PSEUDO DISTANCE MEASURING CIRCUIT IN GPS RECEIVER

摘要

PURPOSE:To improve the measuring resolution of a pseudo distance by using a digital oscillator, and reading a phase of a clock which has synchronized with a PN code. CONSTITUTION:An output 202 of a digital oscillator 201 is clock which has synchronized with a PN code from a satellite, and also the other output 206 of the digital oscillator 201 corresponds to a phase of this clock. When the number of high-order bits of 206 held in a holding circuit 209 is denoted as M, the clock of 202 is shown as an expression I since it synchronizes with the clock of the PN code, and a measuring resolution of the time of the satellite to be measured is shown as an expression II, and by enlarging the number of bits of 206, comparing with a conventional method for measuring the time of a receiver based on the time of the satellite as a reference, the measuring resolution can be improved remarkably.