Chip Scale Atomic Clock–Driven One-Way Radiometric Tracking for Low-Earth-Orbit CubeSat Navigation

Chip scale atomic clocks (CSACs) have the potential to provide CubeSat missions with precision timekeeping capabilities to support onboard radiometric tracking, reducing dependence on ground support. This work considers a baseline orbit determination (OD) scenario for a low-Earth-orbit CubeSat, with one-way radiometric measurements made onboard using a CSAC as the timing reference. Methods for simulating and estimating a stochastic CSAC signature and a temperature-induced frequency variation are presented. Navigation and clock estimation performance are analyzed for both stochastic-only and thermally influenced CSAC signature cases. The models and methods can be extended to other orbital regimes and CubeSat applications requiring precise onboard timing.