Acquisition of reflected GPS signals for remote sensing applications

Reflected GPS (Global Positioning System) signals, known as multipath signals are one of the contributing factors in error sources during navigation and are therefore mitigated during position and velocity calculations. However, they can be utilized in various remote-sensing applications as they contain valuable information regarding the reflecting surface. One of the major challenges for the practical realization of any remote sensing system based on GNSS (Global Navigation Satellite System) signals is the reception of weak reflected signals owing to their appalling signal to noise ratio. This paper describes the detection and acquisition of reflected GPS signals using a custom made LHCP (Left Hand Circularly Polarized) high gain helical antenna and a two-channel GPS front end and data capturing device intended for the simultaneous acquisition of direct and reflected GPS signals. Details of some initial experiments are presented.