activity sensor: an electronic component of many MTI transmitters designed to register if there has been movement between transmissions

anadromous: referring to fish that spend most of their adult lives in salt water but migrate to fresh water to spawn

catadromous: referring to fish that spend most of their adult lives in fresh water but migrate to salt water to spawn

CLS: Collecte Localisation Satellites; the French company that operates the Argos Data Collection System

CRC checksum: Cyclical Redundancy Check; a feature of our GPS-equipped PTTs and fish tags designed to allow the detection of corrupt data in a PTT's transmitted messages, resulting in more reliable datasets

Data Distribution Agreement (DDA): the binding contract between MTI and a user in which the user agrees to pay the designated amount(s) for data distribution from MTI GPS/GSM 20-70 Transmitters and confirms where MTI is to send the transmitted data

delta (Δ): the amount of change in a quantity

Doppler effect: a shift in the perceived frequency of radio waves due to a relative velocity between a source and an observer

geolocation: a set of latitudinal and longitudinal coordinates

GMT: Greenwich Mean Time (or Coordinated Universal Time [UTC]); the time at the Prime Meridian (0° longitude); GMT is not affected by daylight savings time

GPRS: General Packet Radio Service; an upgrade to the 2G technology of GSM to allow for wireless data and internet connection via mobile devices

GPS: Global Positioning System; a navigation system that uses satellites to determine precise locations on Earth via GPS-specific receivers

HDOP: Horizontal Dilution of Precision; a relative accuracy estimation of a GPS location's horizontal coordinates based on the arrangement of GPS satellites used to obtain that location; a lower HDOP value indicates greater statistical accuracy of the corresponding coordinate

location class (LC): An error estimation rating allocated to every computed location dependent upon the geometrical conditions of the satellite pass at the time of receiving messages and on the stability of transmitter frequency; for more information see the Argos User's Manual

parsing software: a computer program provided to users of our GPS-equipped PTTs that decodes the raw hexadecimal data of the transmitted messages into a user-friendly format

Production Form: documentation of all the transmitter order details submitted online by the user via MTI's Production Portal; Production Forms contain information regarding model, programming, feature options, Argos (if applicable), shipping, and billing

PTT: Platform Transmitter Terminal; a transmitter that sends data through the Argos system

Purchase Order: a formal document from the purchasing entity confirming an order and specifying the agreed-upon transmitter model, quantity, price, terms, and delivery date for that order

refurbishment: modifications made to a used transmitter to help make it suitable for additional deployment; see our Avian Transmitter Refurbishment Policy or Fish Tag Refurbishment Policy for details and qualifications

Satellite-in-View (SiV^™): a feature created by MTI that aligns the timing of PTT transmissions with times when a satellite is most likely passing overhead, thus increasing opportunities for successful transmitter-satellite connections while preserving battery life

season: a defined time interval in a PTT's duty cycle characterized by one or more variable programming options; duty cycle seasons of Argos PTTs without GPS can vary by the durations of the ON/OFF periods, the number of ON/OFF cycles, and whether or not Seasonal Ground Track (GT™) will be activated; duty cycle seasons of Argos PTTs with GPS can vary by the hours for data collection, the interval between data transmissions, and whether or not Seasonal GT™ will be activated

SMS: Short Message Service; a messaging component of most mobile telephone systems used for the exchange of brief character messages

telemetry: the process of measuring data remotely and transmitting it to another location

UHF: Ultra High Frequency; refers to frequencies between 300 MHz and 3 GHz

VDOP: Vertical Dilution of Precision; a relative accuracy estimation of a GPS location's vertical coordinates based on the arrangement of GPS satellites used to obtain that location; a lower VDOP value indicates greater statistical accuracy of the corresponding coordinate

VHF: Very High Frequency; refers to frequencies between 30 MHz and 300 MHz

Yagi: a directional antenna that can be paired with a receiver to detect the UHF signals of our Ground Track (GT™) feature, within close proximity, for the real-time location of a PTT