A navigation enhancement performance verification system combining high, medium, and low orbits

Abstract

This invention discloses a navigation enhancement performance verification system integrating high, medium, and low orbit (LEO) orbits. The system includes: test control equipment, a satellite navigation signal simulation system, a general-purpose spectrum analyzer, a signal combiner, an RF data acquisition instrument, a DC regulated power supply, a high-stability clock, and several navigation monitoring receivers, a navigation enhancement payload, and a navigation enhancement transmitter. This test verification system is a hardware-in-the-loop (HIL) simulation test system. Focusing on the navigation enhancement payload and navigation monitoring receivers, the system can realize the verification of navigation enhancement performance integrating LEO, EEO, and LEO orbits, completing the testing and evaluation process of the integrated LEO, EEO, and LEO navigation enhancement system on the ground. This test verification system has a full-process closed-loop testing function, the testing method is simple and easy to implement, and it features low cost and high reliability.

Description

Technical Field

[0001] This invention belongs to the field of navigation enhancement technology, and specifically relates to a navigation enhancement performance verification system that combines high, medium and low orbits. Background Technology

[0002] Low-Earth orbit (LEO) satellite navigation augmentation technology, as an enhancement, backup, and supplement to GNSS (Global Navigation Satellite System) navigation, positioning, and timing, exhibits significant advantages such as high landing power, high accuracy, wide coverage, anti-interference, and high reliability, and has very broad application prospects in military, civilian, and commercial fields. LEO satellites, equipped with high-precision medium- and high-orbit navigation monitoring receivers, generate time-frequency reference signals compliant with the medium- and high-orbit navigation system and achieve high-precision positioning / orbit determination. The acquired raw observations are transmitted to the ground via inter-satellite / satellite-to-ground links. The navigation augmentation payload receives the navigation augmentation information transmitted from the ground via inter-satellite / satellite-to-ground links, enabling the broadcasting of ranging signals and precise ephemeris.

[0003] Traditional GNSS satellite navigation systems based on medium and high Earth orbits (MEO) have evolved into large and complex integrated high-medium-low Earth orbit (HEO) navigation augmentation systems after the addition of low-Earth orbit (LEO) navigation constellations. Since the LEO-based satellite navigation monitoring receiver and navigation augmentation payload are core components of the LEO navigation constellation and the entire integrated HEO-HEO navigation augmentation system, thorough hardware-in-the-loop (HEO-H) ​​simulations and experimental verification are necessary on the ground around the navigation augmentation payload and navigation monitoring receiver. This allows for a systematic, comprehensive, and thorough verification and evaluation of the key functions and technologies of the entire integrated HEO-HEO navigation augmentation system. Therefore, exploring a ground-based verification system for the navigation augmentation performance of integrated HEO-HEO systems is crucial for the construction of such systems. Summary of the Invention

[0004] The purpose of this invention is to provide a navigation enhancement performance verification system that integrates high, medium, and low orbit (LEO) orbits. This system utilizes a hardware-in-the-loop (HIL) simulation of the navigation enhancement payload and navigation monitoring receiver. Through performance verification of the basic functions of the navigation enhancement system, the GNSS positioning / orbit determination function of the spaceborne navigation monitoring receiver, the generation and broadcasting of LEO navigation enhancement signals, the precise orbit determination function integrating high, medium, and low orbits, ground-based precise point positioning, software reconfiguration, and time synchronization, the system achieves navigation enhancement performance verification for the integrated high, medium, and low orbit systems. The testing and evaluation process of the integrated high, medium, and low orbit navigation enhancement system is then completed on the ground.

[0005] A navigation enhancement performance verification system combining high, medium, and low orbits includes: test control equipment, a satellite navigation signal simulation system, a general spectrum analyzer, a signal combiner, a radio frequency data acquisition instrument, a DC regulated power supply, a high-stability clock, and several navigation monitoring receivers, navigation enhancement payloads, and navigation enhancement transmitters;

[0006] The satellite navigation signal simulation system is used to simulate navigation signals played by GNSS satellite navigation systems in both low-Earth orbit (LEO) and ground-based scenarios, and output reference second pulse signals, according to the control commands issued by the test control equipment. The navigation monitoring receiver receives the simulated LEO scenario GNSS satellite navigation signals to achieve functions such as positioning / orbit determination, velocity measurement, and time synchronization. The navigation enhancement payload receives navigation enhancement information from the test control equipment, completes data encoding and framing, and performs signal modulation to generate a LEO navigation enhancement radio frequency signal. After amplification and filtering by the navigation enhancement transmitter, the signal is output to the signal combiner. Simultaneously, the navigation enhancement payload receives the second pulse signal output by the navigation monitoring receiver. The system performs time-frequency calibration by combining the pulse signal and time information. The signal combiner combines the low-orbit navigation enhancement radio frequency signals output by multiple navigation enhancement transmitters and the ground scene GNSS navigation radio frequency signals simulated by the satellite navigation signal simulation system into one channel. The radio frequency data acquisition instrument acquires the combined signal, and the general spectrum analyzer performs spectrum and power analysis on it. The test control equipment issues control command signals, provides navigation enhancement information and reconstruction data, and completes the acquisition, reception and processing of test results. The DC regulated power supply provides power to the navigation enhancement payload and the navigation monitoring receiver, and the high-stability clock provides a unified time-frequency reference for the entire system.

[0007] Furthermore, the satellite navigation signal simulation system is used to simulate GNSS satellite navigation signals received by the navigation receiver under different scenarios based on the control commands issued by the test control equipment and GNSS precise ephemeris information; by generating trajectory, coordinate and other parameter information corresponding to the scenario to be simulated, the corresponding navigation message, pseudocode and carrier are generated, and then the generated navigation message is spread spectrum modulation and carrier modulation, and after digital-to-analog conversion, filtering and up-conversion, the simulated satellite navigation signal is finally formed.

[0008] Furthermore, the scenarios to be simulated in this system include low-Earth orbit (LEO) satellite scenarios and ground scenarios. When simulating LEO scenarios, the system simulates the GNSS satellite navigation signals received by the navigation monitoring receiver on the LEO satellite platform based on the orbital parameter information during the LEO satellite platform's motion. It also supports the simultaneous simulation of GNSS signals received by the onboard receiver in scenarios with multiple LEO satellites. When simulating ground scenarios, the system simulates the GNSS satellite navigation signals received by the receiver at the ground coordinates.

[0009] Furthermore, the test control equipment adopts a modular design, including a communication control unit, a data acquisition unit, a navigation signal processing unit, and an analysis and reporting unit. The communication control unit includes a simulation system communication control module, an augmentation payload communication control module, and a monitoring receiver communication control module. The simulator communication control module issues control commands to the satellite navigation signal simulation system and provides GNSS precise ephemeris information. The augmentation payload communication control module issues control commands, navigation augmentation information, and reconstruction commands and data to the navigation augmentation payload. The monitoring receiver communication control module issues control commands, reconstruction commands, and data to the navigation monitoring receiver. The data acquisition unit includes a simulation system data acquisition module, a monitoring receiver data acquisition module, and a radio frequency (RF) data acquisition module. The simulation system data acquisition module acquires satellite navigation simulation trajectory data and reference second pulses from the satellite navigation signal simulation system. The monitoring receiver data acquisition module receives raw observations, positioning / orbit determination, velocity measurement results, and second pulses from the navigation monitoring receiver. The RF data acquisition module receives navigation RF combined signal acquisition data from the RF data acquisition instrument and performs digital signal down-conversion. The navigation signal processing unit receives navigation RF combined signal acquisition data to realize navigation... The signal software receiver function includes an acquisition module, a tracking processing module, a navigation message parsing module, a positioning observation calculation module, an orbit determination module, a precise single-point positioning module, and a second pulse generation module. The acquisition module receives the down-converted intermediate frequency (IF) signal from the RF data acquisition module of the data acquisition unit, performs rapid search and acquisition of the Doppler frequency and pseudo-code phase of the digital IF signal, and outputs the acquisition results to the tracking processing module. The tracking processing module tracks the signal, obtains code observations, carrier observations, and correlation integral values ​​for each channel. The navigation message parsing module uses the tracking processing results to decode the navigation message, obtaining time, satellite orbit parameters, etc. The observation calculation module, based on the tracking processing results and the time information and correction parameter information in the navigation message, completes the calculation of pseudorange and Doppler for each satellite. The orbit determination module acquires the original observation and ephemeris information of GNSS and low-Earth orbit navigation signals respectively, and combines the original observation and ephemeris information transmitted from the navigation monitoring receiver to complete the high, medium and low-Earth orbit joint precision orbit determination. The precision point positioning module obtains the precision point positioning solution results by using the observation data of GNSS and low-Earth orbit precision satellite orbits, precision satellite clock error corrections and carrier phases. The second pulse generation module corrects the local clock and outputs the second pulse based on the time and observation information.The analysis and reporting unit performs statistical analysis based on the data collected by the data acquisition unit and the results processed by the signal processing unit. This includes a time consistency analysis module, a monitoring receiver performance analysis module, a navigation enhancement signal quality analysis module, an orbit determination accuracy analysis module, and a precise point positioning performance analysis module. The time consistency analysis module compares and analyzes the second pulses generated by the satellite navigation signal simulation system, the several navigation monitoring receivers, and the second pulse generation module of the navigation signal processing unit. The monitoring receiver performance analysis module parses the data transmitted from the satellite navigation signal simulation system and the navigation monitoring receivers, compares the simulated values ​​of the simulation system with the measured values ​​of the receivers, analyzes the loop state of the navigation monitoring receiver, and calculates its original observation accuracy, positioning / orbit determination accuracy, and velocity measurement accuracy. The navigation enhancement signal quality analysis module analyzes the quality of the low-orbit navigation enhancement signal generated and broadcast by the navigation enhancement payload using the navigation signal processing results. The orbit determination accuracy analysis module performs joint analysis and comparison of the high, medium, and low-orbit combined precise orbit determination results and the orbit determination results of the navigation monitoring receivers. The precise point positioning performance analysis module performs statistical analysis on the initial convergence time and positioning accuracy of precise point positioning.

[0010] During the software reconfiguration function verification test, the software data to be reconfigured is imported into the test control device, and the communication control unit sends software reconfiguration instructions and data to the navigation enhancement payload and navigation monitoring receiver according to the pre-agreed transmission protocol format.

[0011] During the time synchronization function verification test, the data acquisition unit of the test control equipment obtains the reference second pulse signal from the satellite navigation signal simulation system and receives the second pulse signals generated by the several navigation monitoring receivers. At the same time, the navigation signal processing unit generates the second pulse signal. The data acquisition unit and the navigation signal processing unit transmit the above-mentioned multiple second pulse signals to the analysis and reporting unit for statistical analysis of their time consistency.

[0012] During the GNSS positioning / orbit determination function verification test of the navigation monitoring receiver, the satellite navigation signal simulation system selects several low-orbit satellites according to the control commands issued by the communication control unit of the test control equipment. Based on the corresponding orbital parameter information, it generates simulated satellite navigation signals and sends them to the navigation monitoring receivers. Simultaneously, the satellite navigation signal simulation system reports the trajectory parameter information of the aforementioned low-orbit satellites to the data acquisition unit of the test control equipment. The data acquisition unit simultaneously receives real-time measurement data and ephemeris data from the navigation monitoring receivers, acquires and stores the data through a high-speed interface, and sends it to the analysis and reporting unit for data parsing. The simulated values ​​from the simulator are compared with the actual measured values ​​from the receivers, and the loop state of the navigation monitoring receiver is analyzed to calculate its original observation accuracy, positioning / orbit determination accuracy, and velocity measurement accuracy.

[0013] During the verification test of the low-Earth orbit (LEO) navigation enhancement signal generation and broadcasting function, the communication control unit transmits the enhanced information, such as the precise ephemeris data of several LEO satellites, to the several navigation enhancement payloads according to a pre-agreed transmission protocol format. The signal combiner combines the LEO navigation enhancement radio frequency signals output by the several navigation enhancement transmitters into one channel. The radio frequency data acquisition instrument acquires the combined signal and transmits it to the data acquisition unit of the test control equipment. Simultaneously, the general-purpose spectrum analyzer performs spectrum and power analysis on the combined signal. The navigation signal processing unit of the test control equipment then uses the frequency point, bandwidth, and other parameters measured by the general-purpose spectrum analyzer... Local carrier and local pseudocode are generated separately, and matched with the navigation enhancement radio frequency combined data for correlation calculation. The carrier Doppler frequency and code phase of the navigation enhancement signal are calculated, and the navigation message is acquired. The positioning solution is completed, and the result is sent to the analysis and reporting unit. The analysis and reporting unit evaluates the acquired observations, ephemeris, and positioning results based on the enhancement information such as the low-orbit satellite precise ephemeris provided by the communication control unit, thereby analyzing the quality of the low-orbit navigation enhancement signal generated and broadcast by the navigation enhancement payload. To ensure that the navigation signal processing unit can achieve positioning solution, there should be no fewer than four navigation enhancement payloads and navigation enhancement transmitters.

[0014] During the verification test of the high-low orbit joint orbit determination function, the navigation enhancement payloads output low-orbit navigation enhancement radio frequency signals through the navigation enhancement transmitter. Simultaneously, the satellite navigation signal simulation system simulates GNSS satellite navigation signals received by the receiver in a ground scenario. The signal combiner combines these signals into one, which is then acquired by the radio frequency data acquisition instrument and transmitted to the data acquisition unit of the test control equipment. The navigation signal processing unit performs acquisition, tracking, and other processing on the acquired navigation signal data, obtaining the raw observation and ephemeris information for both GNSS and low-orbit navigation signals. Combined with the raw observation and ephemeris information transmitted from the navigation monitoring receiver, the high-low orbit joint precision orbit determination is completed, and the orbit determination result is sent to the analysis and reporting unit. The analysis and reporting unit performs a joint analysis of the high-low orbit joint precision orbit determination result and the orbit determination result from the navigation monitoring receiver. To ensure the accuracy of the high-low orbit joint orbit determination, the number of navigation enhancement payloads, navigation enhancement transmitters, and navigation monitoring receivers participating in the orbit determination system should be no less than four each. Furthermore, the accuracy of the high-low orbit joint orbit determination can be compared and analyzed under different numbers of navigation enhancement payloads, navigation enhancement transmitters, and navigation monitoring receivers.

[0015] During the verification test of precise point positioning function, the data acquisition unit of the test control equipment receives GNSS and LOR navigation combined signal acquisition data. The navigation signal processing unit performs acquisition, tracking and other processing on the acquired navigation signal data, and obtains the original observation and ephemeris data of GNSS and LOR navigation signals respectively. Using the precise satellite orbit, precise satellite clock error correction and carrier phase observation data, it performs high, medium and low orbit joint positioning calculation, and sends the results to the analysis and reporting unit to analyze the initial convergence time and positioning accuracy of precise point positioning. To ensure the accuracy of precise point positioning, the navigation enhancement payload and navigation enhancement transmitter participating in the generation of navigation combined signals should each be no less than four. At the same time, the performance of precise point positioning can be compared and analyzed under different numbers of navigation enhancement payloads and transmitters.

[0016] The present invention adopts the above technical solution and has the following beneficial effects:

[0017] This invention provides a navigation enhancement performance verification system integrating high, medium, and low orbit (LEO) orbits. The experimental verification system utilizes hardware-in-the-loop (HIL) simulations of the navigation enhancement payload and navigation monitoring receiver to conduct thorough ground-based testing and verification of the entire system. Through performance verification of the basic functions of the navigation enhancement system, the GNSS positioning / orbit determination function of the spaceborne navigation monitoring receiver, the generation and broadcasting of LEO navigation enhancement signals, the precise orbit determination function integrating high, medium, and low orbits, precise ground-based point positioning, software reconfiguration, and time synchronization, the system verifies and evaluates the key functions and technologies of integrated high, medium, and low orbit navigation enhancement. This experimental verification system features a full-process closed-loop testing capability, a systematic, comprehensive, and thorough testing process, and simple and easy-to-implement testing methods, characterized by low cost and high reliability. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structural composition of a navigation enhancement performance verification system combining high, medium, and low orbits according to an embodiment of the present invention.

[0019] Figure 2 This is a schematic diagram of the structural composition of a test control device according to an embodiment of the present invention. Detailed Implementation

[0020] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The advantages and features of the present invention will become clearer from the following description and claims. It should be noted that the drawings are all in a very simplified form and are not to a precise scale, and are only used to facilitate and clarify the illustration of the embodiments of the present invention.

[0021] It should be noted that, in order to clearly illustrate the content of this invention, several embodiments are provided to further explain different implementations of the invention. These embodiments are enumerated rather than exhaustive. Furthermore, for the sake of brevity, content mentioned in the preceding embodiments is often omitted in the following embodiments. Therefore, content not mentioned in the later embodiments can be referred to in the preceding embodiments.

[0022] like Figure 1 As shown, a navigation enhancement performance verification system combining high, medium, and low orbits is presented, including: test control equipment, a satellite navigation signal simulation system, a general spectrum analyzer, a signal combiner, an RF data acquisition instrument, a DC regulated power supply, a high-stability clock, a time interval counter, and several navigation monitoring receivers, navigation enhancement payloads, and navigation enhancement transmitters. The system verifies the navigation enhancement performance of the high, medium, and low orbits by verifying the basic functions of the navigation enhancement system, the GNSS positioning / orbit determination function of the satellite-borne navigation monitoring receiver, the generation and broadcasting function of low orbit navigation enhancement signals, the precise orbit determination function combining high, medium, and low orbits, the precise single-point positioning on the ground, the software reconstruction function, and the time synchronization function.

[0023] The satellite navigation signal simulation system is interconnected with the navigation monitoring receiver to send the navigation signals simulated by the GNSS satellite navigation system to the navigation monitoring receiver. The test control equipment is interconnected with multiple navigation monitoring receivers, serving two purposes: firstly, to issue control commands and provide reconstruction data to each receiver; and secondly, to receive and collect real-time measurement data, ephemeris data, and second pulses from each receiver. The test control equipment is interconnected with multiple navigation enhancement payloads, issuing control commands and providing ephemeris data and other navigation enhancement information and reconstruction data. The navigation enhancement payloads are interconnected with the navigation monitoring receiver to receive the second pulse signal and time information output by the receiver for time-frequency calibration. The navigation enhancement payloads are interconnected with the navigation enhancement transmitter to output navigation enhancement radio frequency signals. A signal combiner is connected to multiple navigation... The enhanced transmitter and the satellite navigation signal simulation system are interconnected to combine multiple radio frequency signals into one. The radio frequency data acquisition instrument and the signal combiner are interconnected to acquire the combined navigation radio frequency signal. The general spectrum analyzer and the signal combiner are interconnected for spectrum and power analysis. The satellite navigation signal simulation system is interconnected with the test control equipment. On the one hand, the test control equipment issues control commands to the satellite navigation signal simulation system and provides precise ephemeris. On the other hand, the satellite navigation signal simulation system reports simulated satellite navigation signal data, trajectory parameter information, and reference second pulses to the test control equipment. The DC regulated power supply is interconnected with multiple navigation enhancement payloads and navigation monitoring receivers for power supply. The high-stability clock is interconnected with multiple navigation enhancement payloads, navigation monitoring receivers, the satellite navigation signal simulation system, the radio frequency data acquisition instrument, the general spectrum analyzer, and the test control equipment to provide a unified time and frequency reference for the entire system.

[0024] like Figure 2As shown, the test control equipment adopts a modular design, further including a communication control unit, a data acquisition unit, a navigation signal processing unit, and an analysis and reporting unit. The communication control unit includes a simulation system communication control module, an augmentation payload communication control module, and a monitoring receiver communication control module. The simulation system communication control module issues control commands to the satellite navigation signal simulation system and provides GNSS precise ephemeris information. The augmentation payload communication control module issues control commands, navigation augmentation information, and reconstruction commands and data to the navigation augmentation payload. The monitoring receiver communication control module issues control commands, reconstruction commands, and data to the navigation monitoring receiver. The data acquisition unit includes a simulation system data acquisition module, a monitoring receiver data acquisition module, and a radio frequency (RF) data acquisition module. The simulator data acquisition module acquires satellite navigation simulation trajectory data and reference second pulses from the satellite navigation signal simulation system. The monitoring receiver data acquisition module receives raw observations, positioning / orbit determination, velocity measurement results, and second pulses from the navigation monitoring receiver. The RF data acquisition module receives navigation RF combined signal acquisition data from the RF data acquisition instrument and performs digital signal down-conversion. The navigation signal processing unit receives navigation RF combined signal acquisition data and realizes navigation signal software reception. The system includes a capture module, a tracking and processing module, a navigation message parsing module, a positioning observation calculation module, an orbit determination module, a precise point positioning module, and a second pulse generation module. The capture module receives the down-converted intermediate frequency (IF) signal from the RF data acquisition module of the data acquisition unit, performs rapid search and capture of the Doppler frequency and pseudocode phase of the digital IF signal, and outputs the capture results to the tracking and processing module. The tracking and processing module tracks the signal, obtaining code observations, carrier observations, and correlation integral values ​​for each channel. The navigation message parsing module uses the tracking and processing results to decode the navigation message, obtaining time, satellite orbit parameters, and correction parameters. The observation and calculation module calculates the pseudorange and Doppler of each satellite based on the tracking and processing results, combined with the time information and correction parameters in the navigation message. The orbit determination module acquires the original observation and ephemeris information of GNSS and low-Earth orbit navigation signals, and combines the original observation and ephemeris information from the navigation monitoring receiver to complete the high, medium and low-Earth orbit joint precision orbit determination. The precision point positioning module obtains the precision point positioning solution results by using the observation data of GNSS and low-Earth orbit precision satellite orbits, precision satellite clock error corrections and carrier phase. The second pulse generation module corrects the local clock based on time and observation information and outputs the second pulse.The analysis and reporting unit performs statistical analysis based on the data acquired by the data acquisition unit and the results processed by the signal processing unit. This includes a time consistency analysis module, a monitoring receiver performance analysis module, a navigation enhancement signal quality analysis module, an orbit determination accuracy analysis module, and a precise point positioning performance analysis module. The time consistency analysis module compares and analyzes the second pulses generated by the satellite navigation signal simulation system, several navigation monitoring receivers, and the second pulse generation module of the navigation signal processing unit. The monitoring receiver performance analysis module parses the data transmitted from the satellite navigation signal simulation system and the navigation monitoring receivers, compares the simulated values ​​from the simulator with the measured values ​​from the receivers, analyzes the loop state of the navigation monitoring receiver, and calculates its original observation accuracy, positioning / orbit determination accuracy, and velocity measurement accuracy. The navigation enhancement signal quality analysis module analyzes the quality of the low-orbit navigation enhancement signal generated and broadcast by the navigation enhancement payload using the navigation signal processing results. The orbit determination accuracy analysis module performs joint analysis and comparison of the high, medium, and low-orbit combined precise orbit determination results and the orbit determination results from the navigation monitoring receiver. The precise point positioning performance analysis module performs statistical analysis on the initial convergence time and positioning accuracy of precise point positioning.

[0025] The satellite navigation signal simulation system can simulate GNSS satellite navigation signals received by navigation receivers under different scenarios based on the control commands issued by the test control equipment and GNSS precise ephemeris information. The scenarios to be simulated in this system include low-Earth orbit (LEO) satellite scenarios and ground scenarios. By generating trajectory, coordinate, and other parameter information corresponding to the scenario to be simulated, corresponding navigation messages, pseudocodes, and carrier waves are generated. The generated navigation messages are then subjected to spread spectrum modulation and carrier modulation, followed by digital-to-analog conversion, filtering, and up-conversion to finally form the simulated satellite navigation signal. When simulating LEO scenarios, the system simulates the GNSS satellite navigation signals received by the navigation monitoring receiver on the LEO satellite platform based on the orbital parameter information of the LEO satellite platform's motion process. It also supports the simultaneous simulation of GNSS signals received by onboard receivers in scenarios with multiple LEO satellites. When simulating ground scenarios, the system simulates the GNSS satellite navigation signals received by the receiver at the specified ground coordinates.

[0026] During the software reconfiguration function verification test, the software data to be reconfigured is imported into the test control equipment. The communication control unit sends software reconfiguration instructions and data to the navigation enhancement payload and navigation monitoring receiver according to the pre-agreed transmission protocol format.

[0027] During the time synchronization function verification test, the data acquisition unit of the test control equipment obtains the reference second pulse signal from the satellite navigation signal simulation system and receives the second pulse signals generated by several navigation monitoring receivers. At the same time, the navigation signal processing unit generates the second pulse signal. The data acquisition unit and the navigation signal processing unit transmit the above-mentioned multiple second pulse signals to the analysis and reporting unit for statistical analysis of their time consistency.

[0028] During the GNSS positioning / orbit determination function verification test of the navigation monitoring receiver, the satellite navigation signal simulation system selects several low-orbit satellites according to the control commands issued by the communication control unit of the test control equipment. Based on the corresponding orbital parameter information, it generates simulated satellite navigation signals and sends them to several navigation monitoring receivers. At the same time, the satellite navigation signal simulation system reports the trajectory parameter information of the aforementioned low-orbit satellites to the data acquisition unit of the test control equipment. The data acquisition unit simultaneously receives real-time measurement data and ephemeris data from several navigation monitoring receivers, acquires and stores the data through a high-speed interface, and sends it to the analysis report unit for data parsing. The simulated values ​​of the simulation system are compared with the actual measured values ​​of the receivers, and the loop state of the navigation monitoring receivers is analyzed to calculate their original observation accuracy, positioning / orbit determination accuracy, and velocity measurement accuracy.

[0029] During the verification test of the low-Earth orbit (LEO) navigation enhancement signal generation and broadcasting function, the communication control unit transmits the enhanced information, such as the precise ephemeris data of several LEO satellites, to several navigation enhancement payloads according to a pre-agreed transmission protocol format. The signal combiner combines the LEO navigation enhancement radio frequency signals output from several navigation enhancement transmitters into one signal. The radio frequency data acquisition instrument acquires this combined signal and transmits it to the data acquisition unit of the test control equipment. Simultaneously, a general-purpose spectrum analyzer performs spectrum and power analysis on this signal. The navigation signal processing unit of the test control equipment then uses the frequency points, bandwidth, etc., measured by the general-purpose spectrum analyzer... The parameters are used to generate local carrier and local pseudocode, which are then matched and correlated with the navigation enhancement radio frequency combined data to calculate the carrier Doppler frequency and code phase of the navigation enhancement signal, and to obtain the navigation message. The positioning solution is then completed, and the results are sent to the analysis and reporting unit. The analysis and reporting unit evaluates the results based on the enhancement information such as the low-orbit satellite precise ephemeris provided by the communication control unit, thereby analyzing the quality of the low-orbit navigation enhancement signal generated and broadcast by the navigation enhancement payload. To ensure that the navigation signal processing unit can achieve positioning solution, there should be no fewer than four navigation enhancement payloads and navigation enhancement transmitters.

[0030] During the verification test of the high-low orbit joint precision orbit determination function, several navigation enhancement payloads output low-orbit navigation enhancement radio frequency signals through the navigation enhancement transmitter. Simultaneously, a satellite navigation signal simulation system simulates GNSS satellite navigation signals received by a receiver in a ground-based scenario. A signal combiner combines these signals into one, which is then acquired by a radio frequency data acquisition instrument and transmitted to the data acquisition unit of the test control equipment. The navigation signal processing unit performs acquisition, tracking, and other processing on the acquired navigation signal data, obtaining raw observation and ephemeris information for both GNSS and low-orbit navigation signals. Combined with the raw observation and ephemeris information from the navigation monitoring receiver, the high-low orbit joint precision orbit determination is completed, and the orbit determination result is sent to the analysis and reporting unit. The analysis and reporting unit performs a joint analysis of the high-low orbit joint precision orbit determination result and the navigation monitoring receiver orbit determination result. To ensure the accuracy of the high-low orbit joint orbit determination, the number of navigation enhancement payloads, navigation enhancement transmitters, and navigation monitoring receivers participating in the orbit determination system should be no less than four each. Furthermore, the accuracy of the high-low orbit joint orbit determination can be compared and analyzed under different numbers of navigation enhancement payloads, navigation enhancement transmitters, and navigation monitoring receivers.

[0031] During the verification test of precise point positioning function, the data acquisition unit of the test control equipment receives GNSS and LOR navigation combined signal acquisition data. The navigation signal processing unit performs acquisition, tracking and other processing on the acquired navigation signal data, and obtains the original observation and ephemeris data of GNSS and LOR navigation signals respectively. Using the precise satellite orbit, precise satellite clock error correction and carrier phase observation data, the high, medium and low orbit joint positioning solution is performed, and the results are sent to the analysis report unit to analyze the initial convergence time and positioning accuracy of precise point positioning. In order to ensure the accuracy of precise point positioning, the navigation enhancement payload and navigation enhancement transmitter participating in the generation of navigation combined signal should each be no less than four. At the same time, the performance of precise point positioning under different numbers of navigation enhancement payloads and transmitters can be compared and analyzed.

[0032] Through the above specific process, a ground verification system for the combined high, medium, and low orbit navigation enhancement performance was realized. The system verifies and evaluates the key functions and technologies of the combined high, medium, and low orbit navigation enhancement on the ground. The system has the function of full-process closed-loop testing. The testing and verification process is systematic, comprehensive, and thorough. The testing method is simple and easy to implement, and it has the characteristics of low cost and high reliability.

[0033] While this invention can be extended in various ways through modifications and substitutions, and the specification lists and elaborates on several specific embodiments, it should be understood that the inventors' intention was not to limit the invention to the specific embodiments described. Those skilled in the art can make several non-essential improvements and adjustments without departing from the concept of this invention, and these all fall within the scope of protection of this invention. The scope of protection of this patent should be determined by the appended claims.

Claims

1. A navigation performance verification system of high, medium and low orbit combination, characterized in that, The system comprises a test control device, a satellite navigation signal simulation system, a general spectrum analyzer, a signal combiner, a radio frequency data collector, a direct current voltage stabilizer, a high-stability clock, and a plurality of navigation monitoring receivers, a navigation enhancement load, and a navigation enhancement transmitter; The satellite navigation signal simulation system is configured to simulate navigation signals broadcast by a GNSS satellite navigation system in a low-orbit scenario and a ground scenario and output a reference second pulse signal simultaneously according to a control instruction issued by the test control device; The navigation enhancement load receives navigation enhancement information transmitted by the test control device, encodes and frames data, and modulates signals to generate low-orbit navigation enhancement radio frequency signals, which are amplified and filtered by the navigation enhancement transmitter and output to the signal combiner. The signal combiner is configured to combine the low-orbit navigation enhancement radio frequency signals output by the navigation enhancement transmitter and the ground scenario GNSS navigation radio frequency signals simulated by the satellite navigation signal simulation system into one signal, which is collected by the radio frequency data collector and analyzed in terms of spectrum and power by the general spectrum analyzer. The test control device is configured to issue a control instruction signal, provide navigation enhancement information and reconstruction data, and collect, receive, and process test results. The direct current voltage stabilizer provides power supply for the navigation enhancement load and the navigation monitoring receivers, and the high-stability clock provides a unified time-frequency reference for the entire system.

2. The high-low earth orbit combined navigation augmentation performance verification system of claim 1, wherein, The satellite navigation signal simulation system is configured to simulate GNSS satellite navigation signals received by a navigation receiver in different scenarios according to GNSS precise ephemeris information according to a control instruction issued by the test control device. The satellite navigation signal simulation system is specifically configured to generate corresponding navigation messages, pseudorandom codes, and carriers by generating trajectory and coordinate parameter information corresponding to a to-be-simulated scenario, and then perform spread spectrum modulation and carrier modulation on the generated navigation messages, perform digital-to-analog conversion, filtering, and up-conversion, and finally form simulated satellite navigation signals.

3. The high-low earth orbit combined navigation augmentation performance verification system of claim 2, wherein, The to-be-simulated scenarios include low-orbit satellite scenarios and ground scenarios. In the simulation of a low-orbit satellite scenario, the satellite navigation signal simulation system is specifically configured to simulate GNSS satellite navigation signals received by a navigation monitoring receiver carried by a low-orbit satellite platform according to orbit parameter information of the motion process of the low-orbit satellite platform, and support simultaneous simulation of GNSS signals received by a spaceborne receiver in a plurality of low-orbit satellite scenarios. In the simulation of a ground scenario, the satellite navigation signal simulation system is specifically configured to simulate GNSS satellite navigation signals received by a receiver at a coordinate according to the coordinate.

4. The navigation augmentation performance verification system of any one of claims 1 to 3, wherein The test control device comprises a communication control unit, a data collection unit, a navigation signal processing unit, and an analysis report unit. The communication control unit comprises an analog system communication control module, an enhanced load communication control module and a monitoring receiver communication control module, the analog system communication control module is used to issue control instructions to the satellite navigation signal analog system and provide GNSS precise ephemeris information, the enhanced load communication control module is used to issue control instructions, navigation enhancement information and reconstruction instructions and data to the navigation enhanced load, and the monitoring receiver communication control module is used to issue control instructions and reconstruction instructions and data to the navigation monitoring receiver; The data acquisition unit comprises an analog system data acquisition module, a monitoring receiver data acquisition module and a radio frequency data acquisition module, the analog system data acquisition module is used to acquire satellite navigation analog trajectory data and reference second pulses from the satellite navigation signal analog system, the monitoring receiver data acquisition module is used to receive original observation data and positioning / orbiting, velocity measurement result related data and second pulses from the navigation monitoring receiver, and the radio frequency data acquisition module is used to receive navigation radio frequency combined signal acquisition data from the radio frequency data acquisition instrument and complete digital signal down conversion; The navigation signal processing unit receives navigation radio frequency combined signal acquisition data, realizes the function of a navigation signal software receiver, and comprises an acquisition module, a tracking processing module, a navigation message analysis module, a positioning observation calculation module, an orbiting module, a precise point positioning module and a second pulse generation module, the acquisition module receives intermediate frequency signals after down conversion of the radio frequency data acquisition module of the data acquisition unit, completes fast search and acquisition of digital intermediate frequency signal Doppler frequency and pseudo code phase, and outputs the acquisition result to the tracking processing module, the tracking processing module completes signal tracking, obtains code observation, carrier observation and related integral values of each channel, the navigation message analysis module uses tracking processing results to complete decoding of navigation messages, obtains time, satellite orbit parameter and correction parameter information, the observation calculation module calculates satellite pseudo distances and Dopplers according to tracking processing results and in combination with time information and correction parameter information in navigation messages, the orbiting module respectively acquires original observation data and ephemeris information of GNSS and low orbit navigation signals, simultaneously combines original observation data and ephemeris information transmitted by the navigation monitoring receiver, completes high, medium and low joint precise orbiting, the precise point positioning module uses precise satellite orbit, precise satellite clock correction number and carrier phase observation data of GNSS and low orbit to obtain precise point positioning calculation results, and the second pulse generation module corrects a local clock according to time and observation information and outputs second pulses. The analysis reporting unit carries out statistical analysis according to the data collected by the data collection unit and the results processed by the signal processing unit, including a time consistency analysis module, a monitoring receiver performance analysis module, a navigation enhancement signal quality analysis module, an orbit determination accuracy analysis module and a precise point positioning performance analysis module. The time consistency analysis module is used to compare and analyze the second pulses generated by the satellite navigation signal simulation system, the navigation monitoring receivers and the navigation signal processing unit second pulse generation module respectively. The monitoring receiver performance analysis module analyzes the data transmitted by the satellite navigation signal simulation system and the navigation monitoring receivers, compares the simulation values of the simulator with the measured values of the receivers, analyzes the loop state of the navigation monitoring receivers, calculates the original observation accuracy, positioning / orbit determination accuracy and velocity measurement accuracy, and analyzes the low-orbit navigation enhancement signal quality generated by the navigation enhancement payload according to the navigation signal processing results. The orbit determination accuracy analysis module jointly analyzes and compares the high-mid-low joint precise orbit determination results and the navigation monitoring receiver orbit determination results. The precise point positioning performance analysis module is used to complete the statistical analysis of the precise point positioning initialization convergence time and positioning accuracy.

5. The high-mid-low orbit joint navigation enhancement performance verification system of claim 4, wherein: When performing software reconstruction function verification testing, the software data to be reconstructed is first imported into the test control device, and then the communication control unit sends software reconstruction instructions and data to the navigation enhancement payload and navigation monitoring receivers according to the pre-agreed transmission protocol format.

6. The high-mid-low orbit joint navigation enhancement performance verification system of claim 4, wherein: When performing time synchronization function verification testing, the data collection unit of the test control device obtains reference second pulse signals from the satellite navigation signal simulation system and receives second pulse signals generated by the navigation monitoring receivers. At the same time, the navigation signal processing unit generates second pulse signals, and the data collection unit and the navigation signal processing unit transmit the above-mentioned multiple second pulse signals to the analysis reporting unit for statistical analysis of their time consistency.

7. The high-mid-low orbit joint navigation enhancement performance verification system of claim 4, wherein: In the navigation monitoring receiver GNSS positioning / orbiting function verification test, the satellite navigation signal simulation system selects several low-orbit satellites according to the control instructions from the test control device communication control unit, generates simulated satellite navigation signals according to the corresponding orbit parameter information, and sends them to the several navigation monitoring receivers. At the same time, the satellite navigation signal simulation system reports the trajectory parameter information of the several low-orbit satellites to the data acquisition unit of the test control device. The data acquisition unit receives real-time measurement data and ephemeris data from the several navigation monitoring receivers, collects and stores the data through a high-speed interface, and sends them to the analysis report unit for data analysis. The simulated values of the simulation system and the measured values of the receiver are compared, and the loop state of the navigation monitoring receiver is analyzed to calculate the original observation accuracy, positioning / orbiting accuracy, and velocity measurement accuracy.

8. The high-mid-low orbit combined navigation enhancement performance verification system of claim 4, wherein: In the low-orbit navigation enhancement signal generation and broadcast function verification test, the communication control unit transmits the navigation enhancement precise ephemeris enhancement information of several low-orbit satellites to the several navigation enhancement loads according to the pre-agreed transmission protocol format; The signal combiner combines the low-orbit navigation enhancement radio frequency signals output by the several navigation enhancement transmitters into one, and the radio frequency data acquisition instrument collects the combined signal and transmits it to the data acquisition unit of the test control device. At the same time, the general spectrum analyzer analyzes the frequency spectrum and power of the signal; The navigation signal processing unit of the test control device generates local carriers and local pseudocodes according to the frequency and bandwidth parameters measured by the general spectrum analyzer, performs matching correlation operation with the navigation enhancement radio frequency combined collected data, calculates the carrier Doppler frequency and code phase of the navigation enhancement signal, and obtains the navigation message, completes the positioning solution, and sends the results to the analysis report unit. The analysis report unit evaluates the observation, ephemeris, and positioning results based on the low-orbit satellite precise ephemeris enhancement information provided by the communication control unit, analyzes the quality of the low-orbit navigation enhancement signal generated and broadcast by the navigation enhancement load; The navigation enhancement load and the navigation enhancement transmitter are not less than four.

9. The high-mid-low orbit combined navigation enhancement performance verification system of claim 4, wherein: In the high, middle and low combined precise orbit determination function verification test, the navigation enhancement load outputs low orbit navigation enhancement radio frequency signals through the navigation enhancement transmitter, and the satellite navigation signal simulation system simulates the GNSS satellite navigation signals received by the receiver in the ground scene. The signal combiner combines these signals into one, and then the radio frequency data collector collects the signals and transmits them to the data collection unit of the test control device. The navigation signal processing unit performs acquisition and tracking processing on the collected navigation signal data, and obtains the original observation and ephemeris information of the GNSS and low orbit navigation signals. At the same time, combined with the original observation and ephemeris information transmitted by the navigation monitoring receiver, the high, middle and low combined precise orbit determination is completed, and the orbit determination result is sent to the analysis report unit. The analysis report unit analyzes the high, middle and low combined precise orbit determination result and the orbit determination result of the navigation monitoring receiver. The navigation enhancement load, navigation enhancement transmitter and navigation monitoring receiver participating in the orbit determination system are each not less than four, and the high, middle and low combined orbit determination accuracy in different numbers of navigation enhancement load, navigation enhancement transmitter and navigation monitoring receiver is compared and analyzed.

10. The high, middle and low combined navigation enhancement performance verification system of claim 4, wherein: In the precise point positioning function verification test, the data collection unit of the test control device receives the GNSS and low orbit navigation combined signal collection data, and the navigation signal processing unit performs acquisition and tracking processing on the collected navigation signal data, and obtains the original observation and ephemeris data of the GNSS and low orbit navigation signals. The precise satellite orbit, precise satellite clock correction number and carrier phase observation data are used for high, middle and low combined positioning calculation, and the results are sent to the analysis report unit for analysis of the precise point positioning initialization convergence time and positioning accuracy. The navigation enhancement load and navigation enhancement transmitter participating in the generation of navigation combined signals are each not less than four, and the precise point positioning performance in different numbers of navigation enhancement load and transmitter is compared and analyzed.

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