قارن الطرق

	الملاحة النسبية	انتشار SGP4 TLE
المجال	هندسة الطيران والفضاء	هندسة الطيران والفضاء
العائلة	Process / pipeline	Process / pipeline
سنة النشأة	1957	1970s
صاحب الطريقة	Lin-Hsiung Chu	NORAD, USAF
النوع	Guidance law	Propagation method
المصدر التأسيسي	Knox, W. P. (1971). On optimal proportional navigation. IEEE Transactions on Aerospace and Electronic Systems, AES-7(3), 417–426.	Vallado, D. A., Crawford, P., Hujsa, R., & Kelso, T. S. (2006). Revisiting Spacetrack Report Number 3. In AIAA/AAS Astrodynamics Specialist Conference.
الأسماء البديلة	PN, PN law	SGP4, TLE propagation, simplified perturbations
ذات صلة	3	3
الملخص	Proportional Navigation (PN) is a guidance law that generates command accelerations proportional to the rate of change of the line-of-sight angle between a pursuer and target. Introduced by Lin-Hsiung Chu in the 1950s, it became the foundation of modern missile guidance systems. PN solves the pursuit-evasion problem by ensuring that the pursuer intercepts a moving target with minimal computational overhead.	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.