2008 Early Achievement Award

Presented to: Dr. Grace Xingxin Gao

Citation: For contributions to the understanding and performance of the new satellite signals from Galileo and Compass.


Dr. Grace Xingxin Gao has already made truly remarkable contributions to satellite navigation. Her research is dedicated to the signals and receivers used by the new Global Navigation Satellite Systems. Grace was the first to derive the code generators used by the Galileo validation satellites and the first Compass satellite in medium earth orbit. In December 2005, the Europeans launched the first prototype satellite for Galileo, called GIOVE-A. The navigation signals were turned on in January of 2006. Within hours, Grace worked with others in the laboratory to capture the new civil signals in three bands. Within weeks, Grace working independently, derived the underlying algorithms that generate the codes used by GIOVE-A and decoded the codes in all three frequency bands. Her work was published as part of the Inside GNSS cover story “GNSS Album: Images and Spectral Signatures of the New GNSS Signals,” that appeared in May-June 2006. Soon after her publication, receiver companies around the world implemented her codes and built prototype receivers to acquire and track the Galileo satellite.

In April 2007, China launched the first medium earth orbiting satellite that belongs to their Compass system. Using her proven techniques, Grace demodulated the civil codes broadcast by this M1 satellite in all three frequency bands (E2, E5b & E6), and proved that all Compass-M1 codes are Gold codes and derived their code generators as linear shift feedback registers. She also applied these PRN codes in a software receiver to acquire and track the Compass-M1 satellite. In April 2008, the Europeans launched GIOVE-B, which is a pre-production prototype satellite for Galileo. Grace was the first to discover the underlying code generators.

Grace received her doctorate from Stanford University in September 2008. She continues to work on the satellite navigation systems as part of a Stanford research program funded by the FAA. She has presented and published 16 high quality papers at conferences. In 2007, she was an ION GNSS sponsored student where her paper won the Best Presentation of the Session.