Digital camera with GNSS picture location determination

• US 20080218407A1
• Filed: 03/08/2007
• Published: 09/11/2008
• Est. Priority Date: 03/08/2007
• Status: Active Grant

• Current Assignee: Trimble Navigation Limited (Trimble Inc.)
• Original Assignee: Trimble Navigation Limited (Trimble Inc.)
• Inventors: Loomis, Peter Van Wyck, Norda, Carl Jacob
• Granted Patent: US 7,719,467 B2
• Time in Patent Office: Days
• US Class Current: 342/357.01
• CPC Class Codes: G01S 19/14 specially adapted for specific applications
• CPC Class Codes: G01S 5/0036 of measured values, i.e. measurement on mobile and position calculation on base station

Abstract

A digital camera for providing a short burst of global navigation satellite system (GNSS) signal samples in a picture data file with an approximate time for reading by a computer apparatus some time later for determining the geographical location and an accurate time of the picture. An apparatus and method for determining a GNSS position of an event where an event capture device writes a short burst of GNSS signal samples with an approximate time into an event data file and a GNSS sample processor reads the event data file some time later for determining the geographical location and an accurate time of the event.

Claims

1. A digital camera, comprising:

a picture device for taking a picture and converting said picture into picture data;

a global navigation satellite system (GNSS) signal sampler for sampling said GNSS signals when said picture is taken;

a real time clock for generating a time tag for said GNSS signal samples, said time tag having a time uncertainty window greater than a time length of a frame of data bits for said GNSS signals; and

a picture file formatter for writing said picture data, said GNSS signal samples and said time tag into a computer-readable picture data file medium configured for processing by a computer apparatus for determining a GNSS picture position based on said GNSS signal samples and providing said picture with said GNSS picture position to a user.

2. The camera of claim 1, wherein:

the digital camera does not include a code correlator for correlating said GNSS signal samples with a GNSS replica code.

3. The camera of claim 1, wherein:

said time uncertainty window is greater than thirty seconds.

4. The camera of claim 1, wherein:

said time uncertainty window may be up to at least twelve hours.

5. The camera of claim 1, wherein:

said GNSS signal samples represent said GNSS signals for a time period less than a time length between transmissions of encoded data bits having a GNSS system clock time.

6. The camera of claim 5, wherein:

said GNSS signal samples represent less than six seconds of said GNSS signals.

7. The camera of claim 1, wherein:

said picture data file medium is readable by said computer apparatus for determining code phase offsets for said GNSS satellites from said GNSS signal samples;

using said time tag for estimating velocities for said GNSS satellites; and

using said code phase offsets and said estimated velocities for determining said GNSS picture position.

8. The camera of claim 7, wherein:

said picture data file medium is further readable by said computer apparatus for receiving said GNSS signal samples for K said GNSS satellites, said K at least five, in a form to be used by said computer apparatus with said K said GNSS satellite velocities for a resolution of a receiver time error within said time uncertainty window, a replica clocking offset for said code phase offsets, and said GNSS picture position.

9. The camera of claim 8, wherein:

said computer apparatus is constructed for using said GNSS satellite velocities for a satellite velocity positioning matrix having K row vectors corresponding to K said satellites, respectively, and five columns, said five columns including three said columns for estimated unit vectors between an estimated said GNSS picture position and estimated locations-in-space of said K GNSS satellites, one said column for a constant, and one said column for estimated range rates between said estimated GNSS picture position and said estimated locations-in-space of said K GNSS satellites; and

then using said satellite velocity positioning matrix and said code phase offsets for said resolution.

10. The camera of claim 1, wherein:

said picture data file medium further includes data representative of an altitude; and

said computer apparatus is constructed for using said altitude with said GNSS signal samples for determining said GNSS picture position.

11. A method for providing a global navigation satellite system (GNSS)-based position for a picture, comprising:

converting a scene into digital picture data;

sampling GNSS signals from GNSS satellites;

generating a time tag for said GNSS signal samples, said time tag having a time uncertainty window greater than a time length of a frame of data bits for said GNSS signals; and

writing said picture data in association with said GNSS signal samples and said time tag into a computer-readable picture data file medium in a configuration for processing by a computer apparatus for determining a GNSS picture position based on said GNSS signal samples and providing said picture with said GNSS picture position to a user.

12. The method of claim 11, wherein:

providing a digital camera for writing said picture data with said GNSS signal samples and said time tag into said picture data file medium, said digital camera not having a code correlator for correlating said GNSS signal samples with a GNSS replica code.

13. The method of claim 11, wherein:

said time uncertainty window is greater than thirty seconds.

14. The method of claim 11, wherein:

said time uncertainty window may be up to at least twelve hours.

15. The method of claim 11, wherein:

said GNSS signal samples represent said GNSS signals for a time period less than a time period between transmissions of encoded data bits having a GNSS system clock time.

16. The method of claim 15, wherein:

said GNSS signal samples represent less than six seconds of said GNSS signals.

17. The method of claim 11, wherein:

writing into said picture data file medium includes configuring said picture data file medium for processing by said computer apparatus for determining code phase offsets for said GNSS satellites from said GNSS signal samples;

using said time tag for estimating velocities for said GNSS satellites; and

using said code phase offsets and said estimated velocities for determining said GNSS picture position.

18. The method of claim 17, wherein:

writing said picture data file medium further includes configuring said picture data file medium for providing said GNSS signal samples for K said GNSS satellites, said K at least five, in a form to be used by said computer apparatus with said K said GNSS satellite velocities for a resolution of a receiver time error within said time uncertainty window, a replica clocking offset for said code phase offsets, and said GNSS picture position.

19. The method of claim 18, wherein:

said computer apparatus is constructed for using orbital satellite parameters for determining a satellite velocity positioning matrix having K row vectors corresponding to K said satellites, respectively, and five columns, said five columns including three said columns for estimated unit vectors between an estimated said GNSS picture position and estimated locations-in-space of said K GNSS satellites, one said column for a constant, and one said column for estimated range rates between said estimated GNSS picture position and said estimated locations-in-space of said K GNSS satellites, said estimated range rates computed from said estimated unit vectors and said estimated satellite velocities; and

then using said satellite velocity positioning matrix and said code phase offsets for said resolution.

20. The method of claim 11, wherein:

writing data representative of an altitude into said picture data file medium; and

said computer apparatus is constructed for using said altitude with said GNSS signal samples for determining said GNSS picture position.

21. A tangible medium having computer-readable instructions for reading by a computer for carrying out the following steps:

converting a scene into digital picture data;

sampling GNSS signals from GNSS satellites;

generating a time tag for said GNSS signal samples, said time tag having a time uncertainty window greater than a time length of a frame of data bits for said GNSS signals; and

writing said picture data in association with said GNSS signal samples and said time tag into a computer-readable picture data file medium in a configuration for processing by a computer apparatus for determining a GNSS picture position based on said GNSS signal samples and providing said picture with said GNSS picture position to a user.