The Trimble® Aardvark DR+GPS combines dead reckoning (DR) with GPS to produce accurate and instantaneous positions, even under the most difficult conditions. For service providers tracking highvalue or perishable cargo, Aardvark DR+GPS dramatically improves quality of service (QoS). Dead reckoning (DR) estimates position based on heading and distance traveled since the last known position. The more accurate the speed, time and heading inputs, the more accurate the dead reckoning.