Accounting for atmospheric and terrestrial obstacles in geographic positioning
A position fix identifying a geographic location of a receiver is received. The position fix was generated using signals received at the receiver from respective high-altitude signal sources (such as satellites). Imagery of a geographic area that includes the geographic location is also received. The imagery is automatically processed to determine whether one or more of the high-altitude signal sources were occluded from the geographic location when the position fix was generated. In response to determining that one or more of the high-altitude signal sources were occluded from the geographic location when the position fix was generated, the position fix is identified as being potentially erroneous.
1. A computer-based method for improved geopositioning of a receiver that receives positioning signals from signal sources, the method comprising:
evaluating at least one candidate position fix that identifies a geographic location, wherein evaluating the at least one candidate position fix includes:
for a first signal source generating a first candidate position fix using the positioning signals that correspond to the first signal source,
using imagery of a geographic area associated with the geographic location, determining whether the first signal source has an unobstructed line-of-sight to the geographic location when the first candidate position fix was generated, and
wherein if the first signal source has an obstructed line-of-sight to the geographic location, selecting a second signal source that does not have an obstructed line-of-sight based on the evaluating; and
generating a position fix using one or more candidate position fixes for the first signal source if the first signal source had an unobstructed line-of-sight to a respective geographic location or the second signal source if the first signal source has an obstructed line-of-sight to the respective geographic location.
2. The method of claim 1 , wherein the first signal source is a subset of signal sources selected from among the signal sources and the second signal source is a new subset of signal sources selected from among the signal sources.
3. The method of claim 2 , wherein the subset of signal sources corresponds to a minimum number of signal sources required to generate the positioning fix.
4. The method of claim 1 , wherein the signal sources are satellites associated with Global Positioning Service (GPS).
5. The method of claim 1 , wherein using the imagery of the geographic area include using a satellite photograph of an area that encompasses geographic locations corresponding to the candidate position fixes.
6. The method of claim 1 , wherein using the imagery of the geographic area includes using panoramic photographs captured at a surface level.
7. The method of claim 6 , wherein metadata is included with the panoramic photographs.
8. The method of claim 7 , wherein the metadata relates to color depth or image resolution.
9. The method of claim 1 , wherein generating the position fix includes:
identifying a plurality of candidate position fixes of the at least one candidate position fix for the first signal source if the first signal source had an unobstructed line-of-sight to the respective geographic location or the second signal source if the first signal source has the obstructed line-of-sight to the respective geographic location, and
calculating an average of the identified plurality of candidate position fixes to generate the position fix.
10. The method of claim 1 , wherein generating the position fix includes:
identifying the one or more candidate position fixes for the first signal source if the first signal source had an unobstructed line-of-sight to the respective geographic location or the second signal source if the first signal source has the obstructed line-of-sight to the respective geographic location, and
selecting at least one of the one or more candidate position fixes as the position fix.
11. A system, comprising:
one or more processors, the one or more processors configured to:
evaluate at least one candidate position fix that identifies a geographic location, wherein evaluating the at least one candidate position fix includes:
for a first signal source generating a first candidate position fix using positioning signals that correspond to the first signal source,
using imagery of a geographic area associated with the geographic location, determining whether the first signal source has an unobstructed line-of-sight to the geographic location when the first candidate position fix was generated, and
wherein if the first signal source has an obstructed line-of-sight to the geographic location, select a second signal source that does not have an obstructed line-of-sight based on the evaluating; and
generate a position fix using one or more candidate position fixes for the first signal source if the first signal source had an unobstructed line-of-sight to a respective geographic location or the second signal source if the first signal source has an obstructed line-of-sight to the respective geographic location.
12. The system of claim 11 , wherein the first signal source is a subset of signal sources selected from among signal sources and the second signal source is a new subset of signal sources selected from among the signal sources.
13. The system of claim 12 , wherein the subset of signal sources corresponds to a minimum number of signal sources required to generate the positioning fix.
14. The system of claim 11 , wherein the signal sources are satellites associated with Global Positioning Service (GPS).
15. The system of claim 11 , wherein using the imagery of the geographic area include using a satellite photograph of an area that encompasses geographic locations corresponding to the candidate position fixes.
16. The system of claim 11 , wherein using the imagery of the geographic area includes using panoramic photographs captured at a surface level.
17. The system of claim 16 , wherein:
metadata is included with the panoramic photographs, and
the metadata relates to color depth or image resolution.
18. The system of claim 11 , wherein generating the position fix includes:
identifying a plurality of candidate position fixes of the at least one candidate position fix for the first signal source if the first signal source had an unobstructed line-of-sight to the respective geographic location or the second signal source if the first signal source has the obstructed line-of-sight to the respective geographic location, and
calculating an average of the identified plurality of candidate position fixes to generate the position fix.
19. The system of claim 11 , wherein generating the position fix includes:
identifying the one or more candidate position fixes for the first signal source if the first signal source had an unobstructed line-of-sight to the respective geographic location or the second signal source if the first signal source has the obstructed line-of-sight to the respective geographic location, and
selecting at least one of the one or more candidate position fixes as the position fix.
20. A computer-readable medium storing instructions, which when executed by one or more processors, cause the one or more processors to:
evaluate at least one candidate position fix that identifies a geographic location, wherein evaluating the at least one candidate position fix includes:
for a first signal source generating a first candidate position fix using the positioning signals that correspond to the first signal source,
using imagery of a geographic area associated with the geographic location, determining whether the first signal source has an unobstructed line-of-sight to the geographic location when the first candidate position fix was generated, and
wherein if the first signal source has an obstructed line-of-sight to the geographic location, select a second signal source that does not have an obstructed line-of-sight based on the evaluating; and
generate a position fix using one or more candidate position fixes for the first signal source if the first signal source had an unobstructed line-of-sight to a respective geographic location or the second signal source if the first signal source has an obstructed line-of-sight to the respective geographic location.