August 26, 2012: After over a decade of trying, there's finally a wristwatch sized GPS that satisfies military users. The new Garmin Fenix looks like a large digital watch, which it is. But Fenix is also a GPS unit that can store 1,000 waypoints and 10,000 trackpoints and displays track maps on the 70x70 pixel watch face. Fenix also contains an altimeter, barometer, 3-axis electronic compass and temperature sensor. It is also waterproof to 50 meters (164 ft). Track maps can be shared wirelessly with other Fenix watches, smart phones and PCs. There are also all the standard watch features (alarms, timer, stopwatch and the use of chimes or vibration for alerts).

While mainly directed at the civilian market, Garmin did listen to military customers, because Garmin expects thousands of soldiers, marines and SOCOM operators to pay $400 for the Fenix. That's because, although the military provides its ground combat troops with excellent GPS receivers, these devices are always heavier, bulkier and less easy to use than commercial products.

The military is trying to compete. The latest military response is MicroDAGR, a 175 gr (6.5 ounce) GPS about the same size as a smart phone and with a touch screen. While the $1,500 MicroDAGR has most of the larger, and older, DAGR (Defense Advanced Global Positioning System Receiver) features, it is basically smart phone GPS without the smart phone. The troops, especially the ones who have to carry GPS devices long distances, were underwhelmed and much prefer something like Fenix, which can be worn on the wrist. Fenix weighs less than half as much as MicroDAGR and has a battery that lasts much longer.

Six years ago the U.S. Department of Defense had 135,000 portable GPS receivers in service, plus many more embedded in weapons and equipment. Over the next two years the number rose to over 200,000. Now it's over 400,000. But the troops still prefer to carry commercial GPS, especially the kind that's incorporated in most smart phones. There are two reasons for this. For the infantry the biggest thing is that the commercial GPS devices are lighter. That is also the case with batteries in commercial GPS receivers lasting longer. That means you don't have to carry as many batteries. For troops that hike around a lot, mainly the infantry, every little bit helps when it comes to weight. But for mounted troops, DAGR is just fine. Many foreign armed forces agree and many have bought DAGR.

Over the last six years the army has replaced all the older (from the early 1990s) PLGR GPS receivers. These were replaced with the new $2,300 DAGR, which weighs 450 gr (15 ounces) but is small enough (16.5x8.7x4cm/6 3/8x3 7/16x1 9/16 inches) to fit into a standard two-clip ammo pouch. DAGR can get its first position fix within 60 seconds and can run continuously for twelve hours on its battery. There are a number of useful accessories, including an anti-jamming device, a more powerful antenna, and external power cables. DAGR has one major advantage over commercial GPS receivers: it can use the Precise Positioning Service (PPS) signal. PPS allows users to operate reliably when someone is trying to jam GPS signals. But in Afghanistan and Iraq the troops never encountered GPS jammers. So the infantry, whenever they could get away with it, left DAGR at home and carried a commercial model.

DAGR also has the most popular features found in commercial GPS receivers and can easily have its software updated. DAGR has a 43x58mm (1.7x2.3 inch) display and can survive submersion into a meter (39 inches) of water. The display is the major advantage of DAGR, as it can display more useful information, in map form, about where the troops are and where they are going. For troops in a vehicle, PLGR still does the job. The army has put a GPS unit (sometimes a PLGR) in just about every vehicle it has, especially the ones operating overseas.

The next generation GPS device is being designed, sort of. The DAGRs are expected to last for at least another few years. But with GPS being built into so many things, it’s difficult to know what features a special military GPS would have to have to justify the cost. GPS receivers are becoming a feature, not a separate piece of equipment. Thus the popularity of Fenix among the troops.

GPS has changed warfare more than most people realize. It all happened during the 1990s, starting with the 1990-91 Gulf war. The U.S. Army, a pioneer in the use of radio on the battlefield, was still developing GPS when the Gulf War came along. What happened next was a complete surprise to the civilians who watched the war unfold. The GPS (Global Positioning System) provided precise location information (to within 25 meters or less) via a hand held satellite signal receiver. Not all the needed satellites were in orbit when war began but there were enough up there to give coverage over most of the Gulf, except for a few hours in the late afternoon. For an army operating in the desert, GPS was literally a lifesaver. It is very easy to get lost while traveling over (usually) unfamiliar terrain. Maps only appear to add to the confusion and in desert operations "navigation" becomes a major matter of life and death.

All that was changed in the Gulf War because of GPS receivers. This system provided precise location information to anyone with a battery powered SLGR (Small, Lightweight GPS Receiver, or "Slugger") unit. The smallest version weighed nearly a kilogram (two pounds). Knowing who (and what) is where on the battlefield is often a matter of life and death. Calling in artillery fire or air strikes depends on the ground observer (who is often not far from the target) knowing exactly where he is so that the shells or bombs hit the enemy and not friendly troops. Reconnaissance is much more effective with GPS, as the location of the target can be recorded with precision. Marking the location of enemy minefields, a common occurrence during the Persian Gulf War, was much more effective with GPS equipped units.

Some 4,500 GPS receivers were in the Gulf by the end of February, 1991, plus several hundred civilian versions bought by the troops (or their parents) at up to $4,000 each. At the end of the century you could buy a GPS receiver for a hundred dollars. Now, many people have GPS built into their cell phones. Basically the GPS is nothing more than a radio receiver that uses the signals from distant satellites to tell the user where he is. But it has changed military operations more than any other navigation device every employed by the troops.