"New Tools for Networked RTK Integrity Monitoring" research paper, ION GPS/GNSS 2003, Sept. 9-12, 2003, Portland, Oregon
This paper proposes two indicators of ionospheric linearity:
Ionospheric Residual Integrity Monitoring (IRIM): Omitting one reference station from interpolation and then comparing the interpolation results at that station with the real measurements. Compute a weighted RMS over all satellites. This can also be considered as integrity monitoring for residual interpolation and ambiguity resolution in the network.Ionospheric Residual Interpolation Uncertainty (IRIU): With sufficient surrounding reference stations, an interpolation method such as Weighted Linear Interpolation Method (WLIM) produces standard deviation of interpolation. The standard deviation represents the ionospheric linearity over the interpolation region for the field user.