Minimum Performance Standard. This technical standard order (TSO) prescribes the minimum performance standard that airborne supplemental area navigation equipment using global positioning system (GPS) must meet in order to be identified with the applicable TSO marking. Airborne supplemental area navigation equipment using GPS that are to be so identified and that are manufactured on or after the date of this TSO must meet the minimum performance standard of Section 2, RTCA, Inc. Document No. RTCA/DO-208, "Minimum Operational Performance Standards for Airborne Supplemental Navigation Equipment Using Global Positioning System (GPS)," dated July 1991.