Navigation Message Decoding for Rocket-Borne GPS Receivers

Ken HARIMA  Hirobumi SAITO  Takuji EBINUMA  

IEICE TRANSACTIONS on Communications   Vol.E95-B   No.11   pp.3428-3431
Publication Date: 2012/11/01
Online ISSN: 1745-1345
DOI: 10.1587/transcom.E95.B.3428
Print ISSN: 0916-8516
Type of Manuscript: Special Section LETTER (Special Section on Satellite Communication Technologies in Conjunction with Main Topics of JC-SAT2011)
GPS,  rocket-borne,  decoding,  differential demodulation,  

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On rocket-borne GPS receivers, the high dynamics make the use of PLL is impractical and a FLL is used. This in turn leads to a string of errors on the demodulated navigation message. The present paper proposes two decoding algorithms for GPS navigation messages suited for strings of errors. The first philosophy uses parity check syndromes to correct demodulation errors. The second philosophy uses Log Correlation Ratio (LCR) comparison along with parity check syndromes to correct for the most probable error pattern. GPS data availability can be significantly improved by using the latter.