GPS III ready for prime time; how long should a satellite live?

April 24, 2018  - By
Robin Wrinn

Robin Wrinn

This month, we bring you a guest column on the 34th Space Symposium in Colorado Springs, Colorado. Robin Wrinn, a communications professional based in Atlanta, gives her perspective on the premier annual space event, held in April. Among her findings: information on the mission longevity vs. technology innovation debate, GPS IIIF program bids, discussions of time and space, and more.

— Alan Cameron, editor



During recent interviews with Lockheed Martin and Harris Corporation conducted during the 34th Space Symposium (April 16-19) in Colorado Springs, time and space were a frequent focus of discussion, but not in the normal “continuum” kind of way.

Greater mission longevity is one of the key improvements GPS III delivers over those currently in service. Space Vehicles 1-10 have a planned mission life of about 15 years – 25 percent longer than their satellite predecessors. Yet that bragging right begs the question “How long should a satellite ‘live’ up in space with technology innovation occurring almost annually?” After all the last Block IIR-M series satellite was launched in 2009. To put that into perspective, that same year the Canadian company Blackberry (RIM) held 20 percent of the smartphone OS market share and was the second largest OS in the world. Apple had just introduced the iPhone two years earlier.

A partial answer to that question it seems is advanced payload technology. Both Lockheed Martin and Harris Corporation highlighted their advances in payload capabilities that would enable built-in flexibility to adapt satellites in orbit to advances in technology, as well as changes in missions. Lockheed Martin provided the media a tour of their RF (Radio Frequency) Payload Center of Excellence (Payload Center). Meanwhile, Harris Corporation recently announced that is has completed development of the company’s fully digital Mission Data Unit (MDU), which is core to the navigation payload for GPS III 11 +.)

As a reminder, the current Harris payload for SVs 1-10 includes:

  • Greater than three times reduction in range error,
  • Up to eight times increase in anti-jamming power,
  • Added signals – including one (L1C civil signal) compatible with other Global Navigation Satellite Systems (GNSS), like the European Space Agency’s Galileo.
  • And greater signal integrity.

According to Harris, the new, fully digital navigation payload it has engineered will deliver more powerful signals, PLUS the ability to change and upgrade the satellites incrementally over the mission life.

Meanwhile, Lockheed recently announced a partnership with NEC to introduce artificial intelligence for computer learning in orbit. And the company’s Payload Center subject matter experts touted their significant advances in processers and a move toward the next generation of antennas, arrays and transmitters that would drive more flexibility and capability and resilience into satellites.

Observation: It seems the market pressures of ‘new space’ players is prompting delivery of products that can drive more value for less cost. In this case, delivery of a common payload architecture and electronically steered beams to make satellite antennas become any shape you want. Most likely, beams of a different size on demand is a much better business case than a static one built five years ago.

GPS III 1-10 on track. in full production. GPSIII SV1 awaiting U.S. Air Force “Call Up” for Launch

Lockheed Martin’s GPS III SV03 became fully integrated in August 2017. Photo: Lockheed Martin

The day I interviewed Lockheed Martin’s Navigation Systems mission area Program Manager Johnathon Caldwell, the company had submitted its proposal for the U.S. Air Force’s GPS III Follow On (GPS IIIF) program. That same day, April 16, the media was given a tour of Lockheed Martin’s GPS III satellite assembly floor. It was clear from both Lockheed’s press materials and Caldwell that Lockheed Martin believes it is fully recovered from prior production hiccups and is

• “on track” to deliver GPS Space Vehicles (SVs) 1 through 10, and

• deserves to win the bid for GPS IIIF. Now that Boeing has dropped out of the running, it seems they probably have it. (The government has said it will announce the award in March 2019.)

Here is the GPS III SVs 1-10 Update:

SV 01. Declared “Available for Launch” (AFL) by the Air Force on Sept. 28, 2017. Awaiting “Call Up” for launch. A formal date has not been set. “Sometime this year” was the answer Lockheed Martin provided when asked a timeframe.

SV 02. Completed Thermal Vacuum (TVAC) testing, Dec. 2017. Currently in final environmental EMI (electromagnetic)/EMC (electromagnetic compatibility)/PIM (passive intermodulation) testing. AFL expected Summer 2018.

SV 03. Fully integrated, Fall 2017. Currently in TVAC testing, AFL expected. Spring 2019

SV 04. Fully integrated, Spring 2018. Beginning environmental testing, Summer 2018

SVs 05, 06, & 07:

  • 05: Navigation payload recently delivered/integrated
  • 06: Currently in system module build up
  • 07: Beginning build up – Spring 2018

Interview with Harris Corporation’s Jason Hendrix, PNT Program Director.

  1. GPS World readers are familiar with the differences in the GPS III signals as compared to those transmitted by satellites to date. What are the differences in the GPS III satellite payloads that were instituted to enable those new signals?

The main difference is the power. The Air Force’s requirements called for significantly more anti-jamming capability. All the transmitters are a higher power.

  1. What was the most significant obstacle (or top obstacles, plural) in designing and manufacturing this new payload, to new Air Force specifications? How did you overcome it/them?

Same answer really, the higher power. Keeping in mind, we went from a 7-year mission life requirement to a 15 year. That higher power puts more strain on components and new cyber requirements in software. When you couple all that together we are not just upgrading payload technology. It is really engineering a new set of payload requirements. It’s new generation, advanced.

  1. What are the advantages of a digital payload over the alternative? When you say “Our current GPS payload is 70 percent digital” does that refer to the IIR payload? The offered “fully digital navigation payload with enhanced performance” — is that the GPS III payload? What’s the new 30 percent that has gone digital?

The advantages and the 30 percent difference are the timekeeping system portion. We’re moving from a manual, analog timing to digital to deliver to the Air Force more flexibility. It’s a nice option to have to be able to reprogram in orbit and maybe enhance capabilities desired in the future.

  1. Can you provide any perspectives on how Harris is performing now in delivering payloads for SVs 1-10?

We’re now ahead of schedule. We delivered the 5th payload three weeks early (early March 2018). We are on time for 4 and three more are due this year.

Interview with Lockheed Martin’s Navigation Systems Mission Area Program Manager Johnathon Caldwell

  1. Can you provide some general updates on assembly of GPS 1-10?

Photo: LMCO

Vehicle SV01: It is ready and we’re very excited about that. We defer to the Air Force on questions about launch date. But once they call it up we will install the solar panels and take it to a C-17. Then load it in the back of the plane and fly it down to Florida. We will then take it over to the vehicle processing facility and mate it up with the launch vehicle provider. The GNST – the satellite prototype -has gone to the Cape twice already. So, we have conducted a dry run for shipping SV 01.

Vehicle SV02: It has completed thermal vacuum testing – a major milestone. We’re in the last of the environmental tests. And we’re tracking to have that vehicle declared AFL this summer.

Vehicle SV03. It is fully integrated and is in the T-Vac chamber now. The door is closed and it’s going through tests. (Pump down to vacuum is achieved in approximately three hours and the total testing time is 70 days.)

Vehicle SV04: It is fully integrated on the floor. It is in its baseline electrical tests and will be in environmental tests as soon as 3 comes out of the chambers. It is staged to go in right after – 3.

Vehicle SV05: It is about to go through its integration to the propulsion core. And five has its navigation payload. Integrating it this summer.

  1. Any changes in your production approach having completed SV01 that you are fixing in your production approach to SV02, 03 or 04?

No, the performance on Vehicle 01 was as designed there were no technical or design changes necessitated throughout the rest of the fleet. So, it was a very successful from that perspective – from the standpoint of validating the design and wringing it out, Vehicle 01 served its purpose well.

It had a very good T-Vac. I would say overall when you look at the industry, Vehicles 01 – 02, our vacuum test campaigns are the most rigorous test. Both went through their tests quite well. Some of the best I’ve seen.

We consider thermal vacuum the gold standard for testing any satellite before it goes into operations. It really is putting the craft through the paces. When it goes through the testing, the satellite is on. It is working. It is exposing it to the heat and the cold and the zero pressure while the satellite is functional. The entire thermal vac testing from start to end is a little over 70 days. “Test like you fly.” From the time it launches and deployment sequence we test it like it is real. Minus the shaking, the satellite thinks it is getting launched. Meanwhile, our people are looking at the data and its health. T Vac is a huge milestone for a satellite to go through it and come out without any issues. Which is why we are so pleased about the two.

  1. Have there been any production delays since last year.

No, we’ve been quite stable in our production schedule.

  1. Can you shed some light as to how many Lockheed Martin employees are involved in the production of GPS III?

The way we’re organized, there are engineers that flux in and out of the project depending the stage we’re in. This is production program, so we use the skillsets we need at the time we need them, then those engineers go on to do other work. But this also comes back to some of the commonality we’re trying to achieve across out product lines. That when you have common processes, common parts and common procedures in building spacecraft you gain leverage and major cost savings to have flex in resources.

  1. Can you speak to any issues with subcontractors? Any delays?

No, since last year, the Harris production line has stabilized. We’ve been receiving Harris payloads, and we’ve just received the 5th payload and we’re finishing up integration. Vehicle 6 navigation payload is currently in test. And Vehicle 7 and 8 payload production is going according to schedule. We feel Harris has definitely overcome some of the challenges of the past. And we’ve been seeing stable production deliveries. By the end of this year we should receive 3 more payloads and by the first quarter of next year, the 8th, and they are contracted for 9 and 10.

  1. From a civilian perspective, can you remind us what will be different with GPS III?

Three times better accuracy and up to eight times improved anti-jamming capabilities. And it is a longer life vehicle and healthy constellation of satellites that people can rely on. The new L1C signal is common with other GNSS, like Galileo, so as that becomes incorporated into equipment, it will give you more data points for better service, more accuracy and reliability.

  1. For GPS IIIF requirements, are there capabilities that will require innovation or new technology?

We’ve designed with some of those capabilities in mind. If you just look down the list. The regional military protection is about bringing higher power and boosting the signal where the military needs it most. That’s not a particularly new technology per se, but it is bringing a new capability that the current GPS satellites don’t have.

The Search and Rescue payload, again, I wouldn’t consider it a new capability, it is provided by a partner nation, a Canadian company, but it effects those folks in need.

Digital payload. For 11+, fully digital payload for greater flexibility for the government. It allows the government to expand or enhance capabilities of the mission over time. It enables loading new software to do different things.

GPS III was designed with a modular, flexible architecture. Because Lockheed Martin knew that as time goes by, technology evolves. New technology becomes available and the government’s mission needs are likely to change.

Now that ability to evolve is down to the payload with a fully, 100 percent digital payload.

Lockheed Martin has been working on a lot of the GPSIII F design requirements already (preliminary design review level).

  1. Can you speak to the other “Risk Retired” you mentioned in your slides?

Last fall, we had our first time with the OCX zero ground system. It’s one thing to talk to satellite in the high bay, it’s another thing to talk to it with the entire Air Force control network you plan to use when you’re operating. So, we were excited to get that done and run the entire chain from the vehicle out from the Air Force control network the AFCN network, utilizing the OCX system to command the vehicle. It was a big milestone for us. And previously we demonstrated our compatibility of our signals (with OCX).

Our future satellites in our GPS IIIF proposal share a common design with GPS III so they also will be compatible with OCX because we have proven that compatibility.

  1. Can you speak to the GPS III Ground System Support Contracts Lockheed Martin has received?

The government asked us to help provide some gap fillers for the ground system (rmw note: if OCX isn’t there yet). To take the heritage AEP ground system and provide the ability to fly GPS III satellites using that ground system. So that activity has been going well and the critical design review has been completed and it is on track for delivery to the government next year. And subsequently, we were also put on contract for the M-code new signal to add some capabilities to the legacy ground system to begin to furnish early use of that new GPS III M-code signal to the military. We’ve been working hard on that. We conducted our preliminary design review last fall and just recently completed a critical design review to add that capability.