I changed the last code lines like that:
local _lat, _lon = coord.LOtoLL(_unit:getPosition().p)
local _latLngStr = mist.tostringLL(_lat, _lon, 3, false)
local _latLngStrDMS = mist.tostringLL(_lat, _lon, 2, true)
local _mgrsString = mist.tostringMGRS(coord.LLtoMGRS(coord.LOtoLL(_unit:getPosition().p)), 5)
local _altitude = mist.utils.round(mist.utils.metersToFeet(land.getHeight({ x = _unit:getPoint().x, y = _unit:getPoint().z })), 0)
return " @ " .. _latLngStr .. " - MGRS " .. _mgrsString .. " - ALT " .. _altitude .. " Ft - Coordinates: " .. _latLngStrDMS