Once the troops got a taste of satellite communications in the 2003
invasion of Iraq (especially via Blue Force Tracker), there was no going back
to the bad old days. Traditional military radios, be they AM (which have longer
range, but variable sound quality) or FM (clear sound, but line-of-sight range,
and often blocked by hills or buildings), are much less effective than a
satellite based system. But the U.S. Department of Defense has known for
several years that it cannot afford sufficient satellites to meet the growing
demand. So the satellite transponders are now being mounted in smaller and
smaller UAVs, enabling divisions or brigades to put up their own
"satellite substitute," for as long as they are willing to keep their
Shadow 200, or larger, UAV in the air.
satellites cost at least $250 million each, and even the much touted micro-sats
still cost about ten percent of that. These take years to build and launch.
That's not fast enough. While weather balloons, equipped with satellite commo
gear, have been suggested as high
altitude "satellite replacements", there is the control problem. Even
tethered balloons (they look like blimps) are vulnerable. But any
"satellite replacement" is a major advantage because most of the
satellite communications needed by combat troops is with other people in the
same general area. So the commsat replacement (a balloon, UAV or B-52) can do
the job, passing off the long distance stuff to the real commsat.
cause of more commsat use is live video being generated by the increasing
number of vidcams on the battlefield. These vids are being exchanged by the
units cooperating in an operation. Since that's all local, a "satellite
substitute" (a balloon, or aircraft carrying the comm. Gear) will work. That's
why comm gear in UAVs, including special UAVs that just fly circles high in the
sky, is seen as an attractive satellite substitute. These substitutes cost less
than ten percent, per hour in use, of what satellites cost.
satcomm shortage problem began actually during the 1990s, when the U.S. armed
forces moved to satellite communications in a big way, at least for
headquarters. Most of the troops kept using the traditional AM and FM radios, This
made sense, especially where troops often have to set up shop in out of the way
places and need a reliable way to keep in touch with nearby forces on land and
sea as well as bases and headquarters back in the United States. At the time of
the 1991 Gulf War, there was enough satellite military communications capacity
(commonly known as "bandwidth") in the Persian Gulf for about 1300
simultaneous phone calls. Or, as the geeks put it, 100 mega (million) bits per
second. But while the military has a lot more satellite capacity now (the exact
amount is a secret), demand has increased even faster. UAV reconnaissance
aircraft use enormous amounts of satellite capacity. The Global Hawk needed 500
megabits, and Predators about half as much. The major consumer of bandwidth is
the live video.
UAVs have other sensors as well, as do
aircraft. A voice radio connection only takes about 2,000 bits per second, and
each of the multiple channels needed to control the UAVs use about the same.
But it adds up, especially since the military wants high resolution video. At
the moment, the U.S. has far more demand for satellite communications than it
can support. As a result, not all the Predator and Global Hawk UAVs in combat
zones have sufficient bandwidth to send their video back to the United States.
Data compression and using lower resolution is often necessary, or using
satellite substitutes (aircraft carrying transponders) to send the video to
local users. The substitutes are becoming more common, simply because there is
neither the money, nor the time, to get sufficient satellites into orbit.