On-Orbit Reprogrammable Digital Waveform Generator for GPS

ABSTRACT: The primary objective will be to demonstrate software and digital logic capable of generating all current and future GPS waveforms while providing on orbit reprogrammability through the uploading of new shift register coefficients. The software and digital logic will be developed along with COTS development board hardware to simulate what is used in a space program. Testing will be performed with both simulated and currently fielded military radios that have GPS receivers installed. The foundation of the proposed waveform generator is a set of shift registers, each with a varying number of two state devices or stages. This approach has the advantage that the shift registers themselves need only be coded once, but are capable of generating any pattern desired based upon the contents of the binary shift register matrix. Using the proper mix of shift registers and coefficients, any existing or desired code can be generated. The approach to creating a reprogrammable platform would be to reuse the onboard S-band radio and architecture and send the new shift register coefficients up as a data message. The conclusion of a successful Phase I will lead directly into the design of radiation hard electronics during Phase II. BENEFIT: The key benefits are increased mission flexibility, increased mission security, and reduced mission costs. Key commercialization applications include the licensing of the ORDWG technology to alternative designs. Another possibility is that adjacent elements of the research may be licensed or sold. Efforts on Information Assurance (IA), flight qualifying of the Xilinx Virtex-5 based controller for the GPS mission, and leveraging our proven capabilities in precision ADC for the ORDWG-to-power amplifier interface are all opportunities that can be pursued commercially.