Formulation and Characterization of One-Way Radiometric Tracking with the Iris Radio Using a Chip-Scale Atomic Clock

The Iris software radio has been updated to collect one-way Doppler and range data for potential use with deep space autonomous navigation. One-way radiometric data have found limited use because a typical radio oscillator is not sufficiently stable for use in navigation. However, Iris has been paired with a chip-scale atomic clock (CSAC) via an input signal of one pulse per second. With superior stability relative to a typical oscillator, the CSAC has the potential to provide onboard tracking data with sufficient accuracy to support a small satellite mission with modest navigation requirements. In this paper, we develop models of the Iris radio one-way Doppler and range data and analyze their performance in lab testing prior to a future inflight test on NASA's CAPSTONE mission to the Moon. The test results confirm theoretical predictions for range precision measured between 0.38 m and 2.21 m with a range rate of 11 mm/s at 60 s.