DocumentCode :
1311651
Title :
Spread-Spectrum Continuous-Phase-Modulated Signals for Satellite Navigation
Author :
Emmanuele, Andrea ; Zanier, Francesca ; Boccolini, Gabriele ; Luise, Marco
Author_Institution :
Dipt. Ing. dell´´Inf., Univ. di Pisa, Pisa, Italy
Volume :
48
Issue :
4
fYear :
2012
fDate :
10/1/2012 12:00:00 AM
Firstpage :
3234
Lastpage :
3249
Abstract :
Spread-spectrum continuous-phase-modulated (SS-CPM) signals are investigated with application to satellite navigation. In particular, focus is devoted to the special subclasses of SS-CPM with semi-integer modulation index h greater than one. This constitutes a novelty with respect to traditional navigation signal design on one hand (which is based on direct-sequence spread-spectrum (DS-SS) signals with rectangular pulse) and with traditional communication SS-CPM with h>;1 on the other. Main output is that setting the modulation index h<;1 to semi-integer values allows the SS-CPM signals to behave like having subcarriers, exactly in the same way as it happens for the binary offset carrier (BOC) modulation. The main advantage is that CPM ensures a constant envelope at the transmission side, thus being appealing when these features are required at the system level. After a description of signal properties, focus is devoted to ranging code synchronization, by exploitation of the theory on time-delay estimation (TDE). A few delay-lock loop schemes are also presented, based on an offset quadrature phase-shift keying (OQPSK) approximation of the signal at the receiver side, achieved by Laurent´s decomposition at the receiver side. Proposed loops performance are analyzed in terms of Cramer-Rao bound (CRB), rms tracking error, and multipath robustness. An application of SS-CPM for a two-rate-service scheme is proposed.
Keywords :
continuous phase modulation; delay lock loops; quadrature phase shift keying; radio receivers; satellite navigation; spread spectrum communication; synchronisation; BOC modulation; CRB; Cramer-Rao bound; DS-SS signal; Laurent decomposition; OQPSK approximation; SS-CPM signal; TDE; binary offset carrier modulation; code synchronization; delay-lock loop; direct-sequence spread-spectrum signal; loops performance; multipath robustness; navigation signal design; offset quadrature phase-shift keying; receiver; rectangular pulse; satellite navigation; semiinteger modulation index; semiinteger value; signal properties; spread-spectrum continuous-phase-modulated signal; time-delay estimation; tracking error; two-rate-service scheme; Approximation methods; Correlation; Distance measurement; Modulation; Receivers; Satellite navigation systems; Satellites;
fLanguage :
English
Journal_Title :
Aerospace and Electronic Systems, IEEE Transactions on
Publisher :
ieee
ISSN :
0018-9251
Type :
jour
DOI :
10.1109/TAES.2012.6324699
Filename :
6324699
Link To Document :
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