untethered dead reckoning (automotive) (UDR)

Automotive Dead Reckoning(ADR) and Untethered Dead Reckoning (UDR) are methods for improving the positional accuracy of navigation signals.

Both methods are intended to improve position determination in urban areas, since this deteriorates when driving through urban canyons or tunnels due to limited signal reception.

While the ADR method reconciles the GNSS positions of the global navigation systems with the current position, the UDR technique works with a UDR module that determines the vehicle acceleration and deviations from the straight line and uses this, together with the GPS data, to calculate the current position. The inertial measurement unit( IMU) of the UDR module records the acceleration forces and rotational movements and uses them to calculate the driving and location coordinates.