High‐precision attitude determination and control system design and real‐time verification for CubeSats

Abstract

This paper presents the design and real-time verification of a high-precision and low-cost attitude determination and control system (ADCS) for CubeSat based on a micro-electro-mechanical (MEMS) gyroscope. The CubeSat new missions require accurate and sophisticated ADCS with attitude drift adjustment. Moreover, designing an effective ADCS for the CubeSat poses a difficult challenge. The satellite comprises of a two-unit CubeSat, which denotes that the ADCS is designed with small size, tight mass, and energy limitations. The ADCS has been enhanced in the former few years from fairly small resolution of 10 to around 0.6 m. This attitude drift, if not properly compensated, will cause a slow attitude information loss as the error in attitude rises between the actual and estimated. To correct the attitude adrift, the proposed system utilizes a MEMS gyroscope sensor which offers a comparative attitude to the Kalman filter for estimated attitude update. Real-time verification and validation for the ADCS are performed through Matlab/Simulink environment and lab testing to prove the efficacy of the proposed system. Simulation of the ADCS shows accurate results with error of no more than 1 . K E Y W O R D Sattitude determination, CubeSat, gyroscope, MEMS ADCS computer that holds the whole algorithms and the control schemes of the ADCS. The resolution of the ADCS is increased to around 0.6 m in the former 10 years. 6 The CubeSat U-class spacecraft 7 belongs to a category of reduced satellites that is mainly used in research and comprises several numbers of cubic elements. Moreover, the single largest step in reducing software cost is the usage of commercial, off-the-shelf (COTS) software. 8 This is analogous for the adoption of COTS microelectronics in space application. The CubeSats usually employ COTS in their structure: electronics design, and weights around 1.3 kg/unit. 9 For the control of the CubeSat, there are three phases after launch: de-tumbling, initial attitude determination (AD), and recursive AD. As the most prevalently used algorithms in satellite de-tumbling process, B-Dot controller controls the satellite by aligning it with the earth magnetic field vectors. Indeed, all small satellites used some variation of B-Dot as the controller for de-tumbling process. [10][11][12] As for preliminary AD, TRIAD method is one of the initial and simplest solutions to the spacecraft AD problem. This technique entails two sets of vectors: an observation vector from magnetometer and sun sensors, and a vector command for each observation according to its inertial reference frame. In 1977, Davenport presented the first successful application of Wahba's problem to spacecraft AD (as reported by Keat 13 ) using the quaternion parameterization of the direction cosine matrix (DCM) with the q-method algorithm. In 1979 (as reported by Shuster and Oh 14 ), the QUaternion estimator (QUEST) algorithm appeared as an alternative to the q-method. Although less robust than the qmethod, QUEST is the most used algorithm for Wahba's problem. 1...