A virtual observational approach to ill-conditioned problem;

Since the constraint is taken as the virtual observations,the ridge parameter is transformed to weight ratio of the two types of observations,and then the ridge parameter can be selected with the Helmert variance components estimation method.

The virtual observation method with weight prior-determined and its application in orientation of the linear array imagery

The principle of VRS technology is discussed with corresponding formula deduction,and descriptions of VRS corrections and virtual observations generation and positioning algorithm are presented in detail as well as their applications.

This paper provides an adjustment considering the initial data errors,that is an integrated adjustment with the initial data as virtual observations to be adjusted along with the real ones.