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Location Monitoring

Location Monitoring

In 1993, the Administrative Office of the United States Courts awarded its first national contract to provide electronic monitoring services to its defendant/offender population. The first monograph specific to home confinement/electronic monitoring was approved for publication and distribution by the Judicial Conference in 1999. This monograph continues to set forth official policies and procedures for the federal home confinement program (now the Location Monitoring Program), including guidance on managing the program. By 2007, there were over 23,000 defendants/offenders with either a home confinement condition or a condition requiring the use of electronic monitoring.

The previously named "home confinement program" implies that all "electronic monitoring (EM)" occurs primarily at a defendant/offender's residence and is utilized to monitor a defendant/offender's departure and arrival from the residence based on authorized hours. The newly named program, Location Monitoring Program (LMP), emphasizes the full array of location monitoring technologies that can provide functionality to monitor defendant/offender’s location in the community rather than just the residence. Furthermore, the concept behind the location monitoring program is that the technology serves as one of many supervision tools that will assist an officer in verifying a defendant/offender's compliance with any court or parole-commission imposed condition of release.

Location monitoring technology (LMT) provides officers with broad operational considerations for purposes of mitigating defendant/offender risks, providing supervision structure and detecting various patterns of behavior. The location monitoring program is a paradigm shift as it relates to the purpose of electronic monitoring, emphasizing an enhanced community supervision tool. Regardless of the type of location monitoring technology recommended or selected, the appropriate use of the technology can create supervision efficiencies by providing a better allocation of time and therefore avoid under-supervising high-risk defendants/offenders and avoid over-supervising low-risk defendants/offenders. For example, the technology allows an officer to know when defendants/offenders are in or out of their homes, which enables the officer to schedule critical home contacts that include face-to-face contacts with defendants/offenders.

There are three primary types of location monitoring technology: Voice Verification Systems, Radio Frequency (RF) and Global Satellite Positioning (GPS).

Voice Verification Systems 
Voice verification systems can be utilized to place and/or receive random telephone calls to defendants/offenders to verify their presence at an approved location which is typically their home.

Radio Frequency (RF) 
The location monitoring program may incorporate an electronic monitoring system that includes monitoring equipment and 24-hour electronic surveillance designed to alert an officer when a participant leaves a specific location (usually the residence), returns home late (or leaves early) from a pre-approved schedule, or tampers with the electronic monitoring equipment. While subject to electronic monitoring, the participant wears a non-removable, waterproof, and shock-resistant transmitting device around the wrist or ankle 24 hours a day.

The ankle is the preferred location and installing the transmitter on a wrist should only be an option for verified medical reasons. The transmitter emits a radio frequency signal that a monitoring unit connected to the home telephone detects. When the transmitter comes within the signal range of the monitoring unit, the monitoring unit uses the telephone line to call a central monitoring computer to show the participant is in range or at home. The transmitter and monitoring unit work in combination to detect and report the times participants enter and exit their homes.

The location monitoring equipment only reports when a participant enters or leaves the equipment's range--not where the participant has gone or how far the participant has traveled. The range of the monitoring unit in the federal program may be adjustable. In other words, the participant must stay within a designated area / feet or in any lower adjusted range of the monitoring unit in the residence to be considered in range or at home.

Global Positioning Satellite (GPS) 
While subject to GPS monitoring, the defendant/offender’s location is detected via Global Positioning System satellites that transmit signals to location monitoring equipment on the ground. GPS receivers receive satellite signals; they do not transmit. GPS receivers require an unobstructed view of the sky, so they are used only outdoors and they often do not perform well within forested areas or near tall buildings. GPS operations depend on a very accurate time reference, which is provided by atomic clocks. Each GPS satellite transmits data that indicates its location and current time. All GPS satellites synchronize operations so that these repeating signals are transmitted at the same instant. The signals move at the speed of light to the GPS receiver. The distance of the GPS satellites can be determined by estimating the amount of time it takes for their signals to reach the receiver. When the receiver estimates the distance to at least four GPS satellites, it can calculate its position in three dimensions.