Anthony Holincheck, Sceptre Analytics; Janet Cathell, Sceptre Analytics
Keywords: open source, sgp4, sgp4-xp, orbit determination, covariance
Abstract:
The new SGP4-XP algorithm was released by USSF near the end of 2020 and is claimed to offer accuracy that is “statistically equivalent” to the high-precision Special Perturbations algorithm. There are several issues that will likely limit the adoption of SPG4-XP: it still relies on a two-line structure without covariance information, new TLEs are not publicly available, and the software is distributed in binary format only. We present an open source software implementation that addresses each of these issues. By using the well-established practice of generating pseudo observations from lower-precision theories and then performing orbit determination with a higher-precision theory, TLEs for SGP4-XP can be used with any force model. The OD process provides missing covariance data. This process allows organizations that do not wish to run third-party binaries on their operational computers to generate pseudo observations elsewhere and only import the necessary output. For organizations willing to trust these binaries, pseudo observations from SGP4 or other ephemeris can be used to generate SGP4-XP TLEs. This allows users of the new algorithm to generate compatible TLEs from existing sources.
Date of Conference: September 14-17, 2021
Track: Astrodynamics