1. The problem statement, all variables and given/known data I'm doing research with a professor at my college this summer on energy modeling for an electric vehicle. We're trying to figure out a way to make a model to predict how much energy an electric vehicle would need in order to do a certain path, but that requires testing of pre-determined paths, so we're using a GPS unit, mostly for height values. The only problem is that modern day GPS units are not very accurate in the Z direction, so we're having trouble getting consistent slopes of the road. So we've made a pressure differential sensor that finds the difference of pressure from our original point. We can find out initial height fairly accurately, so we were hoping this would work more effectively. The problem we're running into is actually getting height from our pressure. What is an equation that we could use in order to get change of height from our difference of pressure? We are also measuring temperature and relative humidity if that has anything to do with it. 2. Relevant equations Equations I've found thus far searching on the internet: p=p0(1-L*h/T0)^(g*M/(R*L)) where p0 is standard pressure, L is temperature lapse rate, T0 is standard sea level temperature, M is the molar mass of dry air, and R is the universal gas constant. Also, z = (RT/gM).loge(po/p) 3. The attempt at a solution I think I've already mentioned this.