Navigating payload channel model, estimation method, computer storage medium and apparatus

Abstract

The present application relates to navigation payload channel model, estimation method, computer storage medium and device, the method comprises the following steps: S100: ideal single branch modulation signal is acquired, and the single branch modulation signal is generated modulated signal through digital distortion; S200: the modulated signal is synthesized multiplexing signal through signal multiplexing; S300: multiplexing signal analog distortion and generate output signal; S400: according to output signal and local ideal signal carries out signal evaluation.The method of the present application, through the comprehensive solution of signal digital distortion and analog distortion, accurately obtains the channel characteristics of on-orbit transmitting end, and efficiently solves the nonlinear problem of payload transmission channel.

Description

Technical Field

[0001] This invention relates to the field of signal identification technology, and in particular to a navigation payload channel model, estimation method, computer storage medium, and device. Background Technology

[0002] Navigation signals are the only link between satellites and ground user receivers, and their quality is crucial to users’ high-precision PNT service. However, even normally operating satellites in orbit will produce slight signal distortions. More seriously, the nonlinear errors introduced by the non-ideal transmission channel of the navigation payload seriously affect the quality of GNSS signals, causing the signal correlation curve to be distorted and asymmetrical, the S-curve to shift at the zero point, the power spectrum to intermodulation within the band, and out-of-band regeneration during reception processing. These adverse factors will all cause ranging deviations [1], among which the nonlinear effect of high-power amplifiers is the most serious, resulting in GNSS signal quality assessment not meeting the requirements of the official ICD. At the same time, the signal distortion introduced by the transmission channel of the navigation payload is different for each satellite, which is particularly unfavorable for differential positioning. In addition, relevant studies have shown that the nonlinearity of the transmission channel of the navigation payload is a complex combination of various distortions, rather than a simple linear superposition. Navigation signal quality assessment and monitoring is an important means of judging the normal operation of satellites in orbit and can detect abnormal satellite signal states in a timely and effective manner. However, current navigation signal quality assessment and monitoring mainly focus on the "received signal" status at the receiver end, and research on signal distortion sources is still insufficient. However, received signals are often subjected to a mixture of various distortions. In summary, identifying the source of signal distortion is of great significance to supporting GNSS signal quality assessment and monitoring. Therefore, it is necessary to conduct in-depth research on the characteristics of navigation payload transmission channels starting from signal quality assessment.

[0003] The International Civil Aviation Organization (ICAO) has proposed a class of signal distortion models widely used in transmission channel modeling: Threat Model A (TMA), Analog Model B (TMB), and Mixed Distortion Model C (TMC), and most actual received signals belong to this type. However, existing research has shown that the second-order model in TMB is significantly inaccurate for broadband modulated signals. Based on this, some researchers have used multi-order FIR filters to replace the TMB model. One existing approach models the navigation payload transmission channel as a linear FIR filter and estimates the channel characteristics using the least squares method; however, this study did not involve measurement data verification. Another existing approach models the transmission channel as an FIR filter and obtains the FIR filter impulse response by inverting the correlation domain. Kang Li of the National Time Service Center modeled the BDS-2 transmission channel as a TMB model and used the least squares method to obtain the channel characteristics. None of the above studies on transmission channel characteristics include digital distortion, and the applicability of these methods to broadband modulated signals remains to be investigated. Therefore, there is still a gap in the accurate estimation of the characteristics of the transmission channel. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a navigation payload channel model, estimation method, computer storage medium, and device, which can efficiently and accurately estimate the characteristics of the transmission channel.

[0005] To achieve the above objectives, this application proposes a first technical solution:

[0006] A navigation payload channel estimation method, the method specifically includes the following steps:

[0007] S100: The characteristics of the navigation payload transmission channel are obtained by signal quality assessment of the received signal. The characteristics of the navigation payload transmission channel include digital distortion and analog distortion.

[0008] S200: The received signal includes several single-branch signals. The single-branch signal is assumed to have infinite bandwidth. The digital distortion between components is independent. The single-branch signal traverses all digital distortion settings to generate a single-branch modulation signal. The digital distortion value of each single-branch signal is calculated in turn.

[0009] S300: Using the local ideal signal as a reference, each single-branch signal is modulated into a single-branch modulated signal containing digital distortion according to step S200, and the single-branch modulated signals are multiplexed to generate a combined signal containing digital distortion.

[0010] S400: Using the local ideal signal as a reference, the analog distortion characteristics are obtained based on the received signal and the combined signal.

[0011] Furthermore, the simulated distortion is transformed into an Nth-order FIR filter.

[0012] Furthermore, the signal quality assessment for determining the characteristics of the navigation payload transmission channel is performed using a signal distortion model.

[0013] Furthermore, the received signal includes an acquired signal, which is obtained through a signal acquisition system.

[0014] Furthermore, the specific steps for determining the characteristics of the simulated distortion channel include:

[0015] The acquired data is preprocessed using a software receiver to obtain a continuous baseband signal. The continuous baseband signals are then averaged to reduce noise interference. The average value of the accumulated baseband signals is then calculated. :

[0016]

[0017] in The number of sampling points. Here is the filter impulse response matrix. The filter order;

[0018] The digital distortion of a single branch signal is:

[0019]

[0020] in This represents the total number of signal branches;

[0021] No. The branch signal components are:

[0022] .

[0023] Find the filter impulse response matrix Impact response:

[0024] remember For a single-branch input convolution matrix:

[0025] ;

[0026] The process involves generating a modulated signal from a single-branch signal through digital distortion and then calculating the digital distortion value. :

[0027]

[0028] in This refers to the filter's impulse response.

[0029] The analytical equations for the measured signal and the input convolution matrix are obtained as ideal base point digital distortion. :

[0030]

[0031] By digital distortion of ideal baseband signal Back-substitution synthesis of new multiplexed signals At this time, the input signal Includes digital distortion of the actual base point signal ;

[0032] Obtain the estimated characteristic response of the simulated distortion channel. :

[0033] .

[0034] To achieve the above objectives, this application also proposes a second technical solution:

[0035] A navigation payload channel model, the model comprising:

[0036] Digital distortion model is used to generate a modulated signal from a single-branch modulated signal through digital distortion;

[0037] Signal multiplexing models are used to synthesize multiplexed signals from modulated signals.

[0038] A simulated distortion model is used to simulate the distortion of multiplexed signals and generate output signals;

[0039] A signal evaluation model is used to evaluate the output signal against the local ideal signal.

[0040] The signal evaluation between the output signal and the local ideal signal includes performing an autocorrelation operation between the output signal and the local ideal signal.

[0041] The establishment of the navigation payload channel model includes the following steps:

[0042] Several single-branch modulation signals Multiplexed signals are generated by signal multiplexing:

[0043]

[0044] in It is a single-branch modulated signal. For amplitude, For phase, This is a cross-transfer item;

[0045] The inter-branch digital distortions are independent and not limited by bandwidth, and the multiplexed signal is rewritten as follows:

[0046]

[0047] in , , For spreading code rate;

[0048] The simulation is modeled as an Nth-order linear FIR filter; therefore, the simulated distorted signal is the convolution of the input signal and the channel impulse response.

[0049]

[0050] in This is the impulse response of the FIR filter. For convolution calculation;

[0051] The simulated distortion of a single-branch signal is as follows:

[0052]

[0053] The correlation with the local ideal signal is:

[0054]

[0055] in The coherent integration time is typically set to one chip period. For the first Branch autocorrelation function, It is a conjugate matrix.

[0056] To achieve the above objectives, this application proposes a third technical solution:

[0057] A computer-readable storage medium storing a program that, when executed by a processor, causes the processor to perform the steps of the method described above.

[0058] A navigation payload channel estimation device includes a processor and the aforementioned computer-readable storage medium.

[0059] The technical solution of the present invention has the following advantages compared with the prior art:

[0060] The navigation payload channel estimation method described in this invention starts with signal quality assessment and accurately obtains the on-board transmitter channel characteristics by comprehensively solving digital distortion and analog distortion, thus efficiently solving the nonlinearity problem of the payload transmission channel. Attached Figure Description

[0061] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0062] Figure 1 This is a flowchart of the channel joint estimation algorithm of the present invention;

[0063] Figure 2 This is a flowchart of the navigation payload model establishment method of the present invention. Detailed Implementation

[0064] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0065] The signal acquisition system of the present invention can be considered as receiving signals unaffected by multipath interference by high-gain and accurate calibration measurement data. The complete software receiving system can accurately estimate and eliminate the Doppler frequency shift of the signal.

[0066] A software receiver is used to acquire and track the collected signals, while assuming the following conditions are met:

[0067] (1) The I / Q branches are completely separated, and the related outputs of the I / Q branches are uncorrelated;

[0068] (2) The combined effects of signal distortion and external noise will not cause loss of lock, and tracking jitter is negligible;

[0069] (3) Ignore the influence of the space transport layer in a short time and a small area.

[0070] Under the above assumptions, the actual received signal can be considered to be very close to the signal transmitted by the navigation payload.

[0071] This embodiment provides a navigation payload channel estimation method; please refer to [reference needed]. Figure 1 The flowchart shown illustrates the joint channel estimation algorithm. The navigation payload channel estimation method includes the following steps:

[0072] S100: The received signal is evaluated to determine the characteristics of the navigation payload transmission channel, which includes digital distortion and analog distortion.

[0073] S200: The received signal includes several single-branch signals. The single-branch signals are assumed to have infinite bandwidth, and the digital distortion values ​​between components are independent. The single-branch signals traverse all digital distortion settings to generate single-branch modulation signals, and the digital distortion values ​​of each single-branch signal are calculated in turn.

[0074] S300: Using the local ideal signal as a reference, each single-branch signal is modulated into a single-branch modulated signal containing digital distortion according to step S200, and the single-branch modulated signals are multiplexed to generate a combined signal containing digital distortion.

[0075] S400: Using the local ideal signal as a reference, the analog distortion characteristics are obtained based on the received signal and the combined signal.

[0076] Furthermore, the specific steps of the navigation payload channel estimation method are as follows:

[0077] Data is acquired through a signal acquisition system. A software receiver preprocesses the acquired data to obtain a continuous baseband signal. The continuous baseband signal is then averaged to reduce noise interference. The average value of the accumulated baseband signal is then calculated. :

[0078] in The number of sampling points. Here is the filter impulse response matrix. The filter order;

[0079] The digital distortion of a single branch signal is:

[0080]

[0081] in This represents the total number of signal branches;

[0082] No. The branch signal components are:

[0083]

[0084] Find the filter impulse response matrix Impact response:

[0085] remember For a single-branch input convolution matrix:

[0086] ;

[0087] The process involves generating a modulated signal from a single-branch signal through digital distortion and then calculating the digital distortion value. :

[0088]

[0089] in This refers to the filter's impulse response.

[0090] The analytical equations for the measured signal and the input convolution matrix are obtained as ideal base point digital distortion. :

[0091]

[0092] By digital distortion of ideal baseband signal Traversal and substitution to synthesize new multiplexed signals Obtain the digital distortion of the actual base point signal At this time, the input signal Includes digital distortion of the actual base point signal .

[0093] The signal evaluation based on the output signal and the local ideal signal specifically includes: obtaining the estimated value of the analog distortion channel characteristic response using the least squares method. :

[0094] .

[0095] Example 2:

[0096] To determine the characteristics of the navigation payload transmission channel based on the received signal through signal quality assessment, a signal distortion model is established to evaluate the signal quality of the received signal. The signal distortion model in this embodiment employs a navigation payload model, which is modeled as two parts: digital distortion and analog distortion. Digital distortion only introduces a time delay at the chip edges without altering the waveform, using the classic TMA model. Analog distortion acts entirely on the digital distortion. Due to the HPA pre-band-limited filtering, the analog distortion is equivalently modeled as an Nth-order impulse response FIR filter, with filter amplitude and group delay used to characterize the filter's properties.

[0097] This embodiment of a navigation payload channel model includes:

[0098] Digital distortion model is used to generate a modulated signal from a single-branch modulated signal through digital distortion;

[0099] Signal multiplexing models are used to synthesize multiplexed signals from modulated signals.

[0100] A simulated distortion model is used to simulate the distortion of multiplexed signals and generate output signals;

[0101] A signal evaluation model is used to evaluate the output signal against the local ideal signal.

[0102] Please refer to Figure 2The flowchart shown illustrates the method for establishing the navigation payload model. The establishment of the navigation payload channel model includes the following steps:

[0103] Several single-branch modulation signals Multiplexed signals are generated by signal multiplexing:

[0104]

[0105] in It is a single-branch modulated signal. For amplitude, For phase, For the intermodulation term, if the digital distortion between the signal branches is independent and not limited by bandwidth, then the multiplexed signal is rewritten as:

[0106]

[0107] in , , This refers to the spreading code rate, meaning that the digital distortion will not exceed the range of a complete chip.

[0108] The simulation is modeled as an Nth-order linear FIR filter; therefore, the simulated distorted signal is the convolution of the input signal and the channel impulse response.

[0109]

[0110] in This is the impulse response of the FIR filter. This is for convolution calculation.

[0111] Assuming all branches are completely separable, the simulated distortion of a single-branch signal is as follows:

[0112]

[0113] Correspondingly, the correlation with the local ideal signal is:

[0114] in The coherent integration time is typically set to one chip period. For the first Branch autocorrelation function, It is a conjugate matrix.

[0115] The nonlinearity of the navigation payload transmission channel is the result of the combined effects of digital and analog distortions. Both must be considered in the solution to accurately obtain the characteristics of the on-board transmitter channel.

[0116] Example 3:

[0117] This embodiment provides a computer-readable storage medium, characterized in that: the computer-readable storage medium stores a program, which, when executed by a processor, causes the processor to perform the steps of the method described in the above embodiment.

[0118] Example 4:

[0119] This embodiment provides a novel navigation load channel estimation device, including a processor and the aforementioned computer-readable storage medium.

[0120] Those skilled in the art will understand that the embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the embodiments of the present invention can take the form of entirely hardware embodiments, entirely software embodiments, or embodiments combining software and hardware aspects. Furthermore, the embodiments of the present invention can take the form of computer program products implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0121] Note that the above are merely preferred embodiments of the present invention and the technical principles employed.

[0122] Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A navigation payload channel estimation method, characterized in that, The method specifically includes the following steps: S100: The characteristics of the navigation payload transmission channel are obtained by the received signal through signal quality assessment. The characteristics of the navigation payload transmission channel include digital distortion and analog distortion. S200: The received signal includes several single-branch signals. The single-branch signal is assumed to have infinite bandwidth. The digital distortion between components is independent. The single-branch signal traverses all digital distortion settings to generate a single-branch modulation signal. The digital distortion value of each single-branch signal is obtained in turn. S300: Using the local ideal signal as a reference, each single-branch signal is modulated into a single-branch modulated signal containing digital distortion according to step S200, and each single-branch modulated signal is multiplexed to generate a combined signal containing digital distortion. S400: Using the local ideal signal as a reference, the analog distortion characteristics are determined based on the received signal and the combined signal. The specific steps for obtaining the simulated distortion characteristics are as follows: The acquired data is preprocessed using a software receiver to obtain a continuous baseband signal. The continuous baseband signals are then averaged to reduce noise interference. The average value of the accumulated baseband signals is then calculated. : ； ； in The number of sampling points. Here is the filter impulse response matrix. The filter order; The digital distortion of a single branch signal is: ； in This represents the total number of signal branches; No. The branch signal components are: ； Find the filter impulse response matrix Impact response: remember For a single-branch input convolution matrix: ； The single-branch signal is digitally distorted to generate a modulated signal, and the digital distortion value is calculated. : ； in This refers to the filter's impulse response. The analytical equations for the measured signal and the input convolution matrix are obtained as ideal base point digital distortion. : ； This represents the digital distortion of the single-branch signal component being solved. The input matrix; A new multiplexed signal is synthesized by back-substituting the digital distortion of the ideal baseband signal. Back-substitution synthesis of new multiplexed signals At this time, the input signal Includes digital distortion of the actual base point signal ; Obtain the estimated characteristic response of the simulated distortion channel. : 。 2. The navigation payload channel estimation method according to claim 1, characterized in that: The simulated distortion is transformed into an Nth-order FIR filter.

3. The navigation payload channel estimation method according to claim 1, characterized in that: The signal quality assessment for determining the characteristics of the navigation payload transmission channel involves using a signal distortion model to determine these characteristics.

4. The navigation payload channel estimation method according to claim 1, characterized in that: The received signal includes the acquired signal, which is obtained through a signal acquisition system.

5. A method for establishing a navigation payload channel model, characterized in that: The model includes: Digital distortion model is used to generate a modulated signal from a single-branch modulated signal through digital distortion; Signal multiplexing models are used to synthesize multiplexed signals from modulated signals. A simulated distortion model is used to simulate the distortion of multiplexed signals and generate output signals; A signal evaluation model is used to evaluate the output signal against a local ideal signal. The establishment of the navigation payload channel model includes the following steps: Several single-branch modulation signals Multiplexed signals are generated by signal multiplexing: ； in It is a single-branch modulated signal. For amplitude, For phase, For intermodulation terms; wherein, if the digital distortion between the single-branch modulated signals is independent and not limited by bandwidth, the multiplexed signal is rewritten as: ； in , , For spreading code rate; The simulation is modeled as an Nth-order linear FIR filter; therefore, the simulated distorted signal is the convolution of the input signal and the channel impulse response. ； in This is the impulse response of the FIR filter. For convolution calculation; The simulated distortion of a single-branch signal is as follows: ； The correlation with the local ideal signal is: ； ； in The coherent integration time is typically set to one chip period. For the first Branch autocorrelation function, It is a conjugate matrix.

6. The method for establishing the navigation payload channel model according to claim 5, characterized in that: The signal evaluation between the output signal and the local ideal signal includes performing an autocorrelation operation between the output signal and the local ideal signal.

7. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a program that, when executed by a processor, causes the processor to perform the steps of the method as described in any one of claims 1 to 4.

8. A navigation load channel estimation device, characterized in that, Includes the computer-readable storage medium and processor as described in claim 7.

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