Integration of JTIDS and GPS

In the Late 70's and early 80's I was hired by ITT Avionics Division to look at the integration of JTIDS and GPS, as part of their MFBARS program . This would incorporate all digital communication and navigation in one instrument. At that time, I took the approach that the primary purpose of the integration was to enhance positional reliability. I showed that with proper source selection, use of null steering antennas, sharing of time and other GPS related data, it was possible to increase the noise immunity of GPS by more than 20 dB. At the time the concept generated a great deal of excitement. It then seemed to evaporate as GPS became the primary source of navigation for the military and JTIDS became primarily a communications medium. The concepts, however are as valid now as they were 20 years ago.