Ground vehicle soft soil mobility has been studied for decades. Standard measurements, such as cone penetrometer, determine soil strength which helps analyze vehicle mobility. These methods are only available where data can be collected. As off-road vehicles transition to autonomous and semi-autonomous, real time in-situ analysis of soil strength is becoming a necessity. Databases such as GeoWATCH provide coarse (30-90m geospatial resolution) mobility parameter estimates. Hydrologic events can cause rapid changes in mobility which may not be effectively captured by these databases. In order to make real time predictions for autonomous vehicles, it is necessary to develop a method to determine mobility parameters without operator intervention. A system using rut depth measurements (collected via optical and ultrasonic sensors) and vehicle parameters was developed from established methods to estimate soil strength. The results were compared to corresponding physical measurements and raw GeoWATCH data.