June 5, 2015:
With great effort over the last two decades the American military has been able to get enough bandwidth (data transfer capability) to get video and still photos from aircraft and UAVs back to ground stations via satellites. There remains one big drawback in that there isn't enough bandwidth available on the battlefield to move around the data needed to keep the troops updated on what the UAVs, aircraft and satellites are seeing. The bandwidth problem has proved to be a real tough one. Mainly because high speed data transfer on the battlefield first became possible via satellite communications and data was soon being produced far faster than it could be moved around to the people who needed it. This was all about continuing bandwidth shortages. The army in particular is working on solutions. The most obvious one is to edit the data feeds to retain only the essential data.
What is happening to the military has also been experienced by most civilians. The many people who have used civilian digital cameras since they first showed up in the 1990s are well aware of how the size of those picture files has grown by more than fifty times in the last two decades. To these users it is obvious that 1990s digital cameras took useful photos but the current ones capture a lot more detail and military users find that “excessive detail” is the most useful part of a photo or video. So the effort to develop workable software that would send (after the operator selected criteria for what is important) a much smaller data file to the troops, showing only essential data. Working out how all that functions in practice has proven difficult.
Meanwhile the U.S. Air Force has managed to keep up, just barely, with its military communications satellite programs. Three of six AEHF (Advanced Extremely High Frequency) communications satellite are already in orbit and operational. The first of the AEHF satellites was launched on August 2010. It achieved its initial orbit but then it was discovered that its main maneuvering rocket, needed to get the six ton satellite into its permanent fixed 36,000 kilometer orbit, was not working. Efforts to get the main engine going failed. The engineers then went to work and found a way to use the lower thrust maneuvering rockets to still get the AEHF bird into position. But the alternate method was slower and took about nine months. That was a small price to pay for a satellite that is supposed to last 14 years, once you get it in the right position. AEHFs will replace the older MILSTAR birds, providing more abundant and reliable (jam-resistant) communications.
The major consumer of all this new bandwidth 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. This huge growth in bandwidth began in the 1990s, when the U.S. armed forces moved to satellite communications in a big way. 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 bandwidth in the Persian Gulf for about 1,300 simultaneous phone calls (12 megabits 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 per second 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 240 bytes 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. Until recently (when the AEHF birds went up) the U.S. had far more demand for satellite communications than it could support. As a result, not all the Predator and Global Hawk UAVs in combat zones had sufficient bandwidth to send their video back to the United States. Data compression and using lower resolution was 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.
While the larger UAVs need satcomm to send video back to the United States, most of the bandwidth demand now is for local use. Tanks, helicopters, and aircraft are all sending and receiving more vids, maps, and data of all sorts. AEHF is needed to get essential material to higher headquarters as quickly as possible. The basic idea is to keep everyone connected, all the time. More radios and other wireless devices are on the way, as well as more features any Internet user would recognize, all available while under fire. AEHF is an essential link in this data chain.