Development and testing of a remote sensing instrument using GNSS reflectometry concepts

A study has been undertaken by Surrey Satellite Technology Limited (SSTL) with support from the British National Space Centre (BNSC) to upgrade SSTL´s Space GPS Receiver (SGR) into an ocean remote sensing instrument. Software algorithms were added to the SGR to permit on-board characterisation of GPS reflection opportunities. Subsequently, a hardware interface was added to allow for raw data sampling and in-depth data analysis. The upgraded SGR has undergone several levels of testing to date. The real time specular point calculations and an on board slewing capability were demonstrated using a Low Earth Orbit (LEO) spacecraft carrying an SGR for navigation purposes. The ability to map a reflected GPS signal was then accomplished during ground testing from an observatory on a hill above Barcelona, Spain. In preparing the instrument for an upcoming flight experiment, the raw data analysis capability has been undergoing substantial validation and optimisation. The ultimate goal of these experiments is to recover parameters relating to sea-state that may be useful for both scientific and commercial marine users. This paper is intended to detail the initial phases of development and testing of a future low cost ocean remote sensing instrument.