52 FISH AND WILDLIFE TECHNICAL REPORT 30 



GLOSSARY 



Activity Index An index derived from a motion- 

 sensing device on a PTT that, when calibrated to known 

 activity, can be used to estimate activity patterns of 

 free-ranging animals wearing PTT's 



ACWRU Alaska Cooperative Wildlife Research 

 Unit 



ADFG Alaska Department of Fish and Game 



AFWRC Alaska Fish and Wildlife Research Center 



ANWR Arctic National Wildlife Refuge 



Argos The name of the organization operating the 

 system that collects and processes data received by 

 polar orbiting Tiros-N satellites 



Argos DCLS Argos data collection and location sys- 

 tem (see Argos) 



Azimuth A horizontal direction expressed in degrees 

 measured clockwise from an adopted reference direc- 

 tion, usually true north 



Doppler shift Perceived variation in the frequency of 

 a signal on the electromagnetic spectrum caused by 

 movement of either the source or the receiver 



Duty Cycle Programmed pattern of active-inactive 

 transmission periods for a PTT 



Efficiency The rate over time at which location esti- 

 mates and sensor data from a PTT are received by the 

 investigator 



Elevation (PTT) The elevation above sea level (in 

 meters) of the PTT (or animal wearing it) when its 

 location is estimated by Argos 



Elevation (Satellite) The elevation above the hori- 

 zon (in degrees) of the satellite as it makes its closest 

 approach to the PTT 



GIS Geographic information system; computer soft- 

 ware used to analyze and display spatially oriented data 



Independence (of Spatial Data) Locations are sta- 

 tistically independent when locations at time x + 1 are 

 not a function of locations at time x 



LCO Location class zero; a processing option offered 

 by Argos that will estimate PTT location from as few 

 as two messages. Specially designed for the animal- 

 tracking community, this service also provides addi- 

 tional data on location quality when normal processing 

 fails, and provides the alternate location 



LQ Index Location quality index; ranging from 1 to 

 3, used by Argos to guide users regarding the probable 

 precision of a location estimate. LQ1 is the least pre- 

 cise; LQ3 the most precise 



LUT Local user terminal; a computerized satellite- 

 tracking system that receives real-time transmissions 

 from satellites above the horizon and processes Argos 

 data contained with the transmitted signal; also known 

 as direct readout stations 



Message The signal sent by a PTT to the satellite, 

 consisting of identification code, sensor data, etc. 



Polar Orbit An orbit that passes directly over both 

 geographic poles 



PTT Platform transmitter terminal; any transmitter 

 used to send messages to Argos instruments on a 

 satellite 



UHF Ultra-high frequency; frequency band used by 

 PTT's to transmit to the satellite (401.650 MHz is with- 

 in this band) 



UT Universal Time; Greenwich Mean Time 



VHP Very high frequency; frequency band used in 

 conventional radiotelemetry 



VS WR Voltage standing wave ratio; reduction of ef- 

 fective radiated power through an antenna caused by a 

 large mass being close to the antenna. VS WR can result 

 in loss of data because transmissions are not received by 

 the satellite. 



