Patent Publication Number: US-2021173038-A1

Title: Apparatus, system and method of tracking a radio beacon

Description:
TECHNICAL FIELD 
     The present disclosure relates to methods and apparatus for tracking radio beacons in weak Global Navigation Satellite System (GNSS) signal environments. 
     BACKGROUND 
     In some environments, such as indoor or in areas where many natural or manufactured obstacles are present, for example, GNSS signal reception may be weak. In these environments, beacon tracking systems that rely on GNSS signals are generally inoperable. 
     Received signal strength is often used to estimate range of a radio beacon from multiple receivers, which may in turn be used to estimate the radio beacon&#39;s position. When obstacles are present between the radio beacon and the receivers, the radio beacon signals may be blocked or reflections may result such that a determined position is less reliable and less accurate. Tracking a radio beacon based on received signal strength does not generally produce accurate results due to signal fading, which is difficult to decorrelate from dynamics, multipath and Signal-to-Noise Ratio (SNR), for example. 
     In some environments, signal timing may be used for tracking a radio beacon, however, signal timing is not usable with third party hardware because timing synchronization between the beacon and the receiver is currently not achievable. As a result, applications of signal timing based location tracking are limited. 
     SUMMARY 
     In an aspect of the present disclosure there is provided a method of determining direction information of a radio beacon from a starting location comprising: receiving radio beacon signals at an omni-directional antenna in communication with a radio sub-system of an electronic hub device over a first time period and over a second time period and determining a change in omni-directional received signal strength between the first time period and the second time period; receiving the radio beacon signals at a multi-directional antenna in communication with another radio sub-system of the electronic hub device over the first time period and over the second time period, determining changes in received signal strength for antenna directions of the multi-directional antenna between the first time period and the second time period; grouping ones of the changes in received signal strength of the multi-directional antenna into groups corresponding to adjacent antenna directions; determining the direction information of the radio beacon based on inputs, the inputs comprising: the change in omni-directional received signal strength and the pairs of changes in received signal strength of the multi-directional antenna; wherein the starting location of the radio beacon and a location of the first electronic hub device are known. 
     In another aspect of the present disclosure there is provided a method of determining direction information of a radio beacon from a starting location using multiple electronic hub devices comprising: receiving radio beacon signals at omni-directional antennas of the multiple electronic hub devices over a first time period and over a second time period and determining changes in omni-directional received signal strength between the first time period and the second time period for the multiple electronic hub devices; receiving the radio beacon signals at multi-directional antennas of the multiple electronic hub devices over the first time period and over the second time period and determining changes in received signal strength for antenna directions of the multi-directional antennas between the first time period and the second time period; grouping ones of the changes in received signal strength of the multi-directional antennas into groups corresponding to adjacent antenna directions for ones of the electronic hub devices; determining the direction information of the radio beacon based on inputs, the inputs comprising: the changes in omni-directional received signal strength for the of the multiple electronic hub devices and the groups of changes in received signal strength for the multi-directional antenna for the multiple electronic hub devices; wherein the starting location of the radio beacon and locations of the multiple electronic hub devices are known. 
     In another aspect of the present disclosure there is provided a beacon tracking system comprising: a radio beacon movable from a known starting location, the radio beacon generating radio beacon signals; a first electronic hub device comprising: a first processor and a first radio sub-system in communication with a first omni-directional antenna and a first multi-directional antenna, the first omni-directional antenna receiving the radio beacon signals at a first received signal strength and the first multi-directional antenna receiving the radio beacon signals at first received signal strengths for antenna directions of the multi-directional antennas over a first time period and a second time period, the first electronic hub device comprising a first known location; a second electronic hub device comprising: a second processor and a second radio sub-system in communication with a second omni-directional antenna and a second multi-directional antenna, the second omni-directional antenna receiving the radio beacon signals at a second received signal strength and the second multi-directional antenna receiving the radio beacon signals at second received signal strengths for the antenna directions of the multi-directional antenna over the first time period and the second time period, the second electronic hub device comprising a second known location; wherein direction information of the radio beacon is determined based on inputs, the inputs comprising: changes in received signal strength for the first and second omni-directional antennas and changes in received signal strengths for adjacent antenna direction groups for the first and second multi-directional antennas. 
     In still another aspect of the present disclosure there is provided a method of tracking a radio beacon from a starting location comprising: receiving radio beacon signals at a first omni-directional antenna of a first electronic hub device and a second omni-directional antenna of a second electronic hub device over a time period; determining a travel gradient or a direction of travel of the radio beacon from the starting location based on a first received signal strength at the first electronic hub device and a second received signal strength at the second electronic hub device over the time period; wherein the starting location of the radio beacon and locations of the first electronic hub device and the second electronic hub device are known. 
    
    
     
       DRAWINGS 
       The following figures set forth examples in which like reference numerals denote like parts. The present disclosure is not limited to the examples illustrated in the accompanying figures. 
         FIG. 1  is a schematic diagram of electronic hub devices and radio beacons of a radio beacon tracking system according to an example. 
         FIG. 2  is a schematic diagram of an electronic hub device according to an example. 
         FIG. 3  is a schematic diagram of an electronic hub device according to another example. 
         FIG. 4A  depicts a radio beacon signal reception schedule at the electronic hub device of  FIG. 2 . 
         FIG. 4B  depicts a radio beacon signal reception schedule at the electronic hub device of  FIG. 3 . 
         FIG. 4C  depicts another example radio beacon signal reception schedule. 
         FIG. 5  is a schematic diagram of a deployed beacon tracking system according to an example. 
         FIG. 6  is a flowchart depicting a method of tracking a radio beacon according to an example. 
         FIG. 7  is a schematic diagram depicting a radio beacon moving relative to an electronic hub device. 
         FIG. 8A  is a graph depicting received signal strength at the omni-directional antenna of the electronic hub device of  FIG. 2  over a first time period. 
         FIG. 8B  is a graph depicting received signal strength at the omni-directional antenna of the electronic hub device of  FIG. 2  over a second time period. 
         FIG. 9A  is a graph depicting received signal strength at antenna directions of the multi-directional antenna of the electronic hub device of  FIG. 2  over the first time period. 
         FIG. 9B  is a graph depicting received signal strength at antenna directions of the multi-directional antenna of the electronic hub device of  FIG. 2  over the second time period. 
         FIG. 10  is a schematic diagram depicting possible direction outcomes combined to determine direction information of a radio beacon. 
         FIG. 11  shows graphs depicting fuzzy input according to first rules for determining direction information of a radio beacon. 
         FIG. 12  is a graph depicting output of the first rules. 
         FIG. 13  shows graphs depicting fuzzy input according to second rules for determining direction information of a radio beacon. 
         FIG. 14  is a graph depicting output of the second rules. 
         FIG. 15  is a flowchart depicting a method of tracking a radio beacon according to another example. 
     
    
    
     DETAILED DESCRIPTION 
     It will be appreciated that for simplicity and clarity of illustration, where considered appropriate, reference numerals may be repeated among the figures to indicate corresponding or analogous elements. In addition, numerous specific details are set forth in order to provide a thorough understanding of the examples described herein. However, it will be understood by those of ordinary skill in the art that the examples described herein may be practiced without these specific details. Unless explicitly stated, the methods described herein are not constrained to a particular order or sequence. Additionally, some of the described methods or elements thereof can occur or be performed at the same point in time. In other instances, well-known methods, procedures and components have not been described in detail so as not to obscure the examples described herein. Also, the description is not to be considered as limiting the scope of the examples described herein. 
     Referring to  FIG. 1 , an example beacon tracking system  10  including three electronic hub devices  12  and three radio beacons  14  is shown. When performing methods of tracking radio beacons as described herein, the electronic hub devices  12  determine direction gradients  16  of the radio beacons  14 . 
     Tracking a radio beacon  14  includes updating the position of the radio beacon  14  at a relatively fast update rate in order to observe the motion and generate a traversed trajectory of the radio beacon  14 . The radio beacon tracking system  10  may be used for asset tracking and analytics to discover movement patterns for marketing purposes, for example. 
     The radio beacon tracking system  10  is operable in any deployment environment including outdoors, indoors and in environments in which GNSS signal reception is weak, such as in dense urban environments, for example. The radio beacon tracking system  10  has particular advantages when the radio beacons  14  of the system  10  do not have GNSS location capability. Some examples of deployment environments of the radio beacon tracking system  10  include: office structures, retail structures, hospitals, hotels, points of interest, such as tourist attractions, for example, industrial and manufacturing structures, educational campuses, cargo handling ports and resource extraction locations, for example. 
     The radio beacon tracking system  10  of  FIG. 1  is shown as an example. The radio beacon tracking system  10  may include any number of electronic hub devices  12  and radio beacons  14 . Some deployments may include two electronic hub devices  12  and a single radio beacon  14 , a few electronic hub devices  12  and tens of radio beacons  14 , tens of electronic hub devices  12  and hundreds of radio beacons  14  or even larger deployments. The number of radio beacons  14  per pair of electronic hub devices  12  is not fixed and may be determined based on the deployment environment. The radio beacon tracking system  10  is operable with any type of radio signal, such as BLE (Bluetooth™ Low Energy), Bluetooth™, FM, AM, WiFi, Digital TV, ZigBee or 6LoWPan, for example. The radio beacons  14  may be any type of electronic device capable of generating a radio signal including Smartphones, tablets, laptop computers, fitness trackers and other wearable devices and specialized personnel tracking systems, for example. Example radio beacons  14  that may be used with the radio beacon location system  10  include BLE radio beacons manufactured by LSR, Estimote and BlueSense and Fathom, for example. 
     Referring also to  FIG. 2 , the electronic hub device  12  includes a main processor sub-system  16 . The main processor sub-system  16  controls overall operation of the electronic hub device  12 . The main processor sub-system  16  includes a microprocessor  18 , a memory  20  and a communication interface  34 . The communication interface  34  enables communication with a server  38  via a wireless or a wired connection. The server  38  may be a single server or a group of servers in communication with one another. An example of a main processor sub-system  16  is a Single Board Computer (SBC) with an Operating System (OS). 
     The electronic hub device  12  further includes a GNSS antenna  22  to receive GNSS signals and a GNSS sub-system  24  in communication with the main processor sub-system  16  and the GNSS antenna  22 . The GNSS sub-system  24  generates digitized GNSS data corresponding to the GNSS signals for further processing by the main processor sub-system  16 . Examples of a GNSS sub-system  24  include: a standalone GNSS receiver capable of generating a location estimate locally, an Assisted GNSS (A-GNSS) receiver that receives assistance data from another device to provide a location estimate, a Radio Frequency (RF) Front End (FE) in association with a Software Defined Radio (SDR) receiver at the electronic hub device  12  or distributed over one or more servers. 
     The electronic hub device  12  is capable of determining its location using the digitized GNSS data. In environments in which the signals from the GNSS satellites are weak, the electronic hub device  12  may communicate with the server  38  to process the digitized GNSS data over time. Depending on the strength of GNSS signals received, self-location may be immediate or may take hours or days, for example. As such, the electronic hub device  12  may self-locate by determining its location locally or by communicating with the server to determine its location. The electronic hub device  12  may alternatively determine its location using another method, such as using other networking structures located nearby such as Cell-ID and WiFi, for example. Alternatively, the electronic hub device  12  may retrieve information from the memory  20  that was stored at the time the electronic hub device  12  was deployed. In general, the location of the electronic hub device  12  is known and is used to determine locations of the radio beacons  14  in the methods described herein. 
     Radio sub-system  26  receives radio beacon signals from the radio beacons  14  via an antenna  30  and generates digitized data representing received signal strengths of the radio beacon signals received at the electronic hub device  12  at multiple orientations. The radio sub-system  26  communicates with the main processor sub-system  16  of the electronic hub device  12  and an antenna switch  28 . The antenna switch  28  controls the antenna  30  of the electronic hub device  12 . Radio sub-system  26  also functions as a transmitter to transmit radio beacon signals so that other electronic hub devices  12  may locate the electronic hub device  12 . The electronic hub device  12  is also capable of transmitting the digitized data for receipt at another electronic hub device  12 . In an example, the radio sub-system  26  is a standalone receiver of radio signals such as BLE, WiFi, FM, AM, Bluetooth™ and Digital TV, for example, that is capable of down-converting, demodulating and decoding information transmitted by radio beacons  14 . In this example, the standalone receiver may be realized using discrete components or using minimum hardware such as SDRs (Software Defined Radios). 
     The antenna  30  may be a single mechanically steered directional antenna or may include multiple directional antennas, as shown in  FIG. 2 . When the antenna  30  includes multiple directional antennas, any number of antennas that fit within the physical limitations of the radio beacon  14  may be included. In an example in which multiple directional antennas are included, the antenna switch  28  may be operated to select a subset of the multiple directional antennas to receive the radio beacon signals from the radio beacons  14 . A single antenna or a set of antennas may be selected at a time to receive beacon signals from one direction or a set of directions, respectively. In an example, the electronic hub devices  12  include six directional antennas. 
     The electronic hub device  12  further includes an omni-directional antenna  40  in communication with a separate radio sub-system  42  to enable the antenna  30  and the omni-directional antenna  40  to receive radio beacon signals at the same time. In another example, which is shown in  FIG. 3 , the electronic hub device  12  includes a single radio sub-system  26  and the omni-directional antenna  40  is in communication with the antenna switch  28  such that the antenna switch  28  may select the omni-directional antenna  40  between selections of different directions of antenna  30  in order to obtain information regarding radio beacon signals all around the electronic hub device  12 . In another example, the antenna  30  communicates with multiple radio sub-systems associated with multiple directional antennas thereof. Example signal reception schedules for the dual radio sub-system, the single radio sub-system and multiple radio sub-system examples are shown in  FIGS. 4A, 4B and 4C , respectively. As shown, the more radio sub-systems that are included in the electronic hub device  12 , the greater the amount of signal information that may be collected. 
     The electronic hub device  12  is powered by a power supply  36 , which communicates with the main processor sub-system  16  via a power interface  32 . In an example, the power supply  36  is one or more batteries. In another example, the power supply  36  is an electrical outlet. 
     The radio beacon  14  may be any type of radio signal transmitting device. All of the radio beacons  14  of the beacon location system  10  may be the same type of device, or alternatively, one or more of the radio beacons  14  may be a different type of device. Referring back to  FIG. 1 , the radio beacons are identified as radio beacon A, radio beacon B and radio beacon C for the purpose of this description. Locations of the radio beacons  14  are (X A , Y A , Z A ), (X B , Y B , Z B ) and (X C , Y C , Z C ), respectively. Referring to  FIG. 5 , coverage areas  46  over which the electronic hub devices  12  and  12 ′ are able to receive radio beacon signals from the radio beacons  14  are shown. According to the methods described herein, the radio beacons  14  that are within the coverage areas of one or both electronic hub devices  12  and  12 ′ may be tracked. In the example of  FIG. 5 , additional electronic hub devices  12  may be deployed so that more of the radio beacons  14  are within the coverage areas of at least one other electronic hub devices  12  to improve tracking accuracy. 
     After starting locations of the radio beacons  14  have been determined, a method of tracking radio beacons  14  of a beacon tracking system  10  in a deployment environment may be performed. The starting locations may be determined by: 1) determining a distance based on received signal strength of radio beacon signals at the electronic hub device  12  and another device in communication with and having a known location relative to the electronic hub device  12 ; 2) determining an angle of arrival of radio beacon signals at the electronic hub device  12  and at another device in communication with and having a known location and orientation relative the electronic hub device  12 ; or 3) determining a distance based on received signal strength of radio beacon signals at the electronic hub device  12  and determining an angle of arrival of radio beacon signals at the electronic hub device  12 . The starting locations of the radio beacons  14  may alternatively be determined by another location determination method. 
     Tracking of a radio beacon  14  includes determining direction information of the radio beacon  14  over two or more time periods. The direction information may be a direction gradient, which includes speed information, or may be a direction of travel. 
     As shown in  FIG. 6 , a method of tracking a radio beacon  14  includes: at  50 , receiving radio beacon signals from a radio beacon having a known starting position at an omni-directional antenna  40  in communication with a radio sub-system  42  of an electronic hub device  12  over a first time period and over a second time period and determining a change in omni-directional received signal strength (ΔRSS omni ) between the first time period and the second time period, at  52 , receiving the radio beacon signals at a multi-directional antenna  30  in communication with another radio sub-system  26  of the electronic hub device  12  over the first time period and over the second time period, determining changes in received signal strength for n antenna directions of the multi-directional antenna (ΔRSS multi_1  . . . ΔRSS multi_n ) between the first time period and the second time period, at  54 , grouping ones of the changes in received signal strength for the antenna directions of the multi-directional antenna  30  into groups, such as pairs, for example, corresponding to adjacent antenna directions (such as directly adjacent antenna directions: ΔRSS multi_n  and ΔRSS multi_n+1 , ΔRSS multi_n+1  and ΔRSS multi_n+2  . . . ) at  56 , determining the direction information of the radio beacon  14  based on inputs and a known location of the electronic hub device  12 , the inputs comprising: the change in omni-directional received signal strength and the pairs of changes in received signal strength for the antenna directions of the multi-directional antenna  30 . According to an example, instead of directly adjacent antenna directions, approximately adjacent antenna directions may be used, such as: ΔRSS multi_n  and ΔRSS multi_n+2 , ΔRSS multi_n+1  and ΔRSS multi_n+3 , for example. In addition, groups of three or more antenna directions may be used. In general, group size and arrangements of antenna directions may be selected depending on the radio beacon signal reception schedule and scan rate of the multi-directional antenna  20 . 
     According to an example, the direction information is determined by combining at least some of the inputs according to a relationship between the inputs and possible direction outcomes and then combining the possible direction outcomes. The possible direction outcomes include: moving toward or away from one of the antenna directions of the multi-directional antenna  30  of the electronic hub device  12 , moving toward or away from between one of the pairs of adjacent antenna directions of the multi-directional antenna  30  of the electronic hub device  12 , moving away from or in front of one of the antenna directions of the multi-directional antenna  30  (i.e. perpendicular to antenna direction) and no change relative to the electronic hub device  12 . 
     According to an example, the at least some of the inputs are combined by assigning weights to the inputs and then combining the inputs based on rules to determine the possible direction outcomes. The relationship between the inputs and the direction information may be implemented in fuzzy logic, for example. 
     Referring to  FIG. 7 , an example of a radio beacon  14  that is tracked by an electronic hub device  12  according to the method of  FIG. 6  is shown. Both a starting location of the radio beacon  14  and a location of the electronic hub device  12  are known. The electronic hub device  12  comprises a multi-directional antenna  30  having six individual antennas represented as  1 ,  2 ,  3 ,  4 ,  5 , and  6  and an omni-directional antenna  40  represented by  0 . The antennas of the multi-directional antenna  30  are located such that the individual antennas are able to scan about the entire circumference of the electronic hub device  12 , as shown. In the example of  FIG. 7 , a radio beacon  14  travels in a direction that is tangent to the electronic hub device  12 . 
     Operation of the method of tracking a radio beacon of  FIG. 6  will now be described with reference to  FIG. 7 . At  50 , the omni-directional antenna  40  of the electronic hub device  12  receives radio beacon signals from the radio beacon  14  over a first time period, t 0  to t 1 , and over a second time period, t 1  to t 2 , and a change in omni-directional received signal strength is determined as follows: 
       Δ RSS   omni   =RSS   omni_time_period_2   −RSS   omni_time_period_1  
 
     Example received signal strengths for time period  1  and time period  2  for the omni-directional antenna  40  are plotted in  FIGS. 8A and 8B , respectively. According to  FIGS. 8A and 8B , the RSS omni_time_period_1 =−75 dB and the RSS omni_time_period_2 =−70 dB. Therefore, ΔRSS omni =5 dB. The RSS is averaged over the time period in order to reduce noise. 
     At  52 , the multi-directional antenna  30  of the electronic hub device  12  receives radio beacon signals from the radio beacon  14  over the first time period, t 0  to t 1 , and over the second time period, t 1  to t 2 , and determines changes in received signal strength for six antenna directions of the multi-directional antenna  30  as follows: 
     
       
      
       ΔRSS 
       multi_1 
       =RSS 
       multi_1_time_period_2 
       −RSS 
       multi_1_time_period_1  
      
     
       Δ RSS   multi_2   =RSS   multi_2_time_period_2   −RSS   multi_2_time_period_1  
 
       Δ RSS   multi_3   =RSS   multi_3_time_period_2   −RSS   multi_3_time_period_1  
 
       Δ RSS   multi_4   =RSS   multi_4_time_period_2   −RSS   multi_4_time_period_1  
 
       Δ RSS   multi_5   =RSS   multi_5_time_period_2   −RSS   multi_5_time_period_1  
 
       Δ RSS   multi_6   =RSS   multi_6_time_period_2   −RSS   multi_6_time_period_1  
 
     Example received signal strengths for time period  1  and time period  2  for the six antennas of the multi-directional antenna  40  are plotted in  FIGS. 9A and 9B , respectively. According to  FIGS. 9A and 9B , ΔRSS multi_1 =7 dB, ΔRSS multi_2 =55 dB, ΔRSS multi_3 =5 dB, ΔRSS multi_4 =14 dB, ΔRSS multi_5 =0 dB and ΔRSS multi_6 =0 dB. 
     At  54 , the changes in received signal strength for the antenna directions of the multi-directional antenna  30  are grouped into pairs corresponding to adjacent antenna directions as follows: ΔRSS multi_1  and ΔRSS multi_2 , ΔRSS multi_2  and ΔRSS multi_3 , ΔRSS multi_3  and ΔRSS multi_4 , ΔRSS multi_4  and ΔRSS multi_5 , ΔRSS multi_5  and ΔRSS multi_6 , and ΔRSS multi_6  and ΔRSS multi_1 . 
     At  56 , the direction information of the radio beacon  14  is determined based on the change in omni-directional received signal strength and the pairs of changes in received signal strength for the antenna directions of the multi-directional antenna  30 . Relationships between the inputs: ΔRSS omni , ΔRSS multi_1  and ΔRSS multi_2 , ΔRSS multi_2  and ΔRSS multi_3 , ΔRSS multi_3  and ΔRSS multi_4 , ΔRSS multi_4  and ΔRSS multi_5 , ΔRSS multi_5  and ΔRSS multi_6 , and ΔRSS multi_6  and ΔRSS multi_1  and the direction information may be understood with reference to  FIG. 10  in which the direction information is shown as a plurality of arrows  58 . The arrows  58  are the vector sums of the possible direction outcome arrows in the adjacent table. The possible direction outcome arrows are based on the change in received signal strength from the omni-directional antenna  40  and pairs of changes in received signal strength of adjacent antenna directions of the multi-directional antenna  30 . 
     According to another example, determination of the direction information may be implemented in fuzzy logic based on a rule set. First rules of the rule set are based on the change in omni-directional received signal strength and the changes in received signal strength of each of the multi-directional antenna directions and second rules of the rule set are based on the change in omni-directional received signal strength and the changes in received signal strength of each of the multi-directional antenna direction pairs. 
       FIG. 11  represents the fuzzy sets associated with the inputs for first rules. According to the example, five fuzzy sets are defined for the inputs. The weights corresponding to the fuzzy sets are: small, positive (+ve) medium, negative (−ve) medium, positive (+ve) large and negative (−ve) large. The fuzzy sets have Gaussian distributions for the ΔRSS of the omni-directional antenna  40  and a combination of Gaussian and linear distributions for the ΔRSS of the antenna directions of the multi-directional antenna  30 , as shown in  FIG. 11 . 
       FIG. 12  represents the fuzzy sets associated with the outputs of the first rules. According to the example, five fuzzy sets are defined for the outputs. The fuzzy sets correspond to: static, positive (+ve) walking, (−ve) negative walking, positive (+ve) running and (−ve) negative running. The fuzzy sets have Gaussian distributions, as shown in  FIG. 12 . 
     Example first rules include: 
     If ΔRSS omni  is small and ΔRSS multi_n  is −ve medium then speed=−ve walking.
 
If ΔRSS omni  is +ve medium and ΔRSS multi_n  is small then speed=+ve walking.
 
If ΔRSS omni  is +ve medium and ΔRSS multi_n  is +ve medium then speed=+ve walking.
 
If ΔRSS omni  is +ve medium and ΔRSS multi_n  is +ve large then speed=+ve running.
 
If ΔRSS omni  is +ve large and ΔRSS multi_n  is +ve medium then speed=+ve running.
 
If ΔRSS omni  is +ve large and ΔRSS multi_n  is +ve large then speed=+ve running.
 
If ΔRSS omni  is −ve medium and ΔRSS multi_n  is small then speed=−ve walking.
 
If ΔRSS omni  is −ve medium and ΔRSS multi_n  is −ve medium then speed=−ve walking.
 
If ΔRSS omni  is −ve medium and ΔRSS multi_n  is −ve large then speed=−ve running.
 
If ΔRSS omni  is −ve large and ΔRSS multi_n  is −ve medium then speed=−ve running.
 
If ΔRSS omni  is −ve large and ΔRSS multi_n  is −ve large then speed=−ve running.
 
     As shown, the inputs are ΔRSS omni =20.100 dB and ΔRSS multi_1 =9.200 dB and the output is 2.29 m/s after defuzzification. The defuzzification method used is centroid defuzzification, however, other methods of defuzzification, such as centre of mass or majority rule, for example, may alternatively be used. 
     In the example described herein, the output of the first rules is speed. Direction determination will be described with respect to  FIGS. 13 and 14 .  FIG. 13  represents the fuzzy sets associated with the second rules. According to the example, three fuzzy sets are defined for the inputs. The weights corresponding to the fuzzy sets are: small, medium and large. The fuzzy sets have Gaussian distributions for the ΔRSS of the omni-directional antenna  40  and a combination of Gaussian and linear distributions for the ΔRSS of the antenna directions of the multi-directional antenna  30 , as shown in  FIG. 13 . 
       FIG. 14  represents the fuzzy sets associated with the outputs of the second rules. According to the example, three fuzzy sets are defined for the outputs. The fuzzy sets correspond to: antenna n (Ant multi_n ) a midpoint between antenna n and antenna n+1 (Ant mid ), and antenna n+1(Ant multi_n+1 ) The fuzzy sets have Gaussian distributions, as shown in  FIG. 13 . 
     Example second rules include: 
     If ΔRSS omni  is small and ΔRSS multi_n  small and ΔRSS multi_n+1  is small then direction is Ant mid .
 
If ΔRSS omni  is small and ΔRSS multi_n  is small and ΔRSS multi_n+1  is medium then direction is Ant multi_n+1 .
 
If ΔRSS omni  is small and ΔRSS multi_n  is small and ΔRSS multi_n+1  is large then direction is Ant multi_n+1 .
 
If ΔRSS omni  is small and ΔRSS multi_n  is medium and ΔRSS multi_n+1 2 is small then direction is Ant multi_n .
 
If ΔRSS omni  is small and ΔRSS multi_n  is medium and ΔRSS multi_n+1  is medium then direction is Ant mid .
 
If ΔRSS omni  is small and ΔRSS multi_n  is medium and ΔRSS multi_n+1  is large then direction is Ant multi_n+1 .
 
If ΔRSS omni  is small and ΔRSS multi_n  is large and ΔRSS multi_n+1  is small then direction is Ant multi_n .
 
If ΔRSS omni  is small and ΔRSS multi_n  is large and ΔRSS multi_n+1  is medium then direction is Ant multi_n .
 
If ΔRSS omni  is small and ΔRSS multi_n  is large and ΔRSS multi_n+1  is large then direction is Ant mid .
 
If ΔRSS omni  is medium and ΔRSS multi_n  is small and ΔRSS multi_n+1  is small then direction is Ant mid .
 
If ΔRSS omni  is medium and ΔRSS multi_n  is small and ΔRSS multi_n+1  is medium then direction is Ant multi_n+1 .
 
If ΔRSS omni  is medium and ΔRSS multi_n  is small and ΔRSS multi_n+1  is large then direction is Ant multi_n+1 .
 
If ΔRSS omni  is medium and ΔRSS multi_n  is medium and ΔRSS multi_n+1  is small then direction is Ant multi_n .
 
If ΔRSS omni  is medium and ΔRSS multi_n  is medium and ΔRSS multi_n+1  is medium then direction is Ant mid .
 
If ΔRSS omni  is medium and ΔRSS multi_n  is medium and ΔRSS multi_n+1  is large then direction is Ant multi_n+1 .
 
If ΔRSS omni  is medium and ΔRSS multi_n  is large and ΔRSS multi_n+1  is small then direction is Ant multi_n .
 
If ΔRSS omni  is medium and ΔRSS multi_n  is large and ΔRSS multi_n+1  is medium then direction is Ant multi_n .
 
If ΔRSS omni  is medium and ΔRSS multi_n  is large and ΔRSS multi_n+1  is large then direction is Ant mid .
 
If ΔRSS omni  is large and ΔRSS multi_n  is small and ΔRSS multi_n+1  is small then direction is Ant mid .
 
If ΔRSS omni  is large and ΔRSS multi_n  is small and ΔRSS multi_n+1  is medium then direction is Ant multi_n+1 .
 
If ΔRSS omni  is large and ΔRSS multi_n  is small and ΔRSS multi_n+1  is large then direction is Ant multi_n+1 .
 
If ΔRSS omni  is large and ΔRSS multi_n  is medium and ΔRSS multi_n+1  is small then direction is Ant multi_n .
 
If ΔRSS omni  is large and ΔRSS multi_n  is medium and ΔRSS multi_n+1  is medium then direction is Ant mid .
 
If ΔRSS omni  is large and ΔRSS multi_n  is medium and ΔRSS multi_n+1  is large then direction is Ant multi_n+1 .
 
If ΔRSS omni  is large and ΔRSS multi_n  is large and ΔRSS multi_n+1  is small then direction is Ant multi_n .
 
If ΔRSS omni  is large and ΔRSS multi_n  is large and ΔRSS multi_n+1  is medium then direction is Ant multi_n .
 
if ΔRSS omni  is large and ΔRSS multi_n  is large and ΔRSS multi_n+1  is large then direction is Ant mid .
 
     As shown the inputs are ΔRSS omni =20.100 dB and ΔRSS multi_1 =9.200 dB and ΔRSS multi_2 =29.750 dB. The output is 53.22 degrees after defuzzification. The angle measurement begins at the start of the scan angle for the first antenna of the adjacent antenna pair. The defuzzification method used is centroid defuzzification, however, other methods of defuzzification, such as centre of mass or majority rule, for example, may alternatively be used. In the example described herein, the output of the first rules is speed and the output of the second rules is direction. 
     The fuzzy logic method is disclosed by way of example herein. The number of fuzzy sets for the first rules and the second rules is not limited and is determined based on operational specifications. Also, the first rules and second rules may be modified based on different deployment environment or different types of antenna hardware, for example. 
     When other electronic hub devices  12  having known locations also receive radio beacon signals from the radio beacon  14 , the method determines: a change in omni-directional received signal strength and changes in multi-directional received signal strength of the antenna directions for the other electronic hub devices  12 . Multi-hub direction information is then determined by combining direction information determined for each electronic hub device  12 . 
     Referring to  FIG. 15 , another method of tracking a radio beacon  14  is shown. The method of  FIG. 15  tracks a radio beacon  14  using multiple electronic hub devices  12 , such as two or more electronic hub devices, for example. The method includes: at  60 , receiving radio beacon signals from a radio beacon  14  having a known starting location at omni-directional antennas  40  of the multiple electronic hub devices  12  over a first time period and over a second time period and determining changes in omni-directional received signal strength between the first time period and the second time period for the multiple electronic hub devices  12 , at  62 , receiving the radio beacon signals at multi-directional antennas of the multiple electronic hub devices  12  over the first time period and over the second time period and determining changes in received signal strength for antenna directions of the multi-directional antennas between the first time period and the second time period, at  64 , grouping ones of the changes in received signal strength of the multi-directional antennas into groups, such as pairs, for example, corresponding to adjacent antenna directions for ones of the multiple electronic hub devices  12 , and at  66 , determining the direction information of the radio beacon based on known locations of the multiple electronic hub devices  12  and inputs, the inputs comprising: the changes in omni-directional received signal strength for the multiple electronic hub devices  12  and the pairs of changes in received signal strength for the multi-directional antenna for the multiple electronic hub devices  12 . 
     The method of  FIG. 15  is similar to the method of  FIG. 6 , however, includes one set of inputs: ΔRSS omni , ΔRSS multi_1  and ΔRSS multi_2 , ΔRSS multi_2  and ΔRSS multi_3 , ΔRSS multi_3  and ΔRSS multi_4 , ΔRSS multi_4  and ΔRSS multi_5 , ΔRSS multi_5  and ΔRSS multi_6 , and ΔRSS multi_6  and ΔRSS multi_1  for each of the multiple electronic hub devices  12 , for example. According to the method of  FIG. 15 , the direction information is determined by combining possible direction outcomes associated with each of the electronic hub devices  12 . 
     The method of  FIG. 15  includes more than one electronic hub device  12 . As such, any number of electronic hub devices  12  may be used. As will be understood by persons skilled in the art, the more densely distributed the electronic hub devices  12  are within a deployment environment, the more accurate the direction information determined by the method of  FIG. 15 . The accuracy may further be improved by receiving radio beacon signals over multiple time periods over a long period of time. 
     In an example, radio beacon signals received at the omni-directional antenna and the antennas of the first multi-directional antenna are compared in order to reduce noise and signal fading effects. As will be understood by persons skilled in the art, received signal strengths may be averaged over the time periods. 
     Disclosed herein are methods, apparatus and systems for tracking a radio beacon  14  from a known starting location. The radio beacon  14  may be tracked by one or more electronic hub devices  12  having known locations. The one or more electronic hub devices  12  may have the same antenna array architecture and components. Alternatively, when more than one electronic hub device  12  is used, one of the electronic hub devices  12  may include only one of: an omni-directional antenna  40  and a multi-directional antenna  30 , for example. 
     The radio beacon tracking system  10  is useful for radio beacons  14  that are configurable by the electronic hub devices  12  and for third party devices, such as Smartphones and tablets, for example. The radio beacon tracking system  10  may track third party radio beacons  14  within a coverage area of the radio beacon tracking system  10  and may track movement of third party devices that are passing through the coverage area. 
     From received signal strengths of radio beacon signals received at the omni-directional and multi-directional antennas  40 ,  30  of a single electronic hub device  12 , over at least two time periods, a direction gradient or a direction of travel of the radio beacon may be determined. Although it may be possible to track a radio beacon  14  using two or more omni-directional antennas  40  or one or more multi-directional antennas  30 , by combining the antenna types in an electronic hub device  12  and relying on received signal strength information from both types of antennas, the accuracy of radio beacon tracking may be significantly improved. 
     Traditionally when determining radio beacon location, omni-directional antennas have been used solely for the purpose of proximity detection. Because they are non-directional, location of a radio beacon  14  with a single omni directional antenna is not possible. At most, a single omni-directional antenna is capable of determining range of a radio beacon  14  with respect thereto. In order to estimate a location of the radio beacon  14  using an omni-directional antenna only, at least three observations from three different electronic hub devices  12  that are not arranged co-linearly are relied upon. In typical electronic hub device  12  deployment environments in which a distance between electronic hub devices  12  is approximately 15-20 meters, such an estimation may only be determined through use of a very complicated estimator. Combining received signal strength information from the different antenna types may simplify radio beacon tracking by taking advantage of sensor array processing, for example. 
     Another advantage of combining received signal strength information from omni-directional and multi-directional antennas is that the omni-directional antenna may perform more than one role. For example, the radio sub-system  42  of the omni-directional antenna  40  may be capable of switching to a communication mode. When the radio beacon  14  is reliably located within a particular angular range with respect to the electronic hub device  12 , input from the antenna directions associated with the angular range may solely be used for tracking. 
     Specific examples have been shown and described herein. However, modifications and variations may occur to those skilled in the art. All such modifications and variations are believed to be within the scope and sphere of the present disclosure.