I am trying to understand RAIM. My teacher explained three RAIM methods, I will just quote all of them because I think that the jargon might not be consistent.
Maximum separation / Position comparison method (PCM): Different combinations of satellites calculate the position of the receiver and these results are compared with statistical methods
Pseudo-Range residual / Range comparison method (RCM): All satellites calculate one solution. The residuals of the pseudo ranges are then investigated with statistical methods.
Parity space: The teacher said that the system of equations of the satellites is transformed orthogonally with constraint equations. And these constraint equations are used to detect statistical inconsistencies.
My question: Could someone explain me in normal words what the parity space method does? If there is a simple/short mathematical explanation that would be great. Did I explain the first and second method correctly?