An automated radio telemetry system automatically tracks locations
with computers, which requires less fieldwork from biologists. The
system uses Loran-C technology, the same technology used by the
Coast Guard, Navy, and other maritime vessels to pin-point their
locations in the ocean.*
Regularly monitoring animal movements helps researchers answer
questions about the response of deer and elk to intensive timber
management, cattle grazing, vehicle traffic and hunting on National
Forests. The Loran-C tracking system provides the most accurate,
efficient and cost-effective vehicle, for recording animal movements
over several years.
The automated animal tracking system begins and ends with a computer,
and consists of five towers that average 150 feet in height, two
base station computer systems linked to Loran-C hardware. and 180
collared animals. The collars contain Loran-C receivers, VHF transmitters,
pagers, and batteries with an 16-month life. While these batteries
can power the units for 2 full May through mid-December field seasons,
they are changed whenever possible to insure adequate coverage.
The electronics are connected to a rubberized strip and fitted into
PVC pipe. The pipe is heated and molded around one of several forms,
depending on the size and species of animal the collar will be used
for. Each collar weighs less than three pounds, and is weather and
A base station computer sends out a location request to a different
collar every 20 seconds. Once a collar receives the computer's signal,
a pager inside the collar turns on a transmitter and receiver. During
the next 10 seconds, the receiver collects Loran-C signals from
six out-of-state Loran towers located in Havre, Montana; Williams
Lake, British Columbia; George, Washington; Fallon, Nevada; Searchlight,
Nevada; and Middleton, California. The transmitter inside the animal's
collar then sends the signals to one of Starkey's field station
towers. The tower, in turn, retransmits the signals over a microwave
link to the base station's Loran-C hardware. Positioning software
translates the Loran signals into Northing and Easting coordinates,
and then computes locations using differential statistics.
The locations are stored on a hard drive in the computer and later
archived to tape. They can also be displayed in real-time on an
interactive computerized map in relation to roads, and to forage
and other habitat features.
The telemetry system at Starkey can compute one location every
20 seconds, day and night, and is accurate to within 50 meters.
By the end of the 10 year study, the automated tracking system will
have generated more than four million locations--over 100 times
more than are capable using conventional tracking methods. Traditionally,
researchers use headsets and antennae to judge the signal strength
and bearing of collared animals, often spending hours to determine
a single location.
Time and air temperature readings are also provided with each animal
location. In addition, the system at Starkey is capable of transmitting
pulse rates from animals equipped with special heart monitors.
Implementation costs are approximately $1.3 million. With the automated
telemetry system, each subject location costs less than $1, compared
to over $75 per location with conventional tracking methods.
* The automated animal tracking system used at
Starkey was designed and built by the USDA Forest Service and the
Navigation and Weather Division of Tracor Aerospace, Inc., in Austin,
Texas. (This information is given for the convenience of the reader
and does not constitute official endorsement by the US Department
of Agriculture of this firm to the exclusion of others that may be