Design And Implementation Of Small Satellite Binary-star Simulator

Satellites need to be in service for a long time after launch and maintenance is difficult to achieve.Therefore,in the process of developing satellites,comprehensive and reliable testing of their functional systems is required.At the same time,satellite testing accompanies the entire satellite development cycle as an important link.For satellite testing,semi-physical closed-loop testing is more real-time and robust.It can effectively implement satellite attitude control simulation tests.The test results are closer to the real scene and effectively reduce the cost and risk of testing.Based on the modular design ideas and the design requirements of the small satellite semiphysical simulation test system,this paper designs and implements a set of miniaturized dualstar simulators for the test system.The simulator can simulate the electrical interface and working timing of real components on the satellite.On the one hand,it can cooperate with the design verification of the small satellite test system;on the other hand,it completes the test with the dynamic system in the initial stage of small satellite development.In the test process,it is also possible to simulate small satellites injecting multiple faults during orbital operation,in order to detect problems early and avoid losses,which has great significance for ensuring the safety of small satellites.The article first establishes a simulation model for the method of determining the orbit and attitude of a small satellite,and describes the working principle and composition design of the closed-loop test.Then,the design requirements and technical indicators of the small satellite simulator are refined and analyzed.The design is divided into three parts: hardware,firmware and software for implementation,and the design schemes are given respectively.Through overall planning,this paper develops a general-purpose sensor hardware interface module.Its working timing and logic control rely on the FPGA.Model calculations rely on a DSP with 32-bit floating-point arithmetic capability.Different sensors are completed through multiple general-purpose boards Requirements for the simulator.The hardware design scheme and related circuit design of the applied functional components are introduced in detail,the firmware and program design are explained,and the satellite fault injection interface is provided.Finally,in response to the time synchronization requirements of the dual-star simulator,the clock synchronization protocol was simulated through the communication interface during ground testing.In the end,this subject is oriented to the needs of a small satellite,and a small satellite simulator including a gyro,a star sensor,and a sun sensor is built,and its function is verified by a ground test platform.The test results show that the small satellite simulator designed this time can realize the data transmission function of the ground test and the model calculation function,which can meet the requirements of system performance indicators,and the closedloop simulation time is less than 10 ms required by the task.The overall operation of the simulator is reliable and stable,which can cooperate with the small satellite ground test task.