NASA NTRS · 20150004694
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Kovalik, Joe. 2012-11-15. Lunar Lasercom OCTL Terminal (LLOT): Status November 2012. https://ntrs.nasa.gov/citations/20150004694
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The Orion Optical Navigation (OpNav) System is a first-of-its-kind navigation capability that was demonstrated in space on the Artemis I mission. The OpNav System was tested under a variety of conditions, resulting in over one thousand images of Earth, Moon, and starfields. Pairing the images with ground tracking information, not only did Artemis I provide a basis to evaluate the performance of the Orion OpNav system, but produced a valuable set of imagery/data that can be used to further development and testing of other optical navigation systems.
Spacecraft carrying optical communication lasers can be treated as artificial stars, whose relative astrometry to Gaia reference stars provides spacecraft positions in the plane-of-sky for optical navigation. To be comparable to current Deep Space Network delta-Differential One-way Ranging measurements, thus sufficient for navigation, nanoradian optical astrometry is required. Here we describe our error budget, techniques for achieving nanoradian level ground-base astrometry, and preliminary results from a 1 m telescope. We discuss also how these spacecraft may serve as artificial reference stars for adaptive optics, high precision astrometry to detect exoplanets, and tying reference frames defined by radio and optical measurements.
We present a high-precision ranging and range-rate measurement system via an optical-ranging or combined ranging-communication link. A complete bench-top optical communication system was built. It included a ground terminal and a space terminal. Ranging and range rate tests were conducted in two configurations. In the communication configuration with 622 data rate, we achieved a two-way range-rate error of 2 microns/s, or a modified Allan deviation of 9 x 10 (exp -15) with 10 second averaging time. Ranging and range-rate as a function of Bit Error Rate of the communication link is reported. They are not sensitive to the link error rate. In the single-frequency amplitude modulation mode, we report a two-way range rate error of 0.8 microns/s, or a modified Allan deviation of 2.6 x 10 (exp -15) with 10 second averaging time. We identified the major noise sources in the current system as the transmitter modulation injected noise and receiver electronics generated noise. A new improved system will be constructed to further improve the system performance for both operating modes.