High-accuracy navigating apparatus with step-driven projected chart
First Claim
1. A navigational apparatus for use with a craft, said apparatus comprising:
- an optical projection system having an optical path terminating in a visible display field;
an optically projectable map locatable in the optical path of said projection system, said map providing a scaled representation of a geographical area and including at least two calibration indicia at respective positions on said map corresponding to predetermined known coordinates,map transport means for controllably effecting relative movement between said map and said projection system in accordance with applied transport control signals;
map calibration means for for moving said calibration indicia to a predetermined position within said projection system and for then coordinating said known coordinates with the position of the map transport means to derive calibration data used in thereafter generating transport control signals; and
transport drive means for generating said transport control signals in accordance with said calibration data and in accordance with supplied craft position data to vary said map position relative to said projection means in accordance with the geographic position of said craft.
1 Assignment
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Accused Products
Abstract
A small fraction of the area shown in an ultraminiature color transparency of a standard navigating chart is projected onto a viewing screen, and the transparency is moved by a precision step-driven transport mechanism to hold the present position of the ship (or other craft) at crosshairs on the screen. The transport mechanism is controlled by a digital electronic computer that receives data from a human operator, from speed and direction sensors carried in the craft, and/or from radio navigational-aid (such as Loran) signals. The computer includes separate dedicated microprocessors for managing the transport mechanism and the receipt of sensor or radio signals, and a master general-purpose processor for performing calculations and coordinating the system functions with operator instructions.
The computer calculates position, "course to steer," and other parameters based on dead reckoning, manually entered bearings of navigational objects, and/or the data automatically received from such radio aids; and it controls the transparency transport on the basis of calculated position. By comparing dead-reckoning results with actual position fixes the computer determines set and drift, and it reads out "course to steer" that is corrected for set and drift. The computer can also control an autopilot, automatically setting a heading that produces the desired track, practically independent of currents.
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Citations
11 Claims
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1. A navigational apparatus for use with a craft, said apparatus comprising:
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an optical projection system having an optical path terminating in a visible display field; an optically projectable map locatable in the optical path of said projection system, said map providing a scaled representation of a geographical area and including at least two calibration indicia at respective positions on said map corresponding to predetermined known coordinates, map transport means for controllably effecting relative movement between said map and said projection system in accordance with applied transport control signals; map calibration means for for moving said calibration indicia to a predetermined position within said projection system and for then coordinating said known coordinates with the position of the map transport means to derive calibration data used in thereafter generating transport control signals; and transport drive means for generating said transport control signals in accordance with said calibration data and in accordance with supplied craft position data to vary said map position relative to said projection means in accordance with the geographic position of said craft. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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Specification