GPS/Iridium Terrestrial Systems

TGW-4570-4 GPS/Iridium system
TGW-4570-4 GPS/Iridium on a brown butyl collar with CAST-4 option

These collars collect GPS positions and transfer the data to the user through the Iridium satellite system.

Telonics GPS/Iridium collars can be used to remotely obtain location and other data from terrestrial animals anywhere in the world. Telonics Quick Fix Pseudoranging (QFP) can be incorporated into these collars. The collars can include mortality, activity, and temperature sensors; and/or geofencing technology. Users can define GPS, Iridium, VHF, and sensor schedules to best meet their project requirements. Iridium is a two-way system, which allows confirmation of messages received and remote modification of programmed parameters.

Key Features

Features relative to use of Telonics transmitters operating through the Iridium system:

  • The Iridium satellite network consists of 66 cross-linked satellites in low earth orbit (LEO), and provides continuous coverage world-wide.
  • Iridium is a two-way system. The Iridium module on the animal checks for an adequate link prior to data transmission, and data acknowledged as successfully received does not need to be repeated. The two-way link also allows commands to be sent to the Iridium unit while it is deployed on wildlife. Depending on what software and hardware options are selected, this can allow changing between auxiliary schedules, changing other programmed parameters, or remotely triggering a collar-release mechanism.
  • With Telonics GPS units, a single Iridium message can contain up to 70-80 GPS positions, or about 10 QFP positions.
  • QFP is Telonics quick fix positioning technology that obtains the data necessary to calculate a GPS position in as little as about 3 seconds. This allows positions to be determined much more quickly and with less energy expenditure than a standard GPS position. Telonics Iridium units can be configured to collect only GPS, only QFP, or a mix of the two location types. Locations can all be transmitted, or some can be stored but not transmitted.
  • Transmissions can contain a mortality flag (which relates to whether there has been movement detected by an accelerometer within a user-defined period) and a low-voltage flag (which indicates the battery may die soon). Programming and accounts can be set up to receive real-time notification of mortality events via email.
  • Activity or temperature data can be collected and transmitted via Iridium, and/or stored on board for downloading if the collar is recovered.
  • Telonics GPS Iridium units are FCC and IC certified and available for use throughout the United States and Canada with no additional licensing required for the data transfer component.
  • Data is normally retrieved through a third-party, metOcean telematics, which offers the least expensive data retrieval option for users. Data rates depend on the amount of data transferred, but are frequently as low as about ~$10.00/unit/month with an Iridium transmission every other day. Data hosting is available for an additional $5 a month per transmitter, which eliminates the need for an email account specifically dedicated to data reception. There is a one-time activation fee of $30 or $40 per transmitter.
  • The link margin between the collar and satellite is less for Iridium than for Globalstar or Argos, thus Iridium is best suited for applications where the animals typically have a good view of the sky; and transmission of the Iridium message may suffer in areas with dense canopy cover.

Other key features:

  • In addition to the GPS and Iridium portions of these collars, they typically include a VHF transmitter. The VHF transmitters can be used to locate or monitor the animals from the ground or aircraft, and aid in recovery of a collar at the end of a study.
  • Users can program or reprogram Telonics GPS/Iridium units through use of Telonics Product Programmer (TPP). TPP can be used to obtain estimates of battery life and data acquisition costs through metOcean telematics under various possible programming scenarios prior to deployment. TPP is also used to send commands to the Iridium unit once it is deployed if desired.
  • GPS/QFP collection schedules, Iridium transmission schedules, VHF schedules, and sensor options can all be user-defined. Scheduling can be programmed to change over time (e.g. seasonal changes where monitoring might be more or less intensive at certain times of the year). Some Iridium units (TGW-4X77 series) allow the primary and up to three auxiliary schedules to be programmed, with easy switching between schedules controllable via TPP.
  • Data retrieved through the Iridium system, or downloaded from a collar in hand, are processed using Telonics Data Converter (TDC). TDC is used to convert raw data from Telonics transmitters into data reports and to display locations on Google Earth and Google Maps. You can review, save, and edit TDC reports in Microsoft Excel or other spreadsheet programs.
  • All positions determined and sensor data collected is stored-on-board the collar, thus if the collar is able to be recovered, stored data can supplement what was transmitted through Iridium.
  • Telonics CR-2a, CR-5, or CR-7 programmable collar release mechanisms can be added to collars of appropriate size (the CR-2a and CR-5 require at least a 2-inch wide collar and the CR-7 requires at least a 1.5-inch wide collar). Iridium’s two-way link allows remote triggering of either the CR-5 or CR-7 with certain models and when that option is selected at the time of order.
  • A real-time clock and calendar controls all timing functions and is re-synchronized with GPS time to assure high accuracy timing. All timing is programmed using Coordinated Universal Time (UTC).
  • When turned off using a magnetic switch, these units consume less than 10 µA; this allows storage for extended periods with minimal impact on operational life.
  • Units can be refurbished to their original condition at Telonics.


  • TGW-4*70-4 models are the basic GPS/Iridium series
  • TGW-4*77-4 models allow for auxiliary schedules and geofencing
  • TGW-4*79-4 models allow for auxiliary schedules, geofencing, and inclusion of Salt-water-switch technology
  • TGWR-4570-4 and TGWR-4577-4 have user replaceable batteries
Model Housing Dimensions*
L x W x H (in, cm)
Housing Weight (g) Estimated Weight with Collar (g)
2.1 x 1.3 x 1.1
5.5 x 3.3 x 3.0
72 ~115 - 130
2.3 x 1.4 x 1.1
5.9 x 3.6 x 2.7
115 ~180 - 310
2.5 x 1.8 x 1.4
6.5 x 4.6 x 3.6
180 ~350 - 700
2.8 x 2.0 x 1.5
7.3 x 5.1 x 3.7
260 ~500 - 880
3.5 x 2.7 x 2.3
8.9 x 6.9 x 5.9
590 ~900 - 1500
3.0 x 2.0 x 1.4
7.6 x 5.1 x 3.6
260 ~500 - 800

Examples of Operational Life

Battery life varies among models, with larger models having greater battery capacity. Within a given model, battery life is dependent on the number of attempted GPS positions, number of Iridium data transmissions, VHF schedule, and operational temperature. GPS (and/or QFP), Iridium, and VHF schedules are all user definable. Operational life estimates for all models shown below are calculated by Telonics Product Programmer (TPP), and are provided as examples only, with other options possible. The estimates provided assume all GPS and/or QFP data is transmitted. Battery life can be extended if some of the locations (GPS or QFP) are exclusively stored on board and not transmitted.

Please consult with Telonics for assistance determining what would work best for your application.

Collar Configurations for Smaller, Down to Approximately Fox-sized, Animals

These smaller configurations have one battery powering both the GPS/Iridium and VHF portions of the unit. Battery capacity of these units is limited by their small size, and battery life is more impacted by temperature than in larger configurations. Use of QFP can substantially increase battery life of these small units. These configurations can and typically do include VHF transmitters; however, the VHF can have major impacts on operational life, so it is often only scheduled to be operational during limited periods.

Battery life estimates for these small units assume temperatures of 25°C, an average VHF pulse period of 1500 msec (40 beats per minute), Iridium transmitting every other day (except weekly when GPS/QFP interval is 1 day, or more frequently as required by QFP). Average time to GPS fix is assumed to be 75 seconds and average time to QFP fix is assumed as 15 seconds. Considerably lower temperatures will result in shorter battery life. Faster VHF pulse rates would decrease battery life. Changes in other settings or assumptions would impact battery life estimates in either a positive or negative manner.

Estimated Battery life (years) and Iridium Data Recovery costs (through metOcean telematics):

Configuration GPS/QFP Schedule With GPS (no QFP) With QFP rather than standard GPS
10 hr/week
Monthly Fee
10 hr/week
Monthly Fee
1/day 2.4 - 3.0 1.9 - 2.3 $10 3.2 - 3.9 2.3 - 2.8 $10
4/day 0.8 - 1.0 0.7 - 0.9 $10 1.7 - 2.1 1.4 - 1.7 $12
6/day 0.6 - 0.7 0.6 - 0.7 $10 1.3 - 1.6 1.1 - 1.4 $13
12/day 0.3 - 0.4 0.3 - 0.4 $10 0.7 - 0.9 0.7 - 0.9 $16
1/day 3.5 - 4.3 2.8 - 3.4 $10 4.6 - 5.6 3.4 - 4.1 $10
4/day 1.2 - 1.5 1.1 - 1.4 $10 2.5 - 3.1 2.1 - 2.6 $12
6/day 0.9 - 1.1 0.8 - 1.0 $10 1.9 - 2.3 1.7 - 2.0 $13
12/day 0.5 - 0.6 0.5 - 0.6 $10 1.1 - 1.4 1.0 - 1.3 $16

Collar Configurations for Medium to Large Mammals

These configurations have a primary battery pack which is used to power the GPS/Iridium portion of the unit, and a second, smaller battery for the VHF. Typically the units are programmed to have the VHF use the primary battery during most of its life, but switch to the second battery when the primary battery is nearing the end of its life to assure that the VHF is available to aid in collar recovery if desired. The VHF can alternatively be programmed to use the secondary battery at all times. Estimates of life below are given without VHF (or without VHF drawing on the primary battery), and with an average of 4-hours per day using the primary battery. Note that if the VHF is powered separately, low intensity duty cycles, delayed start, and/or triggering VHF through Auxiliary schedules would be needed to match the longer GPS/Iridium lives noted below.

Battery life estimates for these units assume temperatures of 0°C, an average VHF pulse period of 1500 msec (40 beats per minute), and Iridium transmitting every other day (or more frequently as required by QFP). Average time to GPS fix is assumed to be 75 seconds. Considerably lower temperatures will result in shorter battery life. Faster VHF pulse rates would decrease battery life. Changes in other settings or assumptions would impact battery life estimates in either a positive or negative manner. QFP is typically not used in these larger configurations, though it can be included and would extend estimates of battery life (average time to QFP fix is assumed as 15 seconds).

Estimated Battery life (years) and Iridium Data Recovery costs (through metOcean telematics):

Configuration GPS/QFP Schedule With GPS (no QFP) With QFP rather than standard GPS
4 hr/day
Monthly Fee
4 hr/day
Monthly Fee
1/day 4.5 - 5.3 3.1 - 3.8 $10 5.9 - 7.1 3.7 - 4.5 $10
4/day 2.2 - 2.7 1.8 - 2.2 $10 3.4 - 4.1 2.5 - 3.1 $13
6/day 1.7 - 2.0 1.4 - 1.8 $10 2.6 - 3.2 2.1 - 2.6 $14
12/day 1.0 - 1.2 0.9 - 1.1 $10 1.6 - 1.9 1.4 - 1.7 $16
24/day 0.5 - 0.6 0.5 - 0.6 $13 0.9 - 1.1 0.8 - 1.0 $27
1 GPS/day 9.5 - 10+ 6.8 - 8.2 $10 10+ 8.1 - 9.7 $10
4 GPS/day 5.0 - 6.2 4.2 - 5.1 $10 7.5 - 9.1 5.7 - 6.9 $13
6 GPS/day 3.8 - 4.8 3.3 - 4.1 $10 6.0 - 7.3 4.8 - 5.8 $14
12 GPS/day 2.2 - 2.8 2.0 - 2.6 $10 3.7 - 4.5 3.2 - 3.9 $16
24 GPS/day 1.2 - 1.5 1.2 - 1.5 $13 2.1- 2.6 1.9 - 2.4 $27
1 GPS/day 10+ 10+ $10 10+ 10+ $10
4 GPS/day 9.5 - 10+ 7.9 - 9.4 $10 10+ 10+ $13
6 GPS/day 7.4 - 8.8 6.4 - 7.7 $10 10+ 9.1 - 10+ $14
12 GPS/day 4.5 - 5.4 4.1 - 4.9 $10 7.3 - 8.7 6.3 - 7.6 $16
24 GPS/day 2.5 - 3.0 2.4 - 2.9 $13 4.3 - 5.2 3.9 - 4.8 $27

* The TGWR-4570-4 and TGWR-4577-4 are designed as user-replaceable battery configurations. The TGWR-4577-4 allows auxiliary schedules and geofencing, the TGWR-4570-4 does not. These units are powered by a single D-sized lithium battery, with the GPS/iridium and VHF both drawing on the same power supply. Thus, there are no options with these two configurations regarding or how the VHF is powered.

Optional Geofencing

Telonics TGW-4*77 and TGAV-4*77-4 series GPS/Iridium systems can support geofenced areas. Multiple geofence types are available to define areas of special interest, which may overlap:

  • Rectangle - upper left and lower right coordinates are specified.
  • Circle - center point and radius are specified.
  • Polygon - Up to 50 points may be specified. Polygons may be concave or convex.

The following parameters can be separately defined when the unit is inside and outside the defined geofenced area:

  • Acquisition schedule for GPS, QFP-GPS, and any included sensors (e.g. underwater, activity, and temperature)
  • VHF Beacon schedule
  • Iridium transmission interval, transmission retry delay, and message expiration

A geofence can be described as a virtual boundary around a physical geographical space, defined by a set of coordinates surrounding an area. Geofences may be established and maintained by a range of GPS-enabled devices including smartphones and devices designed for commercial applications like trucking and farming. Geofencing has also proven to be a useful tool for animal tracking studies.

Geofencing allows one or more geographical areas to be defined and provides customized data acquisition and transmission behavior based on whether the study subject is in "inside" or "outside" the geofence(s). A study subject is considered "inside" when inside any defined geofence, and is considered "outside" when outside all defined geofences.

The speed of detecting that an animal has crossed a geofenced boundary depends on how much time has elapsed between crossing the boundary and acquisition of the next GPS position. Therefore, the rate at which fix attempts are scheduled directly influences the time it will take the unit to detect boundary transitions. QFP-GPS data do not provide a resolved position until post processing has occurred, so QFP-GPS data cannot contribute to the detection of boundary transitions.

Optional Auxiliary Schedule Sets

With Telonics TGW-4*77-4 and TGAV-4*77 series GPS/Iridium systems, up to 3 Auxiliary schedule sets can be defined. Auxiliary schedules are useful for increasing or decreasing the intensity of data collection and/or data transmission. Auxiliary schedules are also useful for adjusting the VHF beacon duty cycle to save energy when there are no plans to be out in the field monitoring units with a VHF receiver. Auxiliary schedules can provide the following options to the primary schedule:

  • Alternate schedules for collection of GPS, QFP-GPS, underwater, activity, and/or temperature data
  • Alternate VHF Beacon transmission periods
  • Alternate Iridium transmission interval, transmission retry delay, and message expiration

GPS/Iridium systems can be directed to execute an Auxiliary schedule (or return to the primary schedule) by sending commands over the Iridium data link.

Commands to GPS/Iridium systems are sent via email using Telonics Product Programmer (TPP). Internet connectivity and an email provider are required.

After receiving a schedule change command, GPS/Iridium systems will switch to the specified schedule immediately and will continue to execute that schedule until otherwise commanded. Sent commands are received by the fielded unit at the time of a scheduled Iridium transmission, or units can be programmed to check for messages more frequently by defining a “command check interval” which is shorter than the Iridium transmission interval.

Specifications: Electronic and Packaging - GPS/Iridium

TGW-xxxx Terrestrial Wildlife Configurations

General System Specifications

Timing AccuracyTiming is synchronized to GPS time when available. If the GPS time is not then internal timing accuracy is:
6 min/year at 25° C
30 min/yr -20 to +40° C
47 min/yr -40 to +70° C
Available SensorsMortality, Activity, Temperature, Low Voltage
Memory CapacityCapable of storing 100K fixes in nonvolatile flash memory in association with other sensor data.

GPS Receiver Specifications

Performance-163 dBm tracking sensitivity -147 dBm acquisition sensitivity
Time to First Fix (TTFF)35sec typical (with clear view of sky)
Quick Fix Pseudoranging (QFP) 3 sec typical (with clear view of sky)

Iridium Transmitter Module Specifications

GeneralFCC ID Q639603N
Industry Canada ID 4629A-9603N
Frequency Range 1616-1626.5 MHz.
Applicable FCC Rules CFR Title 47, parts 2, 15, and 25
Power Output 1.0 w (average)
Mechanical/EnvironmentalOperating Temperature Range -40 to +60 °C
Iridium Antenna SpecificationsIn collar-mounted wildlife configurations the Iridium antenna is mounted on the dorsal surface of the neck. The antenna is installed in a high impact nonconductive plastic housing. The form of the housing presents sloping sides so that it will be impervious to chewing and gnawing as is possible. A highly armored antenna cable connects the antenna to the instrument package.

VHF Transmitter Component Specifications

OPERATION INTERLOCK: All elements of the VHF transmitter component are forced off whenever the Iridium transmitter module is on. This interlock device forcibly prevents simultaneous operation of the two transmitters, thus they are not considered to be co-located under FCC regulations.

Available Frequency OptionsOption 702 134-139 MHz
Option 705 140-154 MHz
Option 707 146-160 MHz
Option 715 156-172 MHz
Option 720 160-177 MHz
Option 740 174-192 MHz
Option 750 191-210 MHz
Option 760 210-237 MHz

Note: The frequency can be programmed in 100 Hz steps within a given frequency range.
Frequency StabilityBetter than ±3 ppm at room temperature;
±5 ppm total tolerance over full temperature range
Operating Temperature-40° to + 70° C
Pulse WidthProgrammable (10 to 250 msec)
Pulse PeriodProgrammable (560 to 5000 msec)
5 separate pulse period values selectable:
Period 1 (indicates last GPS fix successful)
Period 2 (indicates last GPS fix QFP-GPS, if equipped)
Period 3 (indicates last GPS fix unsuccessful)
Mortality period (if no motion for selected time)
Dead Battery period
Available SensorsMortality Sensor (parameters are user programmable)
Transmitter TimingProgrammable seasons and duty cycles.
Power OutputProgrammable Low/Medium/High power. Effective Isotropic Radiated Power (EIRP) varies, depending on packaging, antenna configuration, and immediate environmental conditions.
* California Users: This transmitter meets the California requirement of EIRP <0.009 W for all configurations.
Emission Designator2k00P0N
Harmonic SuppressionBetter than 30 dB (>40 dB typical)
Spurious Emissions<-35 dBc at 10 kHz offset from carrier
FrequencyAging: <2 ppm/yr
Shock: <1 ppm 3000 g x 0.3 ms x ½ sine x 3 dir
VSWRRF output stable to 10:1 VSWR, all phases
Radiated harmonic levels are degraded with poor load VSWR.
Spurious emission specification maintained for >10:1 VSWR
ProgrammingTransmitter parameters programmable via antenna "1-pin" interface and Telonics TPP PC software.

Packing/Housing Specifications

Hermetic Metal CanistersElectronics are sealed in hermetic metal canisters containing the electronics, batteries, and all interconnects. Glass to metal feed-thru technology is used to exit antennas and power. This packing is hermetic and can be tested utilizing a helium leak bomb test for hermeticity to assure < 1 part in 106 atmospheric CC per second.

Collar Specifications

Collared DesignsCollar designs are species specific.

Notice to United States Users

This device complies with Part 15 of the FCC Rules. Operation is subject to the following two conditions: (1) this device may not cause harmful interference, and (2) this device must accept any interference received, including interference that may cause undesirable operation.

The user is cautioned that changes or modifications not expressly approved by Telonics could void the user's authority to operate the equipment.

This device contains FCC ID: Q639603N

To satisfy FCC RF Exposure requirements for mobile and base station transmission devices, a separation distance of 20cm or more should be maintained between the antenna of this device and persons during operation. To ensure compliance, operation at closer than this distance is not recommended.

Notice to Canadian Users

Under Industry Canada regulations, this radio transmitter may only operate using the antenna integrated into the device.

This device complies with Industry Canada license-exempt RSS standard(s). Operation is subject to the following two conditions: (1) this device may not cause interference, and (2) this device must accept any interference, including interference that may cause undesired operation of the device.

This device contains IC ID: 4629A-9603N

Photo Gallery

TGW-4*70-4 versions are shown, with TGW-4*77-4 versions similar with additional programming options. Various collar and casting options are shown, with such specifications user-definable at the time of order.


Related Products

TDC Telonics Data Converter Telonics Data Converter (TDC) is used to convert raw data from Telonics transmitters into data reports and to display locations on Google Earth and Google Maps. You can review TDC reports in Microsoft Excel or other spreadsheet programs.

TPP Telonics Product Programmer Telonics Product Programmer (TPP) is a powerful software tool used to program Telonics transmitters, and Telonics CR-5 and CR-7 collar release mechanisms. TPP gives you the ability to modify aspects of your Telonics GEN4 GPS and VHF transmitters including data collection and transmission intervals. TPP is designed for ease of use, with simple point-and-click navigation through the program.

TSC-7A Smart Cable The TSC-7A is a multi-use interface cable terminated with a USB A connector and a male BNC (bayonet style) connector. The cable is used to connect various Telonics products to a computer when using Telonics Product Programmer (TPP), Telonics Data Converter (TDC), or the CR-2a BCP-2 programming software. The BNC connector allows quick and easy attachment of various adapters.

CN008351-001 Adapter Adapter, female BNC to alligator clips for use with the TSC-7A cable. This adapter is used for systems where programming/download connections are made using the antenna tip or saltwater switch buttons.

Legacy Products

The information below is provided for individuals who are still deploying these older systems. Some of the system information or limitations, information on frequency allocation or usage, and/or comments made on "state of the art" may be time sensitive or even outdated. Please contact Telonics if you have any questions about the information provided in this section.

Telonics still supports and refurbishes the following products but no longer sells them new:

Lithium Battery Shipping Regulations

Telonics, Inc. ships all systems containing lithium batteries in accordance with United Nation and US Federal regulations for shipping hazardous materials.

49 Code of Federal Regulations

IATA Dangerous Goods Regulations (current year)

Service Commitment

Since 1970, Telonics has built a reputation based on product quality, product support, service, and customer satisfaction. Telonics strives to produce the highest quality products, and to support those products accordingly.

Because of extreme conditions and the unpredictable nature associated with most telemetry applications, problems occasionally arise. Most problems can be resolved quickly. In all cases, we hope to be able to work in partnership with users to resolve problems to the user's satisfaction and to uphold our demonstrated commitment to excellence. If problems should arise, all products must be returned to our factory for failure analysis.

Warranty: GEN 4 GPS Systems

Telonics warrants its GPS products to be free from defects in material and workmanship for a period of one year from the date acquired. Telonics does not warrant batteries.

Telonics designs and manufactures systems for a variety of applications using several satellite systems (GPS, Argos, Iridium, and Globalstar). At the time of manufacturing, Telonics equipment is tested to verify compatibility with the applicable satellite system(s). Telonics does not warranty equipment against changes in satellite system specifications or satellite operation after the date your equipment was manufactured. Unforeseeable or unplanned system changes would include, but are not limited to, elevated ambient noise levels in the radio frequency bands used for satellite communications, elimination of service in a region of the world, data outages due to technical problems within the satellite system network, or reductions in data transfer capability due to alterations in the constellation as a result of premature space vehicle failures or failure to replace space vehicles in a timely manner.

If a defect occurs, return the equipment to us within the proper time frame at the following address: TELONICS, 932 E. IMPALA AVENUE, MESA AZ USA 85204-6699. The customer shall arrange for and pay all shipping, insurance and related charges incurred in the shipment to and from Telonics under this warranty. Damage to any equipment resulting from misuse, accidents, unauthorized service, extreme conditions, or other causes, is excluded from this warranty. Telonics does not assume responsibility for loss or damage to equipment during shipment. Telonics does not assume responsibility for delays resulting from shipment on commercial or private carriers. We insure all equipment shipped from our facility and suggest that shipments to Telonics also be insured.

Upon the timely return to our facility, if defective, the product will be replaced or repaired at our discretion at no cost to the customer. This remedy is the exclusive remedy. This product is supplied without any further warranties or conditions, expressed or implied, including warranties of merchantability, quality or fitness for particular reason or those arising by laws, statutes or trade usage or course of dealing. The entire risk, as to the results and performance of the product, is assumed by the customer. Neither Telonics, nor its suppliers, shall have any liability to the customer or any other person or entity for any indirect, incidental, special, or consequential damage whatsoever, regardless whether Telonics has been told of the possibility of such damages or that such damages might be foreseeable. Telonics has no responsibility or liability for the claims of any third party. The maximum aggregate to the customer, of Telonics and its suppliers, shall not exceed the amount paid by the customer for the product.