Products

Data Links

Data links are Differential Global Positioning System (DGPS) radio signals transmitted from a reference station or relay antenna at a known location to one or more rover receivers, to provide the positioning correction data that gives Thales Navigation GPS systems maximum accuracy, up to within a centimeter. Data links allow reference stations, relay transmitters and rover receivers to communicate calculations performed at each location to build a preponderance of data that is cross-checked at every point for verified precision.

These data links are critical to collecting reliable GPS data. Thales Navigation has developed data link solutions for optimum system integration, and hardware and software compatibility with the highest market standards, to ensure superior performance and absolute reliability.

A number of factors including range, update rate and error correction rate determine the quality and specific application of a data link.

Thales Navigation has developed data link solutions that are readily adaptable to any application, overcoming the limitations to accuracy associated with vehicle tracking, DGPS, Local Area Differential GPS (LADGPS) and general data transfer.

There are three types of data links deployed in Thales Navigation GPS systems for high-performance accuracy:

  1. HF data link operates in the HF frequency between 1.6 MHz and 3.5 MHz. Primarily designed for LADGPS marine applications, HF data link is optimized for a meter-accurate update rate and easy government frequency allocation. Using a BCPSK modulation, advanced data compression, and high-performance GPS signal correction algorithms, HF data link offers superior accuracy for marine applications. With an operating range of 100 to 800 kilometer, HF data link is integrated into a number of Thales Navigation Marine Survey & Navigation GPS solutions.
  2. UHF data link operates in the UHF frequency between 410 MHz and 470 MHz. Optimized for LADGPS or Real-Time Kinematic (RTK) marine and land survey applications, UHF data link is available in a number of configurations for maximum performance according to the requirements of specific Thales Navigation GPS systems. UHF data link can be configured with a DQPSK modulation, operating at 1200 baud. This configuration is compatible with earlier DGPS and Kinematic Applications in Real Time (KART) applications and uses NDS100MkII signal format. When configured with a GMSK modulation and Long Range Kinematic (LRK) signal format, UHF data link is optimized for LRK or KART kinematic applications. A third option uses a common signal format known as RTCM. UHF data link has a range of 80 kilometers and is integrated into a number of Thales Navigation Marine Survey & Navigation and Land Survey GPS solutions.
  3. UHF bi-directional data link also operates in the UHF range and offers additional flexibility in configuring data processing functionality. Based on the Time Division Multiple Access (TDMA) principle, UHF bi-directional data link uses an MSK modulation optimized for relative positioning systems, used in marine seismic exploration and fleet management. UHF bi-directional data link is integrated into a number of Thales Navigation Marine Survey & Navigation and Fleet Management GPS solutions.