Session
Session 10: Ground Systems
Abstract
Current two-way satellite tracking methods are insufficient to support the growing interest in deep space small satellite missions. To meet the low cost and minimal resource allocations that make CubeSats so appealing, navigation methods must be developed that reduce ground communication requirements. One promising approach is the use of a stable onboard timing reference to enable one-way ground uplink ranging capabilities. The Chip Scale Atomic Clock (CSAC) is a stable oscillator that meets the size, weight, and power requirements for use on CubeSats. Maxwell, a University of Colorado Boulder CubeSat mission, provides the opportunity for a flight test of CSAC-driven one-way ranging. This work presents a preliminary simulation of the mission, modeling the expected LEO orbit determination (OD) performance using CSAC-driven radiometric measurements. The effect of thermal variations on the CSAC behavior are specifically considered, and the OD performance in the presence of both stochastic clock and thermal variations is evaluated. It is shown that the use of a Dynamic Model Compensation algorithm is more effective than a State Noise Compensation algorithm in mitigating the thermal clock effects, for both one second and thirty second data rates. This LEO simulation and eventual Maxwell CSAC flight provide the first steps towards demonstrating the feasibility of CubeSat navigation using one-way ranging.
Investigation of CSAC Driven One-Way Ranging Performance for CubeSat Navigation
Current two-way satellite tracking methods are insufficient to support the growing interest in deep space small satellite missions. To meet the low cost and minimal resource allocations that make CubeSats so appealing, navigation methods must be developed that reduce ground communication requirements. One promising approach is the use of a stable onboard timing reference to enable one-way ground uplink ranging capabilities. The Chip Scale Atomic Clock (CSAC) is a stable oscillator that meets the size, weight, and power requirements for use on CubeSats. Maxwell, a University of Colorado Boulder CubeSat mission, provides the opportunity for a flight test of CSAC-driven one-way ranging. This work presents a preliminary simulation of the mission, modeling the expected LEO orbit determination (OD) performance using CSAC-driven radiometric measurements. The effect of thermal variations on the CSAC behavior are specifically considered, and the OD performance in the presence of both stochastic clock and thermal variations is evaluated. It is shown that the use of a Dynamic Model Compensation algorithm is more effective than a State Noise Compensation algorithm in mitigating the thermal clock effects, for both one second and thirty second data rates. This LEO simulation and eventual Maxwell CSAC flight provide the first steps towards demonstrating the feasibility of CubeSat navigation using one-way ranging.
