While promoting the modernization of the Global Positioning System (GPS), the United States has also launched the Navigation Technology Satellite-3 (NTS-3) pioneer program, actively exploring new satellite navigation technologies in the future, aiming to break through the performance boundary of Positioning, Navigation and Timing (PNT), apply the mature technologies obtained to the future GPS constellation, and further enhance the system's flexibility, flexibility and architectural diversity. The development background and process of the NTS-3 program is briefly combed, and the research and analysis of innovative technologies such as satellite platform design is focused on, on-orbit reprogrammable digital waveform generator, signal power enhancement, satellite atomic clock, automatic and reliable ground control segment and software-defined receiver for NTS-3 application, which can provide reference for the development and upgrading of other satellite navigation system.