Ever-shrinking GPS electronics could bring satellite navigation to everyone
THE MIL & AERO BLOG, 24 June 2014. Two U.S. military research initiatives are taking aim at shrinking the size, weight, and power consumption (SWaP) of Global Positioning System (GPS) satellite navigation electronics in orbit and on the ground.
If successful, these research projects could shrink GPS satellite transceiver payloads such that future GPS orbiting navigation stations might not even require their own satellites. Instead, they might be able to piggy-back on other satellites.
In addition, research in progress also could lead to embeddable GPS receivers for military wearable computing, handheld devices, and countless other applications that are smaller, less obtrusive, and consume less power than ever before.
We might think that today's civil GPS receivers are ubiquitous and easy to use, and this capability is moving into aerospace and defense applications, as well. In short order we could see that same kind of embedded GPS in more applications than we would never have dreamed of only a few years ago.
Related: Boeing, Ball join Air Force project for new L-band RF amplifiers to shrink GPS satellites
It's hard to keep up with military applications of GPS. They're not just for finding the fastest way from point A to point B as they once were. Today small, rugged GPS receivers help parachute cargo loads find their drop zones, guide smart munitions to their targets, help radio users keep track of one another, keep unmanned aerial vehicles (UAVs) on their designated routes, and help riflemen determine their distance to target. The list goes on.
The first program helping bring all this about is sponsored by the U.S. Air Force Research Lab, and seeks to design new L-band radio frequency power amplifiers for GPS satellite payloads. In the future this could help demonstrate the direct digital synthesis of GPS signals.
Direct digital synthesis is a way of producing an analog signal in digital form and then performing a digital-to-analog conversion. Because operations primarily are digital, this process can offer fast switching between output frequencies, fine frequency resolution, and operation over a broad spectrum of frequencies.
Working on this project are the Boeing Space & Intelligence Systems segment in El Segundo, Calif., and to Ball Aerospace in Boulder, Colo., and the Northrop Grumman Corp. Aerospace Systems segment in Redondo Beach, Calif.
Related: Army seeks drastic reductions in the size and power consumption of embedded GPS modules
Direct digital synthesis devices are compact and draw little power, and can generate analog signals efficiently because today's single-chip integrated circuits can generate programmable analog output waveforms simply and with high resolution and accuracy. Translated, that means fewer components for enhanced functionality.
That's the space portion. Now for what may be in store on the ground.
Officials of the U.S. Army Product Director of Positioning Navigation and Timing (PD PNT) at Aberdeen Proving Ground, Md., are sending out feelers to the defense industry in efforts to find companies able to make drastic reductions in the size of standard military embedded GPS modules.
The program, called Embeddable GPS Receiver In Mini-Ground Based Receiver Applications Module (Mini-GRAM-M), is just getting off the ground, but it seeks to shrink today's 3.4-by-2.45-by-0.6-inch GPS module to no larger than 1.5 by 1.5 by 0.5 inches.
Related: DARPA takes another look at precise positioning without GPS in upcoming STOIC program
Furthermore, the Mini-GRAM-M GPS module must weigh no more than 50 grams, and use no more power than 900 milliwatts in transmission mode, no more than 500 milliwatts in receive mode, and have fewer than 30 pins for I/O.
It's a big step, but there must be companies out there able to undertake such a project.
So shrink the size of GPS space payloads, and the embedded receivers on the ground, in the air, and on the water, and who knows what capabilities might emerge.
Suffice it to say that in the future, there will be very few military electronic systems with some sort of GPS capability.
John Keller | Editor
John Keller is editor-in-chief of Military & Aerospace Electronics magazine, which provides extensive coverage and analysis of enabling electronic and optoelectronic technologies in military, space, and commercial aviation applications. A member of the Military & Aerospace Electronics staff since the magazine's founding in 1989, Mr. Keller took over as chief editor in 1995.
