Systems and methods to determine a location of a mobile device

Abstract

Systems and methods to position beacons at traffic choke points, use a mobile device to detect the peaks of beacon signals corresponding to the mobile device traveling through the traffic “choke points”, and thus determine accurately the position and speed of the mobile device in the transport corridor between the choke points. The determined position and speed of the mobile device can be used to improve the performance of other location determination technologies, such as radio frequency fingerprint-based location estimate and/or inertial guidance location estimate.

1 . A method, comprising:
 determining a mobile device being at the first location at a first time period based on a peak of beacon signal power from a first beacon device at a first location of a transport corridor in a multi-floor environment;   determining the mobile device being the second location at a second time period instance based on a peak of beacon signal power from a second beacon device at a second location of the transport corridor;   correlating movement of the mobile device from the first location to the second location with a predetermined traffic speed along the corridor; and   determining a position and a speed of the mobile device at a time period based on the movement of the mobile device from the first location to the second location along the corridor.   
     
     
         2 . The method of  claim 1 , further comprising:
 calibrating, based on the position and the speed of the mobile device, an initial position and an initial speed used in an initial guidance system of the mobile device.   
     
     
         3 . The method of  claim 2 , wherein the mobile device includes motion sensors to measure acceleration and rotation of the mobile device to track a current location of the mobile device from the initial position and the initial speed. 
     
     
         4 . The method of  claim 2 , wherein the position and the speed of the mobile device determined from the movement of the mobile device in the corridor are used as the initial position and the initial speed. 
     
     
         5 . The method of  claim 1 , further comprising:
 improving, based on the position of the mobile device, a position determination result from a radio frequency fingerprint-based location determination system of the mobile device.   
     
     
         6 . The method of  claim 5 , wherein the mobile device includes a transceiver configured to measure a radio frequency fingerprint and the method further comprising determining a location of the mobile device based on correlation the radio frequency fingerprint with a predetermined distribution of radio frequency fingerprints in the multi-floor environment. 
     
     
         7 . The method of  claim 6 , wherein the position of the mobile device determined from the movement of the mobile device in the corridor is used to select a floor from a plurality of floors in the multi-floor environment. 
     
     
         8 . The method of  claim 1 , wherein the transport corridor includes one of:
 a stairway, an escalator, an elevator, an entrance, and an exit.   
     
     
         9 . A system for determining a location of a mobile device, comprising at least one processor and memory that are operable to perform the following method:
 obtaining a radio frequency fingerprint measured by a mobile device;   correlating the radio frequency fingerprint to a predetermined distribution of radio frequency fingerprints in a multi-floor environment;   determining a first location determination result based on the correlating;   obtaining accelerations of the mobile device as a function of time;   determining a second location determination result based on the accelerations;   obtaining, from the mobile device, a first beacon signal from a beacon device disposed at a first location of a transport corridor in the multi-floor environment and a second beacon signal from the beacon device;   determining a first location of the beacon device based on the first beacon signal and a second location of the beacon device based on the second beacon signal; and   computing a location of the mobile device based on the first location of the beacon device, the second location of the beacon device, the first location determination result, and the second location determination result.   
     
     
         10 . The system of  claim 9 , wherein the method further comprises:
 determining a speed of the mobile device based on the first location and the second location of the beacon device;   wherein the second location determination result is determined based at least in part on the speed of the mobile device.   
     
     
         11 . The system of  claim 10 , wherein the transport corridor is one of: an escalator and an elevator. 
     
     
         12 . The system of  claim 11 , wherein the first beacon signal identifies the first location of the beacon device; and the second beacon signal identifies the second location of the beacon device. 
     
     
         13 . The system of  claim 12 , wherein the first location of the beacon device is used to select a floor in the first location determination result. 
     
     
         14 . The system of  claim 9 , wherein the method further comprises:
 obtaining, from the mobile device, a second beacon signal from a second beacon device;   determining a second location of the second beacon device based on the second beacon signal;   determining a speed of the mobile device based on the first location and the second location;   wherein the second location determination result is determined based at least in part on the speed of the mobile device.   
     
     
         15 . A non-transitory computer storage medium storing instructions configured to instruct a computing apparatus to perform a method, the method comprising:
 obtaining a radio frequency fingerprint measured by a mobile device;   correlating the radio frequency fingerprint to a predetermined distribution of radio frequency fingerprints in a multi-floor environment;   determining a first location determination result based on the correlating;   obtaining accelerations of the mobile device as a function of time;   determining a second location determination result based on the accelerations;   obtaining, from the mobile device, a first beacon signal from a beacon device disposed at a first location of a transport corridor in the multi-floor environment and a second beacon signal from the beacon device;   determining a first location of the beacon device based on the first beacon signal and a second location of the beacon device based on the second beacon signal; and   computing a location of the mobile device based on the first location of the beacon device, the second location of the beacon device, the first location determination result, and the second location determination result.   
     
     
         16 . The non-transitory computer storage medium of  claim 15 , wherein the method further comprises:
 determining a speed of the mobile device based on the first location and the second location of the beacon device;   wherein the second location determination result is determined based at least in part on the speed of the mobile device.   
     
     
         17 . The non-transitory computer storage medium of  claim 16 , wherein the transport corridor is one of: an escalator and an elevator. 
     
     
         18 . The non-transitory computer storage medium of  claim 17 , wherein the first beacon signal identifies the first location of the beacon device; and the second beacon signal identifies the second location of the beacon device. 
     
     
         19 . The non-transitory computer storage medium of  claim 18 , wherein the first location of the beacon device is used to select a floor in the first location determination result. 
     
     
         20 . The non-transitory computer storage medium of  claim 15 , wherein the method further comprises:
 obtaining, from the mobile device, a second beacon signal from a second beacon device;   determining a second location of the second beacon device based on the second beacon signal;   determining a speed of the mobile device based on the first location and the second location;   wherein the second location determination result is determined based at least in part on the speed of the mobile device.