A method for position calculation of an antenna is provided. The method comprises calculating ranges between the antenna and the at least three transponders. The calculation includes range measurements between an antenna and at least three transponders. Respective positions of the at least three transponders are known. The method further comprises providing a first coordinate of three coordinates. The three coordinates indicate a position of the antenna. The method further comprises calculating second and third coordinates of the three coordinates based on the calculated ranges between the antenna and the at least three transponders. The method further comprises predicting ranges between the antenna and the at least three transponders based on the provided first coordinate and the calculated two coordinates. The method further comprises performing an optimization process based on the calculated ranges and the predicted ranges to infer an optimized position of the antenna. Further, a system for position calculation and an air vehicle comprising the system are provided.