Patent ID: 8068984
Filing Date: 2011-11-29
Classification: G01C,G01S

Abstract:
1. An apparatus comprising: a system controller; a Global Positioning System receiver coupled to the system controller; a radio frequency locating receiver coupled to the system controller; a precision timing subsystem coupled to the system controller; and an operator interface coupled to the system controller; wherein the system controller is configured to monitor at least one signal quality or location tracking characteristic associated with the Global Positioning System receiver; wherein the system controller is configured to adjust a position fix associated with the radio frequency locating receiver based on a position fix associated with the Global Positioning System receiver in response to a determination that the at least one signal quality or location tracking characteristic indicates that the position fix associated with the Global Positioning System receiver is valid; and wherein the system controller is configured to switch from the position fix associated with the Global Positioning System receiver to the position fix associated with the radio frequency locating receiver as a primary fix in response to a determination that the at least one signal quality or location tracking characteristic indicates that the position fix associated with the Global Positioning System receiver is invalid.