by the ground transponder and updates the initial system state x(0), and the loop starts again.

[0193] S83, for any sampling position, using the first element of RIS as a reference, determines the signal transmission duration corresponding to the sampling position. The signal transmission duration is the time between the start of the signal transmission device in the second rail vehicle transmitting the transmission signal and the second rail vehicle receiving the corresponding reception signal at the corresponding sampling position.

[0194] Based on the previously established virtual line-of-sight link, signals transmitted by the signal transmitter in the second rail vehicle are transmitted, and the transmission time of the signals is obtained. have:

[0195]

[0196] Where τ(t) represents the actual value of the transmission time of the transmitted signal. This indicates that the mean is 0 and the variance is 0. The measurement noise; l1(t) is the distance from the first element of RIS to the first orbital vehicle at time t, and l2(t) is the distance from the second orbital vehicle to the first element of RIS at time t.

[0197] Predict the coordinates of all predicted particles and Substituting these values ​​into τ(t), we obtain the I measured particles, which represent the signal transmission time corresponding to the sampling position. The calculation process can be found in the following equation (20):

[0198]

[0199] Where i = 1, 2, ..., I, I is a positive integer; l1(t) is the distance from the first element of RIS to the first orbital vehicle at time t; Let be the signal transmission duration corresponding to the sampling position of the i-th prediction; This represents the x-coordinate of the sampling position of the first orbital vehicle at the current moment in the i-th prediction. Let represent the ordinate of the sampling position of the first orbital vehicle at the current moment in the i-th prediction. Let be the sampling location for the i-th prediction.

[0200] S84, determine the second positioning position based on multiple sampling positions and the signal transmission duration corresponding to each sampling position.

[0201] First, the weight of each sampling position is determined based on the signal transmission duration corresponding to each sampling position.

[0202] Based on the above equation (20), the signal transmission duration corresponding to the sampling position of the I prediction can be determined. Based on the signal transmission duration corresponding to the sampling position of the I prediction, the weight of each particle can be calculated. The calculation method is shown in the following equation (21):

[0203]

[0204] Where i = 1, 2, ..., I, and I is a positive integer. Let τ(t) be the weight corresponding to the sampling position in the i-th prediction, and let τ(t) represent the actual value of the transmission time of the transmitted signal. Let be the signal transmission duration corresponding to the sampling position of the i-th prediction.

[0205] Then, based on the weights corresponding to each sampling location, a weighted average is performed on multiple sampling locations to obtain the second positioning location of the first track vehicle.

[0206] Specifically, the calculated weights are normalized to obtain the corresponding normalized weights. The calculation process can be found in the following formula (22):

[0207]

[0208] Where i = 1, 2, ..., I, I is a positive integer; The weights corresponding to the sampling positions in the i-th prediction; The normalized weights are the sampling positions corresponding to the i-th prediction.

[0209] The resampling method is used to address the sample degradation problem, that is, to prevent the normalized weights from becoming increasingly concentrated on a certain particle, making its weight close to 1, while the weights of the other particles are close to 0.

[0210] Set the interval [0,1] as follows: Divide the length into I independent sub-intervals, and generate I random numbers uniformly distributed in the interval [0,1]. Calculate the weights of the sub-intervals containing each random number. And based on this weight Re-record the corresponding i-th resampled particle The expression is shown in equation (23) below:

[0211]

[0212] Where i = 1, 2, ..., I, I is a positive integer; and Let x and y represent the position coordinates of the first orbital vehicle at time t, respectively, for the i-th resampled particle. t and y t The predicted value.

[0213] The optimal estimate of the system state equation x(t) by the first rail vehicle at time t is:

[0214]

[0215] in,

[0216] The second positioning position of the first rail vehicle can be obtained based on equation (24), where, Let x be the x-coordinate of the second positioning position of the first rail vehicle. The ordinate is the second positioning position of the first track vehicle.

[0217] The urban rail vehicle positioning method provided in this application embodiment is applied to a processor located in a first rail vehicle. Both the first and second rail vehicles travel on a preset track. First, a virtual line-of-sight link is established between the first and second rail vehicles based on multiple elements included in the RIS (Radio Router System). This virtual line-of-sight link is the link from the second rail vehicle through multiple elements to the first rail vehicle. Then, based on the virtual line-of-sight link, the received signal received by the processor in response to the transmitted signal at the current moment is obtained. This transmitted signal is the signal transmitted by the signal transmitting device in the second rail vehicle. The Doppler frequency shift at the current moment is determined according to the frequency of the received signal and the frequency of the transmitted signal. Based on the first sensor indicated speed of the first rail vehicle at the current moment, the second sensor indicated speed of the second rail vehicle at the current moment, and the Doppler frequency shift, the travel direction of the first rail vehicle is corrected to determine the horizontal correction speed on the x-axis and the vertical correction speed on the y-axis of the first rail vehicle at the current moment. Finally, based on the first positioning position of the first rail vehicle at the previous moment, the horizontal correction speed, the vertical correction speed, and the time difference between the current moment and the previous moment, the second positioning position of the first rail vehicle at the current moment is determined. The solution in this application embodiment can intelligently reflect signals through multiple elements included in the RIS to improve the characteristics of the wireless signal propagation environment. Based on multiple elements in the RIS, a virtual line-of-sight link is established, which solves the problems of signal attenuation and signal heterogeneity caused by the lack of line-of-sight propagation path in complex environments, and effectively improves the positioning accuracy of rail vehicles under the condition of lack of line-of-sight link.

[0218] Figure 9 This is a schematic diagram of the structure of the urban rail vehicle positioning device provided in the embodiments of this application, as shown below. Figure 9 As shown, the device includes:

[0219] Establishment module 91 is used to establish a virtual line-of-sight link between a first track vehicle and a second track vehicle based on multiple elements included in the RIS. Both the first track vehicle and the second track vehicle travel on a preset track. The virtual line-of-sight link is a link between the second track vehicle and the first track vehicle through the multiple elements.

[0220] The acquisition module 92 is used to acquire, based on the virtual line-of-sight link, the received signal received by the processor in the first rail vehicle in response to the transmitted signal at the current moment, wherein the transmitted signal is the signal transmitted by the signal transmitting device in the second rail vehicle;

[0221] The first determining module 93 is used to determine the Doppler frequency shift at the current moment based on the frequency of the received signal and the frequency of the transmitted signal;

[0222] The processing module 94 is used to perform correction processing on the travel direction of the first rail vehicle based on the first sensor indicated speed of the first rail vehicle at the current time, the second sensor indicated speed of the second rail vehicle at the current time, and the Doppler frequency shift, and to determine the horizontal correction speed of the first rail vehicle on the x-axis and the vertical correction speed on the y-axis at the current time.

[0223] The second determining module 95 is used to determine the positioning position of the first rail vehicle at the current moment based on the first positioning position of the first rail vehicle at the previous moment, the horizontal correction speed, the vertical correction speed, and the time difference between the current moment and the previous moment.

[0224] In one possible implementation, the establishment module 91 is specifically used for:

[0225] Obtain the quantity of the plurality of elements and the distance between any two adjacent elements among the plurality of elements;

[0226] Based on the number of the plurality of elements and the distance between any two adjacent elements, a RIS-assisted received signal model is established.

[0227] The RIS phase shift parameter is determined based on the received signal model. The RIS phase shift parameter is used to indicate the phase of the signals reflected by the plurality of elements, so that the signals reflected by the plurality of elements are in a constructive interference relationship.

[0228] The virtual line-of-sight link is established based on the RIS phase shift parameters.

[0229] In one possible implementation, the establishment module 91 is specifically used for:

[0230] Obtain first channel information of the channel from the plurality of elements to the first rail vehicle at the current time, and second channel information of the channel from the second rail vehicle to the plurality of elements at the current time;

[0231] Determine a first functional relationship between the control matrix of the plurality of elements at the current time and the phase shift parameter of each element;

[0232] The received signal model is established based on the first channel information, the second channel information, and the first functional relationship.

[0233] In one possible implementation, the establishment module 91 is specifically used for:

[0234] Based on the received signal model, a second functional relationship is determined between the received signal power at the current moment and the phase shift parameters of each element;

[0235] Based on the second functional relationship, the RIS phase shift parameter is determined, wherein the RIS phase shift parameter is the phase shift parameter that maximizes the received signal power.

[0236] In one possible implementation, the processing module 94 is specifically used for:

[0237] Based on the Doppler frequency shift, the frequency of the transmitted signal, the velocity indicated by the first sensor, the velocity indicated by the second sensor, and the first angle between the direction of the velocity indicated by the second sensor and the transmission direction of the transmitted signal, a second angle between the direction of the velocity indicated by the first sensor and the transmission direction of the received signal is determined.

[0238] Based on the second included angle, the travel direction of the first rail vehicle is corrected to determine the horizontal correction speed and the vertical correction speed.

[0239] In one possible implementation, the processing module 94 is specifically used for:

[0240] Based on the second included angle and the estimated value of the angle from RIS to the first rail vehicle at the previous moment, the third included angle between the direction of the speed indicated by the first sensor and the x-axis is determined.

[0241] The horizontal correction speed and the vertical correction speed are determined based on the magnitude of the speed indicated by the first sensor and the third included angle.

[0242] In one possible implementation, the second determining module 95 is specifically used for:

[0243] Determine the state transition matrix from the previous moment to the current moment based on the time difference;

[0244] Based on the state transition matrix, the first positioning position is predicted using a particle filter to obtain multiple sampling positions of the first track vehicle at the current time.

[0245] For any sampling position, the signal transmission duration corresponding to the sampling position is determined based on the first element of the RIS. The signal transmission duration is the time between the transmission of the signal transmitting device in the second rail vehicle and the receipt of the corresponding signal by the second rail vehicle at the corresponding sampling position.

[0246] The second positioning position is determined based on the plurality of sampling positions and the signal transmission duration corresponding to each sampling position.

[0247] In one possible implementation, the second determining module 95 is specifically used for:

[0248] The weight corresponding to each sampling position is determined based on the signal transmission duration corresponding to each sampling position.

[0249] The second positioning position is obtained by performing a weighted average of the multiple sampling positions according to the weights corresponding to each sampling position.

[0250] Figure 10 An example is a schematic diagram of the physical structure of an electronic device, such as... Figure 10 As shown, the electronic device may include: a processor 1010, a communication interface 1020, a memory 1030, and a communication bus 1040, wherein the processor 1010, the communication interface 1020, and the memory 1030 communicate with each other through the communication bus 1040. The processor 1010 can call logical instructions in the memory 1030 to execute an urban rail vehicle positioning method. This method is applied to a processor located in a first rail vehicle, where both the first and second rail vehicles are traveling on a preset track. The method includes: establishing a virtual line-of-sight link between the first and second rail vehicles based on multiple elements included in the RIS (Real-Line-of-Sight System), wherein the virtual line-of-sight link is a link between the second rail vehicle and the first rail vehicle via the multiple elements; based on the virtual line-of-sight link, acquiring the received signal received by the processor in response to a transmitted signal at the current moment, wherein the transmitted signal is a signal transmitted by a signal transmitting device in the second rail vehicle; and according to the received signal... The Doppler frequency shift at the current moment is determined by the frequency of the signal and the frequency of the transmitted signal; the travel direction of the first rail vehicle is corrected according to the first sensor indicated speed of the first rail vehicle at the current moment, the second sensor indicated speed of the second rail vehicle at the current moment, and the Doppler frequency shift, to determine the horizontal corrected speed of the first rail vehicle on the x-axis and the vertical corrected speed on the y-axis at the current moment; the second positioning position of the first rail vehicle at the current moment is determined according to the first positioning position of the first rail vehicle at the previous moment, the horizontal corrected speed, the vertical corrected speed, and the time difference between the current moment and the previous moment.

[0251] Furthermore, the logical instructions in the aforementioned memory 1030 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0252] On the other hand, this application also provides a computer program product, which includes a computer program that can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the urban rail vehicle positioning method provided in the above embodiments, applied to a processor located in a first rail vehicle. Both the first and second rail vehicles are traveling on a preset track. The method includes: establishing a virtual line-of-sight link between the first and second rail vehicles based on multiple elements included in a RIS, wherein the virtual line-of-sight link is a link between the second rail vehicle and the first rail vehicle via the multiple elements; and obtaining, based on the virtual line-of-sight link, the received signal received by the processor for the transmitted signal at the current moment. The transmitted signal is the signal emitted by the signal transmitting device in the second rail vehicle; the Doppler frequency shift at the current moment is determined based on the frequency of the received signal and the frequency of the transmitted signal; the travel direction of the first rail vehicle is corrected based on the first sensor indicated speed of the first rail vehicle at the current moment, the second sensor indicated speed of the second rail vehicle at the current moment, and the Doppler frequency shift, to determine the horizontal corrected speed of the first rail vehicle on the x-axis and the vertical corrected speed on the y-axis at the current moment; the second positioning position of the first rail vehicle at the current moment is determined based on the first positioning position of the first rail vehicle at the previous moment, the horizontal corrected speed, the vertical corrected speed, and the time difference between the current moment and the previous moment.

[0253] Furthermore, this application also provides a non-transitory computer-readable storage medium storing a computer program thereon. When executed by a processor, this computer program is implemented to perform the urban rail vehicle positioning method provided in the above embodiments. The method is applied to a processor located in a first rail vehicle, where both the first and second rail vehicles are traveling on a preset track. The method includes: establishing a virtual line-of-sight link between the first and second rail vehicles based on multiple elements included in a RIS (Reference System), wherein the virtual line-of-sight link is a link between the second rail vehicle and the first rail vehicle via the multiple elements; and, based on the virtual line-of-sight link, acquiring the received signal received by the processor at the current moment in response to a transmitted signal, wherein the transmitted signal is a signal received by the processor in the second rail vehicle. The signal is transmitted by the signal transmitting device; the Doppler frequency shift at the current moment is determined based on the frequency of the received signal and the frequency of the transmitted signal; the travel direction of the first rail vehicle is corrected based on the first sensor indicated speed of the first rail vehicle at the current moment, the second sensor indicated speed of the second rail vehicle at the current moment, and the Doppler frequency shift, to determine the horizontal corrected speed of the first rail vehicle on the x-axis and the vertical corrected speed on the y-axis at the current moment; the second positioning position of the first rail vehicle at the current moment is determined based on the first positioning position of the first rail vehicle at the previous moment, the horizontal corrected speed, the vertical corrected speed, and the time difference between the current moment and the previous moment.

[0254] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0255] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0256] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A method for positioning an urban rail vehicle, characterized in that, The application is applied to a processor in a first rail vehicle, the first rail vehicle and a second rail vehicle both travel on a preset track, and the method comprises: Based on a plurality of elements included in a reconfigurable intelligent surface (RIS), a virtual line-of-sight (LOS) link is established between the first rail vehicle and the second rail vehicle, the virtual LOS link is a link between signals from the second rail vehicle to the first rail vehicle through the plurality of elements; Based on the virtual LOS link, a received signal received by the processor for a transmitted signal at a current time is obtained, the transmitted signal is a signal transmitted by a signal transmitting device in the second rail vehicle; According to the frequency of the received signal and the frequency of the transmitted signal, a Doppler frequency shift at the current time is determined; According to the first sensor indicated speed of the first rail vehicle at the current time, the second sensor indicated speed of the second rail vehicle at the current time, and the Doppler frequency shift, the travel direction of the first rail vehicle is corrected, and the horizontal correction speed of the first rail vehicle on the x-axis and the vertical correction speed of the first rail vehicle on the y-axis at the current time are determined; According to the first positioning position of the first rail vehicle at the previous time, the horizontal correction speed, the vertical correction speed, and the time difference between the current time and the previous time, the second positioning position of the first rail vehicle at the current time is determined.

2. The method of claim 1, wherein, The method comprises: The number of the plurality of elements, the distance between two adjacent elements in the plurality of elements is obtained; Based on the number of the plurality of elements, the distance between two adjacent elements in the plurality of elements, a received signal model based on RIS assistance is established; Based on the received signal model, the RIS phase shift parameter is determined, the RIS phase shift parameter is used to indicate the phase of the signal reflected by the plurality of elements, so that the signals reflected by the plurality of elements are in constructive interference relationship; Based on the RIS phase shift parameter, the virtual LOS link is established.

3. The method of claim 2, wherein, The method comprises: The first channel information of the channel from the plurality of elements to the first rail vehicle at the current time, and the second channel information of the channel from the second rail vehicle to the plurality of elements at the current time are obtained; A first functional relationship between the control matrix of the plurality of elements at the current time and the phase shift parameter of each element is determined; According to the first channel information, the second channel information and the first functional relationship, the received signal model is established.

4. The method of claim 2, wherein, The method comprises: According to the received signal model, a second functional relationship between the received signal power at the current time and the phase shift parameter of each element is determined; According to the second functional relationship, the RIS phase shift parameter is determined, wherein the RIS phase shift parameter is a phase shift parameter that makes the received signal power take a maximum value.

5. The method according to any one of claims 1 to 4, characterized in that, The running direction of the first rail vehicle is corrected according to the first sensor indicated speed of the first rail vehicle at the current time, the second sensor indicated speed of the second rail vehicle at the current time, and the Doppler frequency shift, to determine a horizontal correction speed of the first rail vehicle on the x-axis and a vertical correction speed of the first rail vehicle on the y-axis at the current time, including: According to the Doppler frequency shift, the frequency of the transmitted signal, the first sensor indicated speed, the second sensor indicated speed, and a first included angle between the direction of the second sensor indicated speed and the transmission direction of the transmitted signal, a second included angle between the direction of the first sensor indicated speed and the transmission direction of the received signal is determined. According to the second included angle, the running direction of the first rail vehicle is corrected to determine the horizontal correction speed and the vertical correction speed.

6. The method of claim 5, wherein, According to the second included angle, and an estimated value of the angle of the RIS to the first rail vehicle at a previous time, a third included angle between the direction of the first sensor indicated speed and the x-axis is determined. According to the size of the first sensor indicated speed and the third included angle, the horizontal correction speed and the vertical correction speed are determined. The second positioning position of the first rail vehicle at the current time is determined according to the first positioning position of the first rail vehicle at a previous time, the horizontal correction speed, the vertical correction speed, and a time difference between the current time and the previous time, including:

7. The method according to any one of claims 1 to 4, characterized in that, A state transition matrix from the previous time to the current time is determined according to the time difference. The first positioning position is predicted based on a particle filter according to the state transition matrix to obtain a plurality of sampling positions of the first rail vehicle at the current time. For any sampling position, a signal transmission time corresponding to the sampling position is determined with the first element of the RIS as a reference, the signal transmission time being a time length between the time when the signal transmitting device in the second rail vehicle transmits the transmitted signal and the time when the second rail vehicle receives the corresponding received signal at the corresponding sampling position. The second positioning position is determined according to the plurality of sampling positions and the signal transmission time corresponding to each sampling position. The second positioning position is determined according to the plurality of sampling positions and the signal transmission time corresponding to each sampling position, including:

8. The method of claim 7, wherein, The weight corresponding to each sampling position is determined according to the signal transmission time corresponding to each sampling position. The second positioning position is obtained by weighted average processing of the plurality of sampling positions according to the weight corresponding to each sampling position. The device includes:

9. An urban rail vehicle positioning device, characterized in that, ​ The establishing module is configured to establish a virtual line-of-sight link between the first rail vehicle and the second rail vehicle based on a plurality of elements included in the RIS, the first rail vehicle and the second rail vehicle both traveling on a preset track, the virtual line-of-sight link being a link between signals from the second rail vehicle passing through the plurality of elements to the first rail vehicle; The acquiring module is configured to acquire, based on the virtual line-of-sight link, a received signal received by a processor in the first rail vehicle at a current time for a transmitted signal, the transmitted signal being a signal transmitted by a signal transmitting device in the second rail vehicle; The first determining module is configured to determine a Doppler frequency shift at the current time according to a frequency of the received signal and a frequency of the transmitted signal; The processing module is configured to perform correction processing on a travel direction of the first rail vehicle according to a first sensor-indicated speed of the first rail vehicle at the current time, a second sensor-indicated speed of the second rail vehicle at the current time, and the Doppler frequency shift, and determine a horizontal correction speed of the first rail vehicle on an x-axis and a vertical correction speed of the first rail vehicle on a y-axis at the current time. The second determining module is configured to determine a positioning position of the first rail vehicle at the current time according to a first positioning position of the first rail vehicle at a previous time, the horizontal correction speed, the vertical correction speed, and a time difference between the current time and the previous time.

10. An electronic device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, The processor implements the urban rail vehicle positioning method according to any one of claims 1 to 8 when executing the program.

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