GNSS positioning using three-dimensional building models

Patent metadata

Field	Value
Publication number	US-9945956-B2
Application number	US-201514848234-A
Country	US
Kind code	B2
Filing date	Sep 8, 2015
Priority date	Sep 8, 2015
Publication date	Apr 17, 2018
Grant date	Apr 17, 2018

Abstract

Techniques for GNSS positioning using three-dimensional (3D) building models are described. A processor of a mobile device can determine a lower bound of uncertainty for an estimated position of the mobile device. The processor can receive an estimated position from a GNSS receiver of the mobile device. The processor can acquire geographic feature data including 3D building models of buildings and other geographic features that are located near the estimated position and may reflect GNSS signals. The processor can then determine a lower bound of uncertainty of the estimated position, regardless of an estimated uncertainty provided by a GNSS estimator. The lower bound can be higher (e.g., have a greater error margin) than the uncertainty value provided by the GNSS estimator. The processor can then present the estimated position, in association with an error margin corresponding to the lower bound of uncertainty, on a map user interface of the mobile device.

First claim

What is claimed is:

1. A method comprising:
receiving, by a processor of a mobile device and from a global navigation satellite system (GNSS) receiver, an estimated position of the mobile device, the estimated position including estimated geographic coordinates and being associated with an uncertainty value;
receiving geographic feature data, the geographic feature data including locations and heights of geographic features that are located sufficiently close to the estimated position to interfere with signals received by the GNSS receiver;
determining, based on at least one of the locations of the geographic features, a count of the geographic features, or the heights of the geographic features, a lower bound of uncertainty of the estimated position that is achievable by the GNSS receiver when the GNSS receiver is located among the geographic features;
determining, based on the lower bound of uncertainty, a new estimated position of the mobile device; and
designating a representation of the lower bound of uncertainty as a representation of uncertainty of the new estimated position of the mobile device.

2. The method of claim 1 , wherein receiving geographic feature data comprises:
determining a signal environment tile based on the estimated position, the signal environment tile representing geographic features located in a geographic region that may interfere with GNSS signal reception, the geographic region being an area surrounding the estimated position;
determining, based on a tile category of the signal environment tile, that the geographic feature data of the signal environment tile can improve position estimate;
submitting the estimated position or an identifier of the signal environment tile to a signal environment tile database, the signal environment tile database storing three-dimensional models on geographic features, the three-dimensional models being organized as a plurality of signal environment tiles; and
receiving the geographic feature data corresponding to the signal environment tile.

3. The method of claim 2 , wherein determining the lower bound of uncertainty of the estimated position comprises determining the lower bound based on a predetermined factor and a width of an average road located in the geographic region enclosing the estimated position.

4. The method of claim 1 , wherein determining the lower bound of uncertainty comprises:
determining satellites that visible by the GNSS receiver at the estimated position;
determining a weight dilution of precision based on the visible satellites; and
determining the lower bound of uncertainty based on the weight dilution of precision.

5. The method of claim 1 , wherein determining the lower bound of uncertainty comprises:
determining whether the count of the geographic features located sufficiently close to the GNSS receiver to interfere reception of the GNSS signals satisfies a feature count threshold;
determining whether an average of heights of the geographic features located sufficiently close to the GNSS receiver to interfere reception of the GNSS signals satisfies a feature height threshold; and
determining the lower bound of uncertainty when both the feature count threshold and feature height are satisfied.

6. The method of claim 1 , comprising:
determining that the estimated geographic coordinates indicate a position inside of a geographic feature; and
designating a set of geographic coordinates outside of the geographic feature as new estimated geographic coordinates of the estimated position.

7. The method of claim 1 , comprising displaying a representation of the estimated position on a map displayed on the mobile device, wherein a size of an area of the estimated position represents the lower bound of uncertainty.

8. A mobile device comprising:
a global navigation satellite system (GNSS) receiver including an interface to adjust coherent integration interval of processing GNSS signals;
one or more processors; and
a non-transitory computer-readable medium storing instructions that, when executed by the one or more processors, cause the one or more processors to perform operations comprising:
receiving, by a processor of the mobile device and from the global navigation satellite system (GNSS) receiver, an estimated position of the mobile device, the estimated position including estimated geographic coordinates and being associated with an uncertainty value;

receiving geographic feature data, the geographic feature data including locations and heights of geographic features that are located sufficiently close to the estimated position to interfere with signals received by the GNSS receiver;
determining, based on at least one of the locations of the geographic features, a count of the geographic features, or the heights of the geographic features, a lower bound of uncertainty of the estimated position that is achievable by the GNSS receiver when the GNSS receiver is located among the geographic features;
determining, based on the lower bound of uncertainty, a new estimated position of the mobile device; and
designating a representation of the lower bound of uncertainty as a representation of uncertainty of the new estimated position of the mobile device.

9. The mobile device of claim 8 , wherein receiving geographic feature data comprises:
determining a signal environment tile based on the estimated position, the signal environment tile representing geographic features located in a geographic region that may interfere with GNSS signal reception, the geographic region being an area surrounding the estimated position;
determining, based on a tile category of the signal environment tile, that the geographic feature data of the signal environment tile can improve position estimate;
submitting the estimated position or an identifier of the signal environment tile to a signal environment tile database, the signal environment tile database storing three-dimensional models on geographic features, the three-dimensional models being organized as a plurality of signal environment tiles; and
receiving the geographic feature data corresponding to the signal environment tile.

10. The mobile device of claim 9 , wherein determining the lower bound of uncertainty of the estimated position comprises determining the lower bound based on a predetermined factor and a width of an average road located in the geographic region enclosing the estimated position.

11. The mobile device of claim 8 , wherein determining the lower bound of uncertainty comprises:
determining satellites that visible by the GNSS receiver at the estimated position;
determining a weight dilution of precision based on the visible satellites; and
determining the lower bound of uncertainty based on the weight dilution of precision.

12. The mobile device of claim 8 , wherein determining the lower bound of uncertainty comprises:
determining whether the count of the geographic features located sufficiently close to the GNSS receiver to interfere reception of the GNSS signals satisfies a feature count threshold;
determining whether an average of heights of the geographic features located sufficiently close to the GNSS receiver to interfere reception of the GNSS signals satisfies a feature height threshold; and
determining the lower bound of uncertainty when both the feature count threshold and feature height are satisfied.

13. A non-transitory computer-readable medium storing instructions that, when executed by one or more processors, cause the one or more processors to perform operations comprising:
receiving geographic information on geographic features in a geographic area, the geographic

Assignees

• Apple Inc

Inventors

• Chhokra Kumar Gaurav
• Macgougan Glenn Donald

Classifications

• G01S19/428

  using multipath or indirect path propagation signals in position determination · CPC title

• G01S19/396 Primary

  Determining accuracy or reliability of position or pseudorange measurements · CPC title

• G01S19/52

  Determining velocity · CPC title

• G01S19/42

  Determining position · CPC title

• G01S19/22

  Multipath-related issues · CPC title