The GPS III requirements concept got started in 2000 and didn’t go through Milestone B (start of full scale development) until 2008. According to the GPS III Selected Acquisition Report, the first space vehicle was baselined to be available for launch in 2014. It was delivered 3 years late (Sep. 2017), and wasn’t actually launched until August 22, 2019.
Why the nearly two year delay to get the satellite into orbit after a three year development delay? There are two concurrent developments programs going on that are needed to make use of the new military “M” code capabilities.
First, the ground segment GPS OCX is being developed by Raytheon. It is already five years behind schedule. The OCX program is legend in the Pentagon, where after a brief prototype phase Raytheon bid about half the expected cost of the contract. They won the competition, and quickly got into trouble. Perhaps due to the schedule incentives, concurrency between software increments increased dramatically and eventually invited a whole bunch of rework.
The first terminal is slated to be ready in early 2020, which surprised me. Block 1, which introduces M-code capabilities, was rescheduled back in 2017 to be delivered in June 2021. Buzz was at the time that even that was aggressive. But looks like Raytheon will deliver something early, even though it still leaves a bit of a gap between satellite launch and getting the capability.
This is a problem that has plagued other satellite programs like MUOS, that in many cases the satellites are ready for launch before the ground terminals are ready. In many cases, satellites are launched and spend up a not insignificant portion of their useable lifetime without providing the new capabilities (usually, however, they are backwards compatible with existing terminals).
Another issue for GPS III is the military ground user equipment. The program was initially called GPS MUE for the block IIF satellites, then was updated into GPS MGUE for GPS III, and now we have MGUE increment 2 after the failure of the first increment. MGUE is designed to make it much more difficult to jam the GPS signal, which it relatively easy and cheap today.
The user equipment, for which there were supposed to separate receivers for ground, maritime, and aviation, is also well behind schedule. They are testing the equipment on the JLTV, Stryker, DDG, and B-2.
According to a 2018 slide deck from the Air Force, GPS MGUE will not finish testing until 2021. M-code user equipment usable on the legacy GPS terminals is slated for 2020. So the pieces are coming together, though perhaps a bit late.
Integrating all the parts of a space system can be tricky. The development of satellites, terminals, and user equipment might proceed at different paces. In this case, the satellite finished first, but it would be a waste to launch the satellite and grind down its lifespan without being able to deliver the desired capabilities.
Given experience, I wonder (as an outsider and a layman) whether it makes sense to start work on the ground terminal first, as well as crucial components of the satellite payload, and only move towards an integration plan after critical uncertainties are resolved. Indeed, getting all the pieces moving at the same time can result in significant standing costs (not to mention opportunity costs) if development turns out to proceed different paces.
Trying to guess at schedule based on historical times between, for example, authority to proceed and IOT&E, only provides the roughest idea of what the timelines will be. Moving incrementally, however, creates the problem of lining up funding which might take a couple years. It could cause the program to stall at a critical point when scaling is needed.
Nevertheless, GPS III system capability will have taken over 20 years to go from concept to operations: 4 years of systems architecture and requirements studies, 2 years to get through the JROC, 2 more years to go through milestone B and award the development contract, six years of baseline development, and another six years of delays.
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