Low-cost inertial/GPS attitude and heading reference system (AHRS) for enhanced and synthetic vision (EV/SV) applications

Fundamental to vision enhancement systems for vehicles are sensors that provide precise, real-time attitude and heading information. While attitude and heading reference systems (AHRS) based on high-performance inertial components exist, such systems are traditionally very expensive and inapplicable to price-sensitive applications/markets. This paper demonstrates an AHRS that combines small, low-cost, solid-state inertial sensors with an advanced GPS-derived attitude determination technology. The resulting AHRS is inexpensive, rugged, and provides information with the accuracy and responsiveness needed to drive many enhanced/synthetic-vision displays, such as tunnel-in-the-sky guidance displays. The instrument also provides GPS position, velocity, and time information. Further, by using complementary and overlapping sources of information for integrity checking, the GPS/Inertial AHRS has robustness to individual sensor failures and can operate safely if GPS were to become unavailable.