Gyrosin compass RDF VAR astronavigation automatic electronic navigation celestial navigation chronometer coastwise navigation compass consolan dead reckoning direction finder electronic navigation fix gyrocompass gyroscopic compass gyrostatic compass inertial navigation system line of position loran magnetic compass magnetic needle navar navigation needle omnidirectional range omnirange pilotage plane sailing point-to-point navigation radar radio beacon radio compass radio direction finder radio navigation sextant sofar sonar tables tacan teleran visual-aural range