New High-Altitude GPS Navigation Results from the Magnetospheric Multiscale Spacecraft and Simulations at Lunar Distances

Winternitz, Luke B.; Bamford, William; Price, Samuel R.

doi:10.33012/2017.15367

“…Additionally, the receiver uses a 20-ms long coherent integration to track weak signals as low as 22 dB-Hz. [3]. The Navigator algorithms have been incorporated into the GPS receiver on the NASA Orion Crew Vehicle, and the design has been licensed to several commercial vendors of GPS receivers.…”

Section: Navigator Gps Receivermentioning

confidence: 99%

“…There are a number of examples in recent years of operational space missions utilizing GPS measurements in GEO and HEO, and the demonstrated navigation performance for these missions has greatly exceeded pre-launch expectations in many cases [1,2,3]. These missions realize such exceptional performance for several reasons: transmitted GPS power levels exceed formal specifications of performance; receiver technology has evolved to reliably track very weak GPS signals; and transmissions from the GPS satellite antenna side lobes, which are completely excluded from performance specifications, contribute significantly to signal availability and improve the geometry of tracked satellites.…”

Section: Introductionmentioning

confidence: 99%

Characterization of on‐orbit GPS transmit antenna patterns for space users

Donaldson

¹

,

Parker

²

,

Moreau

³

et al. 2020

View full text Add to dashboard Cite

The GPS Antenna Characterization Experiment (GPS ACE) has made extensive observations of GPS L1 signals received at geosynchronous (GEO) altitude, with the objective of developing comprehensive models of the signal levels and signal performance in the GPS transmit antenna side lobes. The experiment was originally motivated by the fact that data on the characteristics and performance of the GPS signals available in GEO and other high Earth orbits was limited. The lack of knowledge of the power and accuracy of the side lobe signals on-orbit added risk to missions seeking to employ the side lobes to meet navigation requirements or improve performance. The GPS ACE Project filled that knowledge gap through a collaboration between The Aerospace Corporation and NASA Goddard Spaceflight Center to collect and analyze observations from GPS side lobe transmissions to a satellite at GEO using a highly-sensitive GPS receiver installed at the ground station. The GPS ACE architecture has been in place collecting observations of the GPS constellation with extreme sensitivity for several years. This sensitivity combined with around-the-clock, all-in-view processing enabled full azimuthal coverage of the GPS transmit gain patterns over time to angles beyond 90 degrees off-boresight. Results discussed in this paper include the reconstructed transmit gain patterns, with comparisons to available pre-flight gain measurements from the GPS vehicle contractors. For GPS blocks with extensive ground measurements, the GPS ACE results show remarkable agreement with ground based measurements. For blocks without extensive ground measurements, the GPS ACE results provide the only existing assessments of the full transmit gain patterns. The paper also includes results of pseudorange deviation analysis to assess systematic errors associated with GPS side lobe signals.

show abstract

“…It was first used operationally on NASA's Global Precipitation Measurement (GPM) mission in LEO, and subsequently Navigator was used for the on-board navigation system on the NASA Magnetospheric Multiscale (MMS) mission. The MMS mission features four spacecraft in highly elliptical orbits, and the Navigator receiver has demonstrated robust GPS performance at ranges from the Earth reaching nearly half way to the Moon [3]. The Navigator algorithms have been incorporated into the GPS receiver on the NASA Orion Crew Vehicle, and the design has been licensed to several commercial vendors of GPS receivers.…”

Section: Navigator Gps Receivermentioning

confidence: 99%

Characterization of On-Orbit GPS Transmit Antenna Patterns for Space Users

Donaldson

¹

,

Parker

²

,

Moreau

³

et al. 2018

Proceedings of the 31st International Technical Meeting of the Satellite Division of the Institute of Navigation (ION GNSS+ 201

6

0

View full text Add to dashboard Cite

The GPS Antenna Characterization Experiment (GPS ACE) has made extensive observations of GPS L1 signals received at geosynchronous (GEO) altitude, with the objective of developing comprehensive models of the signal levels and signal performance in the GPS transmit antenna side lobes. The experiment was originally motivated by the fact that data on the characteristics and performance of the GPS signals available in GEO and other high Earth orbits was limited. The lack of knowledge of the power and accuracy of the side lobe signals on-orbit added risk to missions seeking to employ the side lobes to meet navigation requirements or improve performance. The GPS ACE Project filled that knowledge gap through a collaboration between The Aerospace Corporation and NASA Goddard Spaceflight Center to collect and analyze observations from GPS side lobe transmissions to a satellite at GEO using a highly-sensitive GPS receiver installed at the ground station. The GPS ACE architecture has been in place collecting observations of the GPS constellation with extreme sensitivity for several years. This sensitivity combined with around-the-clock, all-in-view processing enabled full azimuthal coverage of the GPS transmit gain patterns over time to angles beyond 90 degrees off-boresight. Results discussed in this paper include the reconstructed transmit gain patterns, with comparisons to available pre-flight gain measurements from the GPS vehicle contractors. For GPS blocks with extensive ground measurements, the GPS ACE results show remarkable agreement with ground based measurements. For blocks without extensive ground measurements, the GPS ACE results provide the only existing assessments of the full transmit gain patterns. The paper also includes results of pseudorange deviation analysis to assess systematic errors associated with GPS side lobe signals.https://ntrs.nasa.gov/search.

show abstract

“…Operational highaltitude use has been documented as early as 2000 for users of GPS at geostationary altitude [5], and for multi-GNSS using both GPS and Russia's GLONASS starting in 2007 [6]. Recent published examples include NASA's Magnetospheric Multiscale (MMS) mission [7], which successfully uses GPS at 40% of lunar distance, and the US Geostationary Operational Environmental Satellite-R (GOES-R) series of weather satellites [8]. A major finding of the AMSAT OSCAR-40 experiment was that in addition to the inherent challenges of high-altitude GNSS use, the characteristics of the transmitted signals reaching this regime were also changing as the design of the GPS satellites evolved.…”

Section: Introductionmentioning

confidence: 99%