Posted by John Keller

You can learn a lot just by watching, and that's the idea behind persistent-surveillance technologies deployed and in development by Logos Technologies Inc. in Fairfax, Va., for military surveillance in South Asia, as well as for homeland security surveillance on the nation's southern border.

Logos is in the business of just watching -- not for anything specific, but the company's scientists are developing intelligent persistent-surveillance technologies that once something of interest happens, they not only can spot the incident and interpret it, but also link events happening before and after an incident that can yield reams of important information.

The key word here is reams -- or more specifically, hundreds of terabytes of imaging data . The Logos Kestrel day/night wide-area persistent surveillance system, for example, is an imaging payload for helium-filled aerostats that remain aloft for about a month, and can store continuous video data for all of that time.

Logos also designs the Lightweight Expeditionary Airborne Persistent Surveillance (LEAPS) payload for small manned aircraft such as the Hawker Beechcraft King Air, as well as for medium-endurance unmanned aerial vehicles (UAVs).

You can think of persistent surveillance as kind of an autonomous police stakeout. The beauty of these autonomous sensor payloads is they don't get tired, bored, distracted, or take coffee breaks.

These kinds of sensors simply watch until something of interest happens -- a moving vehicle, converging vehicles, groups of people on foot, or anything else that might rouse suspicion.

These incidents might indicate an important meeting of high-ranking terrorists, a drug deal going down, the planting of improvised explosive devices (IEDs), or attempts to cross into the U.S. illegally.

Taken in isolation, these incidents are simply moving vehicles or groups of people. Nothing really out of the ordinary. But put these incidents in context of events happening before and after, and sometimes a coherent picture emerges.

What if three or four cars all park close to a specific house within a few minutes of one another? Say that house later is determined to be the hideout of an important terrorist, drug smuggler, or military enemy?

A persistent-surveillance system like Kestrel, LEAPS, or Gorgon Stare can indicate where the converging cars came from, and where they went afterwards. This could lead authorities to important suppliers, criminals, or potential victims.

What is an aerostat-mounted persistent surveillance sensor could watch a road every second for a month? By identifying vehicles that stop at odd times and odd places might indicate the emplacement of IEDs, or some other kind of military ambush.

The possibilities are almost endless.

The story doesn't end there, however. Logos engineers are working to shrink their persistent-surveillance payloads from hundreds to only tens of pounds, as well as developing data storage technologies that make the most of limited bandwidth. These approaches could open up new ways to deploy these sensors on a wide variety of covert platforms.

These persistent-surveillance sensors are watching ... all the time.