Citation
Abstract
In Part I of this two-part article, an error budget is presented for Earth-based delta differential one-way range (ADOR) measurements between two spacecraft. Such observations, made between a planetary orbiter (or lander) and another spacecraft approaching that planet, would provide a powerful target-relative angular tracking data type for approach navigation. Accuracies of better than 5 nrad should be possible for a pair of spacecraft with 8.4-GHz downlinks, incorporating 40-MHz DOR tone spacings, while accuracies approaching 1 nrad will be possible if the spacecraft incorporate 32-GHz downlinks with DOR tone spacings on the order of 250 MHz; these accuracies will be available for the last few weeks or months of planetary approach for typical Earth-Mars trajectories. Operational advantages of this data type are discussed, and ground system requirements needed to enable spacecraft-spacecraft ADOR observations are outlined. This tracking technique could be demonstrated during the final approach phase of the Mars 94 mission, using Mars Observer as the in-orbit reference spacecraft, if the Russian spacecraft includes an 8.4-GHz downlink incorporating DOR tones. Part II of this article will present an analysis of predicted targeting accuracy for this scenario.
Details
- Volume
- 42-110
- Published
- August 15, 1992
- Pages
- 63–76
- File Size
- 858.5 KB