As on-board satellite systems continue to increase in ability to perform self diagnostic checks, it will become more important for satellites to initiate ground communications contact. Currently, the NASA Space Network requires users to pre-arranged times for satellite communications links through the Tracking and Data Relay Satellite (TDRS). One of the challenges in implementing an on-demand access protocol into the Space Network, is the fact that a low Earth orbiting (LEO) satellite's communications will be subject to a doppler shift which is outside the capability of the NASA ground station to lock onto. In a prearranged system, the satellite's doppler is known a priori, and the ground station is able to lock onto the satellite's signal. This paper describes the development of a high speed analog to digital interface into a Digital Signal Processor (DSP). This system will be used for identifying the doppler shift of a LEO satellite through the Space Network, and aiding the ground station equipment in locking onto the signal. Although this interface is specific to one application, it can be used as a basis for interfacing other devices with a DSP.
High Speed A/D DSP Interface for Carrier Doppler Tracking
1998
72 pages
Report
No indication
English
Common Carrier & Satellite , Unmanned Spacecraft , Spacecraft Trajectories & Flight Mechanics , Doppler effect , Satellite communication , Signal processing , Analog to digital converters , Digital systems , Carrier frequencies , Telecommunication , Ground stations , Low earth orbits , Tdr satellites , Carrier to noise ratios
Analysis of INS Derived Doppler Effects on Carrier Tracking Loop
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