Navigation Simulation Method for Ground Testing of Autonomous Orbit Maintenance by Electric Propulsion of Small Satellites

Abstract

This invention discloses a navigation simulation method for ground testing of autonomous orbit maintenance of small satellites using electric propulsion. The method receives satellite time, attitude control, electric propulsion thrust broadcasts, and GNSS positioning broadcast polling from the satellite bus. Based on the received broadcast data, it performs real-time orbit dynamics simulation calculations to recursively calculate the satellite orbit. Navigation parameters are calculated based on the recursion results. In response to the GNSS positioning broadcast polling, a GNSS positioning broadcast data frame simulating an onboard navigation receiver is generated based on the navigation parameters and sent to the satellite bus. This invention achieves real-time closed-loop updates of orbit navigation information based on the satellite's orbit maintenance status by acquiring the satellite's orbit maintenance status in real time and simulating a navigation receiver response. This solves the problem of information loss after the initial orbit maintenance in traditional open-loop testing, enabling realistic and effective closed-loop testing of the entire autonomous orbit maintenance process using electric propulsion. It also has the advantages of low cost and easy integration.

Description

Technical Field

[0001] This invention relates to the field of small satellite ground testing technology, and in particular to a navigation simulation method for ground testing of autonomous orbit maintenance by electric propulsion of small satellites. Background Technology

[0002] Autonomous orbit maintenance by electric propulsion for small satellites refers to the process by which small satellites autonomously maintain their orbits using electric thrusters based on onboard orbit maintenance software. During in-orbit operation, the onboard orbit maintenance software assesses orbital changes using navigation data broadcast on the satellite bus by the onboard navigation receiver, autonomously generates an orbit maintenance plan according to the maintenance strategy, and sends action commands to the electric propulsion subsystem in a timely manner based on the plan. The software also monitors the orbit maintenance execution status in real-time using telemetry from the electric propulsion subsystem and performs fault-tolerant processing when necessary.

[0003] The autonomous orbit maintenance process of small satellites with electric propulsion is complex, demanding real-time performance and high reliability. Therefore, thorough and effective testing during the satellite's ground testing phase is essential. Traditional small satellites control their orbits remotely from the ground. During ground simulation testing, orbit control data blocks are injected into the satellite, and the satellite performs actions according to the ignition attitude, start-up time, and ignition duration specified in the data blocks. This method is clearly unsuitable for autonomous orbit maintenance testing. GNSS dynamic simulators are commonly used ground testing equipment for small satellites. They output simulated GNSS signals, which are received by the onboard navigation receiver, used for navigation calculations, and broadcast navigation data on the satellite bus. However, GNSS dynamic simulators operate using pre-simulated orbit point files and cannot update the orbit in real-time based on the satellite's orbit maintenance status. This causes the navigation data broadcast by the onboard navigation receiver to deviate from the actual orbit after the initial orbit maintenance, rendering it unusable for subsequent orbit maintenance calculations. Therefore, using a GNSS dynamic simulator can only achieve open-loop testing of autonomous orbit maintenance, testing the workflow triggered before the initial orbit maintenance. It cannot effectively test the orbit maintenance process, the post-maintenance process, or the workflow of multiple consecutive orbit maintenance operations. To effectively test the entire workflow of autonomous orbit maintenance by electric propulsion, it is necessary to solve the problem of closed-loop update of orbit navigation information, that is, to update the orbit navigation information in real time according to the satellite orbit maintenance status during the test, so as to realize the closed-loop test of autonomous orbit maintenance.

[0004] Chinese invention patent CN106054913A discloses a verification system for an autonomous orbit control algorithm. Its core components include a simulation computer, a spaceborne computer, a navigation satellite simulator, and a GPS receiver. The navigation satellite simulator sends orbit data from the simulation computer to the GPS receiver, which then feeds back the data to the spaceborne computer. Chinese invention patent CN112214902A discloses a real-time simulation system for satellite attitude and orbit control and stand-alone communication. It includes an orbit and attitude dynamics simulation module, a stand-alone principle simulation module, and a stand-alone data communication module, simulating the principles and communication of stand-alone equipment.

[0005] The aforementioned prior art has the following disadvantages:

[0006] 1. Existing navigation simulation equipment mostly adopts an open-loop working mode. The navigation signals it outputs are based on a pre-set orbit file and cannot be adjusted in real time according to the actual state of the satellite after performing orbit maintenance actions (such as thruster ignition). This causes the simulated orbit to deviate from the actual simulated orbit of the satellite after the first orbit maintenance, and the test then fails.

[0007] 2. The existing system cannot achieve closed-loop testing of the entire process of autonomous orbit maintenance by electric propulsion. In particular, it cannot effectively verify the complex workflow after the first orbit maintenance, during the orbit maintenance process, and in the continuous multiple orbit maintenances. The coverage and authenticity of the ground test are insufficient.

[0008] 3. The existing orbit information generation link is unidirectional (dynamic model - signal generation device - satellite), lacking a mechanism to incorporate the feedback of satellite actuators into the orbit information generation process, making it difficult to construct a real on-orbit logical closed loop of "satellite decision-execution-orbit change-navigation perception-re-decision". Summary of the Invention

[0009] To address the problems existing in the prior art, the present invention aims to provide a navigation simulation method for ground testing of autonomous orbit maintenance by electric propulsion of small satellites. This method can update orbital navigation information in real time according to the satellite's orbit maintenance status, realize closed-loop testing of autonomous orbit maintenance, and improve the authenticity, comprehensiveness, and effectiveness of ground testing.

[0010] To achieve the above-mentioned objectives, this invention provides a navigation simulation method for ground testing of autonomous orbit maintenance using electric propulsion for small satellites, comprising the following steps:

[0011] Step S1: Receive broadcast data from the satellite bus, the broadcast data including at least satellite service time broadcast, attitude control broadcast, electric propulsion thrust broadcast and GNSS positioning broadcast polling;

[0012] Step S2: Based on the broadcast data, perform real-time orbital dynamics simulation calculations, recursively calculate the satellite orbit, and obtain the recursive result;

[0013] Step S3: Calculate navigation parameters based on the recursive results;

[0014] Step S4: In response to the GNSS positioning broadcast polling in step S1, generate a GNSS positioning broadcast data frame simulating a spaceborne navigation receiver based on the navigation parameters, and send it to the satellite bus.

[0015] According to a technical solution of the present invention, in step S2, the satellite orbit is calculated and recursively calculated in real time based on the data type of the broadcast data, specifically including:

[0016] If the received data is an attitude control broadcast, then update the latest attitude parameters;

[0017] If the received data is an electric propulsion thrust broadcast, then update the latest thrust parameters;

[0018] If the received data is a satellite time broadcast, then update the latest satellite time, calculate the thrust vector based on the latest attitude and thrust parameters, perform numerical integration on the orbital dynamics equations, and recursively transfer the satellite position, velocity, and mass from the previous satellite time to the latest satellite time.

[0019] According to one technical solution of the present invention, the orbital dynamics equation adopts a finite thrust model, wherein the acceleration term includes at least the Earth's central gravitational term, the Earth's non-spherical perturbation term, the atmospheric drag perturbation term, and the thrust perturbation term.

[0020] According to one technical solution of the present invention, in step S4, after receiving a GNSS positioning broadcast poll from the satellite bus, a GNSS positioning broadcast data frame is generated from the navigation parameters based on the GNSS positioning broadcast frame data format of the spaceborne navigation receiver specified by the bus communication protocol, and the response is sent to the satellite bus as a response to the GNSS positioning broadcast poll.

[0021] According to one technical solution of the present invention, the navigation simulation method further includes: setting configuration parameters before entering the orbital navigation information closed-loop update process, wherein the configuration parameters include satellite parameters, orbital parameters, orbital dynamics model parameters, and parameters for communication with the satellite bus.

[0022] According to one aspect of the present invention, a navigation simulation device for ground testing of autonomous orbit maintenance by electric propulsion of small satellites is provided, comprising:

[0023] The data communication module is used to communicate with the satellite bus, receive broadcast data from the satellite bus, the broadcast data including at least satellite service time broadcast, attitude control broadcast, electric propulsion thrust broadcast and GNSS positioning broadcast polling, and send GNSS positioning broadcast data frames to the satellite bus;

[0024] The orbital dynamics simulation module is used to perform real-time orbital dynamics simulation calculations. Taking the satellite position, velocity, and mass at the previous time as the initial state, the orbital dynamics equations are numerically integrated based on the broadcast data to obtain the satellite position, velocity, and mass at the latest time.

[0025] The navigation parameter calculation module is used to calculate navigation parameters based on the recursive results;

[0026] The GNSS positioning broadcast simulation module is used to generate GNSS positioning broadcast data frames simulating a spaceborne navigation receiver based on the navigation parameters obtained by the navigation parameter calculation module, and to send them through the data communication module.

[0027] According to one technical solution of the present invention, the orbital dynamics simulation module performs real-time simulation calculations and recursively calculates and extrapolates the satellite orbit based on the data type of the broadcast data, specifically including:

[0028] When the data communication module receives the attitude control broadcast, it updates the latest attitude parameters.

[0029] When the data communication module receives the electric propulsion thrust broadcast, it updates the latest thrust parameters.

[0030] When the data communication module receives a satellite time broadcast, it updates the latest satellite time, calculates the thrust vector based on the latest attitude and thrust parameters, and uses this to drive the numerical integration of the orbital dynamics equations.

[0031] According to one technical solution of the present invention, the GNSS positioning broadcast simulation module is used to: when the data communication module receives the GNSS positioning broadcast polling, generate a GNSS positioning broadcast data frame from the navigation parameters based on the GNSS positioning broadcast frame data format of the spaceborne navigation receiver specified by the bus communication protocol, as a response to the GNSS positioning broadcast polling.

[0032] According to one technical solution of the present invention, it further includes a configuration parameter setting module, which is used to set configuration parameters including satellite parameters, orbit parameters, orbit dynamics model parameters, and parameters for communication with the satellite bus before entering the orbit navigation information closed-loop update process.

[0033] According to one technical solution of the present invention, the device is implemented based on a general-purpose computer and a general-purpose interface conversion device, and is connected to a satellite bus through a standard bus interface.

[0034] Compared with existing technologies, the navigation simulation method for autonomous orbit maintenance ground testing of small satellites using electric propulsion provided by this invention has the following significant technical advantages:

[0035] By acquiring satellite status for real-time orbital dynamics simulation and replacing the GNSS positioning broadcast data frames sent by the onboard navigation receiver to the satellite bus, the orbital navigation information is updated in real time according to the satellite's orbital maintenance status. In ground testing, the navigation information of the entire process of autonomous orbit maintenance by electric propulsion can be realistically simulated.

[0036] This invention enables closed-loop testing for ground testing of autonomous orbit maintenance by electric propulsion of small satellites, allowing the testing to cover the entire process of autonomous orbit maintenance by electric propulsion, and improving the authenticity, comprehensiveness and effectiveness of ground testing;

[0037] This invention can be implemented in software based on a general-purpose computer and a general-purpose interface conversion device, becoming a navigation simulation ground test device. It can be connected to the satellite bus through a standard bus interface and can be easily integrated with existing ground test systems. It can be used for ground tests of small satellite electric propulsion autonomous orbit maintenance in stages such as subsystem desktop joint testing and whole satellite integrated testing. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are merely some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without creative effort.

[0039] Figure 1 This is a flowchart illustrating the navigation simulation method for autonomous orbit maintenance ground testing of small satellites using electric propulsion, as described in this invention.

[0040] Figure 2 This is a functional module architecture diagram of the navigation simulation device for autonomous orbit maintenance ground testing of small satellites using electric propulsion, according to the present invention.

[0041] Figure 3 This is a schematic diagram of the navigation simulation ground inspection equipment implemented based on the present invention;

[0042] Figure 4 A schematic diagram of the satellite CAN bus connection relationship during ground closed-loop testing of autonomous orbit maintenance by electric propulsion.

[0043] Figure 5 This is a flowchart illustrating the navigation simulation method for ground testing of autonomous orbit maintenance of a small satellite using electric propulsion, according to another embodiment of the present invention. Detailed Implementation

[0044] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0045] It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of this application can be combined with each other. The following embodiments only illustrate several implementation methods of this application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the patent application. It should be pointed out that, for those skilled in the art, several modifications and improvements can be made without departing from the concept of this application, and these all fall within the protection scope of this application.

[0046] like Figure 1 and Figure 5 As shown, the present invention provides a navigation simulation method for ground testing of autonomous orbit maintenance of small satellites using electric propulsion, comprising the following steps:

[0047] Step S1: Receive broadcast data from the satellite bus, the broadcast data including at least satellite service time broadcast, attitude control broadcast, electric propulsion thrust broadcast and GNSS positioning broadcast polling;

[0048] Step S2: Based on the broadcast data, perform real-time orbital dynamics simulation calculations, recursively calculate the satellite orbit, and obtain the recursive result;

[0049] Step S3: Calculate navigation parameters based on the recursive results;

[0050] Step S4: In response to the GNSS positioning broadcast polling in step S1, generate a GNSS positioning broadcast data frame simulating a spaceborne navigation receiver based on the navigation parameters, and send it to the satellite bus;

[0051] Step S5: Repeat steps S1 to S4 to continuously update the orbital navigation information based on the satellite's orbital status, forming a closed-loop test.

[0052] First, through step S1, the navigation simulation device connects to the satellite bus, listening to and receiving various data broadcast on the bus in real time. The satellite time broadcast provides an onboard time reference for synchronizing the simulation process; the attitude control broadcast provides the satellite's current orientation in inertial space for calculating the thrust vector direction; the electric propulsion thrust broadcast directly reflects the orbit maintenance execution status, including thrust magnitude and ignition duration, and is the core input for orbit recursion; the GNSS positioning broadcast polling is a signal from other onboard subsystems (such as onboard orbit maintenance software) requesting position data from the navigation receiver, and this invention aims to simulate the receiver's response to this request.

[0053] Next, step S2 drives orbital dynamics simulation based on the received real-time data. Traditional simulation methods are based on preset orbit files, while this invention calculates the orbital position at the next moment in real time based on the satellite's actual attitude and thrust, thereby achieving synchronization between the simulation and the actual state of the satellite, which is beneficial for achieving closed-loop testing.

[0054] Then, step S3 converts the simulated orbital position, velocity, and other data into navigation parameters that conform to the output protocol format of the spaceborne navigation receiver.

[0055] Finally, in step S4, the system listens for GNSS positioning broadcast polling on the bus. Once this poll is detected, the navigation parameters calculated in step S3 are immediately encapsulated into standard data frames and sent to the bus, replacing the actual onboard navigation receiver. After receiving this data, the onboard orbit maintenance software uses it as navigation information to make the next orbit maintenance decision, forming a complete closed loop based on the satellite's actual movements.

[0056] By cyclically executing steps S1 to S4, the orbital navigation information is updated in real time according to the satellite's orbit maintenance status (i.e., thruster action). This ensures that even if the satellite changes its orbit due to orbit maintenance actions during testing, the simulated navigation information can follow synchronously, solving the problem of navigation information distortion caused by the use of preset orbits in traditional GNSS dynamic simulators. Therefore, this method can support effective testing of the entire workflow, including the initial orbit maintenance and subsequent multiple orbit maintenance operations, greatly improving the realism, comprehensiveness, and effectiveness of ground testing. For example, after an orbit maintenance ignition, the onboard orbit maintenance software needs to evaluate the control effect based on the new orbital position and generate the next orbit maintenance plan. This method, by updating navigation information in real time, ensures that the onboard software can always perform calculations based on correct orbital data, thereby fully verifying the logic and function of autonomous orbit maintenance.

[0057] In some embodiments of the present invention, receiving data from the satellite bus includes: transmitting various types of data such as telemetry, broadcasting, and satellite service polling from various subsystems on the satellite bus. To avoid receiving irrelevant data, the bus data is filtered according to the definition of various data formats in the bus communication protocol, and only necessary satellite data is received to obtain parameters such as attitude, thrust, and satellite time required for orbit recursion calculation from relevant broadcasts, as well as GNSS positioning broadcast polling required for simulating GNSS positioning broadcasting by the onboard navigation receiver.

[0058] In some embodiments of the present invention, such as Figure 1 As shown, in step S2, the satellite orbit is calculated and recursively calculated in real time based on the data type of the broadcast data, specifically including:

[0059] If the received data is an attitude control broadcast, then update the latest attitude parameters;

[0060] If the received data is an electric propulsion thrust broadcast, then update the latest thrust parameters;

[0061] If the received data is a satellite time broadcast, the latest satellite time is updated, the thrust vector is calculated based on the latest attitude and thrust parameters, the orbital dynamics equations are numerically integrated, and the satellite position, velocity, and mass from the previous satellite time are recursively applied to the latest satellite time. Specifically, depending on the satellite application scenario, parameters such as the initial orbital elements and initial mass are set via a configuration parameter setting module as initial values ​​for the first integration iteration.

[0062] When the data communication module receives the attitude control broadcast, the simulation module parses the satellite's current three-axis attitude angles or quaternions and updates the "latest attitude parameters" stored in memory. Since attitude determines the transformation relationship of the thrust vector between the body coordinate system and the inertial coordinate system, timely updates of this parameter are crucial for accurately calculating the direction of thrust in inertial space.

[0063] Upon receiving a broadcast of electric propulsion thrust, the simulation module analyzes the current on / off state and thrust magnitude of the electric thruster and updates the "current latest thrust parameters." This is direct evidence that the satellite is performing orbit maintenance maneuvers.

[0064] Upon receiving a satellite time broadcast, the simulation module parses the current satellite time (satellite time). This triggers an orbital recursion calculation. The simulation module first uses the recently updated attitude and thrust parameters to transform the thrust from the body coordinate system to the inertial coordinate system, calculating the thrust vector. Then, using the satellite position, velocity, and mass from the previous satellite time (i.e., the end point of the previous integration step) as the initial state, it calls the orbital dynamics equations for numerical integration, recursively transferring the state variables from the previous satellite time to the latest satellite time. The integration step size is the time difference between the two satellite time broadcasts. After integration, the latest satellite position, velocity, and mass are stored for the next calculation and navigation parameter generation.

[0065] By processing bus data by type and using satellite time broadcast as an integration trigger event, the orbit recursion calculation is strictly synchronized with the satellite time, and the input parameters (attitude, thrust) are all the latest real state, which greatly improves the real-time performance and accuracy of orbit simulation, and makes the generated simulated GNSS data more reflective of the satellite's real dynamics.

[0066] In some embodiments of the present invention, the orbital dynamics equations employ a finite thrust model, wherein the acceleration terms include at least the Earth's central gravitational term, the Earth's non-spherical perturbation term, the atmospheric drag perturbation term, and the thrust perturbation term.

[0067] In order to accurately simulate the orbital changes of low-Earth orbit small satellites under electric propulsion, the dynamic model cannot only consider the Earth's central gravity.

[0068] The non-spherical perturbation of the Earth is a major factor in the orbital perturbation of low-Earth orbit (LEO) satellites and must be considered. Atmospheric drag perturbation has a significant impact on small LEO satellites, and its magnitude is related to factors such as the satellite's windward area, mass, and atmospheric density. An accurate model is crucial to ensuring the accuracy of orbital decay simulation. The thrust perturbation term is directly derived from the electric propulsion system. This invention incorporates this perturbation term into the dynamic equations in real time and accurately by receiving electric propulsion thrust broadcasts. The orbital dynamic equations can be expressed as:

[0069]

[0070] In the formula, , , These are the first derivatives of the satellite's position, velocity, and mass with respect to time, respectively. , , These are the satellite's position, velocity, and mass, respectively. , , , These are, respectively, the Earth's central gravitational acceleration, the Earth's non-spherical perturbation acceleration, the atmospheric drag perturbation acceleration, and the thrust acceleration; For electric propulsion thrust; For the specific impulse of an electric thruster; This is the gravitational acceleration at sea level.

[0071] By employing a finite thrust dynamics model that includes multiple key perturbation terms, the orbit recursion results are made closer to the actual situation of satellite operation in orbit. As a result, the generated simulated GNSS data has higher confidence and can more effectively evaluate the performance of the onboard orbit maintenance software in complex dynamic environments.

[0072] In some embodiments of the present invention, in step S4, after receiving a GNSS positioning broadcast poll from the satellite bus, a GNSS positioning broadcast data frame is generated from the navigation parameters based on the GNSS positioning broadcast frame data format of the spaceborne navigation receiver specified by the bus communication protocol, and the response is sent to the satellite bus as a response to the GNSS positioning broadcast poll.

[0073] By accurately simulating the "polling-response" communication protocol of the onboard navigation receiver, the data generated by this method is completely transparent to the onboard system. It can be connected to the test system without any modification to the onboard software, ensuring the convenience and authenticity of the test.

[0074] In some embodiments of the present invention, the navigation simulation method further includes setting configuration parameters before entering the orbital navigation information closed-loop update process. The configuration parameters include satellite parameters, orbital parameters, orbital dynamics model parameters, and parameters for communication with the satellite bus.

[0075] In this embodiment, when the navigation simulation ground testing equipment is used for ground closed-loop testing of autonomous orbit maintenance of a small satellite with electric propulsion, the satellite CAN bus connection relationship is as follows: Figure 4 As shown in the diagram. The onboard navigation receiver is not connected to the satellite CAN bus; the navigation simulation ground inspection equipment is connected to the satellite CAN bus, performing GNSS positioning broadcasts on the bus in place of the onboard receiver. The satellite service subsystem performs attitude, thrust, and navigation broadcast polling and satellite time broadcasts on the bus; the attitude control subsystem performs attitude control broadcasts on the bus; and the electric propulsion subsystem performs electric propulsion thrust broadcasts on the bus.

[0076] After the local inspection software starts, the first step is to configure the parameters, including:

[0077] (1) Set satellite parameters, including: initial mass, windward area, drag coefficient, electric thruster installation matrix, electric thruster specific impulse, etc.;

[0078] (2) Set the satellite orbit, including: epoch time, semi-major axis, eccentricity, inclination, right ascension of the ascending node, argument of perigee, true anomaly, etc.;

[0079] (3) Set the parameters of the orbital dynamics model, including: the order of the Earth's non-spherical perturbation, the atmospheric density model parameters, the integrator parameters, etc.;

[0080] (4) Set the parameters for communication with the bus, that is, set the working parameters of the USBCAN adapter box and the data frame identification parameters of GNSS positioning broadcast according to the bus communication protocol. The former includes: working mode, baud rate, mask code, receive code, etc., so that the ground inspection equipment can filter and receive satellite time broadcast, attitude control broadcast, electric propulsion thrust broadcast, GNSS positioning broadcast polling, etc. from the satellite CAN bus; the latter includes parameters such as priority, station address, frame type, etc., so that the data frames sent by the ground inspection equipment to the satellite CAN bus conform to the GNSS positioning broadcast frame format, thereby replacing the onboard navigation receiver to perform GNSS positioning broadcast on the satellite CAN bus.

[0081] By providing a flexible configuration parameter interface, the navigation simulation device of the present invention has good versatility and adaptability, and can be quickly applied to test tasks of different types of small satellites to meet diverse test requirements.

[0082] like Figure 2 As shown, according to one aspect of the present invention, a navigation simulation device for ground testing of autonomous orbit maintenance by electric propulsion of small satellites is proposed, comprising:

[0083] The data communication module is used to communicate with the satellite bus, receive broadcast data from the satellite bus, the broadcast data including at least satellite service time broadcast, attitude control broadcast, electric propulsion thrust broadcast and GNSS positioning broadcast polling, and send GNSS positioning broadcast data frames to the satellite bus;

[0084] The orbit dynamics simulation module is used for real-time orbit dynamics simulation calculations. Taking the satellite position, velocity, and mass of the previous satellite as the initial state, it performs numerical integration on the orbit dynamics equations using the finite thrust model based on the latest attitude, thrust, and satellite time parameters extracted from the satellite bus-related broadcast data to obtain the satellite position, velocity, and mass at the latest satellite time.

[0085] The navigation parameter calculation module is used to calculate navigation parameters, based on the satellite position and velocity at the latest satellite time, to calculate the navigation parameters specified in the GNSS positioning broadcast data protocol;

[0086] The GNSS positioning broadcast simulation module is used to generate GNSS positioning broadcast data frames simulating a spaceborne navigation receiver based on the navigation parameters obtained by the navigation parameter calculation module, and to send them through the data communication module.

[0087] In some embodiments of the present invention, the orbital dynamics simulation module performs real-time simulation calculations and recursive calculations of the satellite orbit based on the data type of the broadcast data, specifically including:

[0088] When the data communication module receives the attitude control broadcast, it updates the latest attitude parameters.

[0089] When the data communication module receives the electric propulsion thrust broadcast, it updates the latest thrust parameters.

[0090] When the data communication module receives a satellite time broadcast, it updates the latest satellite time, calculates the thrust vector based on the latest attitude and thrust parameters, and uses this to drive the numerical integration of the orbital dynamics equations.

[0091] In some embodiments of the present invention, the GNSS positioning broadcast simulation module is used to: when the data communication module receives a GNSS positioning broadcast poll, generate a GNSS positioning broadcast data frame from the navigation parameters based on the GNSS positioning broadcast frame data format of the spaceborne navigation receiver specified by the bus communication protocol, as a response to the GNSS positioning broadcast poll.

[0092] In some embodiments of the present invention, a configuration parameter setting module is also included, which is used to set configuration parameters, including satellite parameters, orbit parameters, orbit dynamics model parameters, and parameters for communication with the satellite bus, before entering the orbit navigation information closed-loop update process.

[0093] In some embodiments of the present invention, the device is implemented based on a general-purpose computer and a general-purpose interface conversion device, and is connected to a satellite bus through a standard bus interface.

[0094] The following design is based on the method and apparatus described in this invention to create a navigation simulation ground inspection device.

[0095] This embodiment implements a navigation simulation ground inspection device based on the method and apparatus described in this invention. For example... Figure 3 As shown, the navigation simulation ground inspection equipment consists of a general-purpose industrial control computer, a USBCAN adapter box, and connecting cables. The functional modules described in this invention are integrated into the ground inspection software of the embodiment. The industrial control computer is used to run the ground inspection software; one end of the USBCAN adapter box is connected to the satellite CAN bus, and the other end is connected to the industrial control computer, for bidirectional data communication between the satellite CAN bus and the industrial control computer.

[0096] In this embodiment, the navigation simulation ground inspection equipment is used for ground closed-loop testing of autonomous orbit maintenance of a small satellite with electric propulsion. The satellite CAN bus connection relationship is as follows: Figure 4 As shown in the diagram. The onboard navigation receiver is not connected to the satellite CAN bus; the navigation simulation ground inspection equipment is connected to the satellite CAN bus, performing GNSS positioning broadcasts on the bus in place of the onboard receiver. The satellite service subsystem performs attitude, thrust, and navigation broadcast polling and satellite time broadcasts on the bus; the attitude control subsystem performs attitude control broadcasts on the bus; and the electric propulsion subsystem performs electric propulsion thrust broadcasts on the bus.

[0097] According to one aspect of the present invention, an electronic device is provided, comprising: one or more processors, one or more memories, and one or more computer programs; wherein the processor is connected to the memory, and the one or more computer programs are stored in the memory; when the electronic device is running, the processor executes the one or more computer programs stored in the memory to cause the electronic device to perform a navigation simulation method for autonomous orbit maintenance ground testing of small satellite electric propulsion as described in any of the above technical solutions.

[0098] The processor can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor can be a microprocessor or any conventional processor.

[0099] The memory can be an internal storage unit of the terminal device, such as a hard drive or RAM. Alternatively, it can be an external storage device, such as a plug-in hard drive, Smart Media Card (SMC), Secure Digital (SD) card, or Flash Card. Furthermore, the memory can include both internal and external storage units. The memory is used to store the computer program and other programs and data required by the terminal device. It can also be used to temporarily store data that has been output or will be output.

[0100] According to one aspect of the present invention, a computer-readable storage medium is provided for storing computer instructions, which, when executed by a processor, implement a navigation simulation method for autonomous orbit maintenance ground testing of a small satellite with electric propulsion, as described in any of the above technical solutions.

[0101] For example, computer-readable storage media can be read-only memory (ROM), random access memory (RAM), read-only optical disc (CD-ROM), magnetic tape, floppy disk, and optical data storage devices. They can be implemented using computer-executable program code, thus allowing them to be stored in a storage device for execution by a computing device, or they can be fabricated as separate integrated circuit modules, or multiple modules or steps can be fabricated as a single integrated circuit module. Therefore, this invention is not limited to any particular hardware and software combination.

[0102] The present invention provides a navigation simulation method for ground testing of autonomous orbit maintenance of small satellites using electric propulsion, which has the following beneficial effects:

[0103] This invention acquires the satellite's orbital status (electric propulsion thrust, attitude, and satellite time) in real time from the satellite bus, drives the orbital dynamics model to perform real-time simulation and recursion, and replaces the onboard navigation receiver to simulate, generate, and broadcast GNSS positioning data that matches the current orbital status on the bus. This forms a complete closed-loop test environment based on real satellite status feedback, solving the technical problem that traditional GNSS simulators can only perform open-loop tests and cannot update orbital information in real time based on satellite orbital actions.

[0104] This invention can realistically simulate the complete logic of "satellite decision-actuator action-orbit change-GNSS perception-satellite re-decision" during on-orbit operation in ground tests, and realize effective closed-loop testing of the entire process of autonomous orbit maintenance by electric propulsion (including the first orbit maintenance, the orbit maintenance process and multiple consecutive orbit maintenance), which greatly improves the authenticity, coverage and effectiveness of ground tests.

[0105] This invention can be implemented in software using a general-purpose computer and a general-purpose interface conversion device, resulting in a lightweight navigation simulation ground testing device. This device connects to the satellite bus via a standard bus interface, allowing for easy integration with existing ground testing systems. It is suitable for different stages, including subsystem desktop testing and overall satellite integrated testing, exhibiting excellent versatility and cost-effectiveness.

[0106] This invention breaks away from the technical bias that traditional navigation simulation equipment is independent of satellite status. It transforms the "orbit information generator" into a link in the test loop and constructs a "digital twin orbit" that is completely synchronized with the satellite's physical (simulated) actions through the information flow of "bus listening - real-time simulation - simulated response - bus broadcast". This provides a new approach and means for high-fidelity ground testing of satellite intelligent autonomous functions.

[0107] The above description is merely one embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to the technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. A navigation simulation method for ground testing of autonomous orbit maintenance using electric propulsion for small satellites, characterized in that, Includes the following steps: Step S1: Receive broadcast data from the satellite bus, the broadcast data including at least satellite service time broadcast, attitude control broadcast, electric propulsion thrust broadcast and GNSS positioning broadcast polling; Step S2: Based on the broadcast data, perform real-time orbital dynamics simulation calculations, recursively calculate the satellite orbit, and obtain the recursive result; Step S3: Calculate navigation parameters based on the recursive results; Step S4: In response to the GNSS positioning broadcast polling in step S1, generate a GNSS positioning broadcast data frame simulating a spaceborne navigation receiver based on the navigation parameters, and send it to the satellite bus.

2. The navigation simulation method for ground testing of autonomous orbit maintenance of small satellites using electric propulsion, as described in claim 1, is characterized in that... In step S2, the satellite orbit is calculated and recursively calculated in real time based on the data type of the broadcast data, specifically including: If the received data is an attitude control broadcast, then update the latest attitude parameters; If the received data is an electric propulsion thrust broadcast, then update the latest thrust parameters; If the received data is a satellite time broadcast, then update the latest satellite time, calculate the thrust vector based on the latest attitude and thrust parameters, perform numerical integration on the orbital dynamics equations, and recursively transfer the satellite position, velocity, and mass from the previous satellite time to the latest satellite time.

3. The navigation simulation method for ground testing of autonomous orbit maintenance of small satellites using electric propulsion, as described in claim 2, is characterized in that... The orbital dynamics equations employ a finite thrust model, wherein the acceleration terms include at least the Earth's central gravitational term, the Earth's non-spherical perturbation term, the atmospheric drag perturbation term, and the thrust perturbation term.

4. The navigation simulation method for ground testing of autonomous orbit maintenance of small satellites using electric propulsion, as described in claim 1, is characterized in that... In step S4, after receiving a GNSS positioning broadcast poll from the satellite bus, a GNSS positioning broadcast data frame is generated from the navigation parameters based on the GNSS positioning broadcast frame data format specified by the bus communication protocol, as a response to the GNSS positioning broadcast poll, and the response is sent to the satellite bus.

5. The navigation simulation method for ground testing of autonomous orbit maintenance of small satellites using electric propulsion, as described in claim 1, is characterized in that... Also includes: Before entering the closed-loop update process of orbit navigation information, configuration parameters are set, including satellite parameters, orbit parameters, orbit dynamics model parameters, and parameters for communication with the satellite bus.

6. A navigation simulation device for ground testing of autonomous orbit maintenance using electric propulsion for small satellites, characterized in that, include: The data communication module is used to communicate with the satellite bus, receive broadcast data from the satellite bus, the broadcast data including at least satellite service time broadcast, attitude control broadcast, electric propulsion thrust broadcast and GNSS positioning broadcast polling, and send GNSS positioning broadcast data frames to the satellite bus; The orbital dynamics simulation module is used to perform real-time orbital dynamics simulation calculations. Taking the satellite position, velocity, and mass at the previous time as the initial state, the orbital dynamics equations are numerically integrated based on the broadcast data to obtain the satellite position, velocity, and mass at the latest time. The navigation parameter calculation module is used to calculate navigation parameters based on the recursive results; The GNSS positioning broadcast simulation module is used to generate GNSS positioning broadcast data frames simulating a spaceborne navigation receiver based on the navigation parameters obtained by the navigation parameter calculation module, and to send them through the data communication module.

7. The navigation simulation device for ground testing of autonomous orbit maintenance of small satellites using electric propulsion, as described in claim 6, is characterized in that... The orbital dynamics simulation module performs real-time simulation calculations and recursive calculations of the satellite orbit based on the data type of the broadcast data, specifically including: When the data communication module receives the attitude control broadcast, it updates the latest attitude parameters. When the data communication module receives the electric propulsion thrust broadcast, it updates the latest thrust parameters. When the data communication module receives a satellite time broadcast, it updates the latest satellite time, calculates the thrust vector based on the latest attitude and thrust parameters, and uses this to drive the numerical integration of the orbital dynamics equations.

8. The navigation simulation device for ground testing of autonomous orbit maintenance of small satellites using electric propulsion, as described in claim 6, is characterized in that... The GNSS positioning broadcast simulation module is used to: when the data communication module receives a GNSS positioning broadcast poll, generate a GNSS positioning broadcast data frame from the navigation parameters based on the GNSS positioning broadcast frame data format of the spaceborne navigation receiver specified by the bus communication protocol, as a response to the GNSS positioning broadcast poll.

9. The navigation simulation device for ground testing of autonomous orbit maintenance of small satellites using electric propulsion, as described in claim 6, is characterized in that... It also includes a configuration parameter setting module, which is used to set configuration parameters, including satellite parameters, orbit parameters, orbit dynamics model parameters, and parameters for communication with the satellite bus, before entering the closed-loop update process of orbit navigation information.

10. The navigation simulation device for ground testing of autonomous orbit maintenance of small satellites using electric propulsion, according to any one of claims 6 to 9, characterized in that, The device is based on a general-purpose computer and a general-purpose interface conversion device, and is connected to a satellite bus through a standard bus interface.

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