An equivalent modeling method for satellite-inertial integrated navigation receiving terminal

Abstract

The present application relates to an equivalent modeling method for a satellite-inertial combined navigation receiving terminal. The method comprises: during the operation of the satellite-inertial combined navigation receiving terminal, constructing and updating a receiving antenna model, a capture model, a receiver state judgment model, a user equivalent ranging error model, an inertial navigation drift error model, a tracking state calculation model, a non-tracking state calculation model and an efficiency transfer model in a time-based manner, so as to realize the equivalent modeling of the satellite-inertial combined navigation receiving terminal, and analyzing the effect of navigation elements on the performance evaluation of the carrier platform according to the technical steps of interference-to-signal ratio and equivalent carrier-to-noise ratio calculation, satellite capture state judgment, receiver state judgment, user equivalent ranging error, inertial navigation drift error, satellite navigation positioning error, inertial navigation positioning error and performance index calculation. The method can quickly analyze the effect of navigation elements on the performance evaluation of the carrier platform, and realize efficient performance evaluation of the carrier platform in a complex environment.

Description

Technical Field

[0001] The present application relates to the field of satellite navigation and simulation technology, and in particular to an equivalent modeling method for a satellite-inertial combined navigation receiving terminal. Background Art

[0002] The satellite-inertial combined navigation receiving terminal is a directional positioning navigation system that includes a satellite navigation and positioning system (GPS (Global Positioning System), Beidou satellite navigation system, GNSS (Global Navigation Satellite System)) and an inertial directional positioning navigation system (INS). Among them, satellite navigation and inertial navigation complement each other's advantages. The combination of dual systems can greatly improve the navigation performance of the carrier platform and is a key factor in the performance evaluation of the carrier platform.

[0003] At present, in the performance evaluation of the carrier platform including the satellite-inertial navigation receiving terminal, the performance evaluation of the navigation elements is mostly not involved. In the performance evaluation of the navigation elements, most of them are signal layer tests, and the parameter level performance evaluation is not involved. Therefore, it is necessary to perform equivalent modeling on the components and working operation processes of the satellite-inertial navigation receiving terminal to obtain the impact of the navigation elements on the performance evaluation of the carrier platform, and solve the performance evaluation problem of the carrier platform including the satellite-inertial navigation receiving terminal in a complex environment. Summary of the invention

[0004] Based on this, it is necessary to provide an equivalent modeling method for a satellite-inertial integrated navigation receiving terminal to address the above technical issues.

[0005] An equivalent modeling method for a satellite-inertial integrated navigation receiving terminal, the method comprising:

[0006] Construct a receiving antenna model, receive satellite signals and security threat signals through the receiving antenna model, and calculate the signal-to-interference ratio and equivalent carrier-to-noise ratio of each satellite based on the received signals;

[0007] Construct an acquisition model, and use the acquisition model to obtain the equivalent carrier-to-noise ratio of each satellite output by the receiving antenna model, the receiver acquisition decision threshold input by the receiver, and the first positioning time of the receiver to determine the satellite acquisition status;

[0008] Construct a receiver state judgment model, obtain the equivalent carrier-to-noise ratio of each satellite output by the receiving antenna model, the receiver state judgment threshold input by the receiver, and the satellite capture state judgment result output by the capture model through the receiver state judgment model to perform satellite tracking state judgment, and perform receiver state judgment based on the satellite tracking state judgment result;

[0009] A user equivalent ranging error model is constructed, and the variances of multiple types of measurement errors input by the receiver are obtained by summing up the variances to obtain the variance of the user equivalent ranging error.

[0010] Construct an inertial navigation drift error model, obtain the inertial navigation drift error parameters through the inertial navigation drift error model, and calculate them in combination with the user trajectory to obtain the inertial navigation raw data under the inertial navigation drift error; among which, the inertial navigation drift error parameters include gyro bias, accelerometer bias, gyro random walk and accelerometer random walk;

[0011] When the receiver is in the tracking state, a tracking state calculation model is constructed, and the variance of the user equivalent ranging error output by the user equivalent ranging error model is obtained through the tracking state calculation model to perform satellite guidance solution to obtain the satellite guidance positioning error;

[0012] When the receiver is in a non-tracking state, a non-tracking state calculation model is constructed, and the inertial navigation raw data under the inertial navigation drift error output by the inertial navigation drift error model is obtained through the non-tracking state calculation model to perform inertial navigation solution and obtain the inertial navigation positioning error;

[0013] Constructing an efficiency transfer model, in which, according to the navigation strategy adopted by the carrier platform including the satellite-inertial integrated navigation receiving terminal and the state of the receiver, the positioning error of the carrier platform is output and the efficiency index of the carrier platform is calculated;

[0014] During the operation of the satellite-inertial navigation receiving terminal, the receiving antenna model, capture model, receiver state judgment model, user equivalent ranging error model, inertial navigation drift error model, tracking state calculation model, non-tracking state calculation model and performance transfer model are updated in time to complete the equivalent modeling of the satellite-inertial navigation receiving terminal.

[0015] Among them, the receiving antenna model, capture model, receiver state judgment model, user equivalent ranging error model, inertial navigation drift error model, tracking state calculation model, non-tracking state calculation model and efficiency transfer model are all constructed through simulation.

[0016] In one embodiment, a receiving antenna model is constructed, satellite signals and security threat signals are received through the receiving antenna model, and interference-to-signal ratio and equivalent carrier-to-noise ratio of each satellite are calculated according to the received signals, including:

[0017] According to the receiving antenna type, a common receiving antenna model and an adaptive nulling antenna model are constructed respectively;

[0018] In the common receiving antenna model, the power and direction of satellite signals and security threat signals are received according to the antenna pattern, and after calculating the gain and attenuation of the received satellite signals and security threat signals, the interference-to-signal ratio and equivalent carrier-to-noise ratio of each satellite are calculated as follows:

[0019] Specifically, when the security threat signal is single, the calculation expression of the interference-to-signal ratio of each satellite is:

[0020] ;

[0021] in, For dry letter ratio, is the security threat signal power, is the satellite signal power, in units of ;

[0022] When there are multiple security threat signals, the power scalars of all security threat signals are added together to obtain a total interference-to-signal ratio;

[0023] The calculation expression of the equivalent carrier-to-noise ratio of each satellite is:

[0024] ;

[0025] in, is the equivalent carrier-to-noise ratio, is the carrier-to-noise ratio of the receiver when there is no interference, is the received signal carrier power, is the total received noise power when there is no interference; is the pseudo code rate, is the quality factor of the interference, which is related to the type of interference;

[0026] In the adaptive nulling antenna model, the power and signal direction of the satellite signal and the security threat signal are received, and the steering vectors of the received satellite signal and the security threat signal are calculated. The signal-to-interference ratio and equivalent carrier-to-noise ratio of each satellite are obtained based on the steering vectors of the satellite signal and the security threat signal and the weights of the back end of the antenna array element of the adaptive nulling antenna.

[0027] In one embodiment, a capture model is constructed, and the satellite capture state is determined by obtaining the equivalent carrier-to-noise ratio of each satellite output by the receiving antenna model, the receiver capture decision threshold input by the receiver, and the first positioning time of the receiver through the capture model, including:

[0028] Construct an acquisition model, obtain the equivalent carrier-to-noise ratio of each satellite output by the receiving antenna model, the receiver acquisition decision threshold input by the receiver, and the first positioning time of the receiver through the acquisition model, and set two judgment conditions;

[0029] The first judgment condition is that the equivalent carrier-to-noise ratio of a single satellite output by the receiving antenna model is greater than the receiver capture decision threshold input by the receiver; the second judgment condition is that the first positioning time of the satellite signal is less than the receiver first positioning time input by the receiver;

[0030] When both the first judgment condition and the second judgment condition are satisfied, it is determined that the satellite enters the capture state; otherwise, it is determined that the satellite does not enter the capture state.

[0031] In one embodiment, the first fix time of the satellite signal is expressed as ;in, is the first positioning time of the satellite signal, Acquisition time for satellite signals, is the demodulation time; where the satellite signal acquisition time when there is a security threat signal Expressed as

[0032] ;

[0033] in, is the detection probability and its value ranges from 0 to 1. is the pseudo code rate, is the time uncertainty, is the frequency uncertainty, For the code number, is the number of correlators, is the number of Fourier transform points, is an incoherent cumulative number, and The specific expression is

[0034] ;

[0035] in, is the false detection probability and its value ranges from 0 to 1. is the single chip signal-to-noise ratio, is the equivalent interference power, is the equivalent signal frequency, is the satellite signal structure, is the satellite signal power, is the integration time, For loss.

[0036] In one embodiment, a receiver state determination model is constructed, and satellite tracking state determination is performed by obtaining an equivalent carrier-to-noise ratio of each satellite output by a receiving antenna model, a receiver state determination threshold input by a receiver, and a satellite capture state determination result output by a capture model through the receiver state determination model, and the receiver state determination is performed based on the satellite tracking state determination result, including:

[0037] Construct a receiver state decision model, and obtain the equivalent carrier-to-noise ratio of each satellite output by the receiving antenna model, the receiver state decision threshold input by the receiver, and the satellite capture state decision result output by the capture model through the receiver state decision model;

[0038] For a satellite that has entered the capture state, it is further determined whether the equivalent carrier-to-noise ratio of the satellite is greater than the receiver state decision threshold input by the receiver. If so, it indicates that the satellite has entered the tracking state; otherwise, it indicates that the satellite is still in the capture state.

[0039] For a satellite that has not entered the capture state, the satellite is marked as being in the lost-lock-recapture state;

[0040] When the number of satellites in the tracking state is greater than 4, the receiver is determined to be in the tracking state; otherwise, the receiver is determined to be in the non-tracking state.

[0041] In one embodiment, a user equivalent ranging error model is constructed, and the variances of multiple types of measurement errors input by the receiver are obtained by the user equivalent ranging error model and summed up to obtain the variance of the user equivalent ranging error, which is expressed as

[0042] ;

[0043] in, is the variance of the user equivalent ranging error, is the variance of the satellite ephemeris and satellite clock error model errors generated by the GPS ground monitoring part, is the variance of the atmospheric delay correction error of the signal on the propagation path, is the variance of the measurement error associated with the receiver and multipath.

[0044] In one of the embodiments, when the receiver is in a tracking state, a tracking state calculation model is constructed, and the variance of the user equivalent ranging error output by the user equivalent ranging error model is obtained through the tracking state calculation model to perform satellite guidance solution to obtain the satellite guidance positioning error, including:

[0045] When the receiver is in the tracking state, a tracking state calculation model is constructed. In the tracking state calculation model, the variance of the user equivalent ranging error output by the user equivalent ranging error model is obtained, and the satellite participating in the positioning calculation is selected from the satellites in the tracking state through the receiver satellite selection strategy, and the DOP value of the selected satellite is calculated;

[0046] The satellite guidance solution is performed based on the variance of the user's equivalent ranging error and the DOP value of the selected satellite to obtain the satellite guidance positioning error.

[0047] In one embodiment, when the receiver is in a non-tracking state, a non-tracking state calculation model is constructed, and the inertial navigation raw data under the inertial navigation drift error output by the inertial navigation drift error model is obtained through the non-tracking state calculation model to perform inertial navigation solution to obtain the inertial navigation positioning error, including:

[0048] When the receiver is in a non-tracking state, a non-tracking state calculation model is constructed and the time the receiver is in the non-tracking state is recorded. The inertial navigation original data under the inertial navigation drift error output by the inertial navigation drift error model obtained by the non-tracking state calculation model and the time the receiver is in the non-tracking state are used for inertial navigation solution to obtain the inertial navigation positioning error.

[0049] In one embodiment, a performance transfer model is constructed. In the performance transfer model, according to the navigation strategy adopted by the carrier platform including the satellite-inertial combined navigation receiving terminal and the state of the receiver, the positioning error of the carrier platform is output and the performance index of the carrier platform is calculated and obtained, including:

[0050] Construct an efficiency transfer model, and obtain the navigation strategy adopted by the carrier platform including the satellite-inertial integrated navigation receiving terminal and the receiver state determination result output by the receiver state determination model through the efficiency transfer model;

[0051] When the navigation strategy currently adopted by the carrier platform is satellite-inertial combined navigation and the receiver is in tracking state, the satellite navigation positioning error output by the tracking state calculation model is used as the positioning error of the carrier platform;

[0052] When the navigation strategy currently adopted by the carrier platform is satellite-inertial combined navigation and the receiver is in a non-tracking state, the inertial navigation positioning error output by the non-tracking state calculation model is used as the positioning error of the carrier platform;

[0053] When the carrier platform currently adopts other navigation strategies, the positioning error of the carrier platform is not updated;

[0054] The performance index of the carrier platform is obtained according to the positioning error of the carrier platform; wherein the performance index includes but is not limited to the hit probability of the carrier platform.

[0055] The above-mentioned equivalent modeling method of the satellite-inertial integrated navigation receiving terminal constructs and updates the receiving antenna model, capture model, receiver state judgment model, user equivalent ranging error model, inertial navigation drift error model, tracking state calculation model, non-tracking state calculation model and performance transfer model in the operation process of the satellite-inertial integrated navigation receiving terminal in time, realizes the equivalent modeling of the satellite-inertial integrated navigation receiving terminal, and analyzes the impact of navigation elements on the performance evaluation of the carrier platform according to the technical steps of interference-to-signal ratio and equivalent carrier-to-noise ratio calculation, satellite capture state judgment, receiver state judgment, user equivalent ranging error, inertial navigation drift error, satellite navigation positioning error, inertial navigation positioning error and performance index calculation.

[0056] Compared with the prior art, the present application has the following advantages: 1) Each constructed model is independent, which is convenient for embedding into the comprehensive simulation system of the carrier platform to solve its performance evaluation problem; 2) Compared with the signal layer test evaluation, the equivalent modeling of the satellite-inertial combined navigation receiving terminal can quickly analyze the impact of navigation elements on the performance evaluation of the platform, and has little impact on the performance of the carrier platform during Monte Carlo simulation, and can realize efficient and rapid performance evaluation of the carrier platform including the satellite-inertial combined navigation receiving terminal in a complex environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 It is a flowchart of an equivalent modeling method of a satellite-inertial integrated navigation receiving terminal in one embodiment;

[0058] Figure 2 The figure is a schematic diagram of the operation flow of each model in an embodiment. DETAILED DESCRIPTION

[0059] 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.

[0060] In one embodiment, Figure 1 and Figure 2 As shown, an equivalent modeling method for a satellite-inertial integrated navigation receiving terminal is provided, comprising the following steps:

[0061] Step S1, constructing a receiving antenna model, receiving satellite signals and security threat signals through the receiving antenna model, and calculating the signal-to-interference ratio and equivalent carrier-to-noise ratio of each satellite based on the received signals.

[0062] Specifically, step S1 includes:

[0063] According to the receiving antenna type, a common receiving antenna model and an adaptive nulling antenna model are constructed respectively;

[0064] In the common receiving antenna model, the power and direction of satellite signals and security threat signals are received according to the antenna pattern, and after calculating the gain and attenuation of the received satellite signals and security threat signals, the interference-to-signal ratio and equivalent carrier-to-noise ratio of each satellite are calculated as follows:

[0065] Specifically, when the security threat signal is single, the calculation expression of the interference-to-signal ratio of each satellite is:

[0066] ;

[0067] in, For dry letter ratio, is the security threat signal power, is the satellite signal power, in units of ;

[0068] When there are multiple security threat signals, the power scalars of all security threat signals are added together to obtain a total interference-to-signal ratio;

[0069] The calculation expression of the equivalent carrier-to-noise ratio of each satellite is:

[0070] ;

[0071] in, is the equivalent carrier-to-noise ratio, is the carrier-to-noise ratio of the receiver when there is no interference, is the received signal carrier power, is the total received noise power when there is no interference; is the pseudo code rate, Q is the quality factor of the interference, which is related to the type of interference; specifically, different types of interference Q There are different values; among them, the broadband Gaussian white noise interference Q =2.22, matching the spectral interference Q =1.5, the single-frequency interference at the spectrum peak Q =1;

[0072] In the adaptive nulling antenna model, the power and signal direction of the satellite signal and the security threat signal are received, and the steering vectors of the received satellite signal and the security threat signal are calculated. The signal-to-interference ratio and equivalent carrier-to-noise ratio of each satellite are obtained based on the steering vectors of the satellite signal and the security threat signal and the weights of the back end of the antenna array element of the adaptive nulling antenna.

[0073] Among them, the Interference-to-Signal Ratio (ISR) is an indicator to measure the degree of influence of interference on the signal, and the equivalent carrier-to-noise ratio is an important indicator to evaluate the influence of interference on acquisition, carrier tracking and data demodulation.

[0074] Step S2, constructing an acquisition model, obtaining the equivalent carrier-to-noise ratio of each satellite output by the receiving antenna model, the receiver acquisition decision threshold input by the receiver, and the first positioning time of the receiver through the acquisition model to determine the satellite acquisition status.

[0075] Specifically, step S2 includes:

[0076] Construct an acquisition model, obtain the equivalent carrier-to-noise ratio of each satellite output by the receiving antenna model, the receiver acquisition decision threshold input by the receiver, and the receiver first positioning time through the acquisition model, and set two judgment conditions; wherein the first judgment condition is that the equivalent carrier-to-noise ratio of a single satellite output by the receiving antenna model is greater than the receiver acquisition decision threshold input by the receiver; the second judgment condition is that the first positioning time of the satellite signal is less than the receiver first positioning time input by the receiver;

[0077] When both the first judgment condition and the second judgment condition are satisfied, it is determined that the satellite enters the capture state; otherwise, it is determined that the satellite does not enter the capture state.

[0078] Specifically, the first positioning time of the satellite signal is expressed as ;in, is the first positioning time of the satellite signal, Acquisition time for satellite signals, is the demodulation time; where the satellite signal acquisition time when there is a security threat signal Expressed as

[0079] ;

[0080] in, is the detection probability and its value ranges from 0 to 1. is the pseudo code rate, is the time uncertainty, is the frequency uncertainty, For the code number, is the number of correlators, is the number of Fourier transform points, is an incoherent cumulative number, and The specific expression is

[0081] ;

[0082] in, is the false detection probability and its value ranges from 0 to 1. is the single chip signal-to-noise ratio, is the equivalent interference power, is the equivalent signal frequency, is the satellite signal structure, is the satellite signal power, is the integration time, For loss.

[0083] Step S3, constructing a receiver state judgment model, obtaining the equivalent carrier-to-noise ratio of each satellite output by the receiving antenna model, the receiver state judgment threshold input by the receiver, and the satellite capture state judgment result output by the capture model through the receiver state judgment model to perform satellite tracking state judgment, and performing receiver state judgment based on the satellite tracking state judgment result.

[0084] Specifically, step S3 includes:

[0085] Construct a receiver state decision model, and obtain the equivalent carrier-to-noise ratio of each satellite output by the receiving antenna model, the receiver state decision threshold input by the receiver, and the satellite capture state decision result output by the capture model through the receiver state decision model;

[0086] For a satellite that has entered the capture state, it is further determined whether the equivalent carrier-to-noise ratio of the satellite is greater than the receiver state decision threshold input by the receiver. If so, it indicates that the satellite has entered the tracking state; otherwise, it indicates that the satellite is still in the capture state.

[0087] For a satellite that has not entered the capture state, the satellite is marked as being in the lost-lock-recapture state;

[0088] When the number of satellites in the tracking state is greater than 4, the receiver is determined to be in the tracking state; otherwise, the receiver is determined to be in the non-tracking state.

[0089] Step S4, constructing a user equivalent ranging error model, obtaining the variances of multiple types of measurement errors input by the receiver through the user equivalent ranging error model, performing summation calculation, and obtaining the variance of the user equivalent ranging error.

[0090] Specifically, the variance of the user equivalent ranging error is expressed as

[0091] ;

[0092] in, is the variance of the user equivalent ranging error, is the variance of the satellite ephemeris and satellite clock error model errors generated by the GPS ground monitoring part, is the variance of the atmospheric delay correction error of the signal on the propagation path, is the variance of the measurement error associated with the receiver and multipath.

[0093] Step S5, constructing an inertial navigation drift error model, obtaining inertial navigation drift error parameters through the inertial navigation drift error model and calculating them in combination with the user trajectory to obtain inertial navigation raw data under the inertial navigation drift error; wherein the inertial navigation drift error parameters include gyro bias, accelerometer bias, gyro random walk and accelerometer random walk.

[0094] Step S6: When the receiver is in the tracking state, a tracking state calculation model is constructed, and the variance of the user equivalent ranging error output by the user equivalent ranging error model is obtained through the tracking state calculation model to perform satellite guidance solution to obtain the satellite guidance positioning error.

[0095] Specifically, step S6 includes: when the receiver is in a tracking state, constructing a tracking state calculation model, obtaining the variance of the user equivalent ranging error output by the user equivalent ranging error model in the tracking state calculation model, and selecting a satellite participating in the positioning calculation from the satellites in the tracking state through the receiver satellite selection strategy, and calculating the DOP (Dilution of Precision) value of the selected satellite; performing satellite guidance solution according to the variance of the user equivalent ranging error and the DOP value of the selected satellite to obtain the satellite guidance positioning error.

[0096] Step S7, when the receiver is in a non-tracking state, a non-tracking state calculation model is constructed, and the inertial navigation raw data under the inertial navigation drift error output by the inertial navigation drift error model is obtained through the non-tracking state calculation model to perform inertial navigation solution to obtain the inertial navigation positioning error.

[0097] Specifically, step S7 includes:

[0098] When the receiver is in a non-tracking state, a non-tracking state calculation model is constructed and the time the receiver is in the non-tracking state is recorded. The inertial navigation original data under the inertial navigation drift error output by the inertial navigation drift error model obtained by the non-tracking state calculation model and the time the receiver is in the non-tracking state are used for inertial navigation solution to obtain the inertial navigation positioning error.

[0099] Step S8, constructing a performance transfer model, in which, according to the navigation strategy adopted by the carrier platform including the satellite-inertial navigation receiving terminal and the state of the receiver, the positioning error of the carrier platform is output and the performance index of the carrier platform is calculated.

[0100] Specifically, step S8 includes:

[0101] Construct an efficiency transfer model, and obtain the navigation strategy adopted by the carrier platform including the satellite-inertial integrated navigation receiving terminal and the receiver state determination result output by the receiver state determination model through the efficiency transfer model;

[0102] When the navigation strategy currently adopted by the carrier platform is satellite-inertial combined navigation and the receiver is in tracking state, the satellite navigation positioning error output by the tracking state calculation model is used as the positioning error of the carrier platform;

[0103] When the navigation strategy currently adopted by the carrier platform is satellite-inertial combined navigation and the receiver is in a non-tracking state, the inertial navigation positioning error output by the non-tracking state calculation model is used as the positioning error of the carrier platform;

[0104] When the carrier platform currently adopts other navigation strategies, the positioning error of the carrier platform is not updated;

[0105] The performance index of the carrier platform is obtained according to the positioning error of the carrier platform; wherein the performance index includes but is not limited to the hit probability of the carrier platform.

[0106] Step S9, during the operation of the satellite-inertial integrated navigation receiving terminal, the receiving antenna model, the capture model, the receiver state judgment model, the user equivalent ranging error model, the inertial navigation drift error model, the tracking state calculation model, the non-tracking state calculation model and the performance transfer model are updated in time to complete the equivalent modeling of the satellite-inertial integrated navigation receiving terminal.

[0107] Among them, the receiving antenna model, capture model, receiver state judgment model, user equivalent ranging error model, inertial navigation drift error model, tracking state calculation model, non-tracking state calculation model and efficiency transfer model are all constructed through simulation.

[0108] The above-mentioned equivalent modeling method of a satellite-inertial integrated navigation receiving terminal constructs and updates the receiving antenna model, capture model, receiver state judgment model, user equivalent ranging error model, inertial navigation drift error model, tracking state calculation model, non-tracking state calculation model and performance transfer model in the operation process of the satellite-inertial integrated navigation receiving terminal in time, realizes the equivalent modeling of the satellite-inertial integrated navigation receiving terminal, and analyzes the influence of navigation elements on the performance evaluation of the carrier platform according to technical steps such as interference-to-signal ratio and equivalent carrier-to-noise ratio calculation, satellite capture state judgment, receiver state judgment, user equivalent ranging error, inertial navigation drift error, satellite navigation positioning error, inertial navigation positioning error and performance index calculation, so as to realize efficient and rapid performance evaluation of the carrier platform including the satellite-inertial integrated navigation receiving terminal in a complex environment.

[0109] It should be understood that although Figure 1 and Figure 2 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 1 and Figure 2 At 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.

[0110] 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.

[0111] The above-described 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 present application. 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 present application shall be subject to the attached claims.

Claims

1. An equivalent modeling method for a satellite-inertial integrated navigation receiving terminal, characterized in that: The method comprises: Constructing a receiving antenna model, receiving satellite signals and security threat signals through the receiving antenna model, and calculating the signal-to-interference ratio and equivalent carrier-to-noise ratio of each satellite according to the received signals; Constructing an acquisition model, and determining the satellite acquisition state by obtaining the equivalent carrier-to-noise ratio of each satellite output by the receiving antenna model, the receiver acquisition decision threshold input by the receiver, and the first positioning time of the receiver through the acquisition model; Constructing a receiver state decision model, obtaining the equivalent carrier-to-noise ratio of each satellite output by the receiving antenna model, the receiver state decision threshold input by the receiver, and the satellite capture state decision result output by the capture model through the receiver state decision model to perform satellite tracking state decision, and performing receiver state decision based on the satellite tracking state decision result; Constructing a user equivalent ranging error model, obtaining variances of multiple types of measurement errors input by the receiver through the user equivalent ranging error model, performing summation calculation, and obtaining the variance of the user equivalent ranging error; An inertial navigation drift error model is constructed, and inertial navigation drift error parameters are obtained through the inertial navigation drift error model and calculated in combination with the user trajectory to obtain inertial navigation raw data under inertial navigation drift error; wherein the inertial navigation drift error parameters include gyro bias, accelerometer bias, gyro random walk and accelerometer random walk; When the receiver is in a tracking state, a tracking state calculation model is constructed, and the variance of the user equivalent ranging error output by the user equivalent ranging error model is obtained through the tracking state calculation model to perform satellite guidance solution to obtain the satellite guidance positioning error; When the receiver is in a non-tracking state, a non-tracking state calculation model is constructed, and the inertial navigation raw data under the inertial navigation drift error output by the inertial navigation drift error model is obtained through the non-tracking state calculation model to perform inertial navigation solution to obtain the inertial navigation positioning error; Constructing an efficiency transfer model, in which, according to the navigation strategy adopted by the carrier platform including the satellite-inertial integrated navigation receiving terminal and the state of the receiver, the positioning error of the carrier platform is output and the efficiency index of the carrier platform is calculated and obtained; During the operation of the satellite-inertial integrated navigation receiving terminal, the receiving antenna model, the capture model, the receiver state judgment model, the user equivalent ranging error model, the inertial navigation drift error model, the tracking state calculation model, the non-tracking state calculation model and the performance transfer model are updated in time to complete the equivalent modeling of the satellite-inertial integrated navigation receiving terminal.

2. The method according to claim 1, characterized in that Constructing a receiving antenna model, receiving satellite signals and security threat signals through the receiving antenna model, and calculating the interference-to-signal ratio and equivalent carrier-to-noise ratio of each satellite according to the received signals, including: According to the receiving antenna type, a common receiving antenna model and an adaptive nulling antenna model are constructed respectively; In the common receiving antenna model, the power and signal direction of the satellite signal and the security threat signal are received according to the antenna pattern, and after calculating the gain and attenuation of the received satellite signal and the security threat signal, the interference-to-signal ratio and equivalent carrier-to-noise ratio of each satellite are calculated in the following manner: Specifically, when the security threat signal is single, the calculation expression of the interference-to-signal ratio of each satellite is: ； in, For dry letter ratio, is the security threat signal power, is the satellite signal power, in units of dB ; When there are multiple security threat signals, the power scalars of all security threat signals are added together to obtain a total interference-to-signal ratio; The calculation expression of the equivalent carrier-to-noise ratio of each satellite is: ； in, is the equivalent carrier-to-noise ratio, is the carrier-to-noise ratio of the receiver when there is no interference, is the received signal carrier power, is the total received noise power when there is no interference; is the pseudo code rate, is the quality factor of the interference, which is related to the type of interference; In the adaptive nulling antenna model, the power and signal direction of the satellite signal and the security threat signal are received, and the steering vectors of the received satellite signal and the security threat signal are calculated. The signal-to-interference ratio and the equivalent carrier-to-noise ratio of each satellite are obtained based on the steering vectors of the satellite signal and the security threat signal and the weights of the back end of the antenna array element of the adaptive nulling antenna.

3. The method according to claim 2, characterized in that Constructing an acquisition model, obtaining the equivalent carrier-to-noise ratio of each satellite output by the receiving antenna model, the receiver acquisition decision threshold input by the receiver, and the first positioning time of the receiver through the acquisition model to determine the satellite acquisition state, including: Constructing an acquisition model, obtaining the equivalent carrier-to-noise ratio of each satellite output by the receiving antenna model, the receiver acquisition decision threshold input by the receiver, and the first positioning time of the receiver through the acquisition model, and setting two judgment conditions; The first judgment condition is that the equivalent carrier-to-noise ratio of a single satellite output by the receiving antenna model is greater than the receiver capture decision threshold input by the receiver; the second judgment condition is that the first positioning time of the satellite signal is less than the receiver first positioning time input by the receiver; When both the first judgment condition and the second judgment condition are satisfied, it is determined that the satellite enters the capture state; otherwise, it is determined that the satellite does not enter the capture state.

4. The method according to claim 3, characterized in that The first fix time of the satellite signal is expressed as ;in, is the first positioning time of the satellite signal, Acquisition time for satellite signals, is the demodulation time; where the satellite signal acquisition time when there is a security threat signal Expressed as ； in, is the detection probability and its value ranges from 0 to 1. is the pseudo code rate, is the time uncertainty, is the frequency uncertainty, For the code number, is the number of correlators, is the number of Fourier transform points, is an incoherent cumulative number, and The specific expression is ； in, is the false detection probability and its value ranges from 0 to 1. is the single chip signal-to-noise ratio, is the equivalent interference power, is the equivalent signal frequency, is the satellite signal structure, is the satellite signal power, is the integration time, For loss.

5. The method according to claim 3, characterized in that: Constructing a receiver state decision model, obtaining the equivalent carrier-to-noise ratio of each satellite output by the receiving antenna model, the receiver state decision threshold input by the receiver, and the satellite capture state decision result output by the capture model through the receiver state decision model to perform satellite tracking state decision, and performing receiver state decision based on the satellite tracking state decision result, including: Constructing a receiver state decision model, and obtaining the equivalent carrier-to-noise ratio of each satellite output by the receiving antenna model, the receiver state decision threshold input by the receiver, and the satellite capture state decision result output by the capture model through the receiver state decision model; For a satellite that has entered the capture state, it is further determined whether the equivalent carrier-to-noise ratio of the satellite is greater than the receiver state decision threshold input by the receiver. If so, it indicates that the satellite has entered the tracking state; otherwise, it indicates that the satellite is still in the capture state. For a satellite that has not entered the capture state, the satellite is marked as being in the lost-lock-recapture state; When the number of satellites in the tracking state is greater than 4, the receiver is determined to be in the tracking state; otherwise, the receiver is determined to be in the non-tracking state.

6. The method according to claim 1, characterized in that A user equivalent ranging error model is constructed, and the variances of multiple types of measurement errors input by the receiver are obtained by summing up the variances to obtain the user equivalent ranging error, which is expressed as ； in, is the variance of the user equivalent ranging error, is the variance of the satellite ephemeris and satellite clock error model errors generated by the GPS ground monitoring part, is the variance of the atmospheric delay correction error of the signal on the propagation path, is the variance of the measurement error associated with the receiver and multipath.

7. The method according to claim 1, characterized in that When the receiver is in a tracking state, a tracking state calculation model is constructed, and the variance of the user equivalent ranging error output by the user equivalent ranging error model is obtained through the tracking state calculation model to perform satellite guidance solution to obtain the satellite guidance positioning error, including: When the receiver is in a tracking state, a tracking state calculation model is constructed, in which the variance of the user equivalent ranging error output by the user equivalent ranging error model is obtained, and a satellite participating in the positioning calculation is selected from the satellites in the tracking state through the receiver satellite selection strategy, and the DOP value of the selected satellite is calculated; Satellite guidance solution is performed according to the variance of the user equivalent ranging error and the DOP value of the selected satellite to obtain the satellite guidance positioning error.

8. The method according to claim 1, characterized in that When the receiver is in a non-tracking state, a non-tracking state calculation model is constructed, and the inertial navigation raw data under the inertial navigation drift error output by the inertial navigation drift error model is obtained through the non-tracking state calculation model to perform inertial navigation solution to obtain the inertial navigation positioning error, including: When the receiver is in a non-tracking state, a non-tracking state calculation model is constructed and the time when the receiver is in the non-tracking state is recorded, and an inertial navigation solution is performed according to the inertial navigation raw data under the inertial navigation drift error output by the inertial navigation drift error model obtained by the non-tracking state calculation model and the time when the receiver is in the non-tracking state to obtain the inertial navigation positioning error.

9. The method according to claim 1, characterized in that: Constructing an efficiency transfer model, in which, according to the navigation strategy adopted by the carrier platform including the satellite-inertial integrated navigation receiving terminal and the state of the receiver, the positioning error of the carrier platform is output and the efficiency index of the carrier platform is calculated, including: Constructing an efficiency transfer model, and obtaining the navigation strategy adopted by the carrier platform including the satellite-inertial integrated navigation receiving terminal and the receiver state determination result output by the receiver state determination model through the efficiency transfer model; When the navigation strategy currently adopted by the carrier platform is satellite-inertial combined navigation and the receiver is in a tracking state, the satellite navigation positioning error output by the tracking state calculation model is used as the positioning error of the carrier platform; When the navigation strategy currently adopted by the carrier platform is satellite-inertial combined navigation and the receiver is in a non-tracking state, the inertial navigation positioning error output by the non-tracking state calculation model is used as the positioning error of the carrier platform; When the carrier platform currently adopts other navigation strategies, the positioning error of the carrier platform is not updated; The performance index of the carrier platform is obtained according to the positioning error of the carrier platform; wherein the performance index includes but is not limited to the hit probability of the carrier platform.

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