An approach for close-form solution of multilateration equations

The approach combines both Chan´s algorithm and another close-form algorithm to solve the aircraft multilateration surveillance equations. Results developed are applicable for the surveillance system as a final location solution or as an initial one for the iteration algorithm. However, the ambiguous problem occurs if there are only three TOA measurements. So, the approach will also focus on it and provides an advisable comment to avoid the ambiguity in the receiver stations allocation process for the surveillance system in the airport.