M. Stephen Hodgart

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This paper presents a new approach to resolve integer ambiguity and achieve instantaneous spacecraft attitude from phase information of global positioning system signals, without requiring independent attitude information from traditional attitude sensors. A newly approached algorithm based on Gram-Schmidt orthonormalisation is proposed for medium length(More)
This paper details the research and development of a robust, real-time GPS attitude determination system that has now been demonstrated using the SGR-20 GPS receiver on the Topsat microsatellite. As part of this work a robust integer ambiguity resolution algorithm was developed and validated using data logged in orbit. The new algorithms were integrated(More)
The Double Estimation Technique (DET) is a GNSS signal-tracking concept. DET has the capability to produce reliable unambiguous, full-precision delay estimates from the Binary Offset Carrier (BOC) signals which have been adopted by the modernized and new GNSS, including the European Galileo constellation. DET is robust, being able to function under(More)
A Minimum Shift Keying (MSK) or Fast Frequency Shift Keying (FFSK) coherent demodulating algorithm is discussed. Both carrier synchronisation and optimal symbol correlation are done within two decision switched Costas loops, each operating at one of the reference signal frequencies. Simulation shows the demodulator to be robust against phase distortion and(More)
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