James T. Curran

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The frequency lock loop (FLL) is used in a wide range of communication systems as a means of achieving carrier synchronisation. One particular area in which they have proved invaluable is that of Global Satellite Navigation Systems (GNSS) employing spread spectrum modulation schemes. GNSS signals are typically subject to high dynamics, due to the high(More)
Smoking and alcohol ingestion were analysed in 5100 women confined in Tasmania in 1981. This represented 70% of the total number of confinements. The incidence of smoking throughout pregnancy was 33.6%, and 2.7% of the women studied smoked at some time during pregnancy. Alcohol consumption in pregnancy was recorded for 55.9% of patients. However, 99% were(More)
A novel maximum likelihood-based range estimation algorithm is designed to provide robustness to multipath, which is recognized as a dominant error source in DS-CDMA based navigation systems. The detection-estimation problem is jointly solved to sequentially estimate the parameters of each individual multipath component and predict the existence of a next(More)
An analysis of all births in Tasmania from 1975 to 1983 showed that social class differences in low birth weights were almost entirely restricted to infants between 1500 and 2500 g weight at birth. There was a marginal increase in very low birth weight infants (less than 1500 g) among women whose partners were unemployed or in unskilled work but extremely(More)
A prospective survey of prenatal use of prescription drugs in Tasmania yielded detailed information on drug exposure, delivery and outcome for 56,037 births from 1982 to 1989. First trimester drug use was reported by 30.9% of women, and 17.9% used only supplements of vitamins and/or minerals; 40% used alcohol during the first trimester, and 28.8% smoked(More)
Analysis of cigarette smoking and alcohol consumption patterns recorded in pregnancy could not detect a harmful effect of alcohol at levels below 2 glasses a day. Total abstainers fared very slightly worse than those who drank occasionally. Smoking was associated with lower birth-weight and a worse fetal outcome independent of socioeconomic status, parity,(More)
A novel evaluation of filtering and quantization losses for weak DS-CDMA receivers is presented. Using this method, joint optimization of filter center frequency and bandwidth is conducted for one-, two- and three-bit quantizers. It is demonstrated that a joint loss-analysis of these effects is necessary to optimize front-end design.
Traditionally, the effects of presampling filtering and of quantisation on the processing of GNSS signals have been dealt with in isolation. Analysis of the losses incurred during the quantisation process has almost invariably been based on the assumption that the signals at IF are distorted by additive white Gaussian noise. This paper, in contrast,(More)
Recently, widespread commercial demand for location-based services has presented Global Navigation Satellite System (GNSS) receiver designers with a host of new challenges. Traditionally, receivers for the Global Positioning System (GPS), for example, have been designed to receive high carrier-to-noise-floor ratio (C=N0) line-of-sight (LOS) signals using(More)
Multipath propagation causes major impairments to satellite based navigation systems and is often the dominant source of accuracy degradation and a major issue for high precision Global Navigation Satellite System (GNSS) applications. Most of the commonly used time-of-arrival estimation techniques cannot provide the required estimation accuracy in severely(More)