Ground-Based Nanoradian Optical Astrometry and Applications to Navigation

NASA is now focusing on developing laser communication to allow much higher volumes of scientific data transmitted to Earth from deep space. JPL’s first generation optical communications terminal is planned to fly on the Pysche mission for an initial technical demonstration. Looking to the future, utilizing the optical communications infrastructure for navigation and data transmission could both save mass and power by not requiring a separate radio frequency navigation system. Ground-based optical astrometry, one of the four tasks in the initiative “Navigation and Science in the Optical Era," focuses on demonstrating the capability of using optical astrometry from ground terminals to provide the measurements of position of spacecraft in plane-of-sky for optical navigation.
NASA is now focusing on developing laser communication to allow much higher volumes of scientific data transmitted to Earth from deep space. Ground-based optical astrometry, one of the four tasks in the initiative “Navigation and Science in the Optical Era," focuses on demonstrating the capability of using optical astrometry from ground terminals to provide the measurements of position of spacecraft in plane-of-sky for optical navigation.

The goal of Ground-based Optical Astrometry is to demonstrate the feasibility of ground-based optical astrometry at nanoradian (nrad) level precision, comparable to the current state-of-the-art radio frequency (RF) astrometry precision (1-2nrad) obtained from Deep Space Network delta-Differential One-way Ranging (delta-DOR) measurements. This level of performance would be sufficient to enable plane-of-sky angle determinations for navigation purposes. Unlike the delta-DOR measurements, which require coordination between different DSN receivers, optical astrometric measurements could be done more frequently than twice per day and can be taken simultaneously during the time when optical ground terminals communicate with spacecraft.  Such an approach would be operationally more efficient and could be a step toward removing some of the RF components from the spacecraft, thereby saving mass and power. It also would open a way for navigating deep-space cubesats, whose population is expected to grow quickly in the near future, without overwhelming the current RF DSN facility for their communications and navigation.