13 Jul 2021

Automotive Dead Reckoning Technology

Continuous accurate positioning performance under the most challenging conditions.

Increasingly dense urban environments, garages, and multi‑level interchanges all have one thing in common: they pose significant challenges to navigation systems because they obstruct satellite navigation signals in one way or another. 

As ever more systems such as car navigation, dynamic road pricing, fleet management, and emergency services depend on reliable, uninterrupted positioning and navigation, 3D dead reckoning GNSS and its ability to calculate a position is becoming increasingly important.

Three‑Dimensional Automotive Dead Reckoning (3D ADR) complements traditional GPS and GNSS navigation using intelligent algorithms that process distance, direction, and elevation changes made during satellite signal interruption. u‑blox's 3D ADR GNSS chip, the UBX‑M8030‑Kx‑DR, blends satellite navigation data with individual wheel speed, gyroscope, and accelerometer information to deliver accurate positioning regardless of changes in a vehicle’s speed, heading, or vertical displacement, even when satellite signals are partially or completely blocked. This is especially important when quick navigation decisions must be made immediately upon exiting tunnels and parking garages.

The standard precision solution

The NEO‑M9L automotive dead reckoning module series are operational in temperature ranges of up to 105 °C. Based on u‑blox’s robust M9 GNSS platform, these receivers deliver continuous and accurate navigation in all environments.  The modules offer sensor-based spoofing detection for advanced security and robustness. Offering a low-latency, 50 Hz update rate, the module is capable of calculating its position using its own internal sensors, regardless of satellite visibility, signal quality, and end‑device orientation. The modules’ additional GNSS-only output enables seamless integration into a variety of third-party applications.

The NEO‑M9L modules are the ideal solution for all first-mount applications including integrated navigation systems such as in-vehicle infotainment and head units, integrated telematics control units (TCUs), and telematics tracking systems. Leveraging the unsurpassed accuracy of u-blox ADR technology, high‑end navigation devices can guide drivers through several kilometer‑long tunnels. The receiver also supports wake-on-motion, which enables smart features such as theft protection and power-efficient designs.

The high precision solution

In the automotive industry, high precision positioning information is required for lane-level navigation and autonomous driving. During the early phases of deployment of autonomous driving, these driver assistance features will only be permitted in designated areas. The ability to provide high accuracy in the range of 20 centimeters in open sky environments translates to a high degree of confidence of lane-accurate positioning in a much wider range of driving landscapes.

The evolution of applications for positioning inside the car has been quite striking. The first navigation applications emerged during the 1980’s. The vehicle’s location was displayed on the map and clever routing algorithms helped a driver navigate in unfamiliar territory. Placing the vehicle on a road with an accuracy of tens of meters was sufficient. Next applications came in the form of emergency assistance, where a vehicle involved in an accident notifies the authorities so that help can be summoned. The EU regulation eCall specified an accuracy of 40 meters in partially obstructed sky environments. These systems have been widely deployed in the world.

The third area of applications is V2X, Vehicle-to-Everything communication. Essentially, all actors on or near a road are able to communicate with each other over a short-range radio technology, communicating their position and trajectory in real time. SAE J2945/1 is a widely accepted norm, which states as the goal as the ability to announce the lane being used by a vehicle with a 95% certainty in an open sky environment. This information is used to alert the drivers and potentially initiate maneuvers such as braking. This is the original lane accurate positioning application.

Although open sky environments constitute a majority of road miles driven in some countries, many other landscapes will need to be covered for several reasons. Driver acceptance of the feature will be limited if drivers are inundated with false alarms. Second, regulators tend to adapt regulations as technology improves and demand a commonly agreed upon state of the art. Automotive OEMs recognize this and the race to expand on covered driving scenarios is on.

Finally, in the area of autonomous driving, permissible autonomous driving zones as already mentioned are a key application. Another application is vehicle control. This melds advanced technologies including neural networks, high definition real-time maps, advanced sensor such as LIDAR, and big data. Lane Accurate Position (LAP) is a key element in any autonomous driving solution.

High Precision Dead Reckoning enables decimeter-level accuracies


Lane accurate positioning improves performance in dense cities, parking garages, tunnels and multi-level roads, and just about any condition where GNSS signals are partially or completely obstructed. It is the marriage of dead reckoning technology and high precision algorithms that opens up the possibilities to address these challenging environments.

Dead reckoning complements traditional GPS or GNSS navigation using intelligent algorithms that process distance, direction, and elevation changes made during satellite signal interruption. Further enhancing performance, high precision algorithms with GNSS signals from multiple frequency bands enable navigation levels to reach decimeter-level accuracies.

u-blox’s ZED-F9K combines satellite navigation from up to four global navigation satellite systems with wheel speed, gyroscope, and accelerometer measurements while constraining the position solution to the dynamics of a car to reach an optimum position. Furthermore, the high precision algorithms that enable ultra-precise navigation incorporate Real Time Kinematic (RTK) technology and correction services. Multi-band enables fast convergence and re-convergence of high precision positions.

High Precision GNSS system overview 

ZED-F9K module


  • Continuous lane accurate positioning under the most challenging conditions
  • Decimeter level accuracy for automotive mass markets
  • Ideal for ADAS, V2X and head units
  • Turnkey multi-band, RTK solution with built-in inertial sensor
  • Low latency position update rate of up to 30 Hz

Evaluation tools

You can evaluate our Automotive Dead Reckoning technology using blueprints, application boards or evaluation kits. The EVK‑M8L evaluation kit supports the u‑blox NEO‑M8L while C100-F9K application board supports u-blox ZED‑F9K modules.

To order an evaluation kit, go to our online shop or contact a u‑blox sales representative.

Check out our recent use case

to learn how to determine alignment angles for your dead reckoning products.