Coherent Combination of Signals from Multiple Receiving Sites of NAVSPASUR (Naval Space Surveillance)
Abstract
The Naval Space Surveillance system (NAVSPASUR) is designed to determine orbits for satellites which reflect signals from the NAVSPASUR transmitters. There are several NAVSPASUR receiving sites, each of which has 11 or 12 individual antennas. The relative phase of reflected signals as received at these closely spaced antennas (typically within 200 to 1200 feet of each other) is used to determine the angular location of the satellites. Because of the short baselines between the antennas, the accuracy of an angular position measurement is not high. Typical accuracies are 0.01 degree. If it were possible to combine signals from several NAVSPASUR sites (with typical separations of many hundreds to thousands of kilometers), much higher position accuracies could potentially be determined. It might also be expected that some imaging information could be gained for some larger satellites. This report discusses the requirements for coherent combination of signals received at different NAVSPASUR sites, and notes the limits set by equipment, propagation effects, and the characteristics of the NAVSPASUR signals themselves. By coherent combination, we mean determining the relative phases of signals received at different sites. We conclude that little useful information is likely to result from such operation, mostly because it is unlikely that accurate, absolute phases can be determined.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 10, 1988
- Accession Number
- ADA198871
Entities
People
- David B. Shaffer
- Michael D. Andrews