Satellite And Receiver Clock Errors In Gps

Clock inaccuracies and rounding errors.

Satellite and receiver clock errors in gps.

When a signal is. This eccentricity effect causes the clock rate difference between a gps satellite and a receiver to increase or decrease depending on the altitude of the satellite. The satellite s reported location may not be accurate. A receiver s built in clock may have slight timing errors because it is less accurate than the atomic clocks on gps satellites.

One of the largest errors can be attributed to the satellite clock bias. Introduction gps has been widely used for precise positioning and na vigation applications. Slight inaccuracies in time keeping by the satellites can cause errors in calculating positions. The global positioning system has a clever effective solution to this problem.

As it is shown the satellite clocks reach up to more than math 150 math kilometres which leads to huge position errors. To compensate for the discrepancy the frequency standard on board each satellite is given a rate offset prior to launch making it run slightly slower than the desired frequency on. To achieve this goal most studies have focused on the relationship between gps receiver clock errors and gps positioning precision. Gps coordinates calculated when satellites are clustered close together in the sky suffer from dilution of precision dop a factor that multiplies the uncertainty associated with user equivalent range errors uere errors associated with satellite and receiver clocks the atmosphere satellite orbits and the environmental conditions that.

Figure 1 illustrates the effect of neglecting the gps satellite clock offsets on the user position. It can be quite large especially if the broadcast clock correction is not used by the receiver to bring the time signal acquired from a satellite s onboard clock in line with gps time. Let the gps receiver receive signals from 4 satellites then there are two cases. The more satellites a gps receiver can see the better the accuracy.

In addition to the propagation er rors the receiver position accuracy availability reliabil ity and integrity of gps navigation solution are affected. Number of satellites visible. This study utilizes undifferentiated phase data to calculate gps clock errors and to compare with the frequency of cesium clock directly to verify estimated clock errors by the method used in this paper.