Correction Services

Correction services have been operational in the market for 30 years delivering clock and orbit corrections over the L-Band or IP for land, airborne and near-shore applications. Our redundant infrastructure provides the reliability that autonomous vehicles require for safe operation.


TerraStar X Technology 

Data Provided  Orbits
Phase Biases
Phase Biases
Geographical Coverage  Continental Scope   Continental Scope
Time to Resolve  15 to 45 minutes  Less than a minute 
Accuracy  5 cm  5 cm 


TerraStar X Technology

TerraStar X correction technology eliminates convergence time while providing high accuracy global positioning to enable instant lane-level accuracy in autonomous automotive applications. Available over satellite using Ligado’s SkyTerra satellite or through cellular networks, TerraStar X will position vehicles with 5-centimetre accuracy in under a minute. When combined with GNSS receivers available through Hexagon's Autonomy & Positioning division, this technology allows automotive customers to evaluate positioning performance in real-time.


  • Delivers lane–level (<50 cm) accuracy throughout entire coverage area in less than one minute
  • Scalable for high volume of users
  • Received through either GNSS or over IP/Cellular
  • Reliability and available for 24/7/365 all-weather operations
  • Lower bandwidth requirements vs. RTK


TerraStar X Technology, RTK From the SkyTM

The following is
from “TerraStar X Precise Positioning Enables Autonomous Applications”, presented by Sara Masterson at Multi GNSS Asia, 2018.

Autonomous technology is reshaping the future of mobility and transportation worldwide, and Hexagon’s Positioning Intelligence division (Hexagon PI) is developing cutting-edge positioning solutions to support the growth of this technology.

In June, Hexagon PI introduced TerraStar X GNSS correction technology, which enables centimeter-level accuracy in under a minute. Built on the company’s latest Precise Point Positioning (PPP) algorithms, TerraStar X leverages existing Hexagon capabilities in ground network infrastructure, correction data generation and data packaging for delivery.  TerraStar X also enables integrity and authentication for safety-critical applications like autonomous driving and aviation.

How It Works

TerraStar X combines existing TerraStar global clock and orbit data with regional ionospheric correction data from Hexagon’s vast network of HxGN SmartNet reference stations. This forms the technology foundation for future correction services that deliver RTK From the SkyTM, enabling lane-level positioning on connected cars, Advanced Driver-Assistance Systems (ADAS) and autonomous driving markets. 

HxGN SmartNet consists of a large operational reference station network, consisting of more than 4,500 stations with continuous quality monitoring support. Correction data generation takes place at Hexagon processing centers where service reliability, redundancy and 99.999% guaranteed service uptime ensure corrections are available for users 24/7/365. While TerraStar X utilizes the stations already available, the algorithms are flexible and will accommodate the rollout of new service areas with increased station separation, enabling continental-scale coverage.

TerraStar X technology also offers hybrid delivery channels, including both cellular network and satellite.

Other Applications

Hexagon has been providing highly reliable, precise GNSS corrections for over 20 years. Our GNSS correction services empower world leading companies within precision agriculture, survey, marine, oil and gas, automotive, and transportation applications. Using the NovAtel® OEM7 family of receivers and TerraStar X technology combined with multiple delivery channels, users in these established applications will also have access to RTK from the SkyTM performance.

Proven in Testing

In tests using automotive-grade chipsets, the PPP solution with TerraStar X corrections demonstrates a 64 – 93% horizontal accuracy improvement over the onboard SBAS corrected solution under an open sky condition at a 95% confidence interval.

TerraStar X testbeds are currently being utilized for several advanced AD development programs in North America and Europe, and access can be made available for interested customers.


TerraStar X Technology Testbeds

Evaluate the benefits of TerraStar X technology for precise localization in automotive applications at test beds across North America and in Europe. Trial networks are currently available in California, Arizona, and Michigan over satellite or cellular network, and in Germany using cellular delivery. Commercial solutions designed uniquely for the automotive market will be available in 2019.

California Testbed  Germany Testbed  Michigan Testbed