Bridging GPS outages in the agricultural environment using virtualite measurements

This paper describes the design, analysis and testing of two methods that can be used to bridge GPS outages during an agricultural row cropping operation when using an integrated INS and code-based GPS system. The use of integrated systems in agricultural operations has become of increasing importance in recent years as farming operators are looking at combining different technologies to increase efficiency and to reduce the environmental dasiafootprintpsila of farming operations. Integrated GPS and INS systems are used to provide good long term stability through the GPS system, with higher data rates and reliability from the INS system. However these systems can still suffer from degradation during GPS blockages and increasing the availability of a position solution is one of the key challenges to improving the use of integrated systems in agricultural applications. The ldquovirtualiterdquo concept is a new method that involves the transformation of INS measurements into simulated GPS signals via the creation of virtual satellites (dasiavirtualitesrdquo) that can be processed alongside real GPS measurements.