Mark Hinga, AFRL/RDST
Keywords: Cislunar, Asteroid Angle Only, Autonomous Navigation
Abstract:
Cis-Lunar Autonomous Navigation via Implementation of Optical Asteroid Angle-Only Measurements
Mark B. Hinga, PhD, PE
AFRL/RDST
27 JUL 2020
Autonomous cis- or trans-Lunar spacecraft navigation is critical to mission success as communication to ground stations and access to GPS signals could be lost. However, if the satellite has a camera of sufficient quality, line of sight (unit vector) measurements can be made to known solar system bodies to provide observations which enable autonomous estimation of position and velocity of the spacecraft, that can be telemetered to those interested space based or ground based consumers. An improved Gaussian-Initial Orbit Determination (IOD) algorithm, based on the exact values of the f and g series (free of the 8th order polynomial and range guessing), for spacecraft state estimation, is presented here and exercised in the inertial coordinate frame (2-Body Problem) to provide an initial guess for the Batch IOD that is performed in the Circular Restricted Three Body Problem (CRTBP) reference frame, which ultimately serves to initialize a CRTBP Extended Kalman Filter (EKF) navigator that collects angle only measurements to a known Asteroid 2014 EC (flying by the Earth) to sequentially estimate position and velocity of an observer spacecraft flying on an APOLLO-like trajectory to the Moon. With the addition of simulating/expressing the accelerations that would be sensed in the IMU platform frame due to delta velocities caused by either perturbations or corrective guidance maneuvers, this three phase algorithm is able to autonomously track the spacecraft state on its journey to the Moon while observing the motion of the Asteroid.
This three phase algorithm enables highly-accurate autonomous spacecraft orbit estimation and continued navigation in the CRTBP frame for a single space based observer that is initialized with a limited set of measurements (at least 10) to the Asteroid 2014 EC, in both the inertial and CRTBP frames.
Date of Conference: September 15-18, 2020
Track: Cislunar SSA