Where no WAN has gone before

Satellite tracking of sexual offenders is becoming law enforcement's rising star.


In November 2005, investigators with the United States Park Police contacted the District of Columbia's Court Services and Offender Supervision Agency (CSOSA) in connection with the investigation of an assault that occurred at Logan Circle a month earlier. CSOSA is the agency responsible for supervising more than 15,000 parolees, supervised releases and probationers in Washington, D.C.

Witnesses of the assault had observed the suspect wearing an ankle bracelet and a device attached to his belt — a technology police suspected might match those worn by offenders being monitored by CSOSA using GPS (Global Positioning System) tracking.

CSOSA reviewed its records and was subsequently able to place one offender at the scene of the crime at precisely the time identified by Park Police. In fact, the records showed the suspect departing the area at a rate of speed suggesting he was running. The suspect was later arrested and confessed to the assault.

GPS, augmented by cellular telephone technology, has given criminal justice authorities a new tool to add to the traditional range of noncustodial sentencing options.

The District of Columbia was among the first to evaluate the utility of these GPS satellite tracking systems. Since inception of the GPS Electronic Monitoring pilot in October 2003, approximately 291 different offenders have been placed on the system.

High-tech monitoring

Satellite tracking is used to control and monitor the location of individuals to ensure they are complying with restrictions placed on them by the courts as a condition of their release from prison. It's a high-tech alternative to full-time incarceration.

Two types of monitoring technologies exist — radio frequency (RF) tracking and GPS tracking. RF tracking, which is essentially a binary system — either the subject is home or is not at home — has been around for more than 20 years. GPS, which made its appearance on the criminal justice scene in the past five years, refines that capacity; it has the ability to track subjects at all times, and can locate them within 2 meters on survey maps.

Tracked subjects must wear two pieces of equipment — a tag around their ankle and tracking device on their belt or at waist height. The tag checks that the device is being worn by the subject and is within close proximity of the tracking device, while the tracking device calculates the offender's location and relays it to the monitoring agency.

Some tracking systems are trending toward just one piece of equipment, which is easier for the offender. But current communication capabilities at ankle level are not optimal and can present challenges in reception and transmission.

The advantage of two-piece systems is that GPS reception is generally better because the tracking device is worn at waist level. The downside of the two-piece system is the device can be inadvertently left (or abandoned) on the charger cradle, even though manufacturers have built-in alarms that sound if the subject strays more than 25 feet from the unit.

GPS trends

At this point, the number of agencies using RF monitoring technology still dwarfs GPS satellite tracking market penetration, although the trend is clearly toward GPS.

"We estimate that 110,000 offenders are currently being supervised with electronic RF monitoring in the United States, whereas the GPS market is probably only about 10 percent of that," says Jock Waldo, vice president of sales, marketing and operations for BI Inc., a manufacturer of electronic monitoring equipment.

Waldo says the direction is beginning to change.

"We're seeing GPS momentum pick up as legislative activity is driving the level of agency interest toward GPS," Waldo says.

GPS tracking addresses the hot issue of sex offenders and sexual predators being loose in the community. According to the Bureau of Justice, there are 4.8 million probation and parole offenders living in U.S. communities, many of whom are sex offenders. In the wake of Megan's Law in 1996 and recent events such as the 2005 Jessica Lunsford incident in Florida, more than 30 states have either enacted legislation or have laws pending requiring certain offenders to wear some form of tracking technology.

This content continues onto the next page...
  • Enhance your experience.

    Thank you for your regular readership of and visits to Officer.com. To continue viewing content on this site, please take a few moments to fill out the form below and register on this website.

    Registration is required to help ensure your access to featured content, and to maintain control of access to content that may be sensitive in nature to law enforcement.