19.5.1 Algorithm Flow

The basic flow of the models is;
Initialise
Loop through error sources
Loop through survey legs
Handle tie -on
Loop through survey stations
Use inclination to define mode (for gyro)
Determine inc, az, depth error for each error source i.e. evaluate the weighting functions
Determine the NEV errors for each error source
Sum these according to propagation mode
Transform to HLA axis frame if required