GPS spread spectrum signal transmission over fiber optic links

The NAVSTAR Global Positioning System (GPS) has the capability to compute accurate receiver positions for a variety of space and Earth-based applications. An Earth-based application such as hazardous waste storage site deformation monitoring requires highly accurate, reliable, and routinely available positioning. These positioning needs motivated the development of a fiber optics GPS observational network (FOGON). The FOGON network would operate by placing GPS antennas at known geodetic locations and transmitting the received analog satellite signals along a phase stable fiber optic link to a central processing site. This central site would synchronize the data acquisition of the network and enable single difference operation, which is the strongest possible GPS observable data type. This paper presents the results of a hardware demonstration of the analog transmission of GPS spread spectrum signals over a 4.17-km fiber optic link and through an optical attenuator, with minimal degradation to GPS receiver operation