GPS Wildlife Tracking
From Wikipedia, the free encyclopedia
GPS Wildlife Tracking involves the use of the Global Positioning System to determine the precise location of wild animals to which it is attached and to record their position at regular intervals. The recorded location data can be stored within the tracking unit, or it may be transmitted to a central location data base, or internet-connected computer, using a cellular (GPRS), radio, or satellite modem embedded in the unit. This allows the animal's location to be displayed against a map backdrop either in real-time or when analysing the track later, using customized software.
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[edit] Purpose
When used on wildlife, GPS devices allows sciencists to study their activities and migration patterns.
Animal tracking collars may also be put on domestic animals to locate them in case they get lost. Common domsetic applications are the tracking of pets such as dogs and cats, and in tracking hunting animals, such as Pig Dog Tracking.
[edit] Attachment Techniques
GPS devices on animals are primarily attached using one of 3 primary techniques:
- Harness
- Collar
- Direct Attachment
[edit] Collar Attachment
Collar attachment is the primary attachment technique when the animal being studied has a suitable body type an behavior. Collars could be used on the animal's neck (assuming their head has a larger cicumference than their neck) or on a limb such as a ankle. Examples of suitable animals for nect attachment would be primates, large cats, etc. Limb attachment would work well in animals such as Kiwi Birds, where the foot is much larger than the ankle.
[edit] Harness Attachment
Harness attachments may used in situations where a collar attachment is not suitable, such as animals with necks that are large in diameter, as compared to their head. Examples of this tyope of animal could be pigs, tasmanian devils, etc.
[edit] Direct Attachment
Direct Attachment is used on animals where a collar can not be used, such as birds or turtles. In these cases different ways of attaching the device need to be used.
In the case of birds, the GPS unit must be very lightweight to avoid interfering with the bird's ability to fly or swim, The devices are usually attached by gluing them to the bird. The units will then naturally fall off when the bird next moults.
In the case of reptiles such as crocodiles and turtles, gluing the unit on to the animal using epoxy (or similar materials) is the most common way to mount the unit without causing discomfort. Units used with turtles or other marine animals have to be waterproof and able to resist the corrosive effects of sea water.
Other applications include Rhino tracking devices in which a hole is drilled in the tusk and a devices is implanted in the hole. Transmitters or loggers used in such a setting may suffer from a reduced range when compared to collars as the large mas of Rhino's body will block some of the signal thus reducing its strength and range.
[edit] Software
Duty Cycle Scheduling - GPS devices typically record data about the animal's exact location and store readings at pre-set intervals known as duty-cycles. Upon recovery, data can then be retrieved from the device for analysis such as data plotting on a computer giving detailed information about the animals movements during the period it was collared. By setting the interval between readings, the researcher is able to affect the lifespan of the collar - very frequent readings uses the battery power faster so the collar doesn't last as long, whereas long intervals between readings gives potentially less accurate data but the battery lasts longer.
Release Timers - Some collars can be programmed to drop off at a set time/date rather than the researcher having to dart the animal and remove the collar manually. Some collars also allow the researcher to send a signal to the collar which triggers the automatic release. To make the collar recovery easier, some GPS collars also include a VHF transmitter with its own power supply as this will normally last longer than the GPS battery and so the researcher is able to use the VHF signal to locate the collar either while it is still on the animal, or once it has dropped off. This can prove to be vital as some animals have been observed to pick up a collar that has automatically dropped off and to then run off into the distance, carrying it - subsequent location could prove almost impossible without the collar having a VHF transmitter. Some GPS collars also allow the data to be downloaded remotely, either by a radio link or in areas with GSM mobile phone coverage, by SMS text messages.
[edit] Data Recovery
- Argos - GPS tracking collars which are Argos enabled can transmit data via the Argos satellite system, which has been in use since 1978. Users then download the data directly from Argos using telnet, and process the raw data to extract their transmitted information.
- Manual - Some GPS devices are only data logers, and must be manually recovered to get data from them. Some of these devices also are equipped with VHF or UHF transmitters to ensure that they can be easily relocated.
- GSM - GPS location Data can be transmitted via the GSM phone network, using SMS messages or GPRS transmissions.
- UHF/VHF - GPS Data can be transmitted via radio signals and decoded using a custom radio reciever.
[edit] Major Wildlife GPS Providers
Several major providers are driving technology advances in the field of Wildlife GPS Tracking, including Sirtrack Ltd, Telonics, and Wildlife Computers.
- Sirtrack (New Zealand based, started in 1969) specializes in the manufacture of wildlife tracking equipment. Recent major technologies include MicroGPS, which is the world's smallest wildlife GPS device (21 grams) and FastLoc which is rapid (sub 1 second) GPS receiver with an integrated argos transmitter, designed to operate in situations where traditional GPS systems fail, notably marine wildlife.
- Telonics (US based, founded in 1978) is a equipment manufacturer for meteorology, oceanography, search and rescue, space communications, military instrumentation and wilife tracking. They produce radio receivers and Sattelite PTT Transmitters which are common in wildlife tracking.
- Wildlife Computers (US Based, founded in 1986) is a well known provider of electronic tagging technology for marine animal applications. They market Fast-GPS, (using the same technology as Sirtrack's FastLoc product) which allows a GPS location to be captured in less than a second (unlike traditional GPS) and transmits data via Argos.
