A Triple Estimating Receiver of Multiplexed Binary Offset Carrier (MBOC) Modulated Signals

M.S. Hodgart, R.M. Weiler, M. Unwin

Abstract:	Multiplexed Binary Offset Carrier (MBOC) is an important development of the BOC principle. But there is a tracking problem in realising a BOC receiver by a conventional implementation. For BOC this problem has been characterised as that of ‘false lock’. Here a different point of view identifies the problem as a limited capture range (compared to an equivalent PSK). This problem is exacerbated in the case of MBOC. A radically different approach described here solves the problem by adopting what we name as a triple estimating receiver. Three complementary estimates of the time of arrival (TOA) of the input signal are generated: a lowest accuracy but unambiguous estimate responding purely to the code modulation; and two higher accuracy but integerambiguous estimates responding purely to the two component sub-carrier modulations. The code estimate is used to integer correct the lower resolution sub-carrier estimates which in turn integer corrects the higher resolution estimate. A weighted linear combination provides a signal-to- noise optimal single estimate. The full range capture capability is available because there is never any false lock condition and the full potential accuracy of MBOC is realised. Implementation is by a quadruple loop rather than the double loop conventional receivers.
Published in:	Proceedings of the 21st International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2008) September 16 - 19, 2008 Savannah International Convention Center Savannah, GA
Pages:	877 - 886
Cite this article:	Hodgart, M.S., Weiler, R.M., Unwin, M., "A Triple Estimating Receiver of Multiplexed Binary Offset Carrier (MBOC) Modulated Signals," Proceedings of the 21st International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2008), Savannah, GA, September 2008, pp. 877-886.
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