Signals of Opportunity for Remote Sensing

The next generation of high-resolution numerical weather models require fine-scale (1-5 km) measurements of water vapour over large areas (>20,000 km2). Existing observing techniques such as GPS are not able to meet these requirements. This project will determine the feasibility of a novel technique for measuring water vapour by the reception and processing of digital radio and television signals (DAB & DVB-T also known as Freeview). The project is a step towards the realization of a wide-area water vapour sensor network made possible by the widespread availability of digital broadcast signals. The measurement principle is similar to that of GPS water vapour techniques but has the critical advantage of significantly better spatial and temporal resolution in the boundary layer. The occurrence of water vapour along the path from the transmitter to the receiver introduces a small delay in addition to the delay that might be expected due to the distance alone. The presence of water vapour in an air mass increases the refractive index which reduces the propagation velocity of the radio signal. The small increase in delay can be determined through the measurement of receiver signal phase and can be related to the integrated water vapour along the path.

Applicants are invited to work on any aspect of the project; software radio receiver development, signal processing, GPS precise timing, numerical modelling or data validation. Candidates will be considered from any relevant discipline e.g., Electrical and Electronic Engineering, Physics, Applied Mathematics etc. Prospective candidates are encouraged to contact Dr Robert Watson (r.j.watson@_bath_.ac.uk) directly for further details.