The Global Positioning System (GPS) satellite network is preparing for a major overhaul that will enhance its navigation, timing, and position capabilities both for civilian and military users. The Air Force Research Laboratory (AFRL), which is leading the GPS technology development program, has granted a contract to NuWaves Engineering to develop an advanced triplexer for the navigational payload of the new GPS III satellites.
NuWaves, which supplies RF and microwave components to the Department of Defense (DoD) and commercial satellite companies, recently received an extension on its Small Business Innovation Research (SBIR) contract, which was originally issued last year. The company completed the first phase of the contract with support from Exelis Geospatial Systems’ Positioning, Navigation and Timing division, and will again work with Exelis engineers on the triplexer project.
The contract entails the design and testing of a new broadband triplexer that not only exhibits high-power handling but also delivers low insertion losses over the L-band—the primary spectrum range for GPS carriers. The NuWaves and Exelis team will also incorporate advanced filtering and cross-coupling technologies to minimize loss and maximize bandwidth, while also maintaining high isolation between channels.
The triplexer project builds upon NuWaves’ research under the first phase of the contract. The team proposed a method to significantly reduce the size and weight of multiplexers—diplexers, triplexers, and quadplexers—for multi-carrier radio frequency (RF) signal transmission. The project was targeting “a significant reduction in the GPS III satellite’s launch weight, reducing cost to orbit,” according to Jeff Wells, president of NuWaves.
To that end, NuWaves developed a prototype of a GPS L1-band cavity filter and subjected it to a series of multipaction tests. The approach involved using specialized inserts within the filter cavities, resulting in a design that supports wider bandwidths and high signal power levels. The results of the research project are guiding the design of the new triplexer, according to a statement from NuWaves.
The attempt to reduce the size and weight of the navigational payload aligns with the AFRL’s broader development program. Based out of the Wright-Patterson Air Force Base in Ohio, the AFRL program is focused on exploring advanced L-band signal options and manufacturing components that reduce the size, weight, power, and cost of the GPS satellite payload. According to Colonel David Goldstein, director of the AFRL’s space vehicles directorate, the laboratory has thus far targeted new L-band antenna concepts, gallium-nitride (GaN) amplifiers, on-orbit waveform generators, and signal combining methods.
