[Satellite News 12-19-11] Raytheon Network Centric Systems
has developed several military terminals that have become the first to successfully test with the Pentagon’s on-orbit Advanced Extremely High Frequency (AEHF) satellites.
Earlier this month, Raytheon announced that its operationally fielded Army Secure Mobile Anti-jam Reliable Tactical Terminal (SMART-T) interoperated with the first AEHF satellite launched in August 2010. During this testing, SMART-T to AEHF communications employed the satellite’s eXtended Data Rate (XDR) waveform, moving data more than five times faster than previous EHF systems, as well as compatibility with legacy systems.
Today, the company announced that its Navy Multi-band Terminal (NMT) became the second operationally fielded terminal to interoperate with an on-orbit AEHF satellite. Raytheon Network Centric Systems Vice President of Integrated Communication Systems Scott Whatmough spoke with Satellite News about how these technological breakthroughs will enhance future U.S. Military communications.
Satellite News: You mentioned in a company statement that the successful on-orbit AEHF test results from a three-decade commitment to your EHF/AEHF terminal product line. Could you describe how that 30-year effort started?
Whatmough: I can speak about how it started from personal experience. I began my career at Raytheon in 1986 and the very first program I worked on was a modem for the original Milstar program. Milstar was the very first protected EHF satcom program. During this design phase, there was already another ongoing Navy program in the works called NESP, or the Navy EHF Satellite Program. All of this encompasses a thirty-year time frame, during which Raytheon has been on contract between the Army, Navy and Air Force, without any gaps. It all started with the LDR waveform, which by today’s standards is archaic. You could probably put more data through two tin cans and a piece of string. We’ve evolved several times over since then. When we tackle a new waveform or a new mechanical challenge, we literally have a couple hundred engineers that working on solving those challenges at various points in their career.
Satellite News: From a technological view, what was the biggest challenge for Raytheon in accomplishing the first terminal link to the AEHF satellite with SMART-T?
Whatmough: The number-one challenge in testing these terminals is the XDR waveform. It is a very complicated waveform on the software side. The nature of the protected satcom also includes a very complicated interface. To make matters even more difficult, military requirements demand the ability maintain a robust, jam-resistant link so that the enemy cannot interfere with these important communications.
Another particular challenge with the AEHF systems involves the end-user’s physical pointing of the antenna, especially in severe environments. The beam on AEHF terminals like SMART-T and NMT is very narrow. The satellite you need to reach is far away. Controlling the beam and keeping the link secure is a very challenging mechanical problem.
Satellite News: What makes the eXtended Data Rate (XDR) waveform so complicated?
Whatmough: XDR is a frequency-hopping waveform. It literally and constantly hops around in the frequency band, so the satellite has to hop around with the waveform. Coordinating these frequency hops is a challenge. This is all part of the anti-jamming ability. You never want to be on the same frequency as the jammer waiting to block the signal. The tracking algorithms involved are extremely complex and intricate in order to move that narrow reflector to the satellite.
Satellite News: Could you discuss how the technology and design of your AEHF terminal product line enables you to adapt your terminals to new missions and new platforms?
Whatmough: It was about ten years ago when we could see the next wave of EHF terminals coming and knew that the FAB-T [Family of Advanced Beyond line-of-sight] terminals were on the horizon, as well as the SMART-T variant and the NMT. At the time, we invested in a common modem program. That was designed to allow us to adopt common card sets to various military missions without completely starting from scratch. We designed with that flexibility in mind so that we could meet the Navy, Army and Air Force mission requirements. We did the same thing with the software. We designed the common baseline software so that you could port it over to several variations of the existing hardware and not have to start over again and re-write these difficult algorithms.
This issue is what makes the AEHF market difficult for the people who are new to it. These algorithms involve millions of lines of code. If you write the code correctly, it can be leveraged in a next-generation military application. A lot of those core capabilities and features of the AEHF software are identical from service to service. The fact that we did this on both SMART-T and NMT simultaneously allowed us to leverage the benefits of AEHF much quicker than somebody else would if they had to start writing code.
Satellite News: How important is it to design these terminals with backward compatibility for your military customers?
Whatmough: The U.S. Department of Defense service branches can’t just flip a switch and upgrade all of their legacy systems. Backward compatibility is just as important as adaptation, and in some cases, you could argue that it is more important. To illustrate this, I’ll run through a scenario and use the Navy as an example. When the Navy puts their first NMT terminal into battle, it will have a brand new antenna, a brand new set of electronics below decks and it will be working on the advanced AEHF satellite. But, the terminal has to talk to the other ships in the fleet that are equipped with the old, non-AEHF systems. The XDR waveform has to communicate with the low data-rate (LDR) or the medium data-rate (MDR) waveforms that exist in every other legacy platform out there.
Satellite News: Do military personnel have to go through specific training to use these terminals in the field?
Whatmough: Yes, the complexity of these systems requires an extensive, specialized training program. Unlike your standard push-to-talk military radio systems, these terminals are designated for sensitive, critical missions like nuclear-powered fleets. It is critical for the military to have the most highly trained operators working on these systems.
Satellite News: What does Raytheon have scheduled for its AEHF terminal development program in 2012?
Whatmough: Our scheduled in 2012 basically involves building the terminal products. We’re at a point where the designs are very stable. We’re essentially done with development on both the Army side with SMART-T and the Navy side with NMT. We are now working up to full-scale production on both programs. We’ve delivered all of the SMART-T upgrade kits to the Army and the government has now asked us for additional SMART-T terminals. The Army has not asked for any technology upgrades for the SMART-T and they are very happy with the current capability.
The advanced AEHF portion of the NMT system is being designed, however, NMT also includes other frequency bands and we’re finishing up the final acceptance of those. We expect a full-production decision on the NMT program in the next couple of months. There is one ECP going on with the NMT where the services are going to launch an Enhanced Polar Satellite (EPS). The Navy is now paying us to upgrade our software to interoperate with the EPS. That effort is ongoing.