US 12,152,904 B2
Single star-based orientation method using dual-axis level sensor
Kun Xiong, Beijing (CN); Yinxiao Miao, Beijing (CN); Chunxi Wang, Beijing (CN); Qiufang Shang, Beijing (CN); Shengquan Tang, Beijing (CN); Tao Wang, Beijing (CN); Yue Wu, Beijing (CN); Zhen Wang, Beijing (CN); Qiang Wang, Beijing (CN); Ye Tang, Beijing (CN); and Zhengjie Wang, Beijing (CN)
Assigned to Beijing Aerospace Institute for Metrology and Measurement Technology, Beijing (CN)
Filed by BEIJING AEROSPACE INSTITUTE FOR METROLOGY AND MEASUREMENT TECHNOLOGY, Beijing (CN)
Filed on Apr. 6, 2022, as Appl. No. 17/714,829.
Claims priority of application No. 202111348637.6 (CN), filed on Nov. 15, 2021.
Prior Publication US 2022/0236078 A1, Jul. 28, 2022
Int. Cl. G01C 25/00 (2006.01); G01C 21/02 (2006.01); B64G 1/36 (2006.01); G01S 3/786 (2006.01)
CPC G01C 25/00 (2013.01) [G01C 21/025 (2013.01); B64G 1/361 (2013.01); G01S 3/7867 (2013.01)] 4 Claims
OG exemplary drawing
 
1. A single star-based orientation method using a dual-axis a level sensor and a calibration device, the calibration device comprising a star sensor, a hexahedron connected onto the star sensor, a first theodolite, a second theodolite and a processor:
the method comprising:
collecting, by the dual-axis level sensor, a non-level degree θxpitch on an Xs-axis of a dual-axis level sensor reference system and a non-level degree θypitch on a Ys-axis of the dual-axis level sensor reference system;
obtaining, at the processor, a vector νright by rotating a normal vector of a second side surface of the hexahedron around a Zn-axis of a quasi-horizontal reference system by a preset azimuth angle θdirright; wherein the hexahedron includes a first side surface and the second side surface which are orthogonal;
calculating, at the processor, t4 and t6 through the following equations:

OG Complex Work Unit Math
wherein t4 is a component of the vector νright, on an Xn-axis of the quasi-horizontal reference system; and t6 is a component of the vector νright on the Zn-axis of the quasi-horizontal reference system; α is an angle between the Xs-axis of the dual-axis level sensor reference system and an X-axis of a hexahedron reference system on the star sensor; Δθxpitch is a bias of the dual-axis level sensor on the Xs-axis; and Δθypitch is a bias of the dual-axis level sensor on the Ys-axis;
observing and measuring, by the star sensor, a single astronomical object to obtain an observation vector νPRI in the hexahedron reference system and obtain a reference vector νGND of the single astronomical object in an inertial reference system from a star catalog, wherein the νGND and νPRI satisfy the following equation:
Rz(θz)·Rx(θx)·Ry(θy)·νGND=νPRI;
wherein Ry(θy) denotes that the reference vector νGND rotates around a Y-axis of the hexahedron reference system by an azimuth angle θy; Rx(θx) denotes that the reference vector νGND rotates around the X-axis of the hexahedron reference system by a pitch angle θx; and Rz(θz) denotes that the reference vector νGND rotates around a Z-axis of the hexahedron reference system by a roll angle θz;
calculating, at the processor, the pitch angle θx and the roll angle θz according to the t4 and t6 through the following equations:

OG Complex Work Unit Math
and obtaining, at the processor, νGND=Ry(−θy)·νGND according to νGND0=Rx(−θx)·Rz(−θz)·νPRI; and calculating, at the processor, the azimuth angle θy through the following equation

OG Complex Work Unit Math
wherein [v1 v2 v3]T=νGND; v1−v3 are components of the νGND on three axes of the inertial reference system, respectively; [v4 v5 v6]T=νGND0; and v4−v6 are components of the νGND0 on the Xn-axis, the Yn-axis and the Zn-axis, respectively; and
tracking, by the star sensor, the single astronomical object according to the calculated azimuth angle θy thereby completing the single star-based orientation.