A method for transmitting an energy beam from a group of elements of an external phased array energy projector for a medical ablation treatment. The method comprises transmitting first energy pulses from a subset of elements of the group, measuring signal parameters of first energy signals from reception of first energy pulses by energy sensors, and calculating for the group energy transmission parameters. The method further comprises transmitting second energy pulses by other elements, measuring signal parameters of second energy signals based on a reception the pulses by energy sensors, and calculating for the group a second set of energy transmission parameters. The method further comprises calculating transmission instructions for transmitting a phased array energy beam from the group by combining first and second energy transmission parameters. The method transmits an energy beam based on the transmission instructions.
