On-Vehicle GPS Antenna Measurements

Although GPS antennas are commonly used for vehicle applications, their on-vehicle gain patterns are not known well. Especially, when the antenna is mounted at locations other than the roof center, the antenna gain becomes directional at mid-to-low elevation angles. The goal of this letter is to investigate the GPS passive antenna performance at its actual, on-vehicle mounting locations. For four different antenna locations on a sedan vehicle with sunroof, the antenna gain is measured in a quasi-far-field antenna range. The results are also compared to those of finite ground plane, anechoic chamber measurements.