Integration of dead reckoning system and global positioning system

Abstract

GPS has made land navigation applications affordable and dependable. However there are many situations where GPS solution is either unavailable or unreliable. The former situation occurs when GPS signals do not reach the antenna due to shading effects resulting from high rise buildings and underpasses present in urban environment. The second situation arises from the bad geometry of the satellites in urban canyons. One of the important requirements in land navigation is the heading information and this is also unreliable when the vehicle has low dynamics. These situations demand improvements in the navigation solution provided by the GPS receiver. To solve this dilemma, one of the most popular methods to achieve this is to augment GPS with additional sensors like an odometer, rate gyroscope etc. Dead (or ‘deduced’) reckoning (DR). This involved combining compass heading with the velocity of the object measured by the time taken to travel a fixed length along the road. DR uses measures of heading and velocity to provide a two dimensional positioning solution based on a known starting point (retrieve from GPS). In this report, a GPS-DR integrated system was built by using a GPS receiver and an independent build-in compass. Moreover, several cases studies are done in order to compare results between the GPS system and the GPS-DR system.