PT  - JOURNAL ARTICLE
AU  - Alex V. Conrad
AU  - Penina Axelrad
AU  - Bruce Haines
AU  - Cinzia Zuffada,
AU  - Andrew O’Brien
TI  - Improved GPS-Based Single-Frequency Orbit Determination for the CYGNSS Spacecraft Using GipsyX
AID  - 10.33012/navi.565
DP  - 2023 Mar 20
TA  - NAVIGATION: Journal of the Institute of Navigation
PG  - navi.565
VI  - 70
IP  - 1
4099  - https://navi.ion.org/content/70/1/navi.565.short
4100  - https://navi.ion.org/content/70/1/navi.565.full
SO  - NAVIGATION2023 Mar 20; 70
AB  - This paper presents methods for the precise orbit determination (POD) of a satellite in the CYGNSS constellation based on available single-frequency GPS code and carrier measurements. The contributions include the development and evaluation of procedures for single-frequency POD with GipsyX, improvement of CYGNSS orbit knowledge, and an assessment of its final accuracy. Ionospheric effects are mitigated using the GRAPHIC processing method, and spacecraft multipath effects are calibrated with an azimuth/elevation-dependent antenna calibration map. The method is demonstrated using comparable data from the GRACE mission, from which we infer the expected accuracy of the CYGNSS results. Processing more than 170 days of data from each mission, a 1σ CYGNSS orbit accuracy of 2.8 cm radial, 2.4 cm cross-track, and 6 cm in-track is demonstrated. We expect that achieving this level of performance will expand the set of future scientific investigations that can be undertaken using satellites equipped with single-frequency GNSS.