A Generation of Glidepath and Guidance Parameters of Shipboard Aircraft Based on SRGPS

Shipboard Relative Global Positioning System (SRGPS) is the sea-based variant of Joint Precision Approach and Landing System (JPALS), which will replace the current military navigation and landing system for all ship aircrafts. This paper describes a generation of the glidepath and guidance parameters for the automatic carrier landing system (ACLS) of shipboard aircrafts based on SRGPS. To define the glidepath, three coordinate systems which are cant deck system, ship body system and static deck system are established, the motion of ship such as pitch, roll, yaw, heave and so on can be depicted in the coordinate systems. Based on accurate coordinates in ship body system and the direction cosine matrixes (DCM) between these coordinate systems, the position vectors of the key points of glidepath are gotten, then the glidepath of ACLS is defined and depicted as a vector. After the translation of the position of the aircraft and hook from the GPS coordinate frame to the system in which the glidepath is defined, the calculating procedure of guidance parameters is described. A simulation based on a type of aircraft demonstrates the validation of the generation of glidepath and parameters.