Pseudorange and carrier phase measurement in gps

1. What is pseudo range measurement in GPS?
2. What are the differences between the code pseudorange and carrier phase?
3. What is carrier phase measurement?
4. How does the receiver compute pseudo range and carrier phase?

What is pseudo range measurement in GPS?

The pseudorange is an approximation of the distance between a satellite and a GNSS receiver. A GNSS receiver will attempt to measure the ranges of (at least) four satellites as well as their positions when their positional data were transmitted.

What are the differences between the code pseudorange and carrier phase?

In Global Navigation Satellite System (GNSS) community, pseudorange observables, without integer ambiguity, have large measurement noise, while carrier phase observables, with high measurement accuracy, have integer ambiguity, which restricts the direct use either of them for high-accuracy navigation and positioning.

What is carrier phase measurement?

A: Simply put, the carrier phase measurement is a measure of the range between a satellite and receiver expressed in units of cycles of the carrier frequency.

How does the receiver compute pseudo range and carrier phase?

It is recovered from the measured time difference between the epoch of the signal transmission and the epoch of its reception by the receiver. The actual time measurement is performed with the use of the PRN code. In principle, the receiver and the satellite generate the same PRN sequence.