P. Chippendale

Accurate vehicular positioning using a DAB-GSM hybrid system

The Global Position System (GPS) and the Global Navigation Satellite System (GLONASS) are based on a satellite system. Much work has been carried out on a non-satellite positioning system using the existing Global System of Mobile Communications (GSM) infrastructure. This leads to a GPS-GSM positioning system that manufacturers claim to reliably locate a mobile phone down to resolutions of less than 125 m. The requirement needed to achieve such a resolution with a GPS/GSM positioning system is to have three GSM base stations in a 30 km area. This requirement is difficult to obtain especially in rural areas. The work carried out in this paper shows how to integrate digital audio broadcast (DAB) transmitters with GSM base stations for positioning systems. This novel DAB-GSM hybrid positioning system can reach an accuracy of 40 meters.

Enhanced Image Coding for Noisy Channels

This paper explores the application of a combined error resilient coding scheme to image transmission over time-varying noisy channels. To improve performance at low signal-to-noise ratios, turbo coding is incorporated into the system. Demonstrated through simulations, this novel combination of source and channel coding is shown to correct and restrict errors incurred during transmission over Additive White Gaussian Noise (AWGN) and Rayleigh Fading channels. The error correcting capability of the coding scheme also illustrated with compressed and uncompressed image transmission results which are comparable in terms of their visual quality.

Error resilient image coding for radio channels

This paper explores the application of the error resilient coding scheme, absolute addressed picture element coding (APEL), to progressive image transmission over narrow-band radio channels, such as HF. Picture element (pel) interleaving strategies are explored and APEL coding and its merits are discussed. Demonstrated through air-trial results, this novel image coding approach are shown to restrict error propagation through its unique coding structure and offer reconstructed images of increasing definition as transmissions progress.