Abstract:
A system may include in-vehicle components arranged symmetrically within and delimiting boundaries of a vehicle interior; and a processor programmed to identify signal strength information indicative of distance of a personal device from wireless transceivers of each of the in-vehicle components; and compute, using the signal strength information, a quadrant and diagonal sector including a location of the personal device, and whether the location is within the vehicle interior. A method may include identifying a quadrant of a vehicle including a location of a personal device by comparing signal strength information of pairs of wireless transceivers in adjacent quadrants to signal strength information of wireless transceivers opposite the pairs; and determining a diagonal sector including the location by comparing the signal strength information from the wireless transceiver of the quadrant to the signal strength information from the wireless transceiver in a diagonally-opposite quadrant.

Description:
TECHNICAL FIELD 
       [0001]    Aspects of the disclosure generally relate to tracking of locations of personal devices using a symmetrical layout of references within a vehicle cabin. 
       BACKGROUND 
       [0002]    Smartphone and wearable device sales volumes continue to increase. Thus, more such devices are brought by users into the automotive context. Smartphones can already be used in some vehicle models to access a wide range of vehicle information, to start the vehicle, and to open windows and doors. Some wearables are capable of providing real-time navigation information to the driver. Device manufacturers are implementing frameworks to enable a more seamless integration of their brand of personal devices into the driving experience. 
       SUMMARY 
       [0003]    In a first illustrative embodiment, a system includes first, second, third, and fourth in-vehicle components arranged symmetrically within and delimiting boundaries of a vehicle interior; and a processor programmed to identify signal strength information indicative of distance of a personal device from wireless transceivers of each of the in-vehicle components; and compute, using the signal strength information, a quadrant and diagonal sector including a location of the personal device, and whether the location is within the vehicle interior. 
         [0004]    In a second illustrative embodiment, a computer-implemented method includes identifying a quadrant of a vehicle including a location of a personal device by comparing signal strength information of pairs of wireless transceivers in adjacent quadrants to signal strength information of wireless transceivers opposite the pairs; and determining a diagonal sector including the location by comparing the signal strength information from the wireless transceiver of the quadrant to the signal strength information from the wireless transceiver diagonally-opposite to the quadrant. 
         [0005]    In a third illustrative embodiment, a system includes a personal device including a wireless transceiver; and a processor programmed to identify signal strength information indicative of distance of the personal device from wireless transceivers of each of first, second, third, and fourth in-vehicle components arranged symmetrically within and delimiting boundaries of a vehicle interior; and compute, using the signal strength information, a quadrant and diagonal sector including a location of the personal device. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]      FIG. 1A  illustrates an example system including a vehicle having a mesh of in-vehicle components configured to interact with users and user devices; 
           [0007]      FIG. 1B  illustrates an example in-vehicle component equipped with a wireless transceiver configured to facilitate detection of and identify proximity of the personal devices; 
           [0008]      FIG. 1C  illustrates an example in-vehicle component requesting signal strength from other in-vehicle components of the vehicle; 
           [0009]      FIG. 2  illustrates an example diagram of un-calibrated distance estimates of two reference wireless transceivers from a personal device; 
           [0010]      FIG. 3  illustrates an example diagram of a first solution estimate of the location of the personal device according to signal strength of signals received from in-vehicle components; 
           [0011]      FIG. 4  illustrates an example diagram of a second solution estimate of the location of the personal device according to signal strength of signals received from in-vehicle components; 
           [0012]      FIG. 5  illustrates an example diagram of a symmetrical layout of in-vehicle components delimiting an interior boundary of a vehicle interior; 
           [0013]      FIG. 6  illustrates an example diagram of determining the location of the personal device  104  using four-point lateration; 
           [0014]      FIG. 7  illustrates an example diagram of removing zones from consideration as location targets by comparing couples of signal strengths received from wireless transceivers; 
           [0015]      FIG. 8  illustrates an example diagram of removing diagonal sectors by comparing individual corner transmitter signal strengths; 
           [0016]      FIG. 9  illustrates an example diagram illustrating a region including a location target candidate for the personal device; 
           [0017]      FIG. 10  illustrates an example flow diagram of the lateration method for determining the location estimate for the personal device; 
           [0018]      FIG. 11  illustrates an example diagram of determining a location of the personal device according to a selective weighted average of signal strength; and 
           [0019]      FIG. 12  illustrates an example flow diagram of the lateration process for determining the location estimate for the personal device according to a selective weighted average of signal strength. 
       
    
    
     DETAILED DESCRIPTION 
       [0020]    As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention. 
         [0021]    As smartphones, tablets, and other personal devices become more powerful and interconnected, there is an opportunity to integrate more intelligence and sensing into components of the vehicle interior. Traditional vehicle interior modules, such as reading lights or speakers, may be enhanced with a communication interface (such as Bluetooth Low Energy (BLE)). These enhanced modules of the vehicle interior may be referred to as in-vehicle components. The vehicle occupants may utilize their personal devices to control features of the in-vehicle components by connecting their personal devices to the in-vehicle components over the communications interface. In an example, a vehicle occupant may utilize an application installed to the personal device to turn the reading light on or off, or to adjust a volume of the speaker. In many cases, it may be desirable for a vehicle occupant to be able to control the in-vehicle components that relate to the seat in which the vehicle occupant is located. 
         [0022]    Personal device location and tracking systems and methods may be employed using power signals from the mesh of interior in-vehicle components. For example, the RSSI (signal strength) of the in-vehicle components may be used to determine whether the personal device is located inside or outside a vehicle, and if inside, to which passenger it belongs. Identifying whether a personal device is inside or outside a vehicle can greatly simplify the user experience. In an example, tedious pairing procedures may be avoided for personal devices confirmed as being located within the vehicle interior. In a “mobility” future, where people could use a variety of different vehicles in the course of a day, being able to interact with them without the need for repeated validation procedures may greatly enhance the user experience. 
         [0023]      FIG. 1A  illustrates an example system  100  including a vehicle  102  having a mesh of in-vehicle components  106  configured to interact with users and personal devices  104  of the users. The system  100  may be configured to allow the users, such as vehicle occupants, to seamlessly interact with the in-vehicle components  106  in the vehicle  102  or with any other framework-enabled vehicle  102 . Moreover, the interaction may be performed without requiring the personal devices  104  to have been paired with or be in communication with a head unit or other centralized computing platform of the vehicle  102 . 
         [0024]    The vehicle  102  may include various types of automobile, crossover utility vehicle (CUV), sport utility vehicle (SUV), truck, recreational vehicle (RV), boat, plane or other mobile machine for transporting people or goods. In many cases, the vehicle  102  may be powered by an internal combustion engine. As another possibility, the vehicle  102  may be a hybrid electric vehicle (HEV) powered by both an internal combustion engine and one or more electric motors, such as a series hybrid electric vehicle (SHEV), a parallel hybrid electrical vehicle (PHEV), or a parallel/series hybrid electric vehicle (PSHEV). As the type and configuration of vehicle  102  may vary, the capabilities of the vehicle  102  may correspondingly vary. As some other possibilities, vehicles  102  may have different capabilities with respect to passenger capacity, towing ability and capacity, and storage volume. 
         [0025]    The personal devices  104 -A,  104 -B and  104 -C (collectively  104 ) may include mobile devices of the users, and/or wearable devices of the users. The mobile devices may be any of various types of portable computing device, such as cellular phones, tablet computers, smart watches, laptop computers, portable music players, or other devices capable of networked communication with other mobile devices. The wearable devices may include, as some non-limiting examples, smartwatches, smart glasses, fitness bands, control rings, or other personal mobility or accessory device designed to be worn and to communicate with the user&#39;s mobile device. 
         [0026]    The in-vehicle components  106 -A through  106 -N (collectively  106 ) may include various elements of the vehicle  102  having user-configurable settings. These in-vehicle components  106  may include, as some examples, overhead light in-vehicle components  106 -A through  106 -D, climate control in-vehicle components  106 -E and  106 -F, seat control in-vehicle components  106 -G through  106 -J, and speaker in-vehicle components  106 -K through  106 -N. Other examples of in-vehicle components  106  are possible as well, such as rear seat entertainment screens or automated window shades. In many cases, the in-vehicle component  106  may expose controls such as buttons, sliders, and touchscreens that may be used by the user to configure the particular settings of the in-vehicle component  106 . As some possibilities, the controls of the in-vehicle component  106  may allow the user to set a lighting level of a light control, set a temperature of a climate control, set a volume and source of audio for a speaker, and set a position of a seat. 
         [0027]    The vehicle  102  interior may be divided into multiple zones  108 , where each zone  108  may be associated with a seating position within the vehicle  102  interior. For instance, the front row of the illustrated vehicle  102  may include a first zone  108 -A associated with the driver seating position, and a second zone  108 -B associated with a front passenger seating position. The second row of the illustrated vehicle  102  may include a third zone  108 -C associated with a driver-side rear seating position and a fourth zone  108 -D associated with a passenger-side rear seating position. Variations on the number and arrangement of zones  108  are possible. For instance, an alternate second row may include an additional fifth zone  108  of a second-row middle seating position (not shown). Four occupants are illustrated as being inside the example vehicle  102 , three of whom are using personal devices  104 . A driver occupant in the zone  108 -A is not using a personal device  104 . A front passenger occupant in the zone  108 -B is using the personal device  104 -A. A rear driver-side passenger occupant in the zone  108 -C is using the personal device  104 -B. A rear passenger-side passenger occupant in the zone  108 -D is using the personal device  104 -C. 
         [0028]    Each of the various in-vehicle components  106  present in the vehicle  102  interior may be associated with the one or more of the zones  108 . As some examples, the in-vehicle components  106  may be associated with the zone  108  in which the respective in-vehicle component  106  is located and/or the one (or more) of the zones  108  that is controlled by the respective in-vehicle component  106 . For instance, the light in-vehicle component  106 -C accessible by the front passenger may be associated with the second zone  108 -B, while the light in-vehicle component  106 -D accessible by passenger-side rear may be associated with the fourth zone  108 -D. It should be noted that the illustrated portion of the vehicle  102  in  FIG. 1A  is merely an example, and more, fewer, and/or differently located in-vehicle components  106  and zones  108  may be used. 
         [0029]    Referring to  FIG. 1B , each in-vehicle component  106  may be equipped with a wireless transceiver  110  configured to facilitate detection of and identify proximity of the personal devices  104 . In an example, the wireless transceiver  110  may include a wireless device, such as a Bluetooth Low Energy transceiver configured to enable low energy Bluetooth signal intensity as a locator, to determine the proximity of the personal devices  104 . Detection of proximity of the personal device  104  by the wireless transceiver  110  may, in an example, cause a vehicle component interface application  118  of the detected personal device  104  to be activated. 
         [0030]    In many examples the personal devices  104  may include a wireless transceiver  112  (e.g., a BLUETOOTH module, a ZIGBEE transceiver, a Wi-Fi transceiver, an IrDA transceiver, an RFID transceiver, etc.) configured to communicate with other compatible devices. In an example, the wireless transceiver  112  of the personal device  104  may communicate data with the wireless transceiver  110  of the in-vehicle component  106  over a wireless connection  114 . In another example, a wireless transceiver  112  of a wearable personal device  104  may communicate data with a wireless transceiver  112  of a mobile personal device  104  over a wireless connection  114 . The wireless connections  114  may be a Bluetooth Low Energy (BLE) connection, but other types of local wireless connection  114 , such as Wi-Fi or Zigbee may be utilized as well. 
         [0031]    The personal devices  104  may also include a device modem configured to facilitate communication of the personal devices  104  with other devices over a communications network. The communications network may provide communications services, such as packet-switched network services (e.g., Internet access, VoIP communication services), to devices connected to the communications network. An example of a communications network may include a cellular telephone network. To facilitate the communications over the communications network, personal devices  104  may be associated with unique device identifiers (e.g., mobile device numbers (MDNs), Internet protocol (IP) addresses, identifiers of the device modems, etc.) to identify the communications of the personal devices  104  over the communications network. These personal device  104  identifiers may also be utilized by the in-vehicle component  106  to identify the personal devices  104 . 
         [0032]    The vehicle component interface application  118  may be an application installed to the personal device  104 . The vehicle component interface application  118  may be configured to facilitate vehicle occupant access to features of the in-vehicle components  106  exposed for networked configuration via the wireless transceiver  110 . In some cases, the vehicle component interface application  118  may be configured to identify the available in-vehicle components  106 , identify the available features and current settings of the identified in-vehicle components  106 , and determine which of the available in-vehicle components  106  are within proximity to the vehicle occupant (e.g., in the same zone  108  as the location of the personal device  104 ). The vehicle component interface application  118  may be further configured to display a user interface descriptive of the available features, receive user input, and provide commands based on the user input to allow the user to control the features of the in-vehicle components  106 . Thus, the system  100  may be configured to allow vehicle occupants to seamlessly interact with the in-vehicle components  106  in the vehicle  102 , without requiring the personal devices  104  to have been paired with or be in communication with a head unit of the vehicle  102 . 
         [0033]    To determine the in-vehicle components  106  that are in the same zone as the personal device  104 , the system  100  may use one or more device location-tracking techniques to identify the zone  108  in which the personal device  104  is located. Location-tracking techniques may be classified depending on whether the estimate is based on proximity, angulation or lateration. Proximity methods are “coarse-grained,” and may provide information regarding whether a target is within a predefined range but they do not provide an exact location of the target. Angulation methods estimate a position of the target according to angles between the target and reference locations. Lateration provide an estimate of the target location, starting from available distances between target and references. The distance of the target from a reference can be obtained from a measurement of signal strength  116  over the wireless connection  114  between the wireless transceiver  110  of the in-vehicle component  106  and the wireless transceiver  112  of the personal device  104 , or from a time measurement of either arrival (TOA) or difference of arrival (TDOA). 
         [0034]    One of the advantages of lateration using signal strength  116  is that it can leverage the already-existing received signal strength indication (RSSI) signal strength  116  information available in many communication protocols. For example, iBeacon uses the RSSI signal strength  116  information available in the Bluetooth Low-Energy (BLE) protocol to infer the distance of a beacon from a personal device  104  (i.e. a target), so that specific events can be triggered as the personal device  104  approaches the beacon. Other implementations expand on the concept, leveraging multiple references to estimate the location of the target. When the distance from three reference beacons are known, the location can be estimated in full (trilateration) from the following equations: 
         [0000]        d   1   2 =( x−x   1 ) 2 +( y−y   1 ) 2 +( z−z   1 ) 2    
         [0000]        d   2   2 =( x−x   2 ) 2 +( y−y   2 ) 2 +( z−z   2 ) 2    
         [0000]        d   3   2 =( x−x   3 ) 2 +( y−y   3 ) 2 +( z−z   3 ) 2   (1)
 
         [0035]    In an example, as shown in  FIG. 1C , an in-vehicle component  106 -B may broadcast or otherwise send a request for signal strength  116  to other in-vehicle components  106 -A and  106 -C of the vehicle  102 . This request may cause the other in-vehicle components  106 -A and  106 -C to return wireless signal strength  116  data identified by their respective wireless transceiver  110  for whatever devices they detect (e.g., signal strength  116 -A for the personal device  104  identified by the wireless transceiver  110 -A, signal strength  116 -C for the personal device  104  identified by the wireless transceiver  110 -C). Using these signal strengths  116 -A and  116 -C, as well as signal strength  116 -B determined by the in-vehicle component  106 -B using its wireless transceiver  110 -B, the in-vehicle component  106 -B may use the equations (1) to perform trilateration and locate the personal device  104 . 
         [0036]    However, use of signal strength  116  may require calibration of a known power at a known distance. As an example, the signal power received at a distance d from a transmitter can be calculated as an attenuation of a known power P d0  at a known distance d 0 : 
         [0000]    
       
         
           
             
               
                 
                   
                     P 
                     r 
                   
                   = 
                   
                     
                       P 
                       
                         ( 
                         
                           d 
                           0 
                         
                         ) 
                       
                     
                     
                       
                         ( 
                         
                           d 
                            
                           
                             / 
                           
                            
                           
                             d 
                             0 
                           
                         
                         ) 
                       
                       n 
                     
                   
                 
               
               
                 
                   ( 
                   2 
                   ) 
                 
               
             
           
         
       
     
         [0037]    Notably, the path loss exponent n of equation (2) is a function of the environment. In dynamically changing environments, such as the interior of the vehicle  102 , the value of n is neither a known nor a fixed quantity. Moreover, many different approaches to estimating distance from the signal strength  116  in the presence of unknown environmental factors require significant computational processing power. 
         [0038]    Distance may be estimated from signal strength  116  as follows, with constant A determined by calibration: 
         [0000]      RSSI (dBm)=−10 n  log 10( d )+ A   (3)
 
         [0039]    As a function of distance, and for n in the 2-3 range, distance d may be approximated from the reference signal as follows: 
         [0000]    
       
         
           
             
               
                 
                   d 
                   = 
                   
                     
                       10 
                       
                         RSSI 
                         20 
                       
                     
                      
                     k 
                   
                 
               
               
                 
                   ( 
                   4 
                   ) 
                 
               
             
           
         
       
     
         [0040]    Unless a thorough calibration is performed, one may expect k to be within a certain range, but may be unable to extract a reasonably good estimate for the distance d. 
         [0041]    However, tracking may be achieved by reliance on data from multiple wireless transceivers  110  with an assumption of symmetry in the relative locations of the wireless transceivers  110  and in environmental geometry of the surroundings of the sensors. Accordingly, an improved method to estimate location of personal devices  104  may be performed based on unprocessed signal strength  116  data, utilizing an assumption of a symmetrical layout of the references of the vehicle  102 . These references may include, in an example, the signal strengths from the wireless transceivers  110  of in-vehicle components  106  having a relatively symmetrical layout within the vehicle  102  cabin. In an example, the method may be utilized for determining whether a personal device  104  is located inside or outside the vehicle  102 . 
         [0042]    For sake of explanation, an analysis may be performed of locating an object in one dimension, using two references. In such an example, the single dimension may be considered to be a line traversing a row of seats in a vehicle  102 , e.g., from door to door, at lap level.  FIG. 2  illustrates an example diagram  200  of un-calibrated distance estimates d 1  and d 2  of two reference in-vehicle components  106 - 1  and  106 - 2 , respectively, from a personal device  104  (e.g., device D). Because the instant example is using un-calibrated distance estimates d 1  and d 2  determined between the wireless transceivers  110  of the in-vehicle components  106 - 1  and  106 - 2  and the personal device  104  (e.g., device D at location x), the two “proximity” circles r 1  and r 2  do not touch one another at the location x of the device D. (Properly-calibrated signal strength  116  information from the wireless transceivers  110  of the in-vehicle components  106 - 1  and  106 - 2  would ensure the “proximity” circles r 1  and r 2  determined according to the distance estimates d 1  and d 2  do touch one another at the location x of the device D.) As the distance estimates d 1  and d 2  are un-calibrated, to find the location of device D (i.e., location x) a scalar k may be used to scale the distance estimates d 1  and d 2  until the two “proximity” circles r 1  and r 2  match at x. 
         [0043]    Using equation (4) for distance, and assuming the same wireless transceiver  110  transmitting power level and same environment power attenuation for the two wireless transceivers  110 , the three possible analytical solutions for x 2 &gt;x 1  may be formed as follows: 
         [0000]    
       
         
           
             
               
                 
                   
                     
                       
                         
                           ( 
                           A 
                           ) 
                         
                          
                         
                             
                         
                          
                         
                           x 
                           1 
                         
                       
                       + 
                       
                         kd 
                         1 
                       
                     
                     = 
                     
                       
                         
                           
                             x 
                             2 
                           
                           - 
                           
                             kd 
                             2 
                           
                         
                         ⇒ 
                         k 
                       
                       = 
                       
                         
                           
                             x 
                             2 
                           
                           - 
                           
                             x 
                             1 
                           
                         
                         
                           
                             d 
                             1 
                           
                           + 
                           
                             d 
                             2 
                           
                         
                       
                     
                   
                    
                   
                     
 
                   
                    
                   
                     
                       
                         
                           ( 
                           B 
                           ) 
                         
                          
                         
                             
                         
                          
                         
                           x 
                           1 
                         
                       
                       - 
                       
                         kd 
                         1 
                       
                     
                     = 
                     
                       
                         
                           
                             x 
                             2 
                           
                           - 
                           
                             kd 
                             2 
                           
                         
                         ⇒ 
                         k 
                       
                       = 
                       
                         
                           
                             x 
                             2 
                           
                           - 
                           
                             x 
                             1 
                           
                         
                         
                           
                             d 
                             2 
                           
                           - 
                           
                             d 
                             1 
                           
                         
                       
                     
                   
                    
                   
                     
 
                   
                    
                   
                     
                       
                         
                           ( 
                           C 
                           ) 
                         
                          
                         
                             
                         
                          
                         
                           x 
                           1 
                         
                       
                       + 
                       
                         kd 
                         1 
                       
                     
                     = 
                     
                       
                         
                           
                             x 
                             2 
                           
                           + 
                           
                             kd 
                             2 
                           
                         
                         ⇒ 
                         k 
                       
                       = 
                       
                         
                           
                             x 
                             2 
                           
                           - 
                           
                             x 
                             1 
                           
                         
                         
                           
                             d 
                             1 
                           
                           - 
                           
                             d 
                             2 
                           
                         
                       
                     
                   
                 
               
               
                 
                   ( 
                   5 
                   ) 
                 
               
             
           
         
       
     
         [0044]    It should be noted that solution (B) is possible only for d 2 &gt;d 1 , while solution (C) is possible only for d 1 &gt;d 2 . 
         [0045]      FIG. 3  illustrates an example diagram  300  of a first solution estimate of the location of the personal device  104  according to signal strength  116  of signals received from in-vehicle components  106 . In the case as illustrated in  FIG. 3 , the first solution lies in-between the two reference wireless transceivers  110 -A and  110 -B. 
         [0046]      FIG. 4  illustrates an example diagram  400  of a second solution estimate of the location of the personal device  104  according to signal strength  116  of signals received from in-vehicle components  106 . As illustrated in  FIG. 4 , the second solution lies to the left of reference wireless transceivers  110 -A (i.e., left of the in-vehicle component  106 - 1 ). In other words, given the un-calibrated distance estimates d 1  and d 2  from two reference point wireless transceivers  110 -A and  110 -B, unless the estimates are equal, there are two possible solutions: one in-between the two references, and another outside of the reference with the stronger of the two signal strengths  116 . 
         [0047]      FIG. 5  illustrates an example diagram  500  of a symmetrical layout of in-vehicle components  106 - 1 ,  106 - 2 ,  1 - 6 - 3  and  106 - 4  delimiting an interior boundary of a vehicle  102  interior. Thus, the tracking/locating concept may be extended from one dimension to two dimensions of a vehicle  102  interior. If a personal device  104  is determined to be inside the vehicle  102 , the personal device  104  may be safely granted access to the appropriate vehicle  102  features. If instead the personal device  104  is deemed to be outside of the vehicle  102 , access to the in-vehicle components  106  may be denied, unless some other handshake or confirmation of identity of the personal device  104  can be performed. The location/tracking of the personal device  104  may additionally or alternately be used to locate the zone  108  of the vehicle  102  in which the personal device  104  is located. For instance, the zone  108  may be identified to determine whether the personal device  104  belongs to the driver (e.g., zone  108 -A of  FIG. 1A ), to a front-seat passenger (e.g., zone  108 -B of  FIG. 1A ), or to another vehicle occupant located in a back row of the vehicle  102  cabin (e.g., zones  108 -C or  108 -D of  FIG. 1A ). The location/tracking of the personal device  104  may additionally or alternately be used to extract “rough” gesture metrics from the tracking data. Notably, accuracy of the rough gesture detection may depend on the packet refresh rate of the single strength  116  data captured by the wireless transceivers  110 . 
         [0048]      FIG. 6  illustrates an example diagram  600  of determining the location of the personal device  104  using four-point lateration. As shown, the information available consists of the relative coordinates of the four symmetric reference transmitters, separated by distances X and Y, and the un-calibrated distance estimates, d 1 , d 2 , d 3 , and d 4 , obtained from the signal strength  116  levels captured by the in-vehicle components  106 - 1 ,  106 - 2 ,  1 - 6 - 3  and  106 - 4 , respectively, from the personal device  104 . The personal device  104  is located at X and Y coordinates that are to be determined. These coordinates of the personal device  104  may be referred to herein as D(x, y). 
         [0049]    In an example, location of the personal device  104  may be determined by minimizing the function: 
         [0000]    
       
         
           
             
               
                 
                   
                     ∑ 
                     
                       i 
                       = 
                       1 
                     
                     4 
                   
                    
                   
                     
                       ( 
                       
                         
                           
                             
                               
                                 ( 
                                 
                                   x 
                                   - 
                                   
                                     x 
                                     i 
                                   
                                 
                                 ) 
                               
                               2 
                             
                             + 
                             
                               
                                 ( 
                                 
                                   y 
                                   - 
                                   
                                     y 
                                     i 
                                   
                                 
                                 ) 
                               
                               2 
                             
                           
                         
                         - 
                         
                           kd 
                           i 
                         
                       
                       ) 
                     
                     2 
                   
                 
               
               
                 
                   ( 
                   6 
                   ) 
                 
               
             
           
         
       
     
         [0050]    However, the minimization as illustrated in equation (6) may be computationally expensive, and in some cases beyond the computational capabilities of the in-vehicle component  106  or other embedded microcontroller (MCU) of the vehicle  102  if the desire is to keep the cost of the implementation low. 
         [0051]      FIG. 7  illustrates an example diagram  700  of removing zones  108  from consideration as location targets by comparing couples of signal strengths  116  received from wireless transceivers  110 . The signal strengths  116  may be received from in-vehicle components  106  of the same type located at relatively symmetrical locations within the different zones  108  of the vehicle  102  cabin. By recognizing the symmetrical layout of the vehicle  102 , and the un-calibrated but likely similar sensitivity of the same-type of in-vehicle components  106 , zones  108  of the vehicle  102  may be eliminated as candidate target regions that include the personal device  104  by comparisons of signal strength  116 /distance estimates from the wireless transceivers  110 . 
         [0052]    As illustrated the un-calibrated but similar sensitivity signal strength  116  measurements from in-vehicle components  106 - 1  and  106 - 2  are weaker than the un-calibrated but similar sensitivity signal strength  116  measurements from in-vehicle components  106 - 3  and  106 - 4 , respectively. This is illustrated in the diagram  700  as relatively larger radii r 1  and r 2  as compared to radii r 3  and r 4 . As the signal strength  116  measurements from the in-vehicle components  106 - 1  and  106 - 2  are weaker, these measurement may exclude the possibility of the personal device  104  being located in the bottom half of the vehicle  102  interior/exterior. Additionally, the signal strength  116  measurements from in-vehicle components  106 - 2  and  106 - 4  are weaker than the signal strength  116  measurements from in-vehicle components  106 - 1  and  106 - 3 , respectively. This similarly may exclude the possibility of the personal device  104  being located in the right side of the vehicle  102  interior/exterior. 
         [0053]      FIG. 8  illustrates an example diagram  800  of removing diagonal sectors by comparing signal strengths  116  received from individual corner wireless transceivers  110 . As shown in the diagram  800 , the signal strength  116  measurements from in-vehicle component  106 - 1  is weaker than the signal strength  116  measurements from in-vehicle component  116 - 4 . The personal device  104  therefore cannot be located in the zone  108 -D to the bottom-left of the symmetry diagonal, as shown in the diagram  800 . 
         [0054]      FIG. 9  illustrates an example diagram  900  illustrating a region including a location target candidate for the personal device  104 . Accordingly, by combining the zone  108  quadrant information shown in the diagram  700  and the diagonal sector information illustrated in the diagram  800 , a triangular region  902  including the location of the personal device  104  is identified. The triangular region  902  is as highlighted in the diagram  900 . 
         [0055]    Similar to the single-dimension tracking described above with respect to  FIGS. 2-4 , it can be identified that, properly scaled, the distance estimates d may provide two possible tracking locations, with one solution on the inside of the vehicle  102  and the other on the outside of the vehicle  102 .  FIG. 9  accordingly illustrates a shaded triangle or diagonal sector, on the center-left top quadrant is the location target candidate. Notably, a portion of the diagonal sector is located inside of the vehicle  102 , and another portion of the diagonal sector is located outside of the vehicle  102 . 
         [0056]    While the vehicle  102  interior of the diagram  700  is split into four zones  108 -A,  108 -B,  108 -C and  108 -D, this is but one example. For a vehicle  102  with more than two seating rows, additional couples of reference in-vehicle component  106  wireless transmitters  110  and zones  108  may be added. In an alternate example, six wireless transceivers  110  and zones  108  may be utilized for a three row vehicle  102 . 
         [0057]      FIG. 10  illustrates an example flow diagram of the lateration process  1000  for determining the location estimate for the personal device  104 . In an example, the process  1000  may be performed by one of the in-vehicle components  106  of the vehicle  102  in communication with other in-vehicle components  106  of the vehicle  102 . In another example, the process  1000  may be performed by the personal device  104  in communication with the in-vehicle components  106  of the vehicle  102 . For sake of explanation, the device performing the lateration process  1000  may be referred to as the location estimator device. Also for sake of explanation and as illustrated in the diagrams  100 -A,  500 ,  600 ,  700 ,  800  and  900 , the in-vehicle components  106  may include the four in-vehicle components  106 - 1 ,  106 - 2 ,  106 - 3  and  106 - 4  located at relatively symmetrical locations within the zones  108 -A,  108 -B,  108 -C and  108 -D of the vehicle  102  and operating with similar sensitivity to one another. 
         [0058]    The process  1000  may include three phases. In one phase, the quadrant/diagonal sector indicative of a best estimated location of the personal device  104  is found according to the signal strength  116  measurements. In another phase, an estimate for parameter k to match the center point of that diagonal sector is calculated. Depending whether k falls inside a specific range the location estimator device can infer whether the signal attenuation matches an inside vs. outside the vehicle  102  pattern. In a third phase, if the personal device  104  is found to be inside the vehicle  102 , further iterations, using for example the Newton-Raphson method for finding successively better approximations to the function roots, may be performed to improve the personal device  104  location accuracy. 
         [0059]    More specifically, at operation  1002 , the location estimator device acquires signal strength  116  information. In an example, one of the in-vehicle components  106  may broadcast or otherwise send a request for signal strength  116  to the other in-vehicle components  106  of the vehicle  102 . This request may cause the other in-vehicle components  106  to return wireless signal strength  116  data identified by their respective wireless transceiver  110  for the personal devices  104  that are detected. In another example, the personal device  104  acting as the location estimator device may determine the signal strength  116  of the personal device  104  to the in-vehicle components  106 . Purely for sake of explanation of the process  1000 , the location estimator device may receive signal strength  116 - 1 ,  116 - 2 ,  116 - 3 , and  116 - 4  from in-vehicle components  106 - 1 ,  106 - 2 ,  106 - 3  and  106 - 4 , respectively, located in zones  108 -C,  108 -D,  108 -A and  108 -B, respectively. 
         [0060]    At operation  1004 , the location estimator device determines whether a sum of the signal strength  116 - 1  and signal strength  116 - 2  is greater than a sum of the signal strength  116 - 3  and signal strength  116 - 4 . If so, control passes to operation  1006  in which the personal device  104  is identified as being in front of the middle of the vehicle  102 . Otherwise, control passes to operation  1008  in which the personal device  104  is identified as being rear of the middle of the vehicle  102 . After operation  1006  control passes to operation  1010 . After operation  1008  control passes to operation  1012 . 
         [0061]    At operation  1010 , the location estimator device determines whether a sum of the signal strength  116 - 1  and signal strength  116 - 3  is greater than a sum of the signal strength  116 - 2  and signal strength  116 - 4 . If so, control passes to operation  1014  in which the personal device  104  is identified as being in the front passenger side of the vehicle  102 . Otherwise, control passes to operation  1016  in which the personal device  104  is identified as being in the front driver side of the vehicle  102 . After operation  1014  control passes to operation  1022 . After operation  1016  control passes to operation  1024 . 
         [0062]    At operation  1012 , the location estimator device determines whether a sum of the signal strength  116 - 1  and signal strength  116 - 3  is greater than a sum of the signal strength  116 - 2  and signal strength  116 - 4 . If so, control passes to operation  1018  in which the personal device  104  is identified as being in the rear passenger side of the vehicle  102 . Otherwise, control passes to operation  1020  in which the personal device  104  is identified as being in rear driver side of the vehicle  102 . After operation  1018  control passes to operation  1026 . After operation  1016  control passes to operation  1028 . 
         [0063]    At operation  1022 , the location estimator device determines whether signal strength  116 - 2  is less than signal strength  116 - 3 . If so, control passes to operation  1030  in which the personal device  104  is identified as being in the front passenger side of the vehicle  102  and also the front driver diagonal sector. Otherwise, control passes to operation  1032  in which the personal device  104  is identified as being in the front passenger side of the vehicle  102  and also the rear passenger diagonal sector. After operations  1030  and  1032  control passes to operation  1046 . 
         [0064]    At operation  1024 , the location estimator device determines whether signal strength  116 - 1  is less than signal strength  116 - 4 . If so, control passes to operation  1034  in which the personal device  104  is identified as being in the front driver side of the vehicle  102  and also the front passenger diagonal sector. Otherwise, control passes to operation  1036  in which the personal device  104  is identified as being in the front driver side of the vehicle  102  and also the rear driver diagonal sector. After operations  1034  and  1036  control passes to operation  1046 . 
         [0065]    At operation  1026 , the location estimator device determines whether signal strength  116 - 1  is less than signal strength  116 - 4 . If so, control passes to operation  1038  in which the personal device  104  is identified as being in the rear passenger side of the vehicle  102  and also the front passenger diagonal sector. Otherwise, control passes to operation  1040  in which the personal device  104  is identified as being in the rear passenger side of the vehicle  102  and also the rear driver diagonal sector. After operations  1038  and  1040  control passes to operation  1046 . 
         [0066]    At operation  1028 , the location estimator device determines whether signal strength  116 - 2  is less than signal strength  116 - 3 . If so, control passes to operation  1042  in which the personal device  104  is identified as being in the rear driver side of the vehicle  102  and also the front driver diagonal sector. Otherwise, control passes to operation  1044  in which the personal device  104  is identified as being in the rear driver side of the vehicle  102  and also the rear passenger diagonal sector. After operations  1042  and  1044  control passes to operation  1046 . 
         [0067]    At operation  1046 , the location estimator device calculates k for the center point of the diagonal sector. In an example, the location estimator device selects a center of mass of the diagonal sector identified in operations  1030 - 1044 , and calculates the k that minimizes equation (6) for that point. An initial value for k may be obtained by a weighted average of the individual solutions for k calculated for each in-vehicle component  106  to have the radius matching the center point of the diagonal sector. In some examples, iterations striving at minimizing equation (6) may be used to further refine the estimated location. For instance, the estimate of k at step n+1 is equal to the estimate of k at step n−f(k)/df(k), with f given by equation (6). The estimated k can then be used to determine whether the location estimated inside-the-vehicle  102  is the actual correct choice, or if, instead, the correct location is, still inside the diagonal sector, but on the outside of the vehicle  102  interior. 
         [0068]    At operation  1048 , the location estimator device determines whether the parameter k is within a range considered to be inside the vehicle  102 . In an example, even if the signal strength  116  is un-calibrated, the signal strength  116  measurements may still be assumed to be inside an expected range. This range may translate into a “correct” range for the parameter k. If the estimated k falls into the expected range then control passes to operation  1050  to determine that the personal device  104  is estimated to be inside the vehicle  102 . Otherwise the control passes to operation  1052  to determine that personal device  104  is either outside of the vehicle  102 , or its signal strength  116  is attenuated because the personal device  104  is within a pocket or bag or other attenuated location. After operations  1050  and  1052  the process  1000  ends. 
         [0069]      FIG. 11  illustrates an example diagram  1100  of determining a location of the personal device  104  according to a selective weighted average of signal strength  116 . For example, an identification of the driver to passenger side of the vehicle  102  cabin with stronger signal strength  116  (i.e., shorter estimated distances d) may be identified, and a driver to passenger estimate for the y location may be determined according to a weighted average (i.e. y is closer to transmitter which has shorter estimated distance d). Additionally, an identification of the front to rear side of the vehicle  102  cabin with stronger signal strength  116  (i.e. shorter estimated distances d) may be identified, and a front to back estimate for the x location may be determined according to a weighted average (i.e. x is closer to the wireless transceiver  110  which has a shorter estimated distance d). 
         [0070]      FIG. 12  illustrates an example flow diagram of the lateration process  1200  for determining the location estimate for the personal device  104  according to a selective weighted average of signal strength  116 . Similar to as discussed above with respect to the process  1000 , the process  1200  may be performed by one of the in-vehicle components  106  of the vehicle  102  in communication with other in-vehicle components  106  of the vehicle  102  and/or by the personal device  104  in communication with the in-vehicle components  106  of the vehicle  102 . Also similar to as discussed above with respect to the process  1000 , for sake of explanation, the device performing the lateration process  1000  may be referred to as the location estimator device, and the in-vehicle components  106  may include the four in-vehicle components  106 - 1 ,  106 - 2 ,  106 - 3  and  106 - 4  located at relatively symmetrical locations within the zones  108 -A,  108 -B,  108 -C and  108 -D of the vehicle  102  and operating with similar sensitivity to one another. 
         [0071]    At operation  1202 , the location estimator device acquires signal strength  116  information. In an example, one of the in-vehicle components  106  may broadcast or otherwise send a request for signal strength  116  to the other in-vehicle components  106  of the vehicle  102 . This request may cause the other in-vehicle components  106  to return wireless signal strength  116  data identified by their respective wireless transceiver  110  for the personal devices  104  that are detected. In another example, the personal device  104  acting as the location estimator device may determine the signal strength  116  of the personal device  104  to the in-vehicle components  106 . 
         [0072]    At operation  1204 , the location estimator device determines whether a sum of the signal strength  116 - 1  and signal strength  116 - 2  is less than a sum of the signal strength  116 - 3  and signal strength  116 - 4 . If so, control passes to operation  1208  in which the personal device  104  is identified as being in the front of the vehicle  102 . Otherwise, control passes to operation  1210  in which the personal device  104  is identified as being in the rear of the vehicle  102 . After operation  1208  control passes to operation  1216 . After operation  1210  control passes to operation  1218 . 
         [0073]    At operation  1206 , the location estimator device determines whether a sum of the signal strength  116 - 1  and signal strength  116 - 3  is less than a sum of the signal strength  116 - 2  and signal strength  116 - 4 . If so, control passes to operation  1212  in which the personal device  104  is identified as being in the passenger side of the vehicle  102 . Otherwise, control passes to operation  1214  in which the personal device  104  is identified as being in the driver side of the vehicle  102 . After operation  1212  control passes to operation  1220 . After operation  1214  control passes to operation  1222 . 
         [0074]    At operation  1216 , the location estimator device computes X. In an example, X may be computed as the quantity of d 3 /(d 3 +d 4 )*(r 3 −r 4 ), where r 3 −r 4  is the distance of the two wireless transceivers  110  of the in-vehicle components  106 - 3  and  106 - 4 , and d 3  and d 4  are the initial estimates of the un-calibrated distance from the personal device  104 . After operation  1216 , control passes to operation  1224 . 
         [0075]    At operation  1218 , the location estimator device computes X. In an example, X may be computed as the quantity of d 1 /(d 1 +d 2 )*(r 1 −r 2 ), where r 1 −r 2  is the distance of the two wireless transceivers  110  of the in-vehicle components  106 - 1  and  106 - 2 , and d 1  and d 2  are the initial estimates of the un-calibrated distance from the personal device  104 . After operation  1218 , control passes to operation  1224 . 
         [0076]    At operation  1220 , the location estimator device computes X. In an example, X may be computed as the quantity of d 2 /(d 2 +d 4 )*(r 2 −r 4 ), where r 2 −r 4  is the distance of the two wireless transceivers  110  of the in-vehicle components  106 - 2  and  106 - 4 , and d 2  and d 4  are the initial estimates of the un-calibrated distance from the personal device  104 . After operation  1220 , control passes to operation  1224 . 
         [0077]    At operation  1222 , the location estimator device computes X. In an example, X may be computed as the quantity of d 1 /(d 1 +d 3 )*(r 1 −r 3 ), where r 1 −r 3  is the distance of the two wireless transceivers  110  of the in-vehicle components  106 - 1  and  106 - 3 , and d 1  and d 3  are the initial estimates of the un-calibrated distance from the personal device  104 . After operation  1222 , control passes to operation  1224 . 
         [0078]    At operation  1224 , the location estimator device calculates k for the point (X, Y), e.g., with a procedure analogous to as described above with respect to operation  1046 . 
         [0079]    At operation  1226 , the location estimator device determines whether the parameter k is within a range considered to be inside the vehicle  102 . In an example, even if the signal strength  116  is un-calibrated, the signal strength  116  measurements may still be assumed to be inside an expected range. This range may translate into a “correct” range for the parameter k. If the estimated k falls into the expected range then control passes to operation  1228  to determine that the personal device  104  is estimated to be inside the vehicle  102 . Otherwise the control passes to operation  1230  to determine that personal device  104  is either outside of the vehicle  102 , or its signal strength  116  is attenuated because the personal device  104  is within a pocket or bag or other attenuated location. After operations  1228  and  1230  the process  1200  ends. 
         [0080]    Thus, the described lateration may allow a location estimator device to determine whether a personal device  104  is located inside or outside the vehicle  102 . Using this information, connection to features inside the vehicle  102  may be enabled without the need for pairing the personal device  104 , since location estimator device may have identified whether the personal device  104  is inside the vehicle  102  and authorized to utilize the in-vehicle component  106 , or is outside the vehicle  102  and is not authorized to utilize the in-vehicle component  106 . Additionally, the described lateration may allow a location estimator device to determine the zone  108  of the personal device  104  within the vehicle  102  to allow for the direct selection of vehicle  102  features that are directly connected to the zone  108  seating position. 
         [0081]    Computing devices described herein, such as the personal devices  104  and in-vehicle components  106 , generally include computer-executable instructions, where the instructions may be executable by one or more computing devices such as those listed above. Computer-executable instructions may be compiled or interpreted from computer programs created using a variety of programming languages and/or technologies, including, without limitation, and either alone or in combination, Java™, C, C++, C#, Visual Basic, Java Script, Perl, etc. In general, a processor (e.g., a microprocessor) receives instructions, e.g., from a memory, a computer-readable medium, etc., and executes these instructions, thereby performing one or more processes, including one or more of the processes described herein. Such instructions and other data may be stored and transmitted using a variety of computer-readable media. 
         [0082]    With regard to the processes, systems, methods, heuristics, etc., described herein, it should be understood that, although the steps of such processes, etc., have been described as occurring according to a certain ordered sequence, such processes could be practiced with the described steps performed in an order other than the order described herein. It further should be understood that certain steps could be performed simultaneously, that other steps could be added, or that certain steps described herein could be omitted. In other words, the descriptions of processes herein are provided for the purpose of illustrating certain embodiments, and should in no way be construed so as to limit the claims. 
         [0083]    While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention. Additionally, the features of various implementing embodiments may be combined to form further embodiments of the invention.