Application of portable GPS to practical surveying

摘要

The greatest disadvantage of portable GPS measurement compared to high precision GPS measurement is its poor accuracy. And the greatest advantage of portable GPS measurement is its low cost in equipment for practical surveying purpose. Until now, portable GPS has never been considered for practical surveying due to its inadequate results in measurement. However, effort for improvement has been made for utilizing the portable GPS with the relative positioning system. The only method to improve accuracy in measurement is to adopt differential GPS under the condition that four satellites are set and fixed during measurement at the two stations. Cellular phones are used both as tools for communication and for transferring data between two stations. Throughout the discussion, it is indicated that the portable GPS could be efficiently applicable to positioning in surveying.