Citation
Abstract
This article 1s the second in a series investigating the use of differenced range and Doppler data types for deep-space navigation. Quantitative analysis of X-band (8.4-GHz) differenced Doppler data recently acquired from the Magellan spacecraft has indicated that this data type is much more accurate than was previously thought. While differenced Doppler will be used by Magellan to support navigation during the Venus mapping mission, it might also be useful for navigation in heliocentric space flight as well. This article presents a brief investigation of the ability of differenced Doppler to determine the angular coordinates of spacecraft at interplanetary distances. A simple, analytic error covariance analysis ts developed and used to compute approximate angular accuracy statistics, taking into account the effects of station frequency offset calibration errors on the data. The results indicate that it is theoretically possible to determine spacecraft right ascension to an accuracy of 30 to 40 nrad using about 4 hours of data, while declination may be determined to accuracies of 80 to 300 nrad, except for declinations within 5 deg of the Earth’s equator, where declination accuracy is degraded severely due to unfavorable measurement geometry. If these accuracies could be delivered operationally, differenced Doppler, like differenced range, may be able to serve as a medium-accuracy supplementary or back-up data type to Delta-Differenced One-Way Range (ADOR).
Details
- Volume
- 42-103
- Published
- November 15, 1990
- Pages
- 61–69
- File Size
- 496.9 KB