System of Systems: The long life of GPS III

April 30, 2018  - By

Late Breaking: Ligado

On April 26, the U.S. Department of Transportation publicly released the long-awaited GPS Adjacent Band Compatibility Assessment. See the June issue of GPS World for an expert and measured analysis of this highly impactful document.

The article will be posted online when it becomes available in mid-to-late May.

Merger Mystery

Contrary to the “Out in Front” editorial published in the April issue of GPS World magazine, there was an Izvestia story published on March 28 touting a merger of the GLONASS and BeiDou systems, and there will be an International Conference on Advanced Technologies in Manufacturing and Materials Engineering in Harbin, China, at which such a possibility may hypothetically be discussed.

However, neither hard news nor any official statements have emerged to substantiate such a dubious claim, despite repeated queries to officials of both countries.

Javad Ashjaee (far left, above), CEO of JAVAD GNSS and based in Moscow, communicated that he spoke on a panel at an aerospace technology event organized by the American Chamber of Commerce in Russia, alongside representatives from NASA, Boeing, Honeywell and Roskosmos.

Ashjaee asked the Roskosmos official publicly about the prospect of a GLONASS merger with BeiDou, and “he knew nothing.”

Diverger Dilemma

As this magazine goes to press, stories emerge of a U.K. plan to launch a satellite-navigation system separate from the European Union’s Galileo project. This comes in response to an EU statement that the UK would be shut out of key elements of the European satnav program, particularly the Public Regulated Service, after Brexit.

Historically, in the late 1980s or early 90s the UK drew up plans for its own GNSS prior to the launch of Galileo. And UK-based Surrey Satellite Technology Ltd. built all operational Galileo payloads to date. So the country clearly has the capability. That SSTL is currently owned by Airbus (either German or Dutch division) may or may not constitute a wrinkle.

Finally, the UK spent 1.4 billion euros on Galileo, and may now file for a refund.

The Long Life of GPS III

By Robin Wrinn, Contributing Author

GPS III SV01 in electromagnetic interference, compatibility and passive intermodulation testing. (Photo: Lockheed Martin)

During interviews with Lockheed Martin and Harris Corporation at the 34th Space Symposium, 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 predecessors. Yet that begs the question “How long should a satellite live in space, with technology innovation occurring almost annually?”

Advanced payload technology provides a partial answer to that question. Both Lockheed Martin and Harris Corporation highlighted new payload capabilities with built-in flexibility to adapt satellites in orbit to technology advances, as well as changes in missions.

Lockheed Martin provided the media a tour of their Radio Frequency Payload Center of Excellence. Meanwhile, Harris recently announced completion of the fully digital Mission Data Unit (MDU), 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 L1C, compatible with other GNSS such as Galileo, and
  • greater signal integrity.

According to Harris, the fully digital navigation payload will provide the ability to change and upgrade the satellites incrementally over mission life.

Meanwhile, Lockheed announced a partnership with NEC to introduce artificial intelligence for computer learning in orbit. The company’s Payload Center experts touted significant advances in processers and a move toward next-generation antennas, arrays and transmitters to drive more satellite flexibility, capability and resilience.

Observation: 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.

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 both Boeing and Northrop Grumman have dropped out of the running, Lockheed is virtually assured the contract. The government has said it will announce the award in March 2019.

For an update on GPS III space vehicles 1–10, see the full version of this article.

Harris Corporation Interview

with Jason Hendrix, PNT Program Director

What are the differences in the GPS III satellite payloads that were instituted to enable the 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.

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.

What are the advantages of a digital payload over the alternative?

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.

For more from Harris, see longer version.

Interview with Lockheed Martin

with Johnathon Caldwell, Navigation Systems Mission Area Program Manager

Any changes in your production approach having completed SV01?

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.

For more from Lockheed Martin, see longer version.

About the Author: Alan Cameron

Alan Cameron is the former editor-at-large of GPS World magazine.