The omnipresence global navigation satellite system (GNSS) signals have not only provided high accuracy navigation but also encouraged several remote sensing missions such as FORMOSAT-7 and FORMOSAT-7R. In a GNSS reflectometry mission, the reflected signals are processed to form delay Doppler maps (DDMs) so that the properties including roughness, ocean wind speed, and soil moisture can be retrieved. Currently, GPS reflectometry missions are realized by Surrey TDS-1 and NASA CYGNSS in which the reflected GPS signals are processed. One distinguishable feature of the FORMOSAT-7R GNSS reflectometry mission is its capability to process both GPS and Galileo reflected signals. Galileo signals are modulated through a binary-offset-carrier (BOC) scheme that is different from binary phase shift keying (BPSK) in GPS. Consequently, the receiver design is more complicated. In the paper, the design of the receiver for the processing of Galileo reflected signals is discussed. Several different realizations to perform BOC correlation processing are proposed and assessed in terms of implementation complexity and correlation loss. The results are verified through simulation and experiment.
All Science Journal Classification (ASJC) codes
- Aerospace Engineering
- Space and Planetary Science