Mitigating effects of multipath during position computation

Patent metadata

Field	Value
Publication number	US-9720071-B2
Application number	US-201514882652-A
Country	US
Kind code	B2
Filing date	Oct 14, 2015
Priority date	Oct 20, 2014
Publication date	Aug 1, 2017
Grant date	Aug 1, 2017

Abstract

Estimating an unknown position of a receiver. In some embodiment, trilateration techniques that quantify uncertainty in the estimate of the unknown position are applied. One such technique for estimating a two-dimensional or three-dimensional position of a receiver uses an L-1 norm computation instead of an L-2 norm computation.

First claim

The invention claimed is:

1. A computer-implemented method for determining how to estimate one or more positions of a receiver, wherein the method comprises:
determining whether to estimate a first latitude and a first longitude of a first position of the receiver using a first objective function that calculates an L-1 norm of residuals or a second objective function that calculates an L-2 norm of residuals,
wherein the determination is based on one or more of:—(1) data specifying a geographical region in which the receiver is located, (2) data specifying whether the receiver is indoors or outdoors, or (3) data specifying whether a signal received by the receiver from a transmitter meets a predefined multipath condition.

2. The method of claim 1 , wherein determining whether to estimate the first latitude and the first longitude using the first objective function or the second objective function comprises:
determining to use the first objective function instead of the second objective function to estimate the first latitude and the first longitude based on a cell ID, one or more satellite signals, or one or more local area network signals; and
after determining to use the first objective function instead of the second objective function to estimate the first latitude and the first longitude, estimating the first latitude and the first longitude using the first objective function.

3. The method of claim 1 , wherein determining whether to estimate the first latitude and the first longitude using the first objective function or the second objective function comprises:
determining whether to estimate the first latitude and the first longitude using the first objective function or the second objective function based on the data specifying the geographical region in which the receiver is located;
determining to use the first objective function instead of the second objective function to estimate the first latitude and the first longitude when the data specifying the geographical region in which the receiver is located indicates that the receiver is located in a first type of environment of at least two types of environments; and
after determining to use the first objective function instead of the second objective function to estimate the first latitude and the first longitude, estimating the first latitude and the first longitude using the first objective function.

4. The method of claim 1 , wherein determining whether to estimate the first latitude and the first longitude using the first objective function or the second objective function comprises:
determining whether to estimate the first latitude and the first longitude using the first objective function or the second objective function based on the data specifying the geographical region in which the receiver is located;
determining to use the first objective function instead of the second objective function to estimate the first latitude and the first longitude when the data specifying the geographical region in which the receiver is located indicates that the geographical region includes more than a predefined number of buildings with heights that exceed a threshold height; and
after determining to use the first objective function instead of the second objective function to estimate the first latitude and the first longitude, estimating the first latitude and the first longitude using the first objective function.

5. The method of claim 1 , wherein determining whether to estimate the first latitude and the first longitude using the first objective function or the second objective function comprises:
determining whether to estimate the first latitude and the first longitude using the first objective function or the second objective function based on the data specifying whether the receiver is indoors or outdoors;
determining to use the first objective function instead of the second objective function to estimate the first latitude and the first longitude when the data specifying whether the receiver is indoors or outdoors indicates that the receiver is indoors; and
after determining to use the first objective function instead of the second objective function to estimate the first latitude and the first longitude, estimating the first latitude and the first longitude using the first objective function.

6. The method of claim 1 , wherein determining whether to estimate the first latitude and the first longitude using the first objective function or the second objective function comprises:
determining whether to estimate the first latitude and the first longitude using the first objective function or the second objective function based on the data specifying whether the signal received by the receiver from the transmitter meets the predefined multipath condition;
determining to use the first objective function instead of the second objective function to estimate the first latitude and the first longitude when the data specifying whether the signal received by the receiver meets the predefined multipath condition indicates that the signal meets the predefined multipath condition; and
after determining to use the first objective function instead of the second objective function to estimate the first latitude and the first longitude, estimating the first latitude and the first longitude using the first objective function.

7. The method of claim 1 , wherein determining whether to estimate the first latitude and the first longitude using the first objective function or the second objective function comprises:
determining whether to estimate the first latitude and the first longitude using the first objective function or the second objective function based on the data specifying whether the signal received by the receiver from the transmitter meets the predefined multipath condition;
determining to use the first objective function instead of the second objective function to estimate the first latitude and the first longitude when the data specifying whether the signal received by the receiver meets the predefined multipath condition indicates that a pseudorange measurements corresponding to the signals includes a multipath error that exceeds a threshold amount of error; and
after determining to use the first objective function instead of the second objective function to estimate the first latitude and the first longitude, estimating the first latitude and the first longitude using the first objective function.

8. The method of claim 1 , wherein the method further comprises:
estimating a second latitude and a second longitude of a second position of the receiver using the first objective function;
estimating the second latitude and the second longitude using the second objective function;
using a sensor of the receiver to estimate movement of the receiver to the second position from a previously occupied position of the receiver;
selecting, based on the estimated movement, either the estimates of the second latitude and the second longitude resulting from the first objective function, or the estimates of the second latitude and second first longitude resulting from the second objective function; and
using the selected estimates to generate an estimate of the second position of the receiver.

9. The method of claim 1 , wherein the method further comprises:
estimating a second latitude and a second longitude of a second position of the receiver using the first objective function;
estimating the second latitude and the second longitude using the second objective function;
using a sensor of the receiver to estimate movement of the receiver to the second position from a previously occupied position of the receiver;
estimating the second latitude and the second longitude usi

Assignees

• Nextnav Llc

Inventors

• Sendonaris Andrew
• Raghupathy Arun

Classifications

• G01S5/0218

  Multipath in signal reception · CPC title

• G01S5/0215

  Interference · CPC title

• G01S5/10 Primary

  Position of receiver fixed by co-ordinating a plurality of position lines defined by path-difference measurements {, e.g. omega or decca systems}(G01S5/12 takes precedence {; beacons and receivers cooperating therewith G01S1/306, G01S1/308}) · CPC title

• G01S19/428

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

• G01S19/22 Primary

  Multipath-related issues · CPC title