The Pentagon is now spending $3.3 billion annually to develop and buy unmanned aerial systems (UAS), but this sum is still only 8 percent of the total devoted to all aircraft, according to a new report on UAS by the U.S. Congressional Research Service (CRS).

The Jan. 3, 2012 report, titled "U.S. Unmanned Aerial Systems," mostly rehashes previously published material, but it does contain an updated inventory of UAS platforms in service provided by the DoD’s UAS Task Force. These include 161 MQ-1 A/B Predators, 54 MQ-9 Reapers and 16 RQ-4B Global Hawks in the Air Force; 364 RQ-7 Shadows, 25 MQ-5 Hunters and 26 MQ-1 Warriors and Gray Eagles in the Army; and 122 Scan Eagles with the Navy and Special Operations Command.

The Air Force plans to buy a total of 399 Reapers and the Army a total of 152 Gray Eagles, according to the report. The total acquisition spend on these two General Atomics UASs between 2011 and 2016 will be more than $10.6 billion. Acquisition of the Northrop Grumman Global Hawk and its BAMS Navy derivative is predicted to cost nearly $17 billion between 2011 and 2020. The totals include research, development, test and evaluation; the air vehicles; sensors; and ground stations.

The report offers some comment on UAS loss rates, without providing any new data. It also covers some familiar territory, such as bandwidth and interoperability issues. The development of more autonomous UAVs may not significantly affect escalating bandwidth requirements, since this is driven mostly by the transmission of sensor data, the author suggests. He notes the difficulty of evaluating the costs of complete UAS, and calls for “a uniform cost comparison mechanism.”

The report reviews the Pentagon’s attempts to manage UAS programs over the years, and asks whether it should be centralized, because “great potential exists for duplication of effort.” The report looks forward to new UAS technologies, such as sense-and-avoid, electrical power generated by fuel cells and control of multiple UAVs by a single operator.