METHOD AND APPARATUS FOR GROUND-BASED SURVEYING IN SITES HAVING ONE OR MORE UNSTABLE ZONE(S)

摘要

The invention relates to ground-based surveying on a site (2) which comprises an unstable zone (60) and at least one control point (FCP1, FCP2, FCP6, FCP7; CP1-CP3) placed outside the unstable zone, in which method at least one surveying device (TS8, TS9; ST1-ST3) is used to acquire positional data by sighting least one control point (FCP1, FCP2, FCP6, FCP7; CP1-CP3). The approach comprises: - providing at least one sighting point (UP3-UP5; A-C) within the unstable zone (60 ; 20), - using the surveying device(s) (TS8, TS9; ST1-ST3) to acquire positional data by sighting the at least one sighting point (UP3-UP5; A-C) that is located within the unstable zone (60 ; 20), and - combining the positional data acquired from: i) the at least one control point (FCP1, FCP2, FCP6, FCP7; CP1-CP3) placed outside the unstable zone and ii) at least one sighting point (UP3-UP5; A-C; within the unstable zone (60 ; 20), to produce a positional reference for the surveying device (s). The combining step can be implemented using a bundle adjustment technique.