An Accelerometer Error Compensation Method Based on Forward Velocity Estimation

In low-cost INS systems (such as vehicle INS system, mobile phone INS system), inertial sensors have great error. Standard strap down algorithm which has very serious error accumulation, has been unable to meet the application requirements. To reduce error accumulation effect on navigation accuracy, taking into account the posture keeping unchanged when the vehicles is on urban roads, a navigation solution with fixed posture was presented for vehicle low-cost INS systems. In this solution the initial posture was maintained in the navigation process, and heading was calculated with the vertical angular rate integral. Its central task is the calculating of the forward acceleration. On the basis of this navigation solution, the acceleration error was estimated according to the GPS ground speed when GPS is normal, and this error was used to compensate accelerometer error when GPS outages. After error compensation in this way, fault-tolerant federated filter was formed to fuse the INS and GPS information. Experiments show that this method makes the low-cost integrated GPS / INS navigation system still has a high navigation accuracy in a period of time after the GPS outages.