Strapdown stellar sensor and holographic multiple field of view telescope therefor

Optical apparatus, comprising:

• a primary holographic optical element (HOE) having a first surface for receiving at least one ray bundle representing a wavefront and a second surface for outputting the ray bundle to a first focal point, the primary HOE having a first aberration characteristic for wavelengths within a band of wavelengths;
• a secondary HOE having a concave reflecting surface of radius (r) for directing an incident ray bundle received from said primary HOE so as to form a final real image at a second focal point, said concave reflecting surface being disposed along an axis that runs from said second surface of said primary HOE and that passes through the second focal point, said secondary HOE having a second aberration characteristic for wavelengths within the band of wavelengths that is opposite that of the first aberration characteristic for substantially cancelling an effect of the first aberration characteristic upon the final real image;
• an achromatic lens element disposed in proximity to the first focal point for imaging the primary HOE upon said secondary HOE such that all rays diverging from a single point on the second surface of the primary HOE are brought to a single point on the surface of the secondary HOE;
• and
• mirror means disposed along a plane that passes through the axis at an angle thereto for reflecting the final real image to point off of the axis.

Optical apparatus, comprising:

• a primary holographic optical element (HOE) having a first surface for receiving at least one ray bundle representing a wavefront and a second surface for outputting the ray bundle to a first focal point, the primary HOE having a first aberration characteristic for wavelengths within a band of wavelengths;
• a secondary HOE of negative power having a first surface for receiving an incident ray bundle from said primary HOE and a second surface for outputting the incident ray bundle therefrom, said first surface of said secondary HOE being disposed along an axis that runs from said second surface of said primary HOE and that passes through an achromatic virtual image focal point that is disposed between said primary HOE and said secondary HOE, said secondary HOE having a second aberration characteristic for wavelengths within the band of wavelengths that is opposite that of the first aberration characteristic for substantially cancelling an effect of the first aberration characteristic;
• a first achromatic lens element disposed in proximity to the first focal point for imaging the primary HOE upon said secondary HOE such that all rays diverging from a single point on the second surface of the primary HOE are brought to a single point on the surface of the secondary HOE;
• and
• a second achromatic lens element disposed adjacent to said second surface of said secondary HOE for focussing the ray bundle output therefrom so as to form an achromatic real image at a second focal point.

A strapdown star tracker for generating navigational information from an assumed position given by an inertial measurement unit aboard a vehicle, comprising:

• viewing means having one or more entrance apertures, each having one or more fields of view, for simultaneously imaging a plurality of heavenly bodies;
• means for strapping down said viewing means in a fixed orientation to the vehicle;
• means for converting the images of the viewed heavenly bodies into detectable electrical signals;
• and
• means, coupled to said converting means and responsive thereto, for deriving inertial measurement unit correctional information;
• wherein
• each of said one or more entrance apertures includes a primary holographic optical element (HOE) having a first surface for receiving one or more ray bundles, each representing a wavefront emanating from a heavenly body, and a second surface for outputting the one or more received ray bundles to one or more focal points, the primary HOE having a first aberration characteristic for wavelengths within a band of wavelengths;
• and wherein said viewing means further includes at least one secondary HOE disposed along an axis passing through one of the focal points, at least one secondary HOE having a second aberration characteristic for wavelengths within the band of wavelengths that is opposite that of the first aberration characteristic for substantially cancelling an effect of the first aberration characteristic upon an image of a heavenly body.

An optical system comprising:

• an optical stop comprising a holographic optical element having a plurality of spherical aberration corrector plates each having a different field of view;
• a plurality of concave spherical reflectors individual ones of which are positioned for receiving a corrected wavefront from one of said corrector plates;
• and
• a plurality of radiation detectors individual ones of which are positioned at a focal plane of one of said concave spherical reflectors.