Editing Boeing OC-135B Open Skies (section)

==Flight path==
The aircraft flies on its intended flight path throughout the entire mission with no reliance on ground-based navigation devices. A top-of-the-line commercial system, Litton 92 INS/GPS, which is an integrated [[Inertial guidance system|inertial navigation system]] (INS) with a [[Global Positioning System|global positioning system]] (GPS), provides continuous updates. The GPS updates the INS several times per second to correct any deviations in the flight path. The INS also feeds precise latitude, longitude, time, roll angle and barometric altitude to the DARMS and camera systems. A true airspeed computer feeds true airspeed data to the INS.

A combined altitude radar altimeter provides precise height above ground information to the pilot for navigational purposes as well as a signal to DARMS for film annotation. It is accurate from {{convert|0|-|50000|ft|m|-3}} above the ground level. Plus, a metric altimeter is installed on the pilot's instrument panel for altitude reference when flying in countries that use meters for altitude reference.

The aircraft are being upgraded with the Block 30 Pacer Crag Navigational System upgrade, a first step in making them compliant with ICAO mandated [[Global Air Traffic Management]] and [[Global Air Navigation Standards]] guidelines.