A unit system may be optionally specified during AIM instance initiation. If a unit system is provided, all AIM input values which have associated units must be specified as well. If no unit system is used, AIM inputs, which otherwise would require units, will be assumed unit consistent. Missile Datcom only supports modifying the length unit, which may be set with a JSON string: unitSys = "{"length": "m"}"

• length = "None"
  Length units - must be one of "in", "ft", "cm", "m"