阅读说明：本技术 一种联合gnss导航星座与接收机的同步模拟系统 (Synchronous simulation system combining GNSS navigation constellation and receiver ) 是由 刘坤 蔡霞 张晓敏 万程程 于 2020-12-14 设计创作，主要内容包括：本发明公开了一种联合GNSS导航星座与接收机的同步模拟系统,包括：系统仿真模块、接口模块和时频模块；其中,系统仿真模块包括GNSS导航星座模拟器和GNSS接收机模拟器；GNSS导航星座模拟器根据预设的轨道信息生成导航观测信息,并将导航观测信息传输给所述GNSS接收机模拟器；GNSS接收机模拟器对导航观测信息进行环路跟踪仿真和加噪处理实现定位、定轨或者差分定位处理；所述时频模块采用内部或外部时钟产生标准1PPS信号；所述接口模块用于与外设控制进行信息交互和标准1PPS信号的输出。本发明可快速实现接收机在各种轨道场景下接收机接收导航星状态以及定位定轨的测量状态的模拟,减少了搭建射频收发射物理板卡实物的复杂度。(The invention discloses a synchronous simulation system combining a GNSS navigation constellation and a receiver, which comprises: the system comprises a system simulation module, an interface module and a time frequency module; the system simulation module comprises a GNSS navigation constellation simulator and a GNSS receiver simulator; the GNSS navigation constellation simulator generates navigation observation information according to preset track information and transmits the navigation observation information to the GNSS receiver simulator; the GNSS receiver simulator carries out loop tracking simulation and noise adding processing on the navigation observation information to realize positioning, orbit determination or differential positioning processing; the time frequency module adopts an internal or external clock to generate a standard 1PPS signal; the interface module is used for carrying out information interaction with peripheral control and outputting standard 1PPS signals. The invention can quickly realize the simulation of the receiver receiving navigation satellite state and the measurement state of positioning and orbit determination under various orbit scenes, and reduces the complexity of building a radio frequency transmitting-receiving physical board card entity.)

1. A system for synchronized simulation of a GNSS navigation constellation in combination with a receiver, comprising: the system comprises a system simulation module, an interface module and a time frequency module; wherein the content of the first and second substances,

the system simulation module comprises a GNSS navigation constellation simulator and a GNSS receiver simulator;

the GNSS navigation constellation simulator generates observation data and broadcast ephemeris according to preset orbit information and transmits the observation data and the broadcast ephemeris to the GNSS receiver simulator;

the GNSS receiver simulator performs loop tracking simulation and noise adding processing according to the observation data and the broadcast ephemeris to realize position calculation of the receiver;

the time frequency module adopts an internal or external clock to generate a standard 1PPS signal;

the interface module is used for carrying out information interaction with peripheral control and outputting standard 1PPS signals.

2. The system of claim 1, wherein the GNSS navigation constellation in combination with the receiver is synchronized: the GNSS navigation constellation simulator comprises a coordinate system and time system module, a constant and parameter library, an error simulation module, a user track simulation module, a space propagation simulation module, an antenna directional diagram module, an observation data simulation and switching module, a wide area difference information simulation module, an integrity information simulation module and a navigation message generation module; wherein the content of the first and second substances,

generating basic data by a coordinate system and time system module;

the constant and parameter library provides constant information;

the error simulation module provides controllable error data for the track simulation module, the space propagation simulation module and the user track simulation module respectively;

the user track simulation module simulates and simulates carrier information of different carriers under different motion states according to the basic data and the error data;

the orbit simulation module calculates satellite information of the position and the speed of the navigation satellite at any moment according to the basic data, the constant information and the error data;

the space propagation simulation module calculates propagation delay information according to the satellite information, the carrier information, the ionosphere model and the flow model;

the antenna directional pattern module is used for providing antenna directional pattern simulation information of a satellite end and a user end;

the observation data simulation and switching module outputs observation data according to the carrier information, the satellite information, the propagation delay information and the antenna directional pattern simulation information;

the wide area difference information simulation module generates wide area difference information aiming at the GEO satellite;

the integrity information simulation module generates system integrity information through simulation of integrity of the GNSS navigation system;

and the navigation message generation module calculates an observation value, a state equation and an observation equation according to the satellite information, the wide area difference information and the system integrity information, and performs least square fitting on the observation value, the state equation and the observation equation to obtain the broadcast ephemeris.

3. The system of claim 2, wherein the GNSS navigation constellation in combination with the receiver is synchronized: the GNSS receiver simulator comprises a receiver radio frequency channel simulation module, a receiver loop tracking simulation module, an observation data receiving simulation module, a navigation message receiving module, an observed quantity processing module, a resolving module, a channel tracking state processing module, a receiver clock model module and a receiver noise model module; wherein the content of the first and second substances,

the receiver radio frequency channel simulation module adds radio frequency channel parameter correction to observation data received from the GNSS navigation constellation simulator to obtain observation data with radio frequency channel correction, and sends the observation data to the receiver loop tracking simulation module and the observation data receiving simulation module;

the receiver clock model module models a clock used by a receiver and obtains clock model data to the receiver loop tracking simulation module and the observation data receiving simulation module;

the receiver noise model module is used for providing observation noise parameters for the observation data receiving simulation module;

the receiver loop tracking simulation module tracks and processes the received observation data with the radio frequency channel correction and the clock model data to obtain tracking data;

the channel tracking state processing module outputs the channel tracking state and the tracking data to the resolving module according to a preset receiver tracking threshold to the tracking data;

the observation data receiving simulation module receives observation data with radio frequency channel correction and clock model data, and carries out simulation processing on the observation data according to observation noise parameters to obtain noisy observation data and sends the noisy observation data to the observed quantity processing module;

the navigation message receiving module receives the broadcast ephemeris from the GNSS navigation constellation simulator and interprets the navigation message to obtain the orbit parameters of the navigation satellite and the parameters of the ionosphere, and sends the orbit parameters and the parameters of the ionosphere to the observation quantity processing module;

the observed quantity processing module obtains a navigation position, a navigation speed and an observation pseudo-range according to the noisy observed data, the navigation satellite orbit parameters and the ionosphere parameters and transmits the navigation position, the navigation speed and the observation pseudo-range to the resolving module;

and the resolving module receives the channel tracking state and tracking data, the navigation position, the speed and the observed pseudo range, and performs position resolving of the receiver.

4. The system of claim 1, wherein the GNSS navigation constellation in combination with the receiver is synchronized: the navigation observation information comprises pseudo range, carrier phase, ionosphere delay and troposphere delay.

5. The system of claim 2, wherein the GNSS navigation constellation in combination with the receiver is synchronized: the basic data includes a CGS2000 coordinate system or WGS84 coordinate system and a time system.

6. The system of claim 2, wherein the GNSS navigation constellation in combination with the receiver is synchronized: the constant information includes mathematical constants and geophysical base constants.

7. The system of claim 2, wherein the GNSS navigation constellation in combination with the receiver is synchronized: the carrier information includes user position, velocity, acceleration, and gesture.

8. The system of claim 2, wherein the GNSS navigation constellation in combination with the receiver is synchronized: the propagation delay information includes ionospheric delay and flow delay information.

Technical Field

The invention belongs to the technical field of satellite application, and particularly relates to a synchronous simulation system combining a GNSS navigation constellation and a receiver.

Background

The main purpose of the establishment of the satellite navigation system is to provide real-time, all-weather and global navigation services in three fields of land, sea and air, the current global navigation positioning system has BDS of China, GPS of America, Galileo of Europe and Glonass of Russia, the application of the satellite navigation system is more and more extensive, the application of the satellite navigation system is related to the life of people, along with the development of the navigation system in the aerospace field, the application of the satellite navigation receiver in medium and low high orbit satellites is more and more extensive, the problems that the satellite navigation receiver cannot be recycled and cannot be manually repaired due to the particularity of the application scene of the satellite navigation receiver result in higher requirements on the research and development reliability of the in-orbit navigation receiver, and in addition, for the expression of the in-orbit satellite condition phenomenon, a ground simulation system is generally established to simulate the in-orbit visible navigation state of the satellite receiver.

The satellite navigation ground simulation system takes a satellite navigation system as a prototype, and realizes the hardware equipment construction of navigation signals according to the characteristics of the navigation signals, thereby realizing the modulation signal broadcasting of the navigation signals. The navigation receiver receives navigation signals broadcast by a ground analog simulation system, demodulates the signals, completes text interpretation and observed quantity calculation, and realizes the functions of positioning, orbit determination calculation, differential positioning calculation and the like.

Disclosure of Invention

The technical problem solved by the invention is as follows: the synchronous simulation system combines the GNSS navigation constellation and the receiver, can simultaneously simulate the operation state of the navigation system and the operation state of the simulated receiver, reduces the complexity of the design of a baseband generation module and a radio frequency module of the traditional simulator, can directly simulate the observation information such as pseudo range, carrier phase and the like of the receiver and transmit the observation information to the receiver simulator, and the receiver simulator carries out positioning, orbit determination and calculation according to the received observation information, thereby reducing the design of a radio frequency processing module and a baseband processing module of the receiver; in addition, a plurality of satellite navigation receivers can be simulated simultaneously, so that the transmission of observation information among the receivers is realized, and the in-orbit differential scene simulation of the satellite receivers is realized. The simulation of the whole system takes 1pps as a simulation time reference, one pulse of 1pps represents a 1s time interval, and the simulation can be accelerated by adjusting the 1pps time interval.

The purpose of the invention is realized by the following technical scheme: a system for synchronized simulation of a combined GNSS navigation constellation and receiver, comprising: the system comprises a system simulation module, an interface module and a time frequency module; the system simulation module comprises a GNSS navigation constellation simulator and a GNSS receiver simulator; the GNSS navigation constellation simulator generates observation data and broadcast ephemeris according to preset orbit information and transmits the observation data and the broadcast ephemeris to the GNSS receiver simulator; the GNSS receiver simulator performs loop tracking simulation and noise adding processing according to the observation data and the broadcast ephemeris to realize position calculation of the receiver; the time frequency module adopts an internal or external clock to generate a standard 1PPS signal; the interface module is used for carrying out information interaction with peripheral control and outputting standard 1PPS signals.

In the synchronous simulation system combining the GNSS navigation constellation and the receiver, the GNSS navigation constellation simulator comprises a coordinate system and time system module, a constant and parameter library, an error simulation module, a user track simulation module, an orbit simulation module, a space propagation simulation module, an antenna directional diagram module, an observation data simulation and switching module, a wide area difference information simulation module, an integrity information simulation module and a navigation message generation module; wherein the coordinate system and time system module generates basic data; the constant and parameter library provides constant information; the error simulation module provides controllable error data for the track simulation module, the space propagation simulation module and the user track simulation module respectively; the user track simulation module simulates and simulates carrier information of different carriers under different motion states according to the basic data and the error data; the orbit simulation module calculates satellite information of the position and the speed of the navigation satellite at any moment according to the basic data, the constant information and the error data; the space propagation simulation module calculates propagation delay information according to the satellite information, the carrier information, the ionosphere model and the flow model; the antenna directional pattern module is used for providing antenna directional pattern simulation information of a satellite end and a user end; the observation data simulation and switching module outputs observation data according to the carrier information, the satellite information, the propagation delay information and the antenna directional pattern simulation information; the wide area difference information simulation module generates wide area difference information aiming at the GEO satellite; the integrity information simulation module generates system integrity information through simulation of integrity of the GNSS navigation system; and the navigation message generation module calculates an observation value, a state equation and an observation equation according to the satellite information, the wide area difference information and the system integrity information, and performs least square fitting on the observation value, the state equation and the observation equation to obtain the broadcast ephemeris.

In the synchronous simulation system combining the GNSS navigation constellation and the receiver, the GNSS receiver simulator comprises a receiver radio frequency channel simulation module, a receiver loop tracking simulation module, an observation data receiving simulation module, a navigation message receiving module, an observed quantity processing module, a resolving module, a channel tracking state processing module, a receiver clock model module and a receiver noise model module; the receiver radio frequency channel simulation module adds radio frequency channel parameter correction to observation data received from the GNSS navigation constellation simulator to obtain observation data with radio frequency channel correction, and sends the observation data to the receiver loop tracking simulation module and the observation data receiving simulation module; the receiver clock model module models a clock used by a receiver and obtains clock model data to the receiver loop tracking simulation module and the observation data receiving simulation module; the receiver noise model module is used for providing observation noise parameters for the observation data receiving simulation module; the receiver loop tracking simulation module tracks and processes the received observation data with the radio frequency channel correction and the clock model data to obtain tracking data; the channel tracking state processing module outputs the channel tracking state and the tracking data to the resolving module according to a preset receiver tracking threshold to the tracking data; the observation data receiving simulation module receives observation data with radio frequency channel correction and clock model data, and carries out simulation processing on the observation data according to observation noise parameters to obtain noisy observation data and sends the noisy observation data to the observed quantity processing module; the navigation message receiving module receives the broadcast ephemeris from the GNSS navigation constellation simulator and interprets the navigation message to obtain the orbit parameters of the navigation satellite and the parameters of the ionosphere, and sends the orbit parameters and the parameters of the ionosphere to the observation quantity processing module; the observed quantity processing module obtains a navigation position, a navigation speed and an observation pseudo-range according to the noisy observed data, the navigation satellite orbit parameters and the ionosphere parameters and transmits the navigation position, the navigation speed and the observation pseudo-range to the resolving module; and the resolving module receives the channel tracking state and tracking data, the navigation position, the speed and the observed pseudo range, and performs position resolving of the receiver.

In the synchronous simulation system combining the GNSS navigation constellation and the receiver, the navigation observation information includes pseudo range, carrier phase, ionosphere delay and troposphere delay.

In the above synchronous simulation system combining the GNSS navigation constellation and the receiver, the basic data includes a CGS2000 coordinate system or a WGS84 coordinate system and a time system.

In the above synchronous simulation system combining the GNSS navigation constellation and the receiver, the constant information includes mathematical constants and geophysical basic constants.

In the synchronous simulation system combining the GNSS navigation constellation and the receiver, the carrier information includes a user position, a speed, an acceleration and an attitude.

In the above synchronous simulation system combining the GNSS navigation constellation and the receiver, the propagation delay information includes ionospheric delay and convection delay information.

Compared with the prior art, the invention has the following beneficial effects:

(1) according to the invention, a mode of synchronously simulating a GNSS navigation constellation and a GNSS receiver is adopted, so that the simulation of the receiver receiving the navigation satellite state and the measurement state of positioning and orbit determination under various orbit scenes can be quickly realized, and the complexity of building a radio frequency transmitting-receiving physical board card object is reduced. In addition, the rapid simulation of the receiver during in-orbit operation can be realized through the operational capability of the CPU operation board, and the in-orbit navigation positioning state of the satellite can be rapidly reproduced;

(2) the invention provides a controllable interface board card, which can realize accurate 1PPS time service function, the design of the time frequency board card can realize 10MHz input, the same frequency processing of a simulation system and an external test system or a control system is realized, the phase accuracy of time service is ensured, and the time precision of the whole simulation system is improved.

Drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. Also, like reference numerals are used to refer to like parts throughout the drawings. In the drawings:

FIG. 1 is a block diagram of a synchronous simulation system incorporating a GNSS navigation constellation and a receiver;

FIG. 2 is a flow chart of a signal source equivalent device system;

FIG. 3 is a flow chart of a receiver equivalent;

FIG. 4 is a diagram of a hardware architecture of a synchronous simulator;

FIG. 5 is a schematic diagram of an interface board card;

fig. 6 is a functional block diagram of a time-frequency board card.

Detailed Description

Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict. The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.

As shown in fig. 1, the system for synchronous simulation of a joint GNSS navigation constellation and a receiver includes: the system comprises a system simulation module, an interface module and a time frequency module. The system simulation module comprises a GNSS navigation constellation simulator and a GNSS receiver simulator; the GNSS navigation constellation simulator generates navigation observation information according to preset track information and transmits the navigation observation information to the GNSS receiver simulator; the GNSS receiver simulator carries out loop tracking simulation and noise adding processing on the navigation observation information to realize positioning, orbit determination or differential positioning processing; the time frequency module adopts an internal or external clock to generate a standard 1PPS signal; the interface module is used for carrying out information interaction with peripheral control and outputting standard 1PPS signals.

As shown in fig. 1, the GNSS navigation constellation and receiver combined synchronous simulator integrates a CPU running module, an interface module, a time-frequency module, and a power module. The CPU operation module bears the whole simulation function and can simulate and simulate the GNSS navigation constellation and the GNSS receiver.

As shown in fig. 2, the GNSS navigation constellation simulator includes a coordinate system and time system module, a constant and parameter library, an error simulation module, a user trajectory simulation module, a track simulation module, a spatial propagation simulation module, an antenna directional diagram module, an observation data simulation and switching module, a wide area difference information simulation module, an integrity information simulation module, and a navigation message generation module; the coordinate system and time system module generates basic data such as a CGS2000 coordinate system or a WGS84 coordinate system and time system; the constant and parameter library provides constant information such as mathematical constants, geophysical basic constants and the like; the error simulation module mainly provides controllable error data for the track simulation module, the space propagation simulation module and the user track simulation module; the user track simulation module simulates and simulates the carrier information such as the user position, the speed, the acceleration, the posture and the like of different carriers under different motion states according to the basic data and the error data; the orbit simulation module calculates satellite information such as the position, the speed and the like of a navigation satellite at any moment according to the basic data, the constant information and the error data; the space propagation simulation module calculates propagation delay information such as ionosphere delay, flow delay and the like according to the satellite information, the carrier information, the ionosphere model and the flow model; the antenna directional pattern module mainly carries out satellite end and user end antenna directional pattern simulation information; the observation data simulation and switching module outputs observation data according to the carrier information, the satellite information, the propagation delay information and the antenna directional pattern information, and a user can output the required observation data through configuration; the wide area difference information simulation module generates wide area difference information aiming at the GEO satellite; the integrity information simulation module generates system integrity information through simulation of integrity of the GNSS navigation system; and the navigation message generation module calculates an observation value, a state equation and an observation equation according to the satellite information, the wide area difference information and the system integrity information, and performs least square fitting on the observation ephemeris to obtain the broadcast ephemeris.

As shown in fig. 3, the GNSS receiver simulator includes a receiver radio frequency channel simulation module, a receiver loop tracking simulation module, an observation data receiving simulation module, a navigation message receiving module, an observation amount processing module, a resolving module, a channel tracking state processing module, a receiver clock model, and a receiver noise model module; the receiver clock model models a hardware receiver radio frequency channel according to a receiver radio frequency channel simulation module and adds radio frequency channel parameter correction to observation data received from a GNSS navigation constellation simulator to obtain observation data with radio frequency channel correction, and the observation data is sent to a receiver loop tracking simulation module and an observation data receiving simulation module; the receiver clock model module mainly models a hardware clock used by a receiver and calculates clock model data to the receiver loop tracking simulation module and the observation data receiving simulation module; the receiver noise model module provides noise parameter information for each processing module according to a hardware receiver model; the receiver loop tracking simulation module models a code ring and a carrier ring of a receiver and tracks and processes received observation data with radio frequency channel correction and clock model data according to a model to obtain tracking data; the channel tracking state processing module outputs the channel tracking state and the tracking data to the resolving module according to the tracking threshold of the receiver and the like; the observation data receiving simulation module receives observation data with radio frequency channel correction and clock model data, and carries out simulation processing on the observation data according to observation noise parameters of the receiver to obtain noisy observation data and sends the noisy observation data to the observed quantity processing module; the navigation message receiving module receives the navigation message from the GNSS navigation constellation simulator and interprets the navigation message to obtain navigation satellite orbit parameters, ionosphere parameters and the like, and sends the navigation message to the observation quantity processing module; the observation quantity processing module receives the noisy observation data, the navigation satellite orbit parameter, the ionosphere and other parameters, processes the navigation position, the navigation speed and the observation pseudo range and transmits the processed navigation position, the navigation speed and the observation pseudo range to the resolving module; the resolving module receives data such as channel tracking state and tracking data, navigation position, speed, observation pseudo range and the like, performs positioning resolving, can perform orbit resolving if a user is an orbiting satellite, and can perform differential positioning resolving if receiving data of a differential receiver.

As shown in fig. 4, the GPS receiver general closed-loop simulator device mainly performs data interaction with an external device through a network port, an SPI interface, and a 1553B interface, and generates a 1PPS signal to the GNC controller for time adjustment.

The CPU mainboard can run analog source equivalent device module software and is connected with GNC test equipment through a network port, signal simulation of a receiver can be achieved, a simulation measurement result is sent to the receiver equivalent device through a shared memory, the receiver equivalent device achieves simulation of signal processing behavior of the receiver, and the receiver test result is sent to an interface board through a CPCI bus and used for controlling the GNC controller.

The CPCI back board provides a connection bus, a power supply and the like, is provided with a plurality of slots and can be used for installing a CPU board, a time frequency board and an interface board. The time-frequency board realizes the generation of the reference clock. The interface board realizes a special interface and a general interface, and comprises a 1PPS output interface, an SPI interface and a 1553B interface.

As shown in fig. 5, the interface board adopts an ARM + FPGA structure, a bus of the ARM controller is respectively connected with the FPGA and the 1553B bus controller, and the ARM sends control signals such as chip selection to the bus controller. The FPGA realizes a special interface and a general interface.

As shown in fig. 6, when the time-frequency board has an external frequency standard of 10MHz input, it outputs a 10MHz signal and selects the external frequency standard of 10MHz output; the internal 10MHz crystal oscillator is locked to the external 10MHz signal, so that the output signal of the clock module is synchronous with the external input 10MHz signal; when the external frequency standard is lost, the clock module automatically switches to the internal frequency standard for 10MHz output, and the frequency accuracy of the clock module is maintained by the frequency accuracy of the internal 10MHz VCO crystal oscillator. The time frequency board detects the input of the 1PPS and switches the internal and external 1PPS signals, and transmits the signals to the CPU board, so that the accuracy of the simulation time is ensured.

(1) Satellite signals, visible satellite states and navigation measurement information received by the GNSS receiver are simulated by utilizing satellite orbit information, antenna attitude information, satellite maneuvering information and the like, and spatial information such as ionospheric delay, tropospheric delay and the like is simulated and calculated to simulate the receiver to observe the navigation satellite states in actual space motion.

(2) The method comprises the steps of performing single-point positioning simulation on a GNSS receiver by utilizing information such as antenna delay, hardware equipment delay, thermal noise and the like of the receiver according to processing methods such as a satellite capturing and tracking strategy, a measurement quantity processing method and positioning calculation of the GNSS receiver, and simulating to realize the single-point positioning function of the receiver.

(3) And the orbit determination calculation of the analog receiver is simulated by utilizing the observed quantity information, the positioning information, the track parameter information and the like of the analog receiver, and the partial functions can realize the orbit determination calculation of the receiver and the orbit determination extrapolation when the orbit determination calculation is not satisfied.

(4) Through simulating double-satellite motion and double-receiver positioning, and through data interaction of double receivers, one of the simulated receivers is used as a reference station, and the other simulated receiver is used as a mobile station, double-user differential positioning resolving simulation is realized, and further, simulation of double satellites or double aircrafts is realized, and scenes such as intersection and butt joint can be simulated.

(5) The interface board and the time-frequency board can realize data interaction with the GNC test system, the GNC controller or other controllers and time service to the system, realize system simulation test with the whole aircraft, and effectively simulate the on-orbit running state of the whole system.

In the step (1), by using the user track or the orbit parameter, the attitude or the maneuvering data of the satellite input by the GNC test system and combining the simulation time and the orbit parameter of the GNSS constellation satellite, the pseudo range, the Doppler and the visibility from the navigation satellite to each satellite of the user can be calculated, and the information such as the signal power of the signal reaching the user receiver can be calculated according to the pseudo range.

During simulation of the GNSS receiver in the step (2), the influence of thermal noise of the receiver on the signal power is simulated, the signal-to-noise ratio of the signal is calculated, and the processing processes of acquisition, tracking, lock losing and the like of the GNSS to the satellite are simulated according to the signal-to-noise ratio; observed quantity information (including pseudo range, carrier phase and other information) calculated by the receiver is calculated according to information such as antenna delay, equipment delay and the like, and single-point positioning calculation is carried out according to the observed quantity information.

In the step (3), during simulation of the GNSS receiver, the initial value of the filtering model of the autonomous orbit determination system is obtained by calculation according to observation information, orbit parameters and the like, orbit determination simulation can be switched according to the current working state of the receiver, and orbit determination extrapolation calculation is performed when the receiver cannot be positioned.

In the step (4), the GNSS receiver can perform real-time simulation on two or more than two receivers according to the setting, when the two receivers perform simulation, one receiver can be used as a reference station, and the other receiver can be used as a mobile station and can simulate a differential positioning resolving function; the other two receivers can be mutually used as a reference station/mobile station to realize the differential simulation of the double mobile receivers.

A time-frequency module is designed in the step (5), can generate a second pulse signal for marking to a control system and a test system for time service, and can receive an external second pulse signal and 10MHz at the same time to realize same-frequency time service with external input equipment; in addition, the network port is designed to be capable of carrying out data communication with the test equipment, and output of data such as simulated observation data, orbit determination data and difference results is achieved.

According to the invention, a mode of synchronously simulating a GNSS navigation constellation and a GNSS receiver is adopted, so that the simulation of the receiver receiving the navigation satellite state, positioning, orbit determination and other measurement states under various orbit scenes can be quickly realized, and the complexity of building a radio frequency transmitting-receiving physical board card object is reduced. In addition, the rapid simulation of the receiver during in-orbit operation can be realized through the operational capability of the CPU operation board, and the in-orbit navigation positioning state of the satellite can be rapidly reproduced; the invention provides a controllable interface board card, which can realize accurate 1PPS time service function, the design of the time frequency board card can realize 10MHz input, the same frequency processing of a simulation system and an external test system or a control system is realized, the phase accuracy of time service is ensured, and the time precision of the whole simulation system is improved.

Although the present invention has been described with reference to the preferred embodiments, it is not intended to limit the present invention, and those skilled in the art can make variations and modifications of the present invention without departing from the spirit and scope of the present invention by using the methods and technical contents disclosed above.