<div class="section abstract"><div class="htmlview paragraph">For intelligent vehicles, a fast and accurate estimation of road slope is of
great significance for many aspects, including the steering comfort, fuel
economy, vehicle stability control, driving decision-making, etc. But the
commonly used estimation methods nowadays usually demand additional sensors or
complex dynamic models, causing increase in system complexity as well as
decrease in accuracy. To solve these problems, this paper puts forward a
real-time road slope estimation algorithm leveraging the relationship between
pitch angle and road slope, which only requires low sensors cost and
computational complexity. Firstly, a GNSS/INS fusion system is established to
obtain the pitch angle with respect to the navigation frame, which couples the
vehicle’s pitch angle in vehicle frame and road slope angle. Then, based on the
different characteristics in frequency domain of the two components, frequency
domain analysis is conducted and low-pass filter is used to separate out road
slope signal. Besides, considering the slope change during driving, a parameter
adaption strategy is designed in order to timely track changes of slope
conditions. Experimental results show that the proposed method has a good
real-time performance and the average error is below 0.3 deg even when the road
slope changes rapidly.</div></div>