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 se quentially at pre-chosen points. It is shown how the cost of carrying out a n epoch survey can be reduced by using techniques within the field of opera tional research. An epoch survey design consists partly of a list of sessio ns to be observed, with the length of observing time for each session also specified. The issue of how long to spend observing a session is not addres sed, but cheap session schedules are identified given the required sessions and the cost of moving receivers between points. For small networks, optim al solutions are possible; however, for larger networks, non-optimal soluti ons based upon heuristics have to be accepted. This is necessary because fo r large networks the optimal solution could take days or weeks to determine , whereas heuristic methods can provide results within seconds.