Detailed Terminal Error Analysis for N-Thrust Guidance and Novel Error Mitigation Techniques

Currently, Rendezvous and Docking (RVD) Missions are in high demand due to their applications in on-orbit assembly, servicing, repairing, refueling, debris removal as well as in the spacecraft formation flying. In such missions, the docking objective is achieved by performing maneuvers with the help of state-of-the-art guidance algorithms. Several guidance algorithms were proposed in the literature. This paper explores one of the oldest, simplest, and fuel-efficient N-Thrust guidance strategy and presents a detailed mathematical analysis on terminal error and fuel consumption. N-Thrust guidance assumes initial radial position and transverse velocity to be zero and uses equal thrust radial pulsing at fixed intervals and imparts high terminal guidance error in scenarios where initial radial position and transverse velocity is non zero thus making it unusable for practical scenarios. Novel terminal Error mitigation strategies either by using initial transverse velocity correction or by correcting the radial thrust required are proposed. Comparison on fuel consumption and supporting simulation results are also presented thus enabling this age-old theoretical guidance strategy to be used for practical scenarios.