Alex Gonring, The Aerospace Corporation; Jeffrey Won, The Aerospace Corporation; Derek Chen, The Aerospace Corporation; Mark Mendiola, The Aerospace Corporation; Jaime Cruz, The Aerospace Corporation; Scott Bergonzi, The Aerospace Corporation; Ann Chervenak, The Aerospace Corporation; Vincent Kong, The Aerospace Corporation
Keywords: Commercial space, orbit propagation, orbit determination, covariance propagation, UDL, space domain awareness
Abstract:
The Unified Data Library (UDL) is envisioned to be a one-stop shop for all data pertaining to Space Domain Awareness (SDA). As part of this vision, commercial satellite tracking companies currently push their observation data to the UDL, where it is available to UDL users. However, in order for this data to be utilized by authoritative SDA sources such as CSpOC, the accuracy of the data and reliability of the sources must be independently verified. In this study, we establish the framework necessary for independent verification and validation of data published to the UDL. We begin by analyzing data that LeoLabs (a commercial radar company), has published to the UDL, specifically radar observation and state vector data, for data utility and accuracy.
The data pulled from UDL in this study is exclusively sourced from LeoLabs. LeoLabs is a small, private company focused on low earth orbit (LEO) operations. LeoLabs develops and operates multiple radar stations across the globe, and is currently tracking thousands of objects in LEO. With a goal of providing tracking data, LeoLabs operates a data services platform to facilitate the distribution of their data, in addition to publishing data to the UDL. On the UDL, LeoLabs publishes observations from their radar stations, state and uncertainty estimations for each tracked object, and detailed sensor information which can be used to support SDA activities.
TRACE, The Aerospace Corporation’s Trajectory Analysis and Orbit Determination Program, was used for the analysis. It has been developed and maintained since the 1960s, and is used in the design and analysis of problems associated with high-accuracy orbital trajectory modeling, ephemeris and parameter estimation, and related error analysis. TRACE provides high-fidelity orbit propagation, orbit determination, and covariance analysis. The application is currently implemented in FORTRAN with some modules in C.
In order to independently analyze data from UDL, publicly available precise ephemerides from the European Space Agency’s (ESA) Swarm mission were used for comparison. The Swarm mission is used to provide detailed measurements on the earth’s magnetic field, and the mission provides post-fit ephemerides with a stated accuracy better than those provided by LeoLabs. The Swarm data was first used to establish the baseline accuracy of TRACE’s orbit modeling. Once this was completed, LeoLabs observations, states, uncertainties, and measurement biases were reviewed with orbit determination, orbit prediction, and covariance propagation techniques which are fundamental analyses for SDA applications. Two fundamental questions were addressed: First, how accurate is the observation data provided by LeoLabs? And second, how trustworthy is their orbit determination procedure?
To address the first question, the observation data and state vectors provided by LeoLabs to the UDL were directly compared against the Swarm ephemerides available from ESA to determine the accuracy of the data as well as the stated uncertainties. Accurate LeoLabs data would be expected to match the Swarm ephemerides to within the stated uncertainty. The comparison of observation data to Swarm ephemerides also allowed computation of any remaining biases in the observations.
To address the second question, orbit determination and covariance analysis runs were performed using LeoLabs’ observation data to determine whether their published state vectors matched the information available from their published observations. If our orbit determination results with (presumably) the same data were to indicate significant deviation from LeoLabs’ published state vectors, then it might draw into question the orbit determination methods used by LeoLabs.
The results of the above analyses will be presented to better characterize the data being pushed to the UDL by LeoLabs. The techniques implemented for this review also demonstrate the methods in which new and existing data published to the UDL by any party can be reviewed for quality and accuracy.
Date of Conference: September 15-18, 2020
Track: SSA/SDA