Methods and systems for position tracking

Abstract

Various embodiments are described herein for methods and systems that can be used to track a position of a mobile receiver on a production line. In one example embodiment, the position of the mobile receiver is tracked by receiving at least one information signal from at least one location tag from among a plurality of location tags positioned at fixed locations along the length of a conveyor belt in a production line, by determining a signal strength of the at least one information signal, and by determining the position of the mobile receiver based on the signal strength of the at least one information signal.

What is claimed is: 
     
         1 . A method of tracking the position of a mobile receiver on a production line, the production line having a movable conveyor belt and a plurality of location tags positioned at fixed locations along the length of the conveyor belt, and wherein the mobile receiver, when placed on a moving conveyor belt, is moving with respect to the plurality of location tags such that the distance between the mobile receiver and the plurality of location tags is continuously changing, and wherein the mobile receiver is configured to observe and communicate with one or more location tags within a range of the mobile receiver, the method comprising:
 receiving at least one information signal from at least one location tag;   determining a signal strength of the at least one information signal; and   determining the position of the mobile receiver based on the signal strength of the at least one information signal.   
     
     
         2 . The method of  claim 1 , wherein determining the position of the mobile receiver comprises:
 determining whether the signal strength of the at least one information signal is a local maximum; and   generating an event entry if the signal strength of the at least one information signal is determined to be a local maximum, wherein the event entry indicates that the mobile receiver has reached a minimum distance with respect to the at least one location tag transmitting the at least one information signal having the signal strength determined to be a local maximum.   
     
     
         3 . The method of  claim 2 , wherein:
 determining whether the signal strength of the at least one information signal is a local maximum comprises determining whether the signal strength of the at least one information signal is a local maximum at the mobile receiver; and   generating the event entry comprises generating the event entry at the mobile receiver.   
     
     
         4 . The method of  claim 2 , further comprising:
 transmitting a data signal from the mobile receiver to an external processor, wherein the data signal comprises at least one of the signal strength of the at least one information signal and a location tag identifier corresponding to the at least one location tag transmitting the at least one information signal, and wherein the external processor is communicably linked to the mobile receiver; and   wherein:   determining whether the signal strength of the at least one information signal is a local maximum comprises determining whether the signal strength of the at least one information signal is a local maximum at the external processor; and   generating the event entry comprises generating the event entry at the external processor.   
     
     
         5 . The method of  claim 1 , further comprising:
 transmitting a data signal from the mobile receiver to an external processor, wherein the data signal comprises at least one of the signal strength of the at least one information signal and a location tag identifier corresponding to the at least one location tag transmitting the at least one information signal; and   wherein determining the position of the mobile receiver based on the signal strength of the at least one information signal comprises determining the position of the mobile receiver at the external processor.   
     
     
         6 . The method of  claim 2 , wherein receiving the at least one information signal from at least one location tag comprises receiving a plurality of information signals from each location tag, and determining whether the signal strength of the at least one information signal is a local maximum comprises:
 comparing signal strengths corresponding to one or more information signals to the signal strength of a newly received information signal wherein the one or more information signals were received before the newly received information signal, and wherein the one or more information signals and the at newly received information signal are received from a same location tag; and   determining if the signal strength of the newly received information signal is higher than the signal strengths corresponding to the one or more information signals.   
     
     
         7 . The method of  claim 6 , wherein determining whether the signal strength of the at least one information signal is a local maximum further comprises:
 comparing the signal strength of the newly received information signal to a pre-determined signal strength threshold value; and   determining if the signal strength of the newly received information signal exceeds the pre-determined signal strength threshold value,   wherein the signal strength of the at least one information signal is determined to be the local maximum if the signal strength of the newly received information signal exceeds the pre-determined signal strength threshold value and if the newly received information signal has a higher signal strength than the signal strengths corresponding to the one or more information signals.   
     
     
         8 . The method of  claim 2 , wherein determining whether the signal strength of the at least one information signal is a local maximum comprises:
 receiving, at the mobile receiver, a plurality of information signals from the at least one location tag, the plurality of information signals being received successively; and   comparing signal strengths of the plurality of information signals to each other to identify the information signal having the highest signal strength value.   
     
     
         9 . The method of  claim 3 , further comprising:
 transmitting the event entry to an external processor as soon as it is generated, wherein the external processor is communicably linked to the mobile receiver.   
     
     
         10 . The method of  claim 3 , further comprising:
 buffering a plurality of event entries at the mobile receiver as buffered event entries; and   transmitting the buffered event entries to an external processor, wherein the external processor is communicably linked to the mobile receiver.   
     
     
         11 . The method of  claim 3 , further comprising:
 recording sensor data corresponding to orientation of the mobile receiver and pressure exerted on the mobile receiver;   recording the sensor data and the event entry in a data stream in a unique sequence corresponding to a sequence in which the sensor data was recorded and the event entry was generated by the mobile receiver; and   transmitting the data stream to an external processor, wherein the external processor is communicably linked to the mobile receiver.   
     
     
         12 . The method of  claim 1 , further comprising:
 transmitting one or more information signals from the at least one location tag, wherein the at least one location tag is configurable to change the frequency of transmission of the one or more information signals.   
     
     
         13 . The method of  claim 12 , wherein the at least one location tag is configurable to change the frequency of transmission of the one or more information signals based on an activation signal received from the mobile receiver, wherein:
 prior to receiving the activation signal from the mobile receiver, the at least one location tag is configured to transmit the one or more information signals at a pre-activated frequency, and   subsequent to receiving the activation signal from the mobile receiver, the at least one location tag is configured to transmit the one or more information signals at an activated frequency, wherein the activated frequency is higher than the pre-activated frequency.   
     
     
         14 . The method of  claim 12 , wherein the at least one location tag is configurable to transmit the one or more information signals at an activated frequency for a fixed duration of time, wherein when the fixed duration of time is expired, the at least one location tag transmits the one or more information signals at a pre-activated frequency, wherein the activated frequency is higher than the pre-activated frequency. 
     
     
         15 . The method of  claim 12 , wherein the at least one location tag is configurable to change the frequency of transmission of the one or more information signals based on the signal strength of an information signal transmitted immediately prior to the one or more information signals, wherein:
 if the signal strength of the information signal transmitted immediately prior to the one or more information signals is below a certain threshold, the one or more information signals are transmitted at a pre-activated frequency; and   if the signal strength of the information signal transmitted immediately prior to the one or more information signals is above the certain threshold, the one or more information signals are transmitted at an activated frequency, wherein the activated frequency is higher than the pre-activated frequency.   
     
     
         16 . The method of  claim 12 , wherein the at least one location tag is configurable to transmit the one or more information signals at an activated frequency upon receiving a start signal from the mobile receiver and wherein the at least one location tag is configurable to transmit the one or more information signals at a pre-activated frequency upon receiving a stop signal from the mobile receiver, wherein the activated frequency is higher than the pre-activated frequency. 
     
     
         17 . The method of  claim 2 , further comprising:
 transmitting one or more information signals from the at least one location tag, wherein the at least one location tag is configurable to switch the frequency of transmission of the one or more information signals from an activated frequency to a pre-activated frequency based on the generation of the event entry, wherein the activated frequency is higher than the pre-activated frequency.   
     
     
         18 . The method of  claim 5 , wherein determining the position of the mobile receiver based on the signal strength of the at least one information signal comprises:
 associating a first signal strength corresponding to a first information signal received from a first location tag to a first distance value;   associating a second signal strength corresponding to a second information signal received from a second location tag to a second distance value, wherein the first location tag is adjacent to the second location tag, and wherein the distance between the first location tag and the second location tag are known; and   determining a position of the mobile receiver between the first location tag and the second location tag based on the first distance value, the second distance value and the distance between the first location tag and the second location tag.   
     
     
         19 . A system for tracking the position of a mobile receiver on a production line, the production line having a moving conveyor belt, the system comprising:
 at least one location tag, the at least one location tag positioned at an at least one fixed location along the length of the conveyor belt; and   a mobile receiver, wherein the mobile receiver, when placed on a moving conveyor belt, is moving with respect to the at least one location tag such that the distance between the mobile receiver and the at least one location tag is continuously changing, and wherein the mobile receiver is configured to observe and communicate with one or more location tags within a range of the mobile receiver, the mobile receiver comprising a processor unit, the processor unit being configured to:
 receive at least one information signal from at least one location tag; 
 determine a signal strength of the at least one information signal; and 
 determine the position of the mobile receiver based on the signal strength of the at least one information signal. 
   
     
     
         20 . A computer-readable medium storing computer-executable instructions, the instructions for causing a processor to perform a method of tracking the position of a mobile receiver on a production line, the production line having a moveable conveyor belt and a plurality of location tags positioned at fixed locations along the length of the conveyor belt, and wherein the mobile receiver, when placed on a moving conveyor belt, is moving with respect to the plurality of location tags such that the distance between the mobile receiver and the plurality of location tags is continuously changing, and wherein the mobile receiver is configured to observe and communicate with one or more location tags within a range of the mobile receiver, the method comprising:
 receiving at least one information signal from at least one location tag;   determining a signal strength of the at least one information signal; and   determining the position of the mobile receiver based on the signal strength of the at least one information signal.