DMA (Defense Mapping Agency) Orbit Determination of the Navy Navigation Satellite System for 1987

摘要

The Defense Mapping Agency Hydrographic/Topographic Center (DMAHTC) performs precise orbit computations for Navy Navigation Satellite System (NNSS) satellites, also called TRANSIT, using Doppler observations collected by a worldwide network of stations. Equipment at these sites is configured around either a Tranet II or a Magnavox 1502 DS receiver. Table 1 lists the current stations while Figure 1 shows the tracking network configuration. Recorded Doppler counts, surface weather measurements, and other appropriate data are transmitted daily via satellite communications or over other telecommunication links to DMAHTC for processing, time corrections and orbit determination. There are two classes of NNSS satellites - the Oscar and the Nova. The Nova satellites represent the latest generation of TRANSIT satellites. For Nova satellite 30480 and Oscar satellites 30110, 30130, 30200, 30240 and 30300, data were processed in one-day fits. Table 2 and Figure 2 provide additional information on these satellites. (FR)