Gps Network Design: Logistics Solution Using Optimal and Near-optimal Methods

Although permanently installed global positioning system (GPS) networks are necessary when investigating many geophysical descriptors, there is still a need for epoch surveys consisting of temporarily placing GPS receivers sequentially at pre-chosen points. It is shown how the cost of carrying out an epoch survey can be reduced by using techniques within the ®eld of operational research. An epoch survey design consists partly of a list of sessions to be observed, with the length of observing time for each session also speci®ed. The issue of how long to spend observing a session is not addressed, but cheap session schedules are identi®ed given the required sessions and the cost of moving receivers between points. For small networks, optimal solutions are possible; however, for larger networks, non-optimal solutions based upon heuristics have to be accepted. This is necessary because for large networks the optimal solution could take days or weeks to determine, whereas heuristic methods can provide results within seconds.