A new EKF based algorithm is available for iMAR's iVRU product line, which provides a milestone in performance of unaided Vertical Reference Systems. The algorithm is available for new systems of iVRU series as well as for upgrade.
Standard vertical reference systems require magnetic information or GPS data (velocity) to determine the attitude of a moving vessel acording to the static plumb line. Where such aiding is not available, such systems align to the "dynmic plumb line" direction, which results from the superposition of the "static plumb line direction" and the motion induced acceleration (according to Newton's laws it cannot be distinguished between heavy mass induced acceleration ["gravity"] and dynamic acceleration).
The new EKF based iVRU algorithm uses some very general knowledge of airplane and ship motion to provide real attitide against "static plumb line" even if the vessel is under strong dynamic motion. Furthermore under dynamic motion it provides an estimation of vessel's velocity.
The algorithm is suitable for mid perfrmance FOG based systems as well as for MEMS gyro based systems.