Most calibration happens automatically. Unfortunately many of these receivers were not designed with accurate time-keeping in mind. Fortunately there are also receivers that were designed for precision timekeeping. Contributors for missing entries are very much invited. These parameters qualify the accuracy of a GPS receiver.
Small values express high precision.
The values are computed using an inversion of a 4x4 matrix containing the cosinus values of the angles between the antenna and the satellites. DCF77 Receivers 7.3.1. In comparison to GPS , DCF77 receivers are cheap, and they don't need an antenna with a view at the sky. Germany has a highly accurate clock and a long-wave transmitter that sends out time data at 77.5kHz. This service is commonly known as DCF77 .