A system and method improve guidance system performance. An accuracy improvement module (AIM) can be configured to compare observed and expected inclination compensation factors (ICFs) at a plurality of inclination angles to detect an inaccuracy in antenna height. In response to detecting an inaccuracy, an AIM can determine a revised antenna height that more accurately represents the height of an antenna above ground. A proposed antenna height can be determined using an observed ICF. A fixed vehicle body height can be subtracted from the proposed antenna height to provide a proposed tire radius. The proposed tire radius can be compared to a table of standard tire radii to determine a tire radius value, which can then be added to the fixed vehicle body height to provide a revised antenna height. The revised antenna height can improve the accuracy or calculated ground positions, thereby improving guidance system performance.