TDMA Tracking SystemTDMA Tracking System

TDMA is an intelligent radio data network which integrates .
Offering outstanding configuration flexibility, and the advantages of unique automatic repeater capabilities, TDMA is ideal for complex tracking and communications tasks including:-
• Vessel tracking
• Fleet management
• Port vessel monitoring


TDMA is an intelligent data network system which operates at UHF and VHF frequencies permitting continuous real-time messaging from a wide variety of applications. Operating on a Time Division Multiple Access principle the system is extremely flexible in configuration, giving the mobile data system integrator complete control over messaging rates and content. Each mobile unit within the TDMA system is allocated a unique identity code and transmits its position or other data in a time slot assigned to it. Transmission timing is synchronised by GPS and revised by the control centre as required. All transmitted data carries a tag identifying its origin and destination and this enables other mobile units in the operating area to monitor the data network and automatically forward messages if direct transmission is blocked. This unique technology enhances communication reliability and can significantly extend the operational range of the TDMA system beyond the normal line of sight restrictions.TDMA is ideal for real-time tracking applications allowing the reporting of GPS position of mobile units back to a control centre display system. At the same time, Differential GPS corrections can be broadcast through the network for precise positioning applications. The system operates on a single UHF or VHF frequency and can handle up to 250 mobile reports per radio channel although this capacity can be expanded by the use of additional channels in a cellular configuration.


Data Communication Between Units
As well as position reporting to a control centre and the distribution of RTCM data, messages can be routed from one mobile to another. Selective or group messaging is possible from the control centre as is the facility for units to be configured dynamically. Voice radio traffic can be reduced and communications in crowded frequencies made faster as a result.

Auto Adaptive Repeater Mode

Any TDMA unit in a system can operate intelligently as a repeater. Each mobile unit monitors the communications status of all other units in its local area, and should the path between 2 units be obscured, the unit will automatically deduce which path is blocked and undertake to pass on the message during the next time slot allocated to the originator of the message. In this way messages can be re-broadcast to circumvent radio line of sight limitations or to relay messages made from beyond the network’s normal radio range.

System Capacity

Transmission of data within a ‘cell’ is via a single radio channel. Each unit’s access to the network is configured during initial set-up. A typical mobile reporting interval would be 10 seconds, depending on priority, which would allow spare capacity to be allocated to fast mobiles and any dedicated repeaters. The frequency of position reports from mobile units can be changed by the control centre enabling it to focus on units involved in critical activities.

TDMA transceiver

Channelisation Format

TDMA (Time Division Multiple Access)


Line of sight operating ranges with integrated power output options of up to 10W

Frequency Bands

VHF 136 - 174MHz
UHF 440 - 512MHz

Number Of Channels

The transceivers are configured to use any 10 channels in the band with the system configuration software

Transmitter Power Output

10mW, 500mW or 2W software selectable,
optional 10W integral PA

CCIR Emission Designator


Error Correction:

Byte level Hamming (12,8) code, correcting 1 bit per byte, interleaved into blocks of 20 bytes


Integrated GPS and VHF/UHF with single cable, max power 10W

L1(1.575GHz), Gain 40dB, 5V DC, Azimuth 360 deg, Zenith 0 deg to 90 deg

VHF: 136MHz to 174MHz, -0.3dBd with optional radials, -3dBd surface mounted

UHF: 440 – 512 MHz

Separate GPS and VHF/UHF antennae

GPS Receiver

Standard:        8 channel receiver
High Accuracy: 12 channel receiver
Precision:        Real Time Kinematic

Power Supply

9V to 36V DC. Load dump protection to 250V

Power Consumption

Transmit (2W P.A. 100% duty cycle) 12W
Transmit (10W P.A. 100% duty cycle) 40W
Receive 4W

Transmit (2W P.A. 1 report/sec) 5W
Transmit (10W P.A. 1 report/sec) 7W


Operating -30 ºC to + 60 ºC
Storage -45 ºC to + 70 ºC


Tracs-TDMA and antenna IP 67 compliant.
Dust proof with short term immersion to 1 metre .

GeoPod IP 68 compliant. Dust proof with immersion to 10 metres

Dimensions And Weight

TDMA: L 246mm W 140mm H 95mm, 3kg
GeoPod: L 603mm Diam 90mm, 4.5kg

Excluding connectors with cables

Type Approval

TDMA: Meets ETS 300-113, CE approved

GeoPod: Meets UK MPT 1329 band 458.5 to 458.8 MHz, CE approved