Algorithm research on GPS-based bus-stop auto-announcement system

Aiming at improving the accuracy of bus-stop auto announcement system, based on the Cohen-Sutherland line clipping algorithm, an improved algorithm is proposed. We can divide bus-stop area into 5 parts according longitude and latitude, with only one given collection point. Meanwhile, no collection azimuth angle is needed. According to region code and track code, pulling in judgment and pulling out judgment could be deduced. Accurate judgment could also be available when vehicles turn round. The test result shows that improved algorithm is real-time, keen and feasible.