เปรียบเทียบวิธี

	การแพร่กระจายวงโคจรด้วยวิธี SGP4 TLE	ตัวควบคุม B-Dot
สาขาวิชา	การบินและอวกาศ	การบินและอวกาศ
ตระกูล	Process / pipeline	Process / pipeline
ปีกำเนิด	1970s	1980s
ผู้ริเริ่ม	NORAD, USAF	Spacecraft attitude control engineers
ประเภท	Propagation method	Control law
แหล่งต้นตำรับ	Vallado, D. A., Crawford, P., Hujsa, R., & Kelso, T. S. (2006). Revisiting Spacetrack Report Number 3. In AIAA/AAS Astrodynamics Specialist Conference.	Wertz, J. R. (Ed.). (2002). Spacecraft Attitude Determination and Control. Kluwer Academic.
ชื่อเรียกอื่น	SGP4, TLE propagation, simplified perturbations	B-dot control, magnetic damping, momentum dumping
ที่เกี่ยวข้อง	3	3
สรุป	SGP4 (Simplified General Perturbations 4) is a rapid orbital propagation method that predicts satellite position and velocity from Two-Line Element (TLE) sets published by NORAD. Developed in the 1970s, SGP4 accounts for atmospheric drag, gravitational perturbations, and solar radiation pressure using simplified analytical models. SGP4 is the de facto standard for space surveillance, conjunction assessment, and satellite tracking.	The B-Dot controller (magnetic B-dot control law) is a simple, robust spacecraft attitude control method that uses the rate of change of Earth's magnetic field measured onboard to generate a magnetic dipole moment. Developed in the 1980s, the B-Dot law damps spacecraft angular momentum without requiring a complex attitude estimate or external reference, making it ideal for initial momentum dumping after launch or in contingency scenarios. B-Dot is passive, simple to implement, and effective.