An easy guide to the secrets of #RTK (Real Time Kinematic). First two closely spaced receivers eliminate atmospheric errors and secondly, Calculating accurate distance between Satellite and Receiver using carrier phase. #NTRIP #PPK
The idea is, if we have two receivers "close to each other", the atmospheric errors for signals they observe are almost identical. As a result they can be excluded from the calculations.
By eliminating these errors a rover receiver can better estimate all ambiguities in its positional calculations. The base receiver transmits its position and observed satellite's data to the rover.
The rover uses this information to exclude atmospheric errors from the calculation and better estimate its position.
Carrier Phase Measurement. In this process we use just the Carrier signal and discard the data in it.
The carrier phase is a more advanced way of determining the distance between the satellite and the GNSS receivers. The radio signals from the satellites are traveling in sinusoidal waves to the receiver on the ground. With the carrier phase measurement we can understand where exactly we are in the phase.
This is done by resolving the number of cycles in which the signal is transmitted and received by the receiver. This can be achieved by using a combination of differential GPS (DGPS) correction data, transmitting GPS signal phase information and ambiguity resolution techniques via statistical tests, in real-time.
The period of the carrier frequency, times the speed of light, gives the wavelength, which is about 0.19 meters for the L1 carrier. With a 1% of wavelength accuracy in detecting the leading edge, this component of pseudorange error might be as low as 2 millimeters. This compares to 3 meters for the C/A code and 0.3 meters for the P code. And all these are happening for all the satellites the receiver receives and in Real Time.
Негізгі бет WHAT IS RTK, PPK & NTRIP? How RTK is DIFFERENT from DGPS?
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