Tracking Pursuits From the Air

I guess there is something a little anti-American in liking a Big Brother situation, but I have to say it is mighty reassuring to have a helicopter light up your world during a high-risk traffic stop--or better yet, track a dope dealer running through back yards. Hearing that whup-whup-whup overhead can be almost as comforting as having your beat partner show up just as you start to get that "uh-oh" feeling that things are about to go south. That extra "eye in the sky" can do a ton of work for us footslogging officers on the ground, including making the bad guys act a little nicer than usual.

I know that many departments cannot even begin to justify aircraft, much less a fleet of them. Frankly, our air unit is relatively new to our agency, and we are still growing and learning how to best use this amazing tool. However, agencies that have been in the airborne game for a while understand how different police work can be with a helicopter (or airplane--but helicopters seem to be the preponderance, so we'll concentrate on them).

While most of my articles concentrate on using handheld thermal imagers to make police work easier, this one will look at how airborne imagers can make aircraft wonderful tools for monitoring pursuits.

New Pursuit Rules

Police agencies across the US are instituting more restrictive vehicle pursuit policies, placing an emphasis on protecting the innocent public versus tracking the fleeing motorist who failed to use a turn signal. While administrators may be ordering the ground troops to ease off, the reality is that airborne officers can still monitor and track a fleeing vehicle.

A police helicopter can follow a vehicle without ever placing the innocent public at risk. By monitoring the progress from above, helicopter officers can vector in ground officers safely and effectively. The airborne officers can even track the vehicle to its final destination, or watch for the occupants to bail out and flee on foot.

Obviously, this is extremely easy in the daytime. At night, the helicopter officers need assistance. Commonly, this is done with a spotlight illuminating the fleeing vehicle to ensure that it is tracked properly. The problem, of course, is that the suspect eventually figures out he is being followed from above. Once the bad guy has ruled out divine intervention, the halo of light that tracks his every movement is a pretty darn good clue that someone above is watching.

While this is certainly better than nothing, it still adds risk as the suspects may drive more erratically in order to elude the helicopter. That's where a thermal imager can provide a distinct edge.

Tracking with a TI

An airborne thermal imager is not much different from a handheld version. The basic science and technology are the same, although the greater range and additional features of an aircraft-mounted TI account for a significant price difference. But at their core, handheld and air-mounted TIs do the same thing: make pictures based on heat.

The key is that the heat is naturally occurring; the TI doesn't have to send out any type of signal or beam of light. It is completely passive, merely receiving heat and generating images based on the amounts of heat it receives. This is unlike the spotlight, which has to generate light and project it at the target. This lets the officers see, but also announces to the world exactly where the helicopter crew wants to look.

Tracking with a thermal imager, however, is covert. A helicopter can follow the suspect vehicle as it races on an interstate, or meanders through a residential neighborhood. It can also track the occupants when they leave the car, all without ever identifying its presence to the suspects. It can do this easily because the car and the suspects all generate heat. Better yet, it can do it from 500 feet in the air, never placing a citizen at additional risk of injury.

Police helicopters and aircraft offer incredible advantages to officers on the ground. They are especially helpful at tracking vehicle pursuits, even taking over as the "lead" in the pursuit to prevent ground units from taking unnecessary risks. At night, the air units need technology to track the suspect vehicle.

While spotlights are the most common means of tracking at night, they offer the distinct disadvantage of informing everyone nearby, including the suspect, exactly where the airborne officers are looking. By mounting a thermal imager on an aircraft, officers can gain a discreet, yet effective, monitoring system that allows them to track suspects without their knowledge. This makes the pursuit safer for officers, the public, and even the suspects.

Once the bad guys hear the whup-whup-whup overhead, they'll be surrounded by ground officers and know that things are about to go south--the way it should be.