Search NASA⌕ Search

Engineering topics

Bertiger, W.

Publications and source records attributed to Bertiger, W..

At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2002

GRACE: millimeters and microns in orbit

The Gravity Recovery and Climate Experiment launched March 17, 2002. The GPS data for this experiment are processed to contribute to the recover long wavelength gravity field; remove errors due to long term on-board oscillator drift; and align K/Ka-band measurments between the two spacecraft to 0.1 ns. This paper will concentrate on the use of GPS for these timing and calibration functions and will not address the recovery of the gravity field.

GRACE GPS K/Ka-band↗
NASA NTRS2002

Intial orbit determination results for Jason-1: towards a 1-cm orbit

The U.S/France Jason-1 oceanographic mission is carrying state-of-the-art radiometric tracking systems (GPS and Doris) to support precise orbit determination (POD) requirements. The performance of the systems is strongly reflected in the early POD results. Results of both internal and external (e.g., satellite laser ranging) comparisons support that the 2.5 cm radial Rh4S requirement is being readily met, and provide reasons for optimism that 1 cm can be achieved. We discuss the POD strategy underlying these orbits, as well as the challenging issues that bear on the understanding and characterization of an orbit solution at the l-cm level. We also describe a system for producing science quality orbits in near real time in order to support emerging applications in operational oceanography.

Jason-1 oceanography orbits real time↗
NASA NTRS2001

GPS-assisted GLONASS orbit determination

Using 1 week of data from a network of GPS/ GLONASS dual-tracking receivers, 15-cm accurate GLONASS orbit determination is demonstrated with an approach that combines GPS and GLONASS data.

GLONASS orbit↗
NASA NTRS2001

Precise orbit determination for CHAMP using GPS data from BlackJack Receiver

In this paper we present results for CHAMP POD using the precise GPS measurements collected by the BlackJack receiver through the up-looking antenna. We will describe the quality of the tracking data, the tuning of the reduced-dynamic model for the 400-km orbit, and the various methods of evaluating the orbit accuracy.

CHAMP↗
NASA NTRS2000

Precise orbit determination for the shuttle radar topography mission using a new generation of GPS receiver

The BlackJack family of GPS receivers has been developed at JPL to satisfy NASA's requirements for high-accuracy, dual-frequency, Y-codeless GPS receivers for NASA's Earth science missions. In this paper we will present the challenges that were overcome to meet this accuracy requirement. We will discuss the various reduced dynamic strategies, Space Shuttle dynamic models, and our tests for accuracy that included a military Y-code dual-frequency receiver (MAGR).

SRTM GPS orbit↗