International Telemetering Conference Proceedings / October 26-29, 1998 / Town & Country Resort Hotel and Convention Center, San Diego, California / In any satellite communication, the Doppler shift associated with the satellite’s position
and velocity must be calculated in order to determine the carrier frequency. If the satellite
state vector is unknown then some estimate must be formed of the Doppler-shifted carrier
frequency. One elementary technique is to examine the signal spectrum and base the
estimate on the dominant spectral component. If, however, the carrier is spread (as in
most satellite communications) this technique may fail unless the chip rate-to-data rate
ratio (processing gain) associated with the carrier is small. In this case, there may be
enough spectral energy to allow peak detection against a noise background.
In this paper, we present a method to estimate the frequency (without knowledge of the
Doppler shift) of a spread-spectrum carrier assuming a small processing gain and binary-phase
shift keying (BPSK) modulation. Our method relies on a simple, averaged discrete
Fourier transform along with peak detection. We provide simulation results indicating the
accuracy of this method. In addition, we will describe an all-digital hardware design
based around a Motorola DSP56303 and high-speed A/D which implements this
technique in real-time. The hardware design is to be used in NMSU’s implementation of
NASA’s demand assignment, multiple access (DAMA) service.
| Identifer | oai:union.ndltd.org:arizona.edu/oai:arizona.openrepository.com:10150/607365 |
| Date | 10 1900 |
| Creators | Scaife, Bradley J. |
| Contributors | De Leon, Phillip L., New Mexico State University |
| Publisher | International Foundation for Telemetering |
| Source Sets | University of Arizona |
| Language | en_US |
| Detected Language | English |
| Type | text, Proceedings |
| Rights | Copyright © International Foundation for Telemetering |
| Relation | http://www.telemetry.org/ |
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