| The characteristics of a rubidium clock and the relationship between the clock offset error and position error were investigated. An adaptive filter algorithm and a rubidium clock aided GPS navigation System were developed, based on the characteristics of the rubidium clock. An integrated navigation system consisting of GPS with a rubidium clock, a barometer and a gyro was designed. Decentralized Kalman filters were employed and a software was developed to test the integrated navigation system. Two field tests were conducted at Nose Hill Park, Calgary and in downtown Calgary, respectively. The test results have shown that rubidium clock aided GPS is a practical approach; it can improve positioning accuracy, especially vertical accuracy, significantly; it is able to navigate using three satellites, and therefore, improve the navigation availability significantly; the integrated navigation system developed herein can improve navigation availability, for the case tested, by over 50%. |
