Fig. 2

Temporal variations of a azimuths measured by the GPS compass relative to the sun compass and b numbers of satellites captured for the GPS signals, at a site with open sky (blue) and a site between buildings (red). The first 5 min at the open site, shown in gray, did not give reliable azimuths due to initialization of the GPS compass. At the site between the buildings, data were not collected during the first 5 min