Apparatus and method for navigation

• US 9,109,947 B2
• Filed: 03/15/2012
• Issued: 08/18/2015
• Est. Priority Date: 09/22/2009
• Status: Active Grant

• Current Assignee: Lirhot Systems Ltd.
• Original Assignee: Vorotec, Ltd.
• Inventors: Vorovitchik, Shlomo
• Primary Examiner(s): LEE, JOHN R
• Application Number:
  US13/421,530
• Publication Number:
  US 20120175496A1
• Time in Patent Office: 1,251 Days
• Field of Search: 250/225, 250/203.1, 250/203.3, 250/203.4, 250/206.1, 250/206.2, 332/68, 332/81, 701/513
• US Class Current: 1/1
• CPC Class Codes: G01C 17/34 Sun- or astro-compasses
• CPC Class Codes: G01C 21/02 by astronomical means G01C21/24, G01C21/26 take precedence
• CPC Class Codes: G01J 4/02 Polarimeters of separated-field type; Polarimeters of half-shadow type
• CPC Class Codes: G01J 4/04 Polarimeters using electric detection means G01J4/02 takes precedence

Abstract

An apparatus and system for use in determining location of a celestial body are presented. The apparatus comprises: a polarizer comprising an array of polarized light filter cells and a light sensor array. The array of polarized light filter cells comprises at least a first polarization direction and a second polarization direction different from said first polarization direction. And the polarizer thereby produces polarized light of at least first and second different polarizations. The light sensor array is configured to receive the polarized light from the polarizer and produce data indicative of a pattern of at least one of light polarization intensity and direction. The pattern is indicative of at least one of azimuth and elevation of the celestial body to be located.

Claims

1. An apparatus for use in determining location of a celestial body, the apparatus comprising:

a polarizer comprising an array of polarized light filter cells comprising at least a first polarization direction and a second polarization direction different from said first polarization direction, said polarizer thereby producing polarized light of at least first and second different polarizations; and

a light sensor array configured to receive the polarized light from said polarizer and produce data indicative of a pattern of at least one of light polarization intensity and direction, said pattern being indicative of at least one of azimuth and elevation of the celestial body.

2. An apparatus according to claim 1, comprising a processing unit configured and operable to receive and process said data indicative of the pattern of at least one of light polarization intensity and direction, to derive therefrom a polarization pattern, and utilizing the polarization pattern to determine said at least one of azimuth and elevation of the celestial body.

3. An apparatus according to claim 1, wherein the sensor array is configured to provide said data indicative of the pattern of at least one of light polarization intensity and direction in the form of analogue signal corresponding to a difference in intensity of detected light passed through the filter cells of different polarization directions.

4. An apparatus according to claim 1, wherein said second polarization direction is substantially perpendicular to said first polarization direction.

5. An apparatus according to claim 1, wherein said polarizer comprises circular array of said polarized filter cells arranged in the form of co-centric rings.

6. An apparatus according to claim 2, wherein said processing unit is configured and operable for calculating at least one of intensity and direction of collected light polarization by measuring a difference between light intensity received through polarized filter cell having said first polarization direction and light intensity received through polarized filter cell having said second polarization direction and for deriving said polarization pattern based on said calculations.

7. An apparatus according to claim 1, comprising a wavelength selective filter configured to separate at least one wavelength band from the input light.

8. An apparatus according to claim 2, wherein said processing unit is configured and operable for calculating the polarization pattern for at least one wavelength band.

9. An apparatus according to claim 7, wherein said wavelength selective filter comprises one or more groups of filter cells comprising one or more filter cells configured to allow passage of at least two wavelength bands different from each other, each group being associated with corresponding polarized filter.

10. An apparatus according to claim 1, wherein said polarizer comprises at least a region thereof configured as a radial polarizer.

11. An apparatus according to claim 1, wherein said polarizer comprises at least a region thereof configured as a tangential polarizer.

12. An apparatus according to claim 2, comprising a memory unit configured and operable for storing complementary data of at least one of a list comprising a sun path table, an astronomical chart, a calendar chart, an ephemeris table, a time standard, a skylight polarization chart, a calibrated chart of true north, magnetic north and grid north.

13. An apparatus according to claim 1, comprising an inclinometer for detecting the inclination of said apparatus with respect to a predetermined plane.

14. An apparatus according to claim 2, wherein said processing unit is configured and operable for utilizing said at least one of azimuth and elevation of said celestial body for determining at least one of the following parameters:

(a) location of said apparatus, (b) time of measurement, (c) headings of said apparatus (d) location of said starts.

15. An apparatus according to claim 2, wherein said processing unit is configured for calculating navigational data based on said at least one of azimuth and elevation of said celestial body.

16. An apparatus according to claim 1, defining a certain effective aperture, wherein the polarizer is aligned with the entire effective aperture.

17. An apparatus according to claim 1, defining a certain effective aperture, wherein the polarizer is aligned with a part of the effective aperture, said sensor array thereby concurrently producing said data indicative of the pattern of at least one of light polarization intensity and direction, and data indicative of an image formed by light passing towards the sensor array through a part of the effective aperture outside said part aligned with the polarizer.

18. An apparatus according to claim 1, defining one or more fields of view and being configured and operable to concurrently direct light collected with said one or more field of view onto said light sensor array.

19. An apparatus according to claim 1, comprising an optical system, said optical system comprising one or more optical elements accommodated upstream or downstream of the polarizer, or at both sides of the polarizer.