Martin Unwin

Learn More
We will show that ocean-reflected signals from the global positioning system (GPS) navigation satellite constellation can be detected from a low-earth orbiting satellite and that these signals show rough correlation with independent measurements of the sea winds. We will present waveforms of ocean-reflected GPS signals that have been detected using the(More)
A spaceborne GNSS reflectometry experiment is to be undertaken by Surrey Satellite Technology Limited with support from the British National Space Centre (BNSC) to investigate the reception of reflected GPS signals off the ocean for oceanography applications. The GPS receiver on the UK-DMC satellite has been modified to accommodate a downward (nadir)(More)
As part of the EV-2 Cyclone Global Navigation Satellite System (CYGNSS) mission team, Surrey will be providing the Delay Doppler Mapping Instrument (DDMI) for eight Observatories designed and built by the University of Michigan and Southwest Research Institute (SwRI). Following the success of the GPS ReOectometry Experiment on the UK­ DMC 1 satellite(More)
In this paper we analyse the GPS signals reflected by the surface of the ocean to retrieve information about the sea surface roughness, expressed in statistical terms by means of the sea surface Mean Square Slopes (MSS). Particularly, we perform Delay-Doppler mapping of real scattered GPS signals from the Surrey Satellite Technolody Ltd UK-DMC mission, and(More)
This paper presents the latest development in SSTL's successful SGR range of Space GNSS Receivers. The SGR-ReSI (Remote Sensing Instrument) is a highly versatile and uniquely capable GNSS receiver that has been designed with the low-cost, microsatellite market in mind. Based on COTS parts, the SGR-ReSI builds on the expertise SSTL and SSC have developed in(More)
This paper presents the design of a novel multipath mitigating ground plane for Global Navigation Satellite System (GNSS) antennae. Firstly, the concept of a compact low multipath cross plate reflector ground plane (CPRGP) is presented. In comparison to the choke ring and Electromagnetic Band Gap (EBG) ground planes, the proposed CPRGP has compact size, low(More)
This paper presents the design and development of a dual-band switched-beam microstrip array for Global Navigation Satellite System (GNSS) applications such as ocean reflectometry and remote sensing. In contrast to the traditional Butler matrix, a simple, low cost, broadband and low insertion loss beam switching feed network is proposed, designed and(More)
Dual-band planar antennas for Global Navigation Satellite System (GNSS) based remote sensing are presented. The antenna designed can cover both L1 and L2 bands, centred at 1.575 GHz and 1.227 GHz, respectively. They will be used onboard satellites remote sensing satellites as part of an instrument to measure ocean roughness by GNSS reflectometry, and the(More)
This paper presents an implementation of a simplified filtering estimator for satellite attitude determination using GPS (Global Positioning System) signals. The non-linear system of estimator was modelled using Euler angles parameterisation which applicable for real-time operation onboard-satellite. An approach was to keep a pitch state independent of roll(More)
This paper describes a proposal for a rapid, low cost, nanosatellite mission to demonstrate the concept of GPS ocean reflectometry and to investigate the feasibility of determining sea state for a future operational space-based storm warning systems. The aims of this mission are to prove the general feasibility of GPS ocean reflectometry, to demonstrate sea(More)