After a generation in orbit, GPS satellites still evolving to improve on size and efficiency

THE MIL & AERO COMMENTARY, 17 May 2016. Satellite navigation via the U.S. Global Positioning System (GPS) is so common today that it's nearly taken for granted. Most cell phones have built-in GPS and moving-map technology that can tell you where you are virtually anywhere. Few cars come without GPS receivers.

After big defense cuts, what lies ahead?
After big defense cuts, what lies ahead?
Gps Map 17 May 2016THE MIL & AERO COMMENTARY, 17 May 2016.Satellite navigation via the U.S. Global Positioning System (GPS) is so common today that it's nearly taken for granted. Most cell phones have built-in GPS and moving-map technology that can tell you where you are virtually anywhere. Few cars come without GPS receivers.

The U.S. GPS satellite constellation became fully operational in 1995 -- right around the time the Internet became a household word. My children and grandchildren, for example, have no recollection of a world without GPS and the Internet, and they regard these two monumental technologies as no more wondrous than a light bulb.

It wasn't always so. When I first started covering GPS technology back in the mid '80s there were fewer than 10 orbiting GPS satellites of an eventual 24-satellite constellation. GPS receivers belonged only to the military, and those receivers were big -- sometimes 50-pound boxes.

Anything GPS back then was big news. I and other military tech reporters wrote feverishly about developments in GPS satellite technologies, new ways to miniaturize GPS receivers, and about each new GPS satellite launch. Back then it was like covering the F-35 is today.

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The Gulf War of 1991 was the first armed conflict that involved GPS, and the U.S. military didn't have enough military-issue GPS receivers to go around. In fact, handheld GPS receivers were in such demand among the warfighters on the ground that families were buying some of the first commercially available GPS receivers and sending them to their loved ones on the front lines.

Still, all that's a long time ago, and GPS today isn't anything new.

Behind the scenes, however, the military continues to upgrade and improve the GPS system in space and on the ground to keep U.S. satellite navigation on the leading edge of technology.

One of the newest developments in GPS technology came just this week as the U.S. Air Force awarded a $16.2 million contract to Boeing shrink the size of the digital waveform generator on Global Positioning System (GPS) satellites, as part of the On-Orbit Reprogrammable Digital Waveform Generator (ORDWG) for the GPS Spacecraft Navigation Payload program.

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Boeing is going to improve GPS signal generation by building a new, improved, and smaller digital waveform generator for GPS satellites. The goal is to develop a space-qualified DWG able to replace those in current GPS satellite navigation payloads.

The GPS satellite waveform generator drives the design and size, weight, power, and cost (SWaP-C) of the GPS L-band navigation payload as well as the host spacecraft bus.

Two years ago the Air Force awarded a $7 million contract to the Northrop Grumman Corp. Aerospace Systems segment in Redondo Beach, Calif., to design new L-band radio frequency power amplifiers for the GPS payload to help reduce the size and improve efficiency of GPS satellites.

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Northrop Grumman is upgrading the GPS the direct digital synthesis of GPS signals by designing a digital beam forming element, engineering design unit, and other enabling technologies of the digital phased array GPS payload.

Other GPS improvements are in progress are in the planning stages. Priorities include upgrades to help GPS transmitters and receivers resist the effects of electronic warfare jamming or inadvertent electromagnetic interference, helping GPS signals work together with other navigation systems, and stealthy ways to exploit GPS signals for precision navigation.

So next time you think of the GPS as old-hat technology, think again. Certainly GPS has been in operation for more than a generation, but it's likely it will be a mainstay for precision navigation for many generations more.

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