Terrestrial positioning system calibration

Patent metadata

Field	Value
Publication number	US-9237417-B2
Application number	US-201414173717-A
Country	US
Kind code	B2
Filing date	Feb 5, 2014
Priority date	Feb 7, 2013
Publication date	Jan 12, 2016
Grant date	Jan 12, 2016

Abstract

Embodiments disclosed aggregate a plurality of crowdsourced measurement sets for antennas received from a plurality of Mobile Stations (MS) with a Base Station Almanac (BSA), based on a measurement location estimate and a measurement location uncertainty estimate associated with each measurement set. A map comprising a plurality of map layers may be obtained, where each map layer associates locations in the BSA with spatially variable Forward Link Calibration (FLC) values for the antenna derived from the updated BSA data, wherein each spatially variable FLC value is associated with a corresponding location in the updated BSA data. Map layers, which may also include multipath map and/or received signal strength layers, may be provided to MS′ as location assistance data.

First claim

What is claimed is:

1. A method on a Mobile Station (MS) comprising:
obtaining location assistance data comprising a map with a first plurality of map layers, wherein each map layer in the first plurality of map layers associates location entries in a Base Station Almanac (BSA) with spatially variable Forward Link Calibration (FLC) values for an antenna;
performing, based on the location assistance data, measurements to obtain a measurement set comprising signal measurements for the antenna, wherein a calibration comprising at least one spatially variable FLC value in the location assistance data is applied to at least one measurement in the measurement set; and
sending the measurement set to a BSA server.

2. The method of claim 1 , wherein obtaining the location assistance data comprises:
requesting, based on a location estimate and a location uncertainty estimate for a position of the MS, at least one map layer of the first plurality of map layers from a network entity.

3. The method of claim 1 , wherein performing measurements to obtain the measurement set comprises selecting a signal acquisition strategy based upon: an expected accuracy of the signal measurements for the antenna specified in at least one map layer of the first plurality of map layers, and an a priori location estimate for the MS.

4. The method of claim 3 , wherein the a priori location estimate of the MS is determined based, at least in part on, at least one of:
a recent location of the MS; or
bounding coverage area information for the antenna in the BSA, the bounding coverage area information comprising received signal strength information for the antenna;
a Global Navigation Satellite System (GNSS) position fix; or
a hybrid position fix obtained from a combination of GNSS and non-GNSS positioning sources, the non-GNSS sources positioning comprising one or more of terrestrial transmitters or sensors; or
a previously computed location of the MS.

5. The method of claim 3 , further comprising:
computing a refined location of the MS and a refined location uncertainty by applying the calibration to the measurement set, wherein the at least one spatially variable FLC value used for the calibration corresponds to an FLC value for the a priori position estimate.

6. The method of claim 5 , further comprising:
requesting, based on the refined location and the refined location uncertainty of the MS, at least one additional map layer of the first plurality of map layers as the location assistance data.

7. The method of claim 6 , wherein:
the at least one additional map layer provides information at a granularity corresponding to the refined location and the refined location uncertainty.

8. The method of claim 1 , wherein the map comprises a second plurality of map layers, wherein the second plurality of map layers comprise at least one of:
a received signal strength map layer, the received signal strength layer correlating a received signal strength with map locations, or
a Signal to Noise Ratio (SNR) map layer, the SNR map layer correlating SNRs with map locations, or
a Line of Sight (LOS) map layer, the LOS map layer indicating map locations where LOS conditions are likely with respect to one or more antennas, or
a Non-Line of Sight map layer, the NLOS map layer indicating map locations where NLOS or body blocked conditions are likely with respect to one or more antennas,
a multipath map layer, the multipath map layer further providing an indication of an extent of multipath for the antenna for location entries in the BSA, or
a received signal strength layer, the received signal strength layer further providing an indication of expected absolute received signal strength for the antenna for location entries in the BSA.

9. The method of claim 1 , wherein the map comprises a second plurality of map layers, wherein the second plurality of map layers comprise at least one multipath layer to provide an indication of an extent of multipath for the antenna for location entries in the BSA, wherein the at least one multipath layer comprises at least one of:
a long shadow layer to indicate long shadow regions for the antenna, the long shadow layer further comprising exclusion zones, an indication of a magnitude of multipath, and signal attenuation levels for the antenna in the long shadow regions; or
a short shadow layer to indicate short shadow regions for the antenna, the short shadow layer further comprising timing granularity information for antenna signals in the short shadow regions; or
a transmitting pattern layer to indicate unique transmission patterns in at least one coverage area of the antenna.

10. A Mobile Station (MS) comprising:
a processor, wherein the processor is configured to:
obtain location assistance data comprising a map with a first plurality of map layers, wherein each map layer in the first plurality of map layers associates location entries in a Base Station Almanac (BSA) with spatially variable Forward Link Calibration (FLC) values for an antenna, and
perform, based on the location assistance data, measurements to obtain a measurement set comprising signal measurements for the antenna, wherein a calibration comprising at least one spatially variable FLC value in the location assistance data is applied to at least one measurement in the measurement set; and

a transceiver coupled to the processor, the transceiver to send the measurement set to a BSA server.

11. The MS of claim 10 , wherein, to obtain the location assistance data comprising the map, the processor is configured to:
request, based on a location estimate and a location uncertainty estimate for a measurement position of the MS, at least one map layer of the first plurality of map layers from a network entity.

12. The MS of claim 10 , wherein, to perform measurements to obtain the measurement set, the processor is configured to:
select a signal acquisition strategy based upon: an expected accuracy of the signal measurements for the antenna specified in at least one map layer of the first plurality of map layers, and an a priori location estimate for the MS.

13. The MS of claim 12 , wherein the a priori location estimate of the MS is determined based, at least in part on, at least one of:
a recent location of the MS; or
bounding coverage area information for the antenna in the BSA, the bounding coverage area information comprising received signal strength information for the antenna;
a Global Navigation Satellite System (GNSS) position fix; or
a hybrid position fix obtained from a combination of GNSS and non-GNSS positioning sources, the non-GNSS positioning sources comprising one or more of terrestrial transmitters or sensors; or
a previously computed location of the MS.

14. The MS of claim 12 , wherein the processor is further configured to:
compute a refined location of the MS and a refined location uncertainty by applying the calibration to the measurement set, wherein the at least one spatially variable FLC value used for the calibration corresponds to an FLC value for the a priori position estimate.

15. The MS of claim 14 , wherein the processor is further configured to:
request, based on the refined location and the refined location uncertainty of the MS, at least one additional map layer of the first plurality of map layers as the location assistance data.

16. The MS of claim 15 , wherein the at least one additional map layer provides information at a granularity corresponding to the refined location and the refined location uncertainty.

17. The MS of claim 10 , wherein the map co

Assignees

• Qualcomm Inc

Inventors

• Marshall Grant Alexander
• Moeglein Mark Leo

Classifications

• G01S5/0218

  Multipath in signal reception · CPC title

• G01S5/02525

  Gathering the radio frequency fingerprints · CPC title

• G01S5/0215

  Interference · CPC title

• G01S5/0236

  Assistance data, e.g. base station almanac · CPC title

• G01S5/0252

  Radio frequency fingerprinting · CPC title