An automatic celestial navigation system for navigating both night and day
by observation of K-band or H-band infrared light from multiple stars. In
a first set of preferred embodiments three relatively large aperture
telescopes are rigidly mounted on a movable platform such as a ship or
airplane with each telescope being directed at a substantially different
portion of sky. Embodiments in this first set tend to be relatively large
and heavy, such as about one cubic meter and about 60 pounds. In a second
set of preferred embodiments one or more smaller aperture telescopes are
pivotably mounted on a movable platform such as a ship, airplane or
missile so that the telescope or telescopes can be pivoted to point
toward specific regions of the sky. Embodiments of this second set are
mechanically more complicated than those of the first set, but are much
smaller and lighter and are especially useful for guidance of aircraft
and missiles. Telescope optics focus (on to a pixel array of a sensor)
H-band or K-band light from one or more stars in the field of view of
each telescope. Each system also includes an inclinometer, an accurate
timing device and a computer processor having access to catalogued
infrared star charts. The processor for each system is programmed with
special algorithms to use image data from the infrared sensors,
inclination information from the inclinometer, time information from the
timing device and the catalogued star charts information to determine
positions of the platform. Direction information from two stars is needed
for locating the platform with respect to the celestial sphere. The
computer is also preferably programmed to use this celestial position
information to calculate latitude and longitude which may be displayed on
a display device such as a monitor or used by a guidance control system.
These embodiments are jam proof and insensitive to radio frequency
interference. These systems provide efficient alternatives to GPS when
GPS is unavailable and can be used for periodic augmentation of inertial
navigation systems.