Citation
Abstract
This article is the first in a series of articles investigating the use of differenced data types for deep-space navigation. Subsequent articles will address the primary error sources affecting these data types and other important issues regarding their implementation. At the present time, radio interferometric measurements such as Delta-Differenced One-Way Range (ADOR) are formed by differencing nearsimultaneous spacecraft and quasar time-delay measurements, in order to eliminate the effects of station clock offset errors and other error sources. This article presents a simple error covariance analysis of an alternative tracking scheme, in which differenced (“two-way” minus “three-way”) range data are used directly to estimate the declination and right ascension of a distant spacecraft. The tracking scheme also estimates a measurement bias representing station clock offset and other calibration errors. The results of the analysis indicate that, with clock offset and other calibration data derived from the Global Positioning System (GPS), coupled with improvements in Deep Space Network (DSN) ranging system calibration accuracy, it is theoretically possible to determine spacecraft angular coordinates to accuracies of 30 to 90 nrad using about four hours of differenced range data. This level of accuracy should enable differenced range to support medium-accuracy missions on its own, or serve as a backup to ADOR for missions requiring greater navigation accuracy. Additional work will need to be performed to establish estimates of the complete spacecraft navigation accuracies that may be achieved operationally with combinations of differenced range data and other data types.
Details
- Volume
- 42-103
- Published
- November 15, 1990
- Pages
- 47–60
- File Size
- 664.2 KB