Integration of a Multi-Rate Position Filter in the Navigation System of anUnmanned Aerial Vehicle (UAV) for Precise Navigation in the Local Tangent Plane (LTP)

摘要

Differential Global Positioning System (DGPS) provides highly accurate positioninformation, but at update rates of one Hz which is inadequate for precise aircraft terminal maneuvering such as take off and landing. During this period between updates, an accurate position estimate in Local Tangent Plane (LTP) can be made using complementary filtering of the DGPS position and indicated airspeed. Use of indicated airspeed as the filter velocity input necessitates the transformation from body to inertial (LTP) reference frame using Euler angle information available from the Inertial Measuring Unit (IMU) or DGPS. This filter provides accurate estimates of both vehicle position and existing wind. These filter outputs of position and wind can then be used as inputs to a trajectory controller to ultimately enable autonomous launch and recovery of an Unmanned Aerial Vehicle.