Bence Takács
Assessment of the errors in single point positioning
After turning off Selective Availability (SA) a new chapter began in the GPS-technique. The performance of GPS standard single point positioning technique was discussed in details [4]. It was stated, that in favourable conditions accuracy of several meters is achievable. Recently the number of GPS users has impressively increased; turning off SA has clearly played an important role in the propagation of GPS technique. Turning off SA is considered as a key point not only for the practice, but also for scientific researchers. It is well known, that compared to the artificial degradation of GPS accuracy, the effect of systematic and random errors on single point positioning is practically negligible. Some of the receivers do not take into account some systematic effects, because of the order of magnitude of SA error. Formerly errors on single point measurements could be invetigated only with limited efficiency. Turning off SA offers an opportunity to assess all the systematic and random effects in details; this paper will summarize the most important results of these investigations.