Multipath error elimination method, device and system based on antenna movement

Abstract

The present application relates to a method, device and system for eliminating multipath errors based on antenna motion. The method includes: sampling direct signals and multipath signals at different times based on the motion state of the antenna, calculating the code delay estimation error expression according to the propagation delay difference expression and relative phase expression of the direct signal and the multipath signal at different sampling times; calculating the code delay estimation deviation expression of the direct signal caused by the antenna jitter using the antenna jitter method; calculating the code delay estimation of the direct signal at different sampling times; correcting the code delay estimation of the direct signal at different sampling times to obtain the corrected code delay estimation of the direct signal at different sampling times; averaging the corrected code delay estimation of the direct signal at different sampling times to obtain the code delay estimation result of the direct signal after multipath error elimination. The use of this method can improve the accuracy and practicality of satellite navigation and high-precision measurement.

Description

Technical Field

[0001] The present application relates to the field of satellite navigation and high-precision measurement technology, and in particular to a method, device and system for eliminating multipath errors based on antenna movement. Background Art

[0002] The Global Navigation Satellite System (GNSS) is widely used in space-time positioning, mobile Internet, unmanned driving and other fields. Its rapid development has also put forward higher requirements for positioning accuracy. However, GNSS signals are often blocked by buildings and other obstacles, generating reflection and diffraction signals. These signals mixed with direct signals will cause the correlation function of the receiver to be distorted, and the resulting measurement error is called multipath error. In recent years, with the continuous development of the Beidou navigation satellite system, new features have also been brought to the multipath effect. Beidou's high-orbit (Geostationary Earth Orbit, GEO) satellites and receivers are in a relatively static state, so the multipath error of GEO satellites is more serious than that of other medium and low-orbit satellites. In the pseudo-range observation of the wide-area augmentation system GEO satellite, researchers have found a fixed deviation caused by multipath signals, which cannot be eliminated by long-term averaging and is called the "Standing Multipath" phenomenon. With the increasingly mature elimination technology of clock error, ionospheric error, and tropospheric error, multipath error has gradually become the main factor affecting positioning accuracy.

[0003] The existing traditional methods for suppressing multipath errors can be basically divided into three categories: antenna enhancement technology, baseband processing algorithm and post-processing technology. Antenna enhancement technology reduces the reception of reflected multipath signals by improving the antenna; baseband processing algorithm refers to the processing technology of multipath receivers; post-processing technology reduces multipath errors by post-processing the receiver measurement data. However, the above algorithms are still helpless in the face of GEO satellite fixed deviations. In summary, in existing research, although the traditional method has obvious effects in suppressing multipath errors, the system is also more complex, ordinary receivers cannot be directly applied, and it is helpless for multipath signals from above the antenna, which leads to low positioning accuracy of satellite navigation systems in other complex environments such as cities; although the method of suppressing multipath errors by rotating the antenna has shown good momentum, the existing research has not yet given a suitable movement mode, which leads to the existing antenna rotation movement scheme occupying too much space, which is not convenient for integration and miniaturization design, and its safety and practicality need to be further improved. Summary of the invention

[0004] Based on this, it is necessary to provide a multipath error elimination method, device and system based on antenna movement that can improve the accuracy and practicality of navigation measurement in order to address the above technical problems.

[0005] A multipath error elimination method based on antenna motion, the method comprising:

[0006] Obtaining the navigation message spread spectrum code and message bit information; generating a satellite navigation signal according to the navigation message spread spectrum code and message bit information;

[0007] Using an antenna in motion to receive a satellite navigation signal, a received satellite navigation signal is obtained; the received satellite navigation signal includes a multipath signal and a direct signal;

[0008] Based on the motion state of the antenna, the direct signal and the multipath signal are sampled at different times, and the propagation delay difference expression and relative phase expression of the direct signal and the multipath signal at different sampling times are obtained;

[0009] The code delay estimation error expression of the direct signal caused by the multipath signal is calculated based on the propagation delay difference expression and relative phase expression of the direct signal and the multipath signal at different sampling times;

[0010] The antenna jitter mode is used to calculate the code delay estimation deviation expression of the direct signal caused by the antenna jitter;

[0011] The receiver calculates the code delay estimation of the direct signal at different sampling times according to the early-late chip method; the error term of the code delay estimation includes the code delay estimation error expression of the direct signal caused by the multipath signal and the code delay estimation deviation expression of the direct signal caused by the antenna jitter;

[0012] Correcting the code delay estimates of the direct signals at different sampling moments to obtain corrected code delay estimates of the direct signals at different sampling moments;

[0013] The corrected code delay estimates of the direct signal at different sampling times are averaged to obtain the code delay estimation result of the direct signal after multipath error elimination.

[0014] A multipath error elimination device based on antenna movement, the device comprising:

[0015] A satellite signal generation module is used to obtain the navigation message spread spectrum code and message bit information; and generate a satellite navigation signal according to the navigation message spread spectrum code and message bit information;

[0016] A satellite signal receiving module is used to receive satellite navigation signals to obtain received satellite navigation signals; the received satellite navigation signals include multipath signals and direct signals;

[0017] The antenna driving module is used to drive the antenna to be in motion and sample the direct signal and the multipath signal to obtain the propagation delay difference expression and relative phase expression of the direct signal and the multipath signal at different sampling times;

[0018] A signal processing module is used to calculate the code delay estimation error expression of the direct signal caused by the multipath signal according to the propagation delay difference expression and relative phase expression of the direct signal and the multipath signal at different sampling moments; calculate the code delay estimation deviation expression of the direct signal caused by the antenna jitter using the antenna jitter method; the receiver calculates the code delay estimation of the direct signal at different sampling moments according to the early-late code chip method; the error term of the code delay estimation includes the code delay estimation error expression of the direct signal caused by the multipath signal and the code delay estimation deviation expression of the direct signal caused by the antenna jitter;

[0019] The signal correction and multipath error elimination module is used to correct the code delay estimate of the direct signal at different sampling moments to obtain the corrected code delay estimate of the direct signal at different sampling moments; average the corrected code delay estimate of the direct signal at different sampling moments to obtain the code delay estimate result of the direct signal after multipath error elimination.

[0020] A multipath error elimination system based on antenna movement, comprising a satellite and a user terminal, wherein a satellite signal generation module and a satellite signal transmission module are arranged in the satellite; an antenna driving module, a satellite signal receiving module, a signal processing module and a signal correction and multipath error elimination module are arranged in the user terminal;

[0021] A satellite signal generation module is used to obtain the navigation message spread spectrum code and message bit information; and generate a satellite navigation signal according to the navigation message spread spectrum code and message bit information;

[0022] A satellite signal receiving module is used to receive satellite navigation signals to obtain received satellite navigation signals; the received satellite navigation signals include multipath signals and direct signals;

[0023] The antenna driving module is used to drive the antenna to be in motion and sample the direct signal and the multipath signal to obtain the propagation delay difference expression and relative phase expression of the direct signal and the multipath signal at different sampling times;

[0024] A signal processing module is used to calculate the code delay estimation error expression of the direct signal caused by the multipath signal according to the propagation delay difference expression and relative phase expression of the direct signal and the multipath signal at different sampling moments; calculate the code delay estimation deviation expression of the direct signal caused by the antenna jitter using the antenna jitter method; the receiver calculates the code delay estimation of the direct signal at different sampling moments according to the early-late code chip method; the error term of the code delay estimation includes the code delay estimation error expression of the direct signal caused by the multipath signal and the code delay estimation deviation expression of the direct signal caused by the antenna jitter;

[0025] The signal correction and multipath error elimination module is used to correct the code delay estimate of the direct signal at different sampling moments to obtain the corrected code delay estimate of the direct signal at different sampling moments; average the corrected code delay estimate of the direct signal at different sampling moments to obtain the code delay estimate result of the direct signal after multipath error elimination.

[0026] The above-mentioned multipath error elimination method, device and system based on antenna movement, based on the correlation between multipath error and environment, realizes the rapid change of relative phase between direct signal and multipath signal by changing antenna position, and then realizes the randomization and cancellation of multipath error, which can greatly improve the accuracy of navigation and measurement in both fixed sites and dynamic carriers. At the same time, the present application can be directly applied to various types of receivers, and the positioning accuracy is not limited by the site selection environment. The antenna movement scheme does not need to change the internal structure of the receiver. Any ordinary commercial receiver can be directly applied, saving local resources, achieving low overhead, and having extremely high practicality and safety. Moreover, the scheme is also highly adaptable to the site selection environment. When selecting the antenna site, there is no need to pursue an open environment and avoid multipath signals by raising the antenna, which is conducive to improving the positioning accuracy in complex environments such as cities. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A schematic diagram of a flow chart of a multipath error elimination method based on antenna movement in an embodiment;

[0028] Figure 2 A schematic diagram of an implementation scenario of the present application in an embodiment;

[0029] Figure 3 A diagram illustrating the principle of an embodiment of the present application in one embodiment;

[0030] Figure 4 is a structural block diagram of a multipath error elimination device based on antenna movement in one embodiment;

[0031] Figure 5 The structure diagram of a multipath error elimination system based on antenna motion in one embodiment. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0033] In one embodiment, Figure 1 As shown, a multipath error elimination method based on antenna movement is provided, and the method is applied to Figure 5 A multipath error elimination system based on antenna motion is described as an example, comprising the following steps:

[0034] Step 102, obtaining a navigation message spread spectrum code and message bit information; generating a satellite navigation signal according to the navigation message spread spectrum code and the message bit information; receiving the satellite navigation signal using an antenna in motion to obtain a received satellite navigation signal; the received satellite navigation signal includes a multipath signal and a direct signal.

[0035] like Figure 2 As shown, in this scenario, the satellite obtains the navigation message spread spectrum code and message bit information, performs spread spectrum modulation according to the navigation message spread spectrum code and message bit information to generate a satellite navigation signal, and then sends it to the user terminal. After receiving the signal, the user terminal drives the receiving antenna to realize the continuous movement of the antenna and collect the satellite navigation signal in the moving state.

[0036] If there are reflective objects such as buildings and the ground around the receiving antenna, there will be other reflected signals in addition to the direct signal. In general, the existence of multipath signals is difficult to avoid. The signal received by the antenna is a combination of the direct wave and the reflected wave after interference.

[0037]

[0038] Where: f c Indicates the carrier frequency, f d represents the Doppler frequency shift caused by the relative motion between the satellite and the antenna, τ0 represents the direct signal delay, A represents the amplitude of the direct signal, s(t) is the XOR sum of the pseudo code with a data value of ±1 and the data code, and a i , Δτ i , Δθ i They represent the power ratio, time delay and carrier phase of the i-th multipath signal relative to the direct signal, and n(t) represents additive white Gaussian noise.

[0039] To simplify the analysis, we first consider the case where there is a multipath signal. The baseband signal after down-conversion can be expressed as

[0040] x(t)=Acos(θ e)s(t-τ0)+Aa1cos(θ e +Δθ1)c(t-τ0-Δτ1)

[0041] Where: θ e Represents the carrier phase estimation error. In the code tracking loop, considering the general early-late (EPL) correlator, the discrimination function D can be expressed as

[0042]

[0043] Where: is the estimated code delay, T c is the correlation interval, the autocorrelation function R c (τ) is a left-right symmetric sharp trigonometric function about τ = 0, which can be expressed as

[0044]

[0045] If there is no multipath signal, when the discrimination function D = 0, the phase of the local punctual code is the phase of the satellite signal, and the code phase estimation error is However, the existence of multipath signals causes the correlation function to deform and no longer be symmetrical. As the relative phase of the direct wave and the reflected wave changes, the multipath error presents a "positive and negative alternation" change. Therefore, if the relative phase can be kept in a fast time-varying state, the multipath error will also present a random characteristic similar to white noise, which is convenient for elimination after averaging.

[0046] Step 104, based on the motion state of the antenna, the direct signal and the multipath signal are sampled at different times to obtain the propagation delay difference expression and relative phase expression of the direct signal and the multipath signal at different sampling times; the code delay estimation error expression of the direct signal caused by the multipath signal is calculated according to the propagation delay difference expression and relative phase expression of the direct signal and the multipath signal at different sampling times; the code delay estimation deviation expression of the direct signal caused by the antenna jitter is calculated using the antenna jitter method; the receiver calculates the code delay estimation of the direct signal at different sampling times according to the early-late code chip method; the error terms of the code delay estimation include the code delay estimation error expression of the direct signal caused by the multipath signal and the code delay estimation deviation expression of the direct signal caused by the antenna jitter.

[0047] The relative position between the medium and high orbit satellite and the antenna changes slowly, and the multipath error appears as a "slowly changing" deviation. However, the carrier frequency of the satellite signal is high, and the slight movement of the antenna can cause the relative position of the satellite to change, which in turn causes the relative phase of the direct wave and the reflected wave to change rapidly. Therefore, the receiver measurement error caused by the reflected wave will also appear in a "pseudo-random" state.

[0048] As attached Figure 3As shown, α is the inclination angle of the reflector relative to the horizontal plane, and β is the elevation angle of the satellite. When the antenna is stationary, the initial distance from the phase center O to the reflecting surface is D0. Let’s take the antenna phase center O as the origin and the perpendicular line between the phase center and the reflecting surface as the polar axis to establish a polar coordinate system. Then, at a certain sampling time n, the position of the antenna phase center O' can be expressed as the distance r from O' to O. n , the angle between the line connecting O' and O and the polar axis is ψ n The distance between the phase center O' and the reflecting surface is D0-r n cosψ n The propagation delay difference between the direct signal and the multipath signal at sampling time n is expressed as

[0049] Δτ1(r,ψ)=2(D0-r n cosψ n )sin(β+α) / c

[0050] =Δτ1-r n cosψ n sin(β+α) / c

[0051] The relative phase expression of the nth sampling is:

[0052]

[0053] Assuming that N different motion positions are sampled in one observation period, the estimation error caused by multipath signals will be generated according to the characteristics of the early-late correlator. At this time, the code delay estimation error caused by multipath signals can be given by the following formula:

[0054]

[0055] Where:

[0056] According to the jitter mode of the antenna, the code delay estimation deviation of the direct signal caused by the antenna jitter can be calculated as

[0057] e(r n ,ψ n )=r n sin(β+ψ n +α) / c

[0058] Among them, r n represents the distance from the phase center O' to O of the antenna, ψ n represents the angle between the line connecting O' and O and the polar axis, α is the inclination of the reflector relative to the horizontal plane, β is the elevation angle of the satellite, and c represents the speed of light.

[0059] The receiver calculates the code delay estimate of the direct signal at different sampling times according to the early-late code chip method, and its expression is:

[0060]

[0061] Step 106, correct the code delay estimate of the direct signal at different sampling moments to obtain the corrected code delay estimate of the direct signal at different sampling moments; average the corrected code delay estimate of the direct signal at different sampling moments to obtain the code delay estimate result of the direct signal after multipath error is eliminated.

[0062] When the antenna moves, the multipath error will appear as white noise, so the error can be offset by short-term averaging. However, the movement of the antenna will also affect the estimation of the direct wave, causing deviations in the pseudorange measurement of the direct wave. However, the movement of the antenna is precise and controllable, so the estimation error of the direct wave can be corrected.

[0063] The code delay estimate of the direct signal at different sampling times is corrected to obtain the corrected code delay estimate of the direct signal at different sampling times, which is expressed as

[0064]

[0065] in, The expression for estimating the code delay of the direct signal at different sampling times, τ0 represents the actual code delay of the direct signal, r n represents the distance from the phase center O' to O of the antenna, ψ n represents the angle between the line connecting O' and O and the polar axis, α is the inclination of the reflector relative to the horizontal plane, β is the elevation angle of the satellite, c represents the speed of light, ε(a1,Δτ1,Δθ1,r n ,ψ n ) is the code delay estimation error expression of the direct signal caused by the multipath signal. It can be seen from the above formula that the antenna movement can transform the originally fixed multipath error into (r n ,ψ n ) related fast-changing errors, the multipath errors at different sampling times will show "pseudo-random" characteristics, which can be easily eliminated after averaging.

[0066] The code delay estimation result of the direct signal after multipath error elimination is obtained by averaging the corrected code delay estimation of the direct signal at different sampling times:

[0067]

[0068] In the above-mentioned multipath error elimination method based on antenna movement, the present application is based on the correlation between multipath error and environment, and realizes the rapid change of the relative phase between the direct signal and the multipath signal by changing the antenna position, thereby realizing the randomization and cancellation of multipath error, which can greatly improve the accuracy of navigation and measurement in both fixed sites and dynamic carriers. At the same time, the present application can be directly applied to various types of receivers, and the positioning accuracy is not limited by the site selection environment. The antenna movement scheme does not need to change the internal structure of the receiver. Any ordinary commercial receiver can be directly applied, saving local resources, achieving low overhead, and having extremely high practicality and safety. Moreover, the scheme is also highly adaptable to the site selection environment. When selecting the antenna site, there is no need to pursue an open environment and avoid multipath signals by raising the antenna, which is conducive to improving the positioning accuracy in complex environments such as cities.

[0069] In one embodiment, based on the motion state of the antenna, the direct signal and the multipath signal are sampled at different times to obtain propagation delay difference expressions and relative phase expressions of the direct signal and the multipath signal at different sampling times, including:

[0070] Based on the motion state of the antenna, the direct signal and multipath signal are sampled at different times, and the propagation delay difference expression of the direct signal and multipath signal at different sampling times is obtained as follows:

[0071] Δτ1(r,ψ)=2(D0-r n cosψ n )sin(β+α) / c

[0072] =Δτ1-r n cosψ n sin(β+α) / c

[0073] Among them, α is the inclination angle of the reflector relative to the horizontal plane, β is the elevation angle of the satellite, the initial distance from the phase center O to the reflector when the antenna is stationary is D0, n represents the sampling time, r n represents the distance from the phase center O' to O of the antenna, ψ n represents the angle between the line connecting O' and O and the polar axis, D0-r n cosψ n is the distance between the phase center O' and the reflecting surface, and c is the speed of light.

[0074] In one embodiment, the direct signal and the multipath signal are sampled at different times based on the motion state of the antenna, and the relative phase expressions of the direct signal and the multipath signal at different sampling times are obtained as follows:

[0075]

[0076] Among them, f crepresents the carrier frequency, Δθ1 represents the carrier phase of the i-th multipath signal relative to the direct signal.

[0077] In one embodiment, the code delay estimation error expression of the direct signal caused by the multipath signal is calculated based on the propagation delay difference expression and relative phase expression of the direct signal and the multipath signal at different sampling moments, including: the code delay estimation error expression of the direct signal caused by the multipath signal is calculated based on the propagation delay difference expression and relative phase expression of the direct signal and the multipath signal at different sampling moments as follows:

[0078]

[0079] in, T c is the correlation interval, θ e represents the carrier phase estimation error, Δτ1(r n ,ψ n ) is the expression of propagation delay difference, Δθ1(r n ,ψ n ) is the relative phase expression, a i represents the power ratio of the i-th multipath signal to the direct signal, r n represents the distance from the phase center O' of the antenna to O, ψ n Represents the angle between the line connecting O' and O and the polar axis.

[0080] In one embodiment, the code delay estimation deviation of the direct signal caused by the antenna jitter is calculated and corrected according to the jitter mode of the antenna, including:

[0081] According to the jitter mode of the antenna, the code delay estimation deviation of the direct signal caused by the antenna jitter can be calculated as

[0082] e(r n ,ψ n )=r n sin(β+ψ n +α) / c

[0083] Among them, r n represents the distance from the phase center O' to O of the antenna, ψ n represents the angle between the line connecting O' and O and the polar axis, α is the inclination of the reflector relative to the horizontal plane, β is the elevation angle of the satellite, and c represents the speed of light.

[0084] In one embodiment, the receiver calculates the code delay estimation of the direct signal at different sampling times according to the early-late chip method, including:

[0085] The receiver calculates the code delay estimate of the direct signal at different sampling times according to the early-late code chip method, and its expression is:

[0086]

[0087] Among them, τ0 represents the real delay when the antenna is stationary, e(r n ,ψ n ) represents the code delay estimation deviation expression of the direct signal caused by antenna jitter, ε(a1,Δτ1,Δθ1,r n ,ψ n ) represents the code delay estimation error expression of the direct signal caused by the multipath signal.

[0088] In one embodiment, correcting the code delay estimate of the direct signal at different sampling moments to obtain the corrected code delay estimate of the direct signal at different sampling moments includes:

[0089] The code delay estimate of the direct signal at different sampling times is corrected to obtain the corrected code delay estimate of the direct signal at different sampling times, which is expressed as

[0090]

[0091] in, The expression for estimating the code delay of the direct signal at different sampling times, τ0 represents the actual code delay of the direct signal, r n represents the distance from the phase center O' to O of the antenna, ψ n represents the angle between the line connecting O' and O and the polar axis, α is the inclination of the reflector relative to the horizontal plane, β is the elevation angle of the satellite, c represents the speed of light, ε(a1,Δτ1,Δθ1,r n ,ψ n ) is the expression for the code delay estimation error of the direct signal caused by the multipath signal.

[0092] In one embodiment, the corrected code delay estimates of the direct signal at different sampling times are averaged to obtain the code delay estimation result of the direct signal after multipath error elimination, including:

[0093] The code delay estimation result of the direct signal after multipath error elimination is obtained by averaging the corrected code delay estimation of the direct signal at different sampling times:

[0094]

[0095] It should be understood that although Figure 1 The steps in the flowchart are shown in sequence as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified in this document, there is no strict order restriction for the execution of these steps, and these steps can be executed in other orders. Moreover, Figure 1At least part of the steps may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily executed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be executed in turn or alternately with other steps or at least part of the sub-steps or stages of other steps.

[0096] In one embodiment, Figure 4 As shown, a multipath error elimination device based on antenna movement is provided, comprising: a satellite signal generating module 402, a satellite signal receiving module 404, an antenna driving module 406, a signal processing module 408 and a signal correction and multipath error elimination module 410, wherein:

[0097] The satellite signal generating module 402 is used to obtain the navigation message spreading code and message bit information; and to generate a satellite navigation signal according to the navigation message spreading code and message bit information;

[0098] The satellite signal receiving module 404 is used to receive satellite navigation signals and obtain received satellite navigation signals; the received satellite navigation signals include multipath signals and direct signals;

[0099] The antenna driving module 406 is used to drive the antenna to be in a moving state, and to sample the direct signal and the multipath signal to obtain the propagation delay difference expression and relative phase expression of the direct signal and the multipath signal at different sampling times;

[0100] The signal processing module 408 is used to calculate the code delay estimation error expression of the direct signal caused by the multipath signal according to the propagation delay difference expression and relative phase expression of the direct signal and the multipath signal at different sampling moments; calculate the code delay estimation deviation expression of the direct signal caused by the antenna jitter using the antenna jitter method; the receiver calculates the code delay estimation of the direct signal at different sampling moments according to the early-late code chip method; the error term of the code delay estimation includes the code delay estimation error expression of the direct signal caused by the multipath signal and the code delay estimation deviation expression of the direct signal caused by the antenna jitter;

[0101] The signal correction and multipath error elimination module 410 is used to correct the code delay estimate of the direct signal at different sampling moments to obtain the corrected code delay estimate of the direct signal at different sampling moments; and to average the corrected code delay estimate of the direct signal at different sampling moments to obtain the code delay estimate result of the direct signal after multipath error elimination.

[0102] In a specific embodiment, the antenna position is changed in real time by an antenna driving device to achieve rapid changes in relative phase, and a new observation quantity is introduced at the front end of the signal solution, which can effectively resist multipath interference. This can greatly improve the accuracy of navigation and measurement in both fixed sites and dynamic carriers; and the antenna movement scheme can be directly applied to various types of receivers without changing the internal structure of the receiver, with a small movement range, saving local resources, and achieving low overhead, further improving the practicality of the scheme.

[0103] The specific definition of the multipath error elimination device based on antenna motion can be found in the definition of the multipath error elimination method based on antenna motion above, which will not be repeated here. Each module in the above-mentioned multipath error elimination device based on antenna motion can be implemented in whole or in part by software, hardware and a combination thereof. The above-mentioned modules can be embedded in or independent of the processor in the computer device in the form of hardware, or can be stored in the memory of the computer device in the form of software, so that the processor can call and execute the operations corresponding to the above modules.

[0104] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0105] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A multipath error elimination method based on antenna motion, characterized in that: The method comprises: Acquire a navigation message spread spectrum code and message bit information; generate a satellite navigation signal according to the navigation message spread spectrum code and message bit information; Receiving the satellite navigation signal using an antenna in motion to obtain a received satellite navigation signal; the received satellite navigation signal includes a multipath signal and a direct signal; Based on the motion state of the antenna, the direct signal and the multipath signal are sampled at different times to obtain propagation delay difference expressions and relative phase expressions of the direct signal and the multipath signal at different sampling times; The code delay estimation error expression of the direct signal caused by the multipath signal is calculated according to the propagation delay difference expression and relative phase expression of the direct signal and the multipath signal at different sampling moments; The antenna jitter mode is used to calculate the code delay estimation deviation expression of the direct signal caused by the antenna jitter; The receiver calculates the code delay estimation of the direct signal at different sampling times according to the early-late chip method; the error term of the code delay estimation includes the code delay estimation error expression of the direct signal caused by the multipath signal and the code delay estimation deviation expression of the direct signal caused by the antenna jitter; Correcting the code delay estimate of the direct signal at different sampling moments to obtain corrected code delay estimate of the direct signal at different sampling moments; The corrected code delay estimates of the direct signal at different sampling moments are averaged to obtain a code delay estimation result of the direct signal after multipath error elimination.

2. The method according to claim 1, characterized in that: The direct signal and the multipath signal are sampled at different times based on the motion state of the antenna to obtain propagation delay difference expressions and relative phase expressions of the direct signal and the multipath signal at different sampling times, including: Based on the motion state of the antenna, the direct signal and the multipath signal are sampled at different times, and the propagation delay difference expression of the direct signal and the multipath signal at different sampling times is obtained as follows: Δτ1(r,ψ)=2(D0-r n cosψ n )sin(β+α) / c =Δτ1-r n cosψ n sin(β+α) / c Among them, α is the inclination angle of the reflector relative to the horizontal plane, β is the elevation angle of the satellite, the initial distance from the phase center O to the reflector when the antenna is stationary is D0, n represents the sampling time, r n represents the distance from the phase center O' to O of the antenna, ψ n represents the angle between the line connecting O' and O and the polar axis, D0-r n cosψ n is the distance between the phase center O' and the reflecting surface, and c represents the speed of light.

3. The method according to claim 2, characterized in that The method further comprises: Based on the motion state of the antenna, the direct signal and the multipath signal are sampled at different times, and the relative phase expressions of the direct signal and the multipath signal at different sampling times are obtained as follows: Among them, f c represents the carrier frequency, Δθ1 represents the carrier phase of the first multipath signal relative to the direct signal.

4. The method according to claim 1, characterized in that: The code delay estimation error expression of the direct signal caused by the multipath signal is calculated according to the propagation delay difference expression and relative phase expression of the direct signal and the multipath signal at different sampling times, including: The code delay estimation error expression of the direct signal caused by the multipath signal is calculated based on the propagation delay difference expression and relative phase expression of the direct signal and the multipath signal at different sampling times: in, T c is the correlation interval, θ e represents the carrier phase estimation error, Δτ1(r n ,ψ n ) is the expression of propagation delay difference, Δθ1(r n ,ψ n ) is the relative phase expression, a i represents the power ratio of the i-th multipath signal to the direct signal, r n represents the distance from the phase center O' of the antenna to O, ψ n Represents the angle between the line connecting O' and O and the polar axis.

5. The method according to claim 1, characterized in that: The receiver calculates the code delay estimate of the direct signal at different sampling times according to the early-late chip method, including: The receiver calculates the code delay estimate of the direct signal at different sampling times according to the early-late code chip method, and its expression is: Among them, τ0 represents the real delay when the antenna is stationary, e(r n ,ψ n ) represents the code delay estimation deviation expression of the direct signal caused by antenna jitter, ε(a1,Δτ1,Δθ1,r n ,ψ n ) represents the code delay estimation error expression of the direct signal caused by the multipath signal.

6. The method according to claim 1, characterized in that According to the jitter mode of the antenna, the code delay estimation deviation of the direct signal caused by the antenna jitter is calculated and corrected, including: According to the jitter mode of the antenna, the code delay estimation deviation of the direct signal caused by the antenna jitter can be calculated as e(r n ,ψ n )=r n sin(β+ψ n +a) / c Among them, r n represents the distance from the phase center O' to O of the antenna, ψ n represents the angle between the line connecting O' and O and the polar axis, α is the inclination of the reflector relative to the horizontal plane, β is the elevation angle of the satellite, and c represents the speed of light.

7. The method according to claim 6, further characterized in that: Correcting the code delay estimate of the direct signal at different sampling moments to obtain the corrected code delay estimate of the direct signal at different sampling moments includes: The code delay estimate of the direct signal at different sampling moments is corrected to obtain the corrected code delay estimate of the direct signal at different sampling moments, which is expressed as follows: in, The expression for estimating the code delay of the direct signal at different sampling times, τ0 represents the actual code delay of the direct signal, r n represents the distance from the phase center O' to O of the antenna, ψ n represents the angle between the line connecting O' and O and the polar axis, α is the inclination of the reflector relative to the horizontal plane, β is the elevation angle of the satellite, c represents the speed of light, ε(a1,Δτ1,Δθ1,r n ,ψ n ) is the expression for the code delay estimation error of the direct signal caused by the multipath signal.

8. The method according to claim 7, characterized in that Averaging the corrected code delay estimates of the direct signal at different sampling times to obtain a code delay estimate result of the direct signal after multipath error elimination, including: The code delay estimation result of the direct signal after multipath error elimination is obtained by averaging the corrected code delay estimation of the direct signal at different sampling times:

9. A multipath error elimination device based on antenna motion, characterized in that: The device comprises: A satellite signal generation module, used to obtain a navigation message spread spectrum code and message bit information; and generate a satellite navigation signal according to the navigation message spread spectrum code and message bit information; A satellite signal receiving module, used to receive the satellite navigation signal to obtain a received satellite navigation signal; the received satellite navigation signal includes a multipath signal and a direct signal; The antenna driving module is used to drive the antenna to be in motion and to sample the direct signal and the multipath signal to obtain a propagation delay difference expression and a relative phase expression of the direct signal and the multipath signal at different sampling times; A signal processing module, used to calculate the code delay estimation error expression of the direct signal caused by the multipath signal according to the propagation delay difference expression and relative phase expression of the direct signal and the multipath signal at different sampling moments; calculate the code delay estimation deviation expression of the direct signal caused by the antenna jitter using the antenna jitter method; the receiver calculates the code delay estimation of the direct signal at different sampling moments according to the early-late code chip method; the error term of the code delay estimation includes the code delay estimation error expression of the direct signal caused by the multipath signal and the code delay estimation deviation expression of the direct signal caused by the antenna jitter; The signal correction and multipath error elimination module is used to correct the code delay estimate of the direct signal at different sampling moments to obtain the corrected code delay estimate of the direct signal at different sampling moments; and to average the corrected code delay estimate of the direct signal at different sampling moments to obtain the code delay estimate result of the direct signal after multipath error elimination.

10. A multipath error elimination system based on antenna movement, comprising a satellite and a user terminal, wherein a satellite signal generating module and a satellite signal sending module are arranged in the satellite; The user terminal is provided with an antenna driving module, a satellite signal receiving module, a signal processing module and a signal correction and multipath error elimination module; A satellite signal generation module, used to obtain a navigation message spread spectrum code and message bit information; and generate a satellite navigation signal according to the navigation message spread spectrum code and message bit information; A satellite signal receiving module, used to receive the satellite navigation signal to obtain a received satellite navigation signal; the received satellite navigation signal includes a multipath signal and a direct signal; The antenna driving module is used to drive the antenna to be in motion and to sample the direct signal and the multipath signal to obtain a propagation delay difference expression and a relative phase expression of the direct signal and the multipath signal at different sampling times; A signal processing module, used to calculate the code delay estimation error expression of the direct signal caused by the multipath signal according to the propagation delay difference expression and relative phase expression of the direct signal and the multipath signal at different sampling moments; The antenna jitter mode is used to calculate the code delay estimation deviation expression of the direct signal caused by the antenna jitter; the receiver calculates the code delay estimation of the direct signal at different sampling times according to the early-late code chip method; The error term of the code delay estimation includes an expression for the code delay estimation error of the direct signal caused by the multipath signal and an expression for the code delay estimation deviation of the direct signal caused by the antenna jitter; The signal correction and multipath error elimination module is used to correct the code delay estimate of the direct signal at different sampling moments to obtain the corrected code delay estimate of the direct signal at different sampling moments; and to average the corrected code delay estimate of the direct signal at different sampling moments to obtain the code delay estimate result of the direct signal after multipath error elimination.

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