Batch processing for improved georeferencing
Crowd-sourced location data from client devices is processed using enhanced filtering techniques in non-realtime by a centralized server process to improve the accuracy and reliability of georeferenced geodata. At a server computer, enhanced filtering techniques make use of future information to improve georeferencing of the geodata. In some implementations, the server computer can be configured to implement batch processing of raw GNSS data and other crowd-sourced location data (e.g., wireless scan data, inertial sensor data) using, for example, a smoothing filter or batch estimator. Augmentation data (e.g., satellite ephemeris data, clock offset and ionospheric delay) and sensor data independent of client devices can also be used by the server computer to augment the crowd-sourced location data to further improve georeferencing of geodata.
1. A method comprising:
receiving, by a server computer, raw Global Navigation Satellite System (GNSS) data and wireless scan data obtained from client devices in communication with a wireless network, where the wireless scan data is received from one or more wireless access points of the wire network, and where the raw GNSS data is crowd-sourced, by the server computer from GNSS receivers of the client devices and includes at least one of pseudo-range measurements, delta pseudo-range measurements or Doppler shift measurements;
georeferencing, by the server computer, the one or more wireless access points using raw GNSS data and wireless scan data; and
sending, by the server computer, the georeferenced locations of the wireless access points to a client device.
2. The method of claim 1 , further comprising:
receiving augmentation data from sources other than the client devices; and
georeferencing the one or more wireless access points using the raw GNSS data, wireless scan data and the augmentation data.
3. The method of claim 2 , where the augmentation data includes data for reducing spatially or temporally correlated measurement error sources.
4. The method of claim 2 , where the augmentation data includes data related to time or GNSS satellites.
5. The method of claim 2 , where the augmentation data includes differential Global Positioning System (DGPS) data.
6. The method of claim 1 , wherein georeferencing the one or more wireless access points using the raw GNSS data and wireless scan data includes processing the crowd-sourced data using batch estimation or a smoothing filter.
7. The method of claim 6 , wherein the smoothing filter includes a forward pass estimation followed by a backward recursion.
8. The method of claim 6 , wherein the batch estimation includes iterative least-squares estimation.
9. The method of claim 1 , further comprising:
georeferencing a structure in a multipath environment based on the crowd-sourced raw GNSS data and a radio frequency signature; and
updating a map database with the georeferenced structure.
10. A method comprising:
sending, by a client device, a request to a server computer for estimated locations of wireless access points detected in a wireless scan by the client device;
receiving estimated locations of the wireless access points from the server computer, where the estimated locations are derived from at least one of pseudo-range measurements, delta pseudo-range measurements or Doppler shift measurements crowd-sourced, by the server computer from a plurality of Global Navigation Satellite System (GNSS) receivers; and
calculating an estimated location of the client device using the estimated locations of the wireless access points, where the method is performed by one or more hardware processors.
11. A system comprising:
one or more processors;
memory coupled to the one or more processors and configured for storing instructions, which, when executed by the one or more processors, causes the one or more processors to perform operations comprising:
receiving raw Global Navigation Satellite System (GNSS) data and wireless scan data obtained from client devices in communication with a wireless network, where the wireless scan data is received from one or more wireless access points of the wireless network, and where the raw GNSS data is crowd-sourced, by the server computer from GNSS receivers of the client devices and includes at least one of pseudo-range measurements, delta pseudo-range measurements or Doppler shift measurements;
georeferencing the one or more wireless access points using the raw GNSS data and wireless scan data; and
sending, by the server computer, the georeferenced locations of the wireless access points to a client device.
12. The system of claim 11 , further comprising:
receiving augmentation data from sources other than the client devices; and
georeferencing the one or more wireless access points using the raw GNSS data, wireless scan data and the augmentation data.
13. The system of claim 12 , where the augmentation data includes data for reducing spatially or temporally correlated measurement error sources.
14. The system of claim 12 , where the augmentation data includes data related to time or GNSS satellites.
15. The system of claim 12 , where the augmentation data includes differential Global Positioning System (DGPS) data.
16. The system of claim 11 , wherein georeferencing the one or more wireless access points using the raw GNSS data and wireless scan data includes processing the crowd-sourced data using batch estimation or a smoothing filter.
17. The system of claim 16 , wherein the smoothing filter includes a forward pass estimation followed by a backward recursion.
18. The system of claim 16 , wherein the batch estimation includes iterative least-squares estimation.
19. The system of claim 11 , further comprising:
georeferencing a structure in a multipath environment based on the crowd-sourced raw GNSS data and a radio frequency signature; and
updating a map database with the georeferenced structure.
20. An apparatus comprising:
one or more processors; and
memory coupled to the one or more processors and configured for storing instructions, which, when executed by the one or more processors, causes the one or more processors to perform operations comprising:
sending a request to a server computer for estimated locations of wireless access points detected in a wireless scan by the apparatus;
receiving estimated locations of the wireless access points from the server computer, where the estimated locations are derived from at least one of pseudo-range measurements, delta pseudo-range measurements or Doppler shift measurements crowd-sourced, by the server computer from a plurality of Global Navigation Satellite System (GNSS) receivers;
and calculating an estimated location of the apparatus using the estimated locations of the wireless access points.