Recall that the receiver keeps track of whole waves after the first observation. The triple difference is particularly suitable for detecting and fixing cycle slips. A cycle slip causes an individual outlier in triple-difference residuals. Individual outliers generally can be discovered and removed in adjustments with ease. Triple differences, therefore, serve as a preprocessing step, allowing cycle slips to be eliminated and, at the same time, providing a first solution for the receiver positions.
Double differences have the important advantage of still containing the initial integer ambiguities.
Since we know, however, that the ambiguities should be integers, it is some times possible to force the solution to yield integer estimates for the ambiguities during a second processing step. Centimeter GPS surveying always requires fixed solutions. Single-difference solutions usually are not carried out in typical surveying applications. These solutions require a detailed parameterization of receiver clock errors unless the receiver is connected to an external atomic frequency standard. The latest variations in GPS surveying techniques cleverly explore the geometric strength of solutions and integrate GPS code and carrier-phase observations more fully.