Electronic Monitoring Industry Glossary

A

Ankle Bracelet / Ankle Monitor

A body-worn device fastened to the ankle that tracks location, movement, or other conditions. GPS ankle monitors use satellite and cellular technology to report location to a monitoring center in real time.

Active GPS Tracking

Continuous or periodic transmission of location data to a central server in real time. Enables immediate alerts for zone violations, tampering, or lost signal. Required for most bail bond and pretrial monitoring programs.

Anti-Tamper Detection

Technology that detects attempts to remove, cut, or circumvent the monitoring device. Methods include fiber optic sensors, conductivity-based straps, and heart-rate monitoring. Fiber optic detection achieves zero false positives in field deployments.

B

Bail Bond

A financial guarantee posted by a bail bond agency to secure a defendant's release from custody before trial. The bondsman assumes liability if the defendant fails to appear in court; GPS monitoring reduces that risk.

BLE (Bluetooth Low Energy)

A low-power wireless protocol used in some ankle monitors to communicate with a paired smartphone or hub. BLE connected mode can extend battery life to months by offloading cellular transmission to the paired device.

Bond Forfeiture

When a defendant fails to appear in court, the court may declare the bond forfeited and the bondsman liable for the full bond amount. GPS monitoring with real-time alerts helps prevent FTA and bond forfeiture.

Bond Compliance

The defendant's adherence to conditions set by the court or bail bond agency, such as curfew, exclusion zones, and check-in requirements. GPS monitoring provides objective compliance data for court reporting.

C

CAM (Continuous Alcohol Monitoring)

Technology that measures alcohol in sweat or transdermal vapor at scheduled intervals. Often used alongside GPS monitoring for defendants with alcohol-related conditions.

Cellular Communication (LTE-M, NB-IoT)

Low-power cellular protocols designed for IoT devices. LTE-M and NB-IoT consume less power than 3G/4G, enabling 7-day battery life in GPS ankle monitors. Both are 5G-compatible.

Curfew Monitoring

Enforcement of court-ordered home confinement during specific hours. GPS devices with inclusion zones verify the defendant remains at a designated address during curfew.

Community Supervision

Supervision of offenders in the community rather than in jail or prison. Includes probation, parole, pretrial release, and house arrest. Electronic monitoring is a core tool for community supervision programs.

CEP (Circular Error Probable)

A measure of GPS accuracy: the radius within which 50% of position fixes fall. Sub-2-meter CEP indicates high accuracy; 5–10 meter CEP is common for older single-constellation devices. Higher accuracy matters for court-admissible evidence.

D

Defendant

A person charged with a crime who is awaiting trial. Defendants on bail may be required to wear a GPS ankle monitor as a condition of release.

Dead Zone

An area with no cellular coverage or GPS signal. Devices may store data for later transmission or alert the monitoring center of lost connectivity. LTE-M/NB-IoT often perform better in buildings than legacy cellular.

Dwell Time Alert

An alert triggered when the defendant remains in a designated location for a specified duration. Used to detect loitering near exclusion zones or prolonged stays in prohibited areas.

E

Electronic Monitoring (EM)

The use of electronic devices to supervise offenders in the community. Includes GPS tracking, RF monitoring, alcohol monitoring (SCRAM/CAM), and home detention systems. See bail bond GPS monitoring for an overview.

Exclusion Zone

A geographic area the defendant is prohibited from entering. Examples include victim residences, schools, bars, or specific neighborhoods. Entering an exclusion zone triggers an immediate violation alert.

eSIM

An embedded SIM card that can be provisioned remotely without physical replacement. Enables devices to switch carriers or activate in different regions without a physical SIM swap. Used in advanced GPS monitors like CO-EYE ONE-AC.

F

Fiber Optic Tamper Detection

A tamper-detection method that uses an optical fiber embedded in the strap and case. Cutting or removing the strap interrupts the light path and triggers an alert. Achieves zero false positives and zero false negatives compared to heart-rate or conductivity-based systems.

Failure-to-Appear (FTA)

When a defendant does not show up for a scheduled court date. FTAs result in bond forfeiture, warrants, and liability for bail bond agencies. GPS monitoring with real-time tracking reduces FTA rates.

False Positive / False Negative

A false positive is an alert when no actual violation occurred (e.g., tamper alert from normal movement). A false negative is a missed alert when a violation did occur. Heart-rate-based tamper detection can show 30–50% false positive rates; fiber optic detection eliminates both.

G

Geofence

A virtual perimeter around a geographic area. Used to define inclusion zones (where the defendant must stay) and exclusion zones (where they must not go). Crossing a geofence triggers automated alerts.

GPS (Global Positioning System)

A satellite-based navigation system operated by the US. Modern ankle monitors use multi-constellation positioning (GPS, BeiDou, GLONASS, Galileo) for higher accuracy and faster fixes.

GLONASS

Russia's global navigation satellite system. Used alongside GPS in multi-constellation receivers to improve accuracy and availability, especially in urban canyons or under tree cover.

Galileo

The European Union's global navigation satellite system. Part of multi-constellation GNSS in premium GPS ankle monitors for improved positioning.

GSM

Global System for Mobile communications. Legacy cellular technology; some GPS monitors support GSM fallback for global coverage. Newer devices prefer LTE-M/NB-IoT for power efficiency.

H

Home Detention

Court-ordered confinement to a residence except for approved activities (work, medical, etc.). Electronic monitoring verifies compliance through inclusion zones and curfew enforcement.

House Arrest

Informal term for home detention. Defendants on house arrest wear ankle monitors that alert if they leave the designated premises without authorization.

I

Inclusion Zone

A geographic area where the defendant is required to remain during certain times (e.g., home during curfew). Leaving an active inclusion zone without authorization triggers a violation alert.

IP68 (Ingress Protection)

An international standard rating: 6 = dust-tight, 8 = submersion in water. IP68 GPS ankle monitors can be worn in the shower; defendants do not need to remove the device for hygiene, improving compliance.

Infrared Detection

Some tamper systems use infrared sensors to detect removal or obstruction. Less common in modern GPS ankle monitors than fiber optic or conductivity-based methods.

J

Jurisdictional Compliance

Adherence to state and local laws governing electronic monitoring. Requirements vary by jurisdiction; vendors must ensure devices and practices meet applicable regulations. See electronic monitoring vendors for evaluation criteria.

K

Keep-Alive Signal

A periodic transmission from the device to the monitoring center confirming it is operational and within cellular range. Absence of keep-alive signals triggers a lost-signal alert and may indicate tampering or dead battery.

L

LBS (Location-Based Services)

Cellular-based positioning using cell tower triangulation or WiFi. Used as a fallback when GPS signal is weak (indoors, urban canyons). Less accurate than GPS but ensures some location data when satellites are unavailable.

LTE-M

Long-Term Evolution for Machines. A low-power cellular protocol for IoT devices. Enables 7-day battery life in GPS ankle monitors at 5-minute reporting intervals. 5G-compatible.

Low Battery Alert

A notification sent when the device battery falls below a threshold. Allows staff to contact the defendant for recharging before tracking is lost. 7-day batteries reduce the frequency of low-battery events.

M

Monitoring Center

A central facility (or software platform) that receives location data, geofence alerts, and tamper notifications. Staff respond to alerts per agency policy and court requirements. May be in-house or outsourced to a vendor.

Multi-Constellation Positioning

Use of multiple satellite systems (GPS, BeiDou, GLONASS, Galileo) for location fixes. Provides sub-2-meter accuracy and faster acquisition, especially in challenging environments. Standard in premium GPS ankle monitors.

N

NB-IoT (Narrowband IoT)

A low-power wide-area cellular protocol for IoT. Like LTE-M, it enables extended battery life and better building penetration than legacy cellular. Supported by major carriers globally.

Notification Protocol

The process by which alerts (zone violation, tamper, low battery, lost signal) are communicated to staff. May include SMS, email, platform push, or automated escalation. Response time matters for FTA prevention.

O

One-Piece Device

A GPS ankle monitor that integrates GPS, cellular, battery, and tamper detection into a single unit worn on the ankle. No separate GPS unit to charge or carry. Typically IP68 rated with fiber optic tamper detection.

OTA (Over-the-Air) Update

Remote firmware updates delivered via cellular or Bluetooth. Allows vendors to fix bugs, add features, or patch security issues without physically retrieving devices.

P

Passive GPS Tracking

Location data stored on the device for later download. Does not provide real-time monitoring. Used in some probation or post-conviction programs; not suitable for bail bond or pretrial where immediate alerts are required.

Pretrial Services

Supervision of defendants released before trial. Courts or pretrial agencies may require GPS monitoring to ensure appearance and compliance with release conditions. See defendant GPS tracking.

Probation

Community supervision as an alternative to incarceration after conviction. GPS monitoring may be ordered for high-risk probationers or those with specific conditions (e.g., no contact with victims).

Parole

Supervised release from prison before the full sentence is served. Parolees may wear GPS ankle monitors to enforce geographic restrictions and curfew.

R

Real-Time Tracking

Continuous or near-continuous transmission of location data. Enables immediate response to zone violations and tampering. Essential for bail bond, pretrial, and high-risk probation monitoring.

RF (Radio Frequency) Monitoring

Home detention technology that detects whether the defendant is within range of a base unit. Does not provide GPS location; only confirms presence or absence at home. Used for curfew-only supervision.

RFP (Request for Proposal)

A formal procurement document agencies use to solicit bids from electronic monitoring vendors. Should specify battery life, accuracy, tamper detection, and integration requirements. Free templates available in our resources.

S

SCRAM

Secure Continuous Remote Alcohol Monitor. A brand of transdermal alcohol monitoring device. Often used in conjunction with GPS for defendants with alcohol-related conditions.

Supervision Level

The intensity of monitoring based on risk assessment. May range from phone check-ins to 24/7 GPS with exclusion zones. Higher-risk defendants typically receive more restrictive supervision.

SOS Alert

An emergency button or feature on some devices allowing the defendant to signal distress. Triggers immediate notification to the monitoring center for response.

T

Tamper Alert

A notification triggered when the device detects attempted removal, cutting, or circumvention. Fiber optic tamper detection achieves zero false positives; heart-rate-based systems can generate 30–50% false alarms.

Two-Piece Device

A GPS ankle monitor with a separate body-worn transmitter and GPS/cellular unit. The defendant must charge the GPS unit daily and keep it within Bluetooth range. More operational overhead than one-piece designs.

Track History

A chronological record of the defendant's locations. Used for court reporting, violation documentation, and compliance audits. Higher GPS accuracy improves the evidentiary value of track history.

TPU Strap

Thermoplastic polyurethane strap material used in ankle monitors. Durable, flexible, and resistant to cutting. Fiber optic strands may be embedded in the strap for tamper detection.

V

Violation Report

Documentation of a defendant's failure to comply with conditions—zone violations, tampering, curfew breach, missed check-in. Submitted to the court or supervising agency. GPS data provides objective evidence for reports.

Vibration Alert

A haptic notification on the device warning the defendant of an impending violation (e.g., approaching an exclusion zone). Used as a preventive measure before an actual violation is recorded.

W

WiFi Positioning

Location determination using WiFi access point signals. Used alongside GPS and LBS in multi-source positioning for indoor or urban accuracy. Helps when satellite signals are weak.

Waterproof Rating

The IP (Ingress Protection) code indicating resistance to water and dust. IP68 is standard for premium ankle monitors; defendants can shower without removing the device.

Z

Zone Violation

Entering an exclusion zone or leaving an inclusion zone without authorization. Triggers an immediate alert. Sub-2-meter GPS accuracy strengthens the evidentiary value of zone violation reports in court.