  Locating each node in a wireless sensor network is essential for starting the
monitoring job and sending information about the area. One method that has been
used in hard and inaccessible environments is randomly scattering each node in
the area. In order to reduce the cost of using GPS at each node, some nodes
should be equipped with GPS (anchors), Then using the belief propagation
algorithm, locate other nodes. The number of anchor nodes must be reduced since
they are expensive. Furthermore, the location of these nodes affects the
algorithm's performance. Using multi-objective optimization, an algorithm is
introduced in this paper that minimizes the estimated location error and the
number of anchor nodes. According to simulation results, This algorithm
proposes a set of solutions with less energy consumption and less error than
similar algorithms.
