What EM Technologies are Available?
The electronic monitoring technologies offered by G4S EMI come from our Patrol Suite™ range of products that include the following:
Radio Frequency (RF) Technology
Radio Frequency (RF) technology is also known as tagging or home detention technology. RF Patrol™ is used to verify compliance with curfews. The participant wears a small tamper resistant ankle bracelet which transmits and receives radio frequency signals to and from a box, known as a home monitoring unit (HMU), located centrally in the home. The participant is required to remain at home during specific times of the day. Events or alarms are reported to the monitoring system over a landline or mobile GSM network. The technology reports absences but does not track the whereabouts of the participant when out of the HMU’s range. RF technology is used worldwide and we recommend it as a starting point for any electronic monitoring program.
Voice Verification (VV)
Voice Patrol™ compares a participant’s supervised voice enrollment with sample verifications received from agreed locations. Mathematical algorithms determine the closeness of the verification to the original enrollment. Caller line identification determines whether or not the participant is at the specified place, at the specified time. Enrollments and verifications are generated from a sample of phrases and number combinations which are combined in random order making recording of verifications impossible. Verification calls can be made and received at specific times or at random intervals.
GPS Tracking
Orion Trac Patrol uses satellites orbiting the Earth to track the whereabouts of a participant wearing the device. In the past, the technology has consisted of two pieces; a belt worn GPS device and an ankle worn bracelet. GPS offers users far more data than traditional radio frequency and voice verification technologies. This increased data requires well defined systems and processes for managing it all into a meaningful format. All GPS tracking devices have some limitations which include the need to recharge the battery every day, lack of GPS signals underground or in some buildings, and the reliance on GSM mobile networks for communication. In some countries, it is possible to supplement GPS with position data from the GSM network provider but accuracy is poor and it can be expensive. Orion links with a localized Beacon which turns the Orion unit into a RF transmitter, shutting down GPS for as long as Orion and the Beacon remain in range of each other. This is a useful feature for indoor areas where there is zero or marginal GPS coverage. The latest generation software interfaces with Microsoft Virtual Earth offering detailed bird’s eye view of a participant’s location.
Emerging Technologies
New and emerging technologies include:
- Remote alcohol and drug testing capabilities using breath analysis
- Trans-dermal (skin) techniques
- Measurement of interrupted sleep patterns which may suggest or alcohol drug use
- Area monitoring systems for monitoring inmates in secure environments.
Web Patrol II™ brings all these electronic monitoring technologies together under a single Internet-based flexible monitoring platform. Available in a wide range of languages and with multiple reporting capabilities, it is the focal point of any electronic monitoring program. Users may respond in real time to violations received on screen or from e-mail alerts, or log-on from remote locations to view reports, complete violation reports, or to edit schedules.
