GPS Heading Unit Datasheet (N500151) Revision AGPS Heading Unit ICD (ICDN900502) Revision BGPS Heading Unit Revision B Step FileGHU Adapter Bracket Kit, Type 4.000-P Interface (ANTB-N900977-1) Revision C Step FileAntenna Adapter Bracket, GHU to MPS-10/MPS-55 (ANTB-N900854-1) Revision A Step File