When using the signal from the Global Positioning System for precise estimation of the heading of a vehicle, the main challenge is finding the integer ambiguities that the carrier phase measurements contain. If the distance between the receiver’s antennas, also known as baseline, is used in the process of solving that challenge, the resulting solution’s stability and precision can be enhanced, particularly for single-frequency receivers. This paper presents a study of the overall influence of this baseline length in the precision and accuracy of the heading estimation, using measurements from two single-frequency receivers. Conclusions are presented based on the results from field trials for baselines up to 8m.