PERFORMANCE ENHANCEMENTS FOR LOCAL NETWORK OF BEACONS

1 . A method for estimating one or more positions of a receiver in a network of beacons, the method comprising:

determining a first position estimate of a receiver based on a first set of range measurements corresponding to a network of beacons;

setting a current position of the receiver to the first position estimate;

determining a second position estimate of the receiver based on a second set of range measurements corresponding to the network of beacons;

determining whether the second position estimate is within a predefined area associated with the network of beacons;

when the second position estimate is inside the predefined area:

setting the current position of the receiver as the second position estimate; and

when the second position estimate is not inside the predefined area:

determining a third position estimate of the receiver based on the first position estimate and a first measurement of velocity associated with a first movement of the receiver, and

setting the current position of the receiver as the third position estimate.

2 . The method of claim 1 , wherein after determining the third position estimate, the method comprises:

determining a fourth position estimate of the receiver based on a third set of range measurements corresponding to the network of beacons;

determining whether the fourth position estimate is within the predefined area;

when the fourth position estimate is inside the predefined area:

setting the current position of the receiver as the fourth position estimate; and

when the fourth position estimate is not inside the predefined area:

determining a fifth position estimate of the receiver based on the third position estimate and a second measurement of velocity associated with a second movement of the receiver, and

setting the current position of the receiver as the fifth position estimate.

3 . The method of claim 1 , wherein after determining that the second position estimate is not inside the predefined area, the method comprises:

incrementing a value of a counter.

4 . The method of claim 3 , wherein after incrementing the counter, the method comprises:

determining a fourth position estimate of the receiver based on a third set of range measurements corresponding to the network of beacons;

determining whether the fourth position estimate is within the predefined area;

when the fourth position estimate is inside the predefined area:

setting the current position of the receiver as the fourth position estimate;

when the fourth position estimate is not inside the predefined area:

determining whether the value of the counter meets a threshold condition; and

after determining that the value of the counter does not meet the threshold condition:

determining a fifth position estimate of the receiver based on the third position estimate and a second measurement of velocity associated with a second movement of the receiver, and

setting the current position of the receiver as the fifth position estimate.

5 . The method of claim 4 , wherein after determining that the value of the counter meets the threshold condition, the method comprises: resetting a Kalman filter.

6 . The method of claim 1 , wherein the predefined area is defined by a bounding box formed by the network of beacons.

7 . The method of claim 1 , wherein additional position estimates are determined based on additional measurements of velocity until process noise associated with a Kalman filter reaches a pre-determined amount of process noise, at which point the Kalman filter is reset.

8 . The method of claim 1 , wherein additional position estimates are determined based on additional measurements of velocity until a value of a counter reaches a pre-determined threshold value, at which point the Kalman filter is reset.

9 . The method of claim 1 , wherein the third position estimate is further based on a map of a venue within which the network of beacons is resides.

10 . The method of claim 1 , wherein the network of beacons is disposed inside a building, wherein the network of beacons includes a first beacon that is synchronized to GPS time via a GPS antenna disposed on top of the building, and wherein the network of beacons includes other beacons that synchronize to GPS time based on a timing signal transmitted by the first beacon.

11 . The method of claim 1 , wherein the network of beacons includes at least one beacon coupled to an n-way switch that sends signals to n antennas in n different time slots.

12 . The method of claim 1 , wherein the method further comprises:

comparing atmospheric data from the receiver with atmospheric measurements corresponding to one or more regions of the network of beacons; and

identifying a candidate position estimate based on the comparison between the atmospheric data from the receiver and the atmospheric measurements corresponding to the one or more regions of the network of beacons.

13 . A system comprising one or more processors that perform the method of claim 1 .

14 . A non-transitory machine-readable medium embodying program instructions adapted to be executed to implement the method of claim 1 .