The number and performance of the sensors to be used for a survey is a function of the minimum number of observations required to determine an orbit. This is critical for the definition of the sensor network and the observation planning.Our goal is to obtain an orbit with a smaller number of observations with respect to the classical methods, such as Gauss/Laplace. In the context of space debris surveys, the goal is a full 6-elements orbit from just 2 tracklets, which could be obtained with only 2 exposures. The information contained in a tracklet can be summarized in a 4-dimensional vector called attributable, thus two tracklets are enough for the orbit determination problem to be over-determined. We have proposed an algorithm based upon the integrals of the 2-body problem. We outline the equations and the solution methods which are used in our implementation. We report on the results of a validation test, based upon the processing of one year of data from ESA Optical Ground Station. We conclude that the method is very effective and can be used to find correlations between tracklets, to be confirmed with additional correlations, thus providing a catalog of full 6-elements orbits.