Convair B-58A Hustler Navigator's Station right forward console. The stick at the lower center is the tracking and flight control stick used to make tracking corrections and aircraft heading changes, in conjunction with the tracking and flight controller selector knob. (U.S. Air Force photo)
The primary navigation system, controlled from the navigator's station, guides the airplane over a great circle course to any desired destination without visual references and with a minimum of radio-radar transmission. It is assisted by the bombing system during bomb run, which enables it to maintain a correct bombing course and to accomplish automatic weapon release. Two modes of operation are provided: navigation and bombing. The navigation and bombing modes are used for navigation missions. For bombing missions, the bombing mode is used for guidance to and from the target area. Automatic radar photography can be accomplished whenever the system search radar is not being used for navigation checks. The primary navigation system is basically a Doppler-inertial system using an astrotracker for a standard heading reference. Aircraft course and position are continuously computed by a precise dead reckoning operation, which may be checked and corrected by periodic search radar sightings. Altitude above terrain is obtained by a radio altimeter. All radiating equipment may be operated intermittently if desired, without seriously degrading system accuracy. Automatic great circle steering is performed in the navigation mode. In bomb mode, rhumb line steering is performed, suitably altered to allow for wind drift and Coriolis effects on the pod after release. Evasive action may be taken in the target area. Traverse coordinate operation is provided for accurate polar navigation. A pilot's data indicator at the pilot's station indicate groundtrack, steering error (navigation mode), steering error for weapon release (bomb mode), time-to-go and distance to destination or target. The navigator is supplied distance to destination, a radar view of the terrain ahead, present latitude and longitude, true heading, barometric altitude, radio altitude, terrain elevation, ground speed, true airspeed, star data, and malfunction indications.
The heart of the system is the primary stable table (PNSU) which supplies attitude, heading, and velocity data to other portions of the system. This table is described as being erect, or plumb-bob vertical. While this is a necessary condition, it is not the only critical one. The table must be kept positioned properly in azimuth so that the accelerometers are correctly oriented and a true heading indication may be supplied for the DR process. Once erect, the table is kept stable by the properties of, and signals from, the gyros, accelerometers, earth rate computer, and astrotracker or flux valve. The auxiliary stable table (ARU) is an alternate source of attitude, heading, and velocity, though somewhat less accurate than the primary, and is normally kept in a standby condition.