SYSTEM AND METHOD FOR DETERMINING THE LOCATION OF A MOBILE DEVICE RELATIVE TO THE VEHICLE CABIN

Abstract

Vehicle (104), comprising: a plurality of antennas positioned at locations inside and outside a vehicle cabin (108), each antenna being in wireless communication with an external mobile device (102) and associated with signal strength information; and a central module (110) in communication with the antennas and configured for: identifying the antennas with the two strongest signals, and determining that one of the antennas is positioned outside the vehicle cabin (108) and the other antenna is positioned inside the vehicle cabin (108) opposite the first antenna relative to the vehicle cabin (108); and if a difference between the signal strengths of the identified antennas exceeds a threshold, identifying that the mobile device (102) is in the same position relative to the vehicle (104) as the first antenna (106a).

Description

TECHNICAL FIELDThis application relates generally to passive entry passive start (PEPS) systems, and more particularly to enabling a mobile device to operate as a PEPS key fob to control functions in the vehicle.GENERAL STATE OF THE ARTMany vehicles include a passive entry passive start (PEPS) system, also known as an intelligent access (IA) system, that enables access and start capabilities without any physical manipulation of a conventional key or key fob by the driver or other vehicle user, as long as the user carries a valid key fob on the user's person (e.g., in the hand or in a pocket) or in the nearby ownership such as a handbag, jacket, or briefcase. The PEPS system typically includes a fob with buttons or switches to enable user-initiated control of various vehicle functions, including remote keyless entry (RKE) functions (e.g., locking and unlocking vehicle doors, opening and / or closing the trunk, tailgate, or sliding doors of the vehicle), and / or remote keyless ignition (RKI) functions (e.g., starting the vehicle engine in a non-propelling mode so that the vehicle cannot start). One or more of these key fob functions may be initiated passively (i.e., without physical manipulation of the key fob) by the PEPS system upon detection of certain conditions related to the key fob.For example, an existing PEPS system may perform key checks or other background tasks (i.e., without the user's knowledge) to detect the presence of a key fob within a predetermined proximity to the vehicle, thereby ensuring that a detected key fob is valid (e.g., associated with that vehicle) and / or determining the location of a valid key fob relative to the vehicle cabin (e.g., within or outside the cabin). Based on the results of these key checks, the PEPS system may authorize passive entry (e.g., unlocking the vehicle doors without requiring user selection of an unlock button on the key fob) or passive start (e.g., starting the vehicle engine in a propel mode that allows the vehicle to start in response to user selection of an ignition button within the vehicle). The PEPS system may also perform background and key checks in conjunction with other vehicle functions that require the presence of the key fob for authorization purposes, such as "Sesame Open Pinch" or proximity detection.Based on the ubiquitous nature of smart phones and other mobile devices in the today's technology oriented world, some PEPS systems are further configured to include a phone-as-a-key (PaaK) feature that allows the user's phone to function as the PEPS key fob and eliminates the need to wear a key fob to access and control the vehicle. For example, the PaaK feature allows the phone to be used for conventional key fob functions such as unlocking, locking, remote start, liftgate, and mobilization authorization without the presence of a key fob.While conventional PEPS key fobs use a low frequency (LF) receiver and an ultra high frequency (UHF) transmitter to communicate with the vehicle, the PaaK feature is typically implemented using BLUETOOTH low energy (BLE) communication devices included in both the vehicle and the phone. BLE signals may, however, be more susceptible to signal degradation due to reflection, absorption, and temperature changes, at least due to the difference in operating frequencies, as compared to the LF signals used to locate conventional PEPS key fobs. For example, the LF signals are typically in the 125 kHz or 134.5 kHz bands, while the BLE signals are typically in the 2.4 GHz band. This physical fact makes a PaaK device more difficult to locate than a conventional PEPS key fob.Accordingly, there is still a need in the art for a PEPS system that can implement the PaaK feature with at least the same accuracy and reliability as conventional PEPS key fobs.Further prior art is known from publications D1 US 2012-0244877 A1 and D2 US 2015-0149042 A1.SUMMARYThe invention is intended to solve the above-noted and other problems by providing systems and methods for accurately determining the location of a mobile device, such as a smartphone, relative to a vehicle cabin using a plurality of antennas located inside and outside the vehicle cabin.For example, an embodiment provides a vehicle comprising a plurality of antennas positioned at locations inside and outside a vehicle cabin, each antenna in wireless communication with an external mobile device and associated with signal strength information; and a central module in communication with the antennas and configured to identify the antennas with the two strongest signals and determine a location of a mobile device relative to the vehicle cabin based on the locations of the identified antennas.Another example embodiment includes a method comprising receiving signal strength information associated with a plurality of antennas wirelessly communicating with a mobile device, the antennas positioned at locations inside and outside a vehicle cabin; identifying a first antenna having a first highest signal strength and a second antenna having a second highest signal strength; and determining a location of a mobile device relative to the vehicle cabin based on the locations of the first and second antennas.It is to be understood that this disclosure is defined by the appended claims. The description summarizes aspects of the embodiments and is not to be used to limit the claims. Other implementations are contemplated in accordance with the techniques described herein, as will be apparent to one of ordinary skill in the art upon review of the following drawings and detailed description, and these implementations are intended to be within the scope of this disclosure.BRIEF DESCRIPTION OF THE DRAWINGSFor a better understanding of the invention, reference is made to embodiments which are illustrated in the following drawings. The components in the drawings are not necessarily to scale and related elements may be omitted, or in some cases, proportions may be exaggerated, to emphasize and clearly illustrate the novel features described herein. Furthermore, system components may be variously arranged as known in the art. Further, in the drawings, corresponding parts are denoted by like reference numerals throughout the several views. FIG. 1 illustrates an example environment for determining a location of a mobile device relative to a vehicle cabin using a plurality of vehicle antennas, according to certain embodiments. FIGS. 2-5 are flowcharts of example methods for determining a location of a mobile device relative to a vehicle cabin, in accordance with certain embodiments. FIG. 6 is a block diagram of an example vehicle system, in accordance with certain embodiments.DETAILED DESCRIPTION OF EMBODIMENTSWhile the invention may be embodied in various forms, there are shown in the drawings and described below some exemplary and non-limiting embodiments, with the understanding that the present disclosure is to be considered an explanation of the invention by way of example and is not intended to limit the invention to the specific embodiments illustrated. In this application, the use of disjunction is intended to include conjunction. The use of certain or indeterminate articles is not intended to indicate cardinality. In particular, a reference to "the" object or "an" object is also intended to denote one of a possible plurality of such objects.FIG. 1 illustrates an example environment 100 for determining a current location of a mobile device 102 relative to a vehicle 104 using a plurality of antennas 106 positioned at different locations inside and outside a cabin area 108 of the vehicle 104, according to embodiments. The vehicle 104 includes a passive entry passive start (PEPS) system (such as, for example, the PEPS system 604 shown in FIG. 6 ) to enable a driver or other vehicle user to passively, remotely, and / or keylessly control various operations or functions of the vehicle 104. The mobile device 102 is configured to implement a phone-as-a-key (PaaK) feature of the vehicle's PEPS system or otherwise function as a fob authorized to enable passive, remote, and / or keyless initiation of various vehicle operations once certain conditions have been met, including detection of the mobile device 102 within a predetermined proximity to the vehicle 104 and / or within the vehicle cabin 108. The plurality of antennas 106 are included in the vehicle 104 to support the PaaK feature by detecting the presence and / or location of the mobile device 102 using short-range wireless communication technology (such as BLUETOOTH Low Energy (BLE)) and passing this information to the vehicle 104 for processing in conjunction with the operation of the PEPS system. In embodiments, the number and placement of the antennas 106 within the vehicle 104 may be specifically selected to optimize accurate and reliable detection of the mobile device for purposes of performing the PEPS operations, as described in more detail below.Although not shown, environment 100 may also include one or more key fobs that are assigned to or paired with vehicle 104 and configured to implement aspects of the PEPS system. Each key fob may include one or more buttons or switches to enable direct user control of particular vehicle operations (e.g., by user input input input to the key fob). Each fob may also be configured to enable passive, remote, and / or keyless initiation of particular vehicle operations. For example, the PEPS system may automatically unlock one or more vehicle doors upon detecting the presence of the key fob within a predetermined proximity to the vehicle 104 and upon detecting user contact with the door handle of the vehicle 104.Each key fob may be assigned a unique identifier (ID) or a particular digital identity code that is used to communicatively link or pair the key fob with the vehicle 104 and otherwise confirm the validity of the key fob prior to permitting communication with the vehicle 104. For example, the vehicle 104 may be configured to store the key fob ID from each key fob that is paired or associated with the vehicle 104 and execute only commands originating from key fobs having an ID corresponding to one of the stored key fob IDs (e.g., a valid key fob ID). In some cases, the key fob may transmit the key fob ID with or just before each user-input or passively initiated key fob command, such that the vehicle 104 may easily validate the source of the command.In embodiments, the PEPS system enables remote keyless control of a predetermined series of vehicle operations (also referred to herein as "PEPS operations") when one or more conditions associated with a given vehicle operation have been met. As an example, the PEPS operations may include, but are not limited to, locking and unlocking door locks or other electronic locks of the vehicle 104, opening and / or closing a trunk, tailgate, sliding door, or other electronically operated door of the vehicle 104, opening and / or closing a window or roof of the vehicle 104, and starting an engine of the vehicle 104. It should be appreciated that other vehicle operations may be controlled by the PEPS system and the present disclosure is intended to cover any and all of these operations. The condition(s) that must / must be met prior to initiating each PEPS operation may / may vary depending on the type of vehicle operation, manufacturer specifications, user selected specifications, and / or other relevant factors. In some PEPS operations, such as unlocking one or more door locks and / or opening a sliding door, the PEPS system may be configured to passively initiate the operation (e.g., without receiving a user input command) upon detecting that the mobile device 102 or a valid fob is outside of the vehicle 104, is within a predetermined proximity to the vehicle 104, and / or is approaching the vehicle 104. For other PEPS operations, such as starting the vehicle engine, the PEPS system may be configured to passively initiate the operation (e.g., without requiring a key) upon detecting that the mobile device 102 or the key fob is located within the vehicle cabin 108. It should be appreciated that other conditions including the mobile device 102 may be associated with each PEPS operation, and the present disclosure is intended to cover any and all of these conditions.The mobile device 102 may be any type of portable electronic device including, for example, a smartphone or other mobile phone, a tablet or tablet-like personal computer, a personal digital assistant (PDA), a smart watch or other portable device, and the like. According to embodiments, the mobile device 102 may be paired or associated with the vehicle 104 using known wireless pairing techniques to authorize communication between the mobile device 102 and the vehicle 104. For example, during an initial programming mode, the mobile device 102 may wirelessly transmit to the vehicle 104 or a cloud computing network associated with the vehicle 104 one of the key fob IDs associated with a key fob associated with the vehicle 104 to validate the mobile device 102. The mobile device 102 may communicate with the vehicle 104, or more specifically, a vehicle computing system (VCS) included therein (such as VCS 602 shown in FIG. 6 ) using BLUETOOTH, infrared, radio frequency identification (RFID), near field communication (NFC), WiFi, cellular, satellite-assisted, LTE direct, SDRC, or any other wireless communication technology compatible with the plurality of antennas 106, and / or a telematics control unit (TCU) (such as TCU 606 shown in FIG. 6 ) included in the vehicle 104. The mobile device 102 may include a wireless unit 108 comprising wireless communication circuitry (e.g., one or more antennas, receivers, transmitters, and / or transceivers) to enable communication with the vehicle 104, as is known.In some cases, the mobile device 102 may include a software application 109 (or "vehicle application") configured to communicate with the vehicle 104 using the wireless unit 108 and via a wireless communication network (not shown) such as a WiFi network or other wireless Ethernet, cellular network, and / or satellite. In some cases, the wireless communication network is a cloud computing network communicatively linked to a remote server or cloud computing device (not shown) controlled by and / or associated with the vehicle manufacturer. In some embodiments, a secure wireless communication channel between the vehicle computing system of the vehicle 104 and the cloud computing device may be previously established to enable direct communication between the vehicle 104 and the cloud device without the need for pairing or prior authorization. The secure communication channel may be established by or under monitoring by the vehicle manufacturer.In embodiments, the vehicle application 109 may be a mobile client developed by and / or associated with the vehicle manufacturer and may be customized for the vehicle 104. In some embodiments, the vehicle application 109 may be configured to assist in implementing the PaaK features of the mobile device 102, for example, by providing a user interface on a display screen of the mobile device 102 to control certain features of the PEPS system. In some cases, the user interface may display prompts for entering vehicle operation commands, user selected inputs, or other information for forwarding to the vehicle 104, for example, when the PaaK features are not available or a location of the mobile device 102 cannot be determined, as discussed in more detail below with reference to FIG. 4. The vehicle application 109 may also have vehicle information, such as diagnostic and / or performance information about the vehicle 104, for example in connection with a vehicle infotainment system (such as FORD SYNC® for example). In embodiments, all or a portion of the vehicle application 109 may be stored in a memory (not shown) of the mobile device 102 and executed by a data processor (not shown) of the mobile device 102.In some embodiments, during a PaaK operation of the mobile device 102, each of the plurality of antennas 106 may be configured to transmit a wireless signal to the mobile device 102 and receive corresponding signal strength information from the mobile device 102. For example, the antennas 106 may "anping" the mobile device 102 or otherwise emit a query or search signal in searching for the mobile device 102. In some embodiments, the antennas 106 may be configured to permanently transmit this wireless signal, and the mobile device 102 may be configured to permanently search for the transmitted wireless signal such that the two may be automatically connected once the mobile device 102 is within a wireless communication range of the antennas 106. Upon receipt of the interrogation signal, the mobile device 102 may respond with one or more signals including location information about the device, identification information about the device, signal strength information corresponding to the antennas 106, and / or other information indicating the presence of the mobile device 102.In other embodiments, this may be the opposite. That is, the mobile device 102 may permanently transmit a wireless signal searching for the antennas 106, and the antennas 106 may be configured to permanently search for the transmitted wireless signal (e.g., query or search signal). Once the mobile device 102 is within the wireless communication range of the antennas 106, each of the antennas 106 may respond by sending information indicative of the presence of the antennas, including identification information about the device and signal strength information, to the mobile device 102.In either case, the signal strength information may be provided in the form of a received signal strength indicator (RSSI) value for each antenna 106, as perceived or measured by the device receiving the interrogation signal. That is, when the antennas 106 transmit the interrogation signal, the signal strength for each antenna 106 is measured by the mobile device 102 upon receipt of the interrogation signal from that antenna 106. In these cases, each of the antennas 106 may receive their corresponding RSSI value from the mobile device 102 in feedback, and the antennas 106 may transmit their signal strength information to the central module 110 for processing. Alternatively, the mobile device 102 may send the RSSI value from each antenna directly to the central module 110 for processing. Similarly, when the mobile device 102 is transmitting the interrogation signal, each of the antennas 106 receives the interrogation signal and measures the signal strength of that signal. In these cases, the antennas 106 send their own RSSI values directly to the central module 110 for processing.In other embodiments, the mobile device 102 may be configured to perform signal strength information processing instead of the vehicle 104, or more particularly, the VCS included therein, and then send the processed data to the central module 110. For example, when the mobile device 102 measures the signal strength from each of the antennas 106, the mobile device 102 may first process the signal strength information and then send the processed data to the central module 110. On the other hand, when the antennas 106 measure their signal strength based on the interrogation signal transmitted from the mobile device 102, the mobile device 102 may receive signal strength information from each of the antennas 106 for processing.The antennas 106 may be configured to communicate with the mobile device 102 using a short-range wireless communication network, such as a standard BLUETOOTH network, a BLUETOOTH low energy (BLE) network, an NFC network, an RFID network, etc. The mobile device 102 may not be detected by the antennas 106 until after the mobile device 102 moves within a wireless communication range of the antennas 106 or another predetermined distance to the vehicle 104. In a preferred embodiment, antennas 106 are BLE antennas configured to operate in the 2.4 gigahertz (GHz) band and use up to three channels to transmit and receive signals to and from mobile device 102, for example, by a channel hopping method. In these cases, the wireless unit 108 of the mobile device 102 also includes at least one BLE antenna configured to wirelessly communicate with the antennas 106, for example, once the mobile device 102 is within 100 meters of the vehicle.As shown in FIG. 1, the vehicle 104 further includes a central module 110. According to embodiments, the central module 110 may be configured to communicate with each of the plurality of antennas 106 via a wired or wireless connection and also communicate with the vehicle computing system of the vehicle 104 for performing the PEPS operation or other vehicle commands received from the mobile device 102. In particular, each of the antennas 106 may be configured to provide the signal strength information received from the mobile device 102 to the central module 110. In embodiments, the central module 110 may be configured to process the processed information and identify a location of the mobile device 102 based on the received information, for example using one or more methods illustrated in FIGS. 2-5, as discussed in more detail below. Based on the identified location, the central module 110 may be further configured to enable either a passive start operation of the PEPS system when the mobile device 102 is inside the vehicle cabin 108 or a passive access operation of the PEPS system when the mobile device 102 is outside the vehicle cabin 108. For example, the central module 110 may enable the passive start operation by instructing the vehicle computing system or powertrain control module to start the vehicle engine and may enable the passive entry operation by instructing the vehicle computing system or body control module to unlock the vehicle doors.As shown in FIG. 1, the antennas 106 may be positioned at various locations on the vehicle 104 inside and outside of the vehicle cabin 108. In embodiments, the exact location of the antennas 106, as well as the number of antennas 106 placed at each location and / or across the entire vehicle 104, may be specifically selected to ensure accurate, repeatable, and reliable detection of the mobile device 102 during the PEPS operation. For example, the placement and number of antennas 106 may be configured to more accurately determine whether mobile device 102 is located inside or outside vehicle cabin 108, adjacent a driver side, a passenger side, a front end, or a rear end of vehicle 104, and / or in a front, middle, or rear occupant side of vehicle 104.FIG. 1 shows an example embodiment in which a first antenna 106 ais positioned outside the vehicle cabin 108 adjacent to a front driver side door 112 of the vehicle 104, while a second antenna 106 bis positioned inside the vehicle cabin 108 adjacent to the front driver side door 112. Additionally, a third antenna 106 cis positioned outside the vehicle cabin 108 adjacent a front passenger side door 114 of the vehicle 104, while a fourth antenna 106 dis positioned inside the vehicle cabin 108 adjacent the front passenger side door 114. As shown in FIG. 1, the plurality of antennas 106 may also include a fifth antenna 106 epositioned adjacent to a driver's rear side door 116 and a sixth antenna 106 fpositioned adjacent to a passenger's rear side door 118. The fifth and sixth antennas 106 eand 106 fmay be positioned inside or outside the rear doors 116 and 118, respectively. In some cases, one or more additional antennas (not shown) may be added to the doors 116 and 118 such that an antenna is positioned on both the inner and outer surfaces of the doors.The exact location of the antennas 106 a- 106 f(also referred to herein as "door antennas") on the doors 112, 114, 116, and 118 may vary depending on a number of factors including, for example, the make and model of the vehicle 104, vehicle manufacturer preferences, antenna performance optimization, and / or the amount of available space for antenna placement. As an example, the interior door antennas may be located on or within an interior door panel or other interior surface of the vehicle doors, an interior trim panel of a pillar (e.g., A pillar, B pillar, or C pillar) adjacent the interior of the vehicle doors, or any other surface adjacent the interior of the vehicle doors. Similarly, the exterior door antennas may be located on or within an exterior door panel or other exterior surface of the vehicle doors, an exterior panel of a pillar adjacent the exterior of the vehicle doors, or a rocker, side mirror, vent, or any other surface adjacent the interior of the vehicle doors.As illustrated, the antennas 106 may further include a seventh antenna 106 gpositioned within the vehicle cabin 108 between the two front doors 112 and 114, for example, adjacent to a center console (not shown) located between the two front seats, a front dashboard (not shown) located forward of a front occupant row, a front headliner (not shown) located over a front occupant region, or any other surface in the front occupant region of the cabin 108. Additionally, the antennas 106 may include an eighth antenna 106 hpositioned within the vehicle cabin 108 between the two rear doors 116 and 118, for example, at or within a rear headliner (not shown) located over a rear occupant area, a rear dashboard or rear shelf located behind the rear occupant seats, or any other surface in the rear occupant area of the cabin 108.The illustrated embodiment also includes a ninth antenna 106 ipositioned outside the vehicle cabin 108 adjacent a rear tailgate 120 of the vehicle 104. As an example, the ninth antenna 106 imay be positioned on or within an exterior door panel or other exterior surface of the tailgate 120, a rear bumper of the vehicle 104, or any other surface adjacent the exterior of the tailgate 120. As illustrated, the plurality of antennas 106 may also include a tenth antenna 106 jpositioned within the vehicle cabin 108 adjacent to the tailgate 120 and a trunk 122 of the vehicle 104. As an example, the tenth antenna 106 jmay be positioned on or within a decklid or other interior surface of the trunk 122, an interior door panel or other surface of the tailgate 120, or any other surface adjacent the interior of the tailgate 120 and / or the trunk 122.Other embodiments may include additional antennas 106 positioned at other suitable locations within or outside of the vehicle 104, including, for example, adjacent a front end of the vehicle 104 (e.g., at or within a front vehicle bumper, adjacent an application or sticker zone at the front end of the vehicle 104, at or within a vent at the front end of the vehicle 104, etc.), and / or adjacent a third occupant row, if present in the vehicle, within or outside of the vehicle cabin 108 (e.g., at or within a headliner for the third row, an inner or outer surface of a pillar adjacent the third row, or an outer rocker adjacent the third row). It should be appreciated that the locations and number of antennas 106 illustrated and described herein, including FIG. 1, are / are intended to be an explanation of the techniques described herein and that the present disclosure is not limited to the antenna arrangement illustrated and described herein. Further, the scope of the present disclosure is intended to include any number of antennas 106 in any combination of locations inside and outside of the vehicle 104.FIG. 2 illustrates an example method 200 for determining the location of a mobile device relative to a vehicle cabin, according to embodiments. The method 200 may be performed by a vehicle system (such as the vehicle system 600 shown in FIG. 6 ) included in a vehicle (such as the vehicle 104 shown in FIG. 1 ), or more particularly, a computing device included therein, such as the central module 608 shown in FIG. 6 or the central module 110 shown in FIG. 1. For example, the method 200 may be implemented, at least in part, by a processor (not shown) of the computing device executing a software application stored in a memory (not shown) of the computing device. Further, to perform the operations of method 200, the computing device may interact with a plurality of antennas (such as antennas 106 shown in FIG. 1 ) positioned at various locations inside and outside a vehicle cabin (such as vehicle cabin 108 shown in FIG. 1 ). The antennas interact with a mobile device (such as mobile device 102 shown in FIG. 1 ) paired with the vehicle or otherwise functioning as a PaaK device associated with the PEPS system of the vehicle.As shown in FIG. 2, the method 200 begins at step 202, where the processor receives signal strength information for each of the antennas. The signal strength information for a given antenna may be a received signal strength indicator (RSSI) value, as perceived or measured by the device receiving the wireless signal for the request for signal strength information. In some embodiments, the processor receives the signal strength information for each of the antennas from the mobile device via the central module. For example, the mobile device may measure the signal strength of each antenna in response to a polling signal received from the antenna and send the signal strength information for each antenna directly to the central module. Alternatively, each of the antennas may measure its own signal strength in response to a polling signal received from the mobile device and transmit the measured signal strength to the mobile device, and the mobile device may transmit signal strength information for the antennas to the central module. In other embodiments, the processor receives the signal strength information for a given antenna from the corresponding antenna via the central module. For example, the mobile device may measure the signal strength from each antenna and transmit the measured signal strength to the corresponding antenna, and each of the antennas may transmit its signal strength information to the central module. Alternatively, each of the antennas may measure its own signal strength in response to a polling signal received from the mobile device and send the measured signal strength information directly to the central module.In step 204, the processor compares the signal strength information for the plurality of antennas and identifies the antenna having the first highest signal strength (also referred to as the "first antenna") and the antenna having the second highest signal strength (also referred to as the "second antenna"). In some embodiments, if the two strongest signals have the same RSSI value, the two corresponding antennas may be referred to as the first and second antennas.In some embodiments, the method 200 also includes determining the location of the first and second antennas within the vehicle. In some embodiments, the processor may determine the vehicle location for each antenna based on the location information transmitted by the antenna to the central module, the location information identifying the location of the antenna within the vehicle (e.g., adjacent to the front driver side door within the vehicle cabin or adjacent to the rear passenger side door outside the vehicle cabin, etc.). In other embodiments, each antenna may send antenna identification information (e.g., an antenna identifier) to the central module and the processor may determine the vehicle location of the antenna using a look-up table or other database stored in the memory, the look-up table listing the vehicle location associated with each antenna identifier.In step 206, the processor determines a location of the mobile device relative to the vehicle cabin based on the vehicle locations of the first and second antennas. In some embodiments, the method 200 further includes step 208, wherein the processor enables a passive start function or a passive access function depending on whether the location of the mobile device is inside or outside the vehicle cabin.FIG. 3 illustrates an example method 300 for performing the operations that may be included in step 206, in accordance with embodiments. As shown, the method 300 begins at step 302, where the processor determines whether both the first antenna and the second antenna are located within the vehicle cabin. If an affirmative determination is made (e.g., "Yes"), the method 300 proceeds to step 304, where the processor identifies that the mobile device is within the vehicle cabin. For example, referring to FIG. 1, if the antenna having the first highest signal strength is the antenna 106 blocated within the front driver side door 112 and the antenna having the second highest signal strength is the antenna 106 glocated within the front occupant area of the vehicle cabin 108, the processor determines that the mobile device 102 is located within the vehicle cabin 108. In some embodiments, the method 300 continues to step 306 once the processor identifies that the mobile device is within the vehicle cabin, where the processor enables a passive start function of the PEPS system similar to step 208 in FIG. 2. In other embodiments, the processor may enable one or more PEPS operations in response to the location of the mobile device being identified as being within the vehicle.If a negative determination is made (e.g., "No") in step 302, the method 300 proceeds to step 308, where the processor determines whether both the first antenna and the second antenna are located outside the vehicle cabin. If an affirmative determination is made (e.g., "Yes"), the method 300 proceeds to step 310, where the processor identifies that the mobile device is outside the vehicle cabin. For example, referring to FIG. 1, if the antenna having the first highest signal strength is the antenna 106 alocated outside the front driver side door 112 and the antenna having the second highest signal strength is the antenna 106 elocated outside the rear driver side door 116, the processor determines that the mobile device 102 is located outside the vehicle cabin 108. In some embodiments, the method 300 continues to step 312 once the processor identifies that the mobile device is outside the vehicle cabin, where the processor enables a passive access function of the PEPS system similar to step 208 in FIG. 2. In other embodiments, the processor may enable one or more PEPS operations in response to the location of the mobile device being identified as being outside the vehicle.If a negative determination is made (e.g., "No") in step 308, the method 300 continues to step 314. As an example, a negative determination may be made in step 308 when the processor determines that one of the first and second antennas is outside the vehicle cabin and the other of the first and second antennas is inside the vehicle cabin. In step 314, the processor calculates a difference between the first high signal strength associated with the first antenna and the signal strength of an antenna positioned opposite the first antenna relative to the vehicle cabin (also referred to herein as an "opposite antenna"). For example, if the first antenna is located outside of one of the vehicle doors, the corresponding opposing antenna would be the antenna located inside that vehicle door. As another example, if the first antenna is located within the vehicle trunk or rear tailgate (e.g., antenna 106 jillustrated in FIG. 1 ), the corresponding opposing antenna would be the antenna located outside the trunk or tailgate (e.g., antenna 106 iillustrated in FIG. 1 ). In some cases, the opposing antenna may be the second antenna having the second highest signal strength, for example, wherein the first antenna is the antenna 106 alocated outside the front driver side door 112 and the second antenna is the antenna 106 blocated inside the front driver side door 114 as shown in FIG. 1.In step 316, the processor determines whether the difference calculated in step 314 is greater than a threshold. If the difference is equal to or exceeds the threshold (e.g., "Yes"), the method 300 continues to step 318, where the processor identifies that the mobile device is in the same position relative to the vehicle as the first antenna. For example, if the first antenna is within the vehicle cabin, then in step 318, the processor determines that the mobile device is also within the vehicle cabin. Similarly, if the first antenna is outside the vehicle cabin, then in step 318, the processor determines that the mobile device is also outside the vehicle cabin. If the difference calculated in step 314 does not exceed the threshold (e.g., "No"), the method 300 continues to step 320, where the processor 300 initiates an alternative authorization sequence associated with the PEPS system. In embodiments, the threshold may be chosen to correspond to a significant margin between the signal strengths of the inner and outer antennas. If the difference calculated in step 314 is equal to or exceeds this margin, the external location of the mobile device can be determined with sufficient certainty. However, if the difference in signal strength between these two antennas does not exceed the threshold, the current location of the mobile device cannot be determined with sufficient certainty.In some embodiments, the method 300 continues from step 318 to step 322, where the processor enables a passive start function or a passive access function depending on the location of the mobile device identified in step 318, similar to step 208 in FIG. 2. For example, if the location of the mobile device is outside the vehicle cabin, the processor may enable a passive access function. Similarly, when the location of the mobile device is within the vehicle cabin, the processor may enable a passive start function.FIGS. 4 and 5 illustrate two alternative methods 400 and 500 for performing the alternative authorization sequence initiated in step 320 of FIG. 3, according to embodiments. Referring first to FIG. 4, the alternative authorization sequence provided by the method 400 begins at step 402, where the processor causes an active authorization request to be displayed on a display screen of the mobile device. For example, the mobile device may indicate the active authorization request in response to a wireless signal being received from the processor and / or the vehicle including a command to indicate the request. In embodiments, the active authorization request may be presented using a graphical user interface generated by the mobile device, or more particularly a software application executed by the mobile device (such as: the vehicle application 109 shown in FIG. 1 ). The active authorization request may be configured to inform the user of the mobile device that the vehicle cannot determine the exact location of the mobile device and request a user input indicating which PEPS operation the user like to perform (e.g., start the engine, unlock one or more vehicle doors, open a liftgate or trunk, etc.). In step 404, the processor receives the user-selected input or vehicle command from the mobile device. For example, the mobile device may transmit a wireless signal comprising the user-selected command to the processor and / or the vehicle. In step 406, the processor executes the received command and / or provides the received command to a corresponding unit of the vehicle computing system to perform the command. For example, a command to start the engine may be provided to the powertrain control module of the vehicle computing system while a command to unlock the doors is provided to the body control module of the vehicle computing system. In other embodiments, the method 400 may be performed using a display screen included in the vehicle (such as the human machine interface (HMI) 622 illustrated in FIG. 6 ) and a graphical user interface displayed on the vehicle screen.Referring now to FIG. 5, the alternative authorization sequence provided by the method 500 begins at step 502, where the processor causes a reduction in a transmit power level associated with the first antenna and the transmit power level associated with the corresponding opposing antenna identified at step 314 of FIG. 3. For example, in some embodiments, the processor may send a command signal to each of the first antenna and the opposing antenna that instructs the antennas to reduce their respective transmit power levels. In response, the signal strength measured by the mobile device for each of the first antenna and the opposing antenna may be affected. In other embodiments, the processor may send a command signal to the mobile device instructing the mobile device to reduce its transmit power level. In response to this instruction, the signal strength measured by each of the first antenna and the opposing antenna may be affected. In either case, the method 500 may further include the processor receiving new signal strength information (e.g., RSSI values) associated with each of the first antenna and the opposing antenna and comparing, for each of the two antennas, the new signal strength information with the old signal strength information previously received in step 202 of the method 200.In step 504, the processor uses the results of this comparison to identify that one of the two antennas exhibits a greater drop in signal strength due to the reduction in transmit power than the other antenna. For example, if one of the two antennas has a high signal strength caused primarily by reflections and other external factors, the drop in transmit power will result in a higher level of signal degradation, thereby causing a relatively greater drop in signal strength compared to the other antenna. On the other hand, if one of the two antennas has a high signal strength because the mobile device is relatively close to the antenna, the drop in transmission power will cause a proportional drop in signal strength for that antenna.In step 506, the processor determines whether the antenna identified in step 504 is outside the vehicle cabin. If an affirmative determination is made (e.g., "Yes"), the method 500 proceeds to step 508 where the processor identifies that the mobile device is outside the vehicle cabin. In some embodiments, the method 500 proceeds from step 508 to step 510, where the processor enables a passive access function of the PEPS system similar to step 312 in FIG. 3. On the other hand, if a negative determination is made in step 506 (e.g., "No"), the identified antenna is determined to be within the vehicle and the method 500 proceeds to step 512 where the processor for the mobile device identifies to be within the vehicle cabin. In some embodiments, the method 500 proceeds from step 512 to step 514, where the processor enables a passive start function of the PEPS system similar to step 306 of FIG. 3. In other embodiments, step 510 may enable other PEPS operations that require a location of the mobile device outside, and step 514 may enable other PEPS operations that require a location of the mobile device inside.In some embodiments, the method 200 may end when any of steps 306, 312, or 322 shown in FIG. 3 is reached if the location of the mobile device may be identified with sufficient certainty. Otherwise, the method 200 may end upon completion of step 406 shown in FIG. 4 or of one of steps 510 and 514 shown in FIG. 5, depending on which alternative authorization sequence is initiated in step 320 of FIG. 3.FIG. 6 shows an example vehicle system 600 including a vehicle computing system (VCS) 602 that may be included in the vehicle 104, for example as part of a vehicle electronics system or infotainment system of the vehicle 104, according to embodiments. The VCS 602 may be an infotainment system, such as the SYNC® system manufactured by FORD MOTOR COMPANY®. Other embodiments of the VCS 602 may include other, fewer, or additional components as compared to those described below and illustrated in FIG. 6. In embodiments, the components of the vehicle system 600 may be configured to communicate with the mobile device 102 and receive, process, and execute the command inputs received therefrom, either actively or passively.As shown in FIG. 6, the vehicle system 600 also includes a central module 608 in wired or wireless communication with the VCS 602 and a plurality of antenna modules 610 in wired or wireless communication with the central module 608. In some embodiments, the central module 608 is configured to communicate with the antenna modules 610 using a short-range wireless communication network, such as a BLUETOOTH Low Energy (BLE) network. The central module 608 may be similar to the central module 110 included in the vehicle 104 shown in FIG. 1. In embodiments, the central module 608 includes a computing device (not shown) comprising at least one memory for storing one or more computer programs comprising software instructions and a processor for executing the software instructions. For example, the stored computer programs may include software instructions for implementing one or more of the methods 200, 300, 400, and 500. The central module 608 also includes wireless communication circuitry (not shown) (e.g., one or more antennas, transmitters, receivers, and / or transceivers) to enable wireless communication with the antenna modules 610, and in some cases with the VCS 602. In a preferred embodiment, the central module 608 includes a BLUETOOTH, BLE, or other short-range receiver (not shown) for receiving vehicle commands and / or data transmitted by the key fob, the mobile / PaaK device, and / or the antenna modules 610, and / or a BLUETOOTH, BLE, or other short-range transmitter (not shown) for transmitting data to the key fob, the PaaK device, and / or the antenna modules 610.Each of the antenna modules 610 includes an antenna, such as one of the antennas 106 shown in FIG. 1, as well as other wireless communication circuitry (not shown) for enabling wireless communication with a mobile device, such as the mobile device 102 shown in FIG. 1, and in some cases with the central module 608. In a preferred embodiment, the antenna modules 610 are configured to communicate with the mobile device using a short-range wireless communication network, such as a BLUETOOTH Low Energy (BLE) network. Each antenna module 610 may also include a computing device (not shown) comprising at least one memory for storing one or more computer programs comprising software instructions and a processor for executing the software instructions. For example, the stored computer programs may include software instructions related to initiating communication with the mobile device and / or providing information received from the mobile device to the central module 608. In some cases, the memory also stores antenna identification information (e.g., an antenna identifier (ID)) for uniquely identifying the antenna module 610 and / or the antenna included therein. In some cases, the memory also stores location information to identify the location of the antenna module 610 in the vehicle. The exact number of antenna modules 610 included in the vehicle system 600 may depend on the number of antennas 106 included in the vehicle 104. In certain embodiments, the vehicle system 600 includes at least three antenna modules 610 to accurately and reliably detect the location of the mobile device.As shown in FIG. 6, the VCS 602 may include a data processor 612 (e.g., an electronic data processor), a data storage device 614, and a vehicle data bus 616. The VCS 602 may further include various electronic control units (ECUs) responsible for monitoring and controlling the electrical systems or subsystems of the vehicle 104. Each ECU may include, for example, one or more inputs and outputs for detecting, receiving, and / or transmitting data, a memory for storing the data, and a processor for processing the data and / or generating new information based thereon. In the illustrated embodiment, the ECUs of the VCS 602 include the passive entry passive start (PEPS) system 604, telematics control unit (TCU) 606, a body control module (BCM) 618, a powertrain control module (PCM) 620, and a human machine interface (HMI) 622.The ECUs of the VCS 602 may be interconnected through the vehicle bus 616 (such as a controller area network (CAN) bus) that forwards data to and from different ECUs, as well as other vehicle and / or auxiliary components in communication with the VCS 602. Further, the data processor 612 may communicate with each of the ECU and the data storage device 614 via the data bus 616 to perform one or more functions and / or support interactions with the mobile device 102 and / or the central module 608, including those associated with one or more of the methods 200, 300, 400, and 500 illustrated in FIGS. 2-5. The PEPS system 604 is an ECU configured to control and monitor passive, remote, and / or keyless interactions between a fob (not shown) and the vehicle 104 or the mobile device 102 and the vehicle 104, where the mobile device operates as a phone-as-a-key (PaaK) device. In embodiments, the PEPS system 604 may include a remote keyless entry system and a remote keyless ignition system. In some embodiments, the PEPS system 604 is a separate, stand-alone ECU that is connected to the BCM 618, PCM 620, TCU 606, and other ECUs of the vehicle 104 via the vehicle bus 616 to perform PEPS operations and other vehicle commands. For example, the PEPS system 604 may receive vehicle commands from the key fob, the mobile device, and / or the central module 608 via the TCU 606, process the commands to identify the corresponding ECU to perform the command, send the command to the identified ECU, and confirm execution of the command. In other embodiments, the PEPS system 604 may include multiple segments integrated into different ECUs of the VCS 602, such as the BCM 618, the PCM 620, and / or the TCU 606, to process the PEPS commands received at each ECU. In still other embodiments, the PEPS system 604 may be included in an ECU, such as the TCU 606, to handle or process PEPS commands when received by the TCU 606.In some cases, vehicle commands are received at the PEPS system 604 directly from the PaaK / mobile device, for example, if the operation of the vehicle command is not dependent on the location of the mobile device relative to the vehicle cabin. In other cases, vehicle commands may be received at the PEPS system 604 via the central module 608, for example, if the vehicle command is a PEPS operation that can only be performed after the central module 608 determines the location of the PaaK / mobile device. As an example, a passive entry command may be executed only when the central module 608 determines that the mobile device is outside the vehicle, and a passive start command may be executed only when the central module 608 determines that the mobile device is inside the vehicle. In still other cases, the mobile device may communicate vehicle commands directly to the central module 608 and the central module 608 may forward the commands to the PEPS system 604 for execution regardless of whether a particular location of the mobile device is required to execute the command (such as remote start, remote / active access, or other RKE functions).The body control module (BCM) 618 is an ECU for controlling and monitoring various electronic accessories in a body of the vehicle 104. In embodiments, the BCM 618 is an ECU that controls the doors, trunk, and / or tailgate of the vehicle 104, including locking, unlocking, opening, and / or closing these units. In some embodiments, the BCM 618 also controls the window lifting devices, roof opening devices (e.g., sunroof, sunroof, folding roof, etc.), and interior lighting of the vehicle 104. The BCM 618 may also control other electrically powered components in the body of the vehicle 104, such as air conditioning units, electrically adjustable mirrors, and electrically adjustable seats. In cases where the BCM 618 controls and monitors only the doors of the vehicle 104, the BCM 618 may be referred to as a door control unit (DCU), as is known. The BCM 618 may be configured to implement commands received from the key fob, the PaaK device, and / or the central module 608 that relate to doors, windows, or other body components controlled by the BCM 618.The powertrain control module (PCM) 620 is an ECU for controlling and monitoring the engine and transmission of the vehicle 104. In some embodiments, the PCM 620 may be divided into two separate ECUs, specifically an engine control unit and a transmission control unit. In any case, the PCM 620 may be configured to control starting and stopping of the engine of the vehicle 104, and may implement commands for starting the engine received from the key fob, the mobile device, and / or the central module 608.Telematics control unit (TCU) 606 is an ECU to enable vehicle 104 to connect to various wireless networks, including, for example, GPS, WiFi, cellular, BLUETOOTH, BLUETOOTH Low Energy (BLE), NFC, RFID, satellite, and / or infrared. In embodiments, the TCU 606 (also referred to as "Fahrzeugtelematikeinheit") includes a wireless communication module 624 comprising one or more antennas, radios, modems, receivers, and / or transmitters (not shown) for connection to the various wireless networks. For example, the wireless communication module 624 may include a mobile communication unit (not shown) for wirelessly communicating over a cellular network (e.g., GSM, GPRS, LTE, 3G, 4G, CDMA, etc.), a 612.11 network (e.g., WiFi), a WiMax network, and / or a satellite network. The TCU 606 may also be configured to control the tracking of the vehicle 104 using longitude and latitude values obtained from a GPS satellite. In a preferred embodiment, the wireless communication module 624 includes a BLUETOOTH, BLE, or other short-range receiver (not shown) for receiving vehicle commands and / or data transmitted by the key fob or PaaK device and / or a BLUETOOTH, BLE, or other short-range transmitter (not shown) for transmitting data to the key fob or PaaK device.In embodiments, the TCU 606 receives external data, including command inputs from the key fob and / or the PaaK device, via the wireless communication module 624 and provides the external data to a corresponding ECU of the VCS 602. For example, when the TCU 606 receives a door lock command, the TCU 606 sends the command to the BCM 618 over the vehicle bus 616. Similarly, for example, if the TCU 606 receives an engine start command, the TCU 606 sends the command to the PCM 620 over the vehicle bus 616. In some embodiments, the TCU 606 also receives internal data from other ECUs of the VCS 602 and / or the data processor 612, with instructions to transmit the internal data n to the mobile device, the central module 608, or another component of the vehicle system 600.The human machine interface (HMI) 622 (also referred to as a "user interface") may be an ECU for enabling user interaction with the vehicle 104 and presenting vehicle information to the operator or driver of the vehicle. Although not shown, the HMI 622 may include an instrument panel (IP), a media display screen, as well as one or more input devices and / or output devices for inputting, entering, receiving, capturing, displaying, or outputting data in connection with the vehicle computing system 602, the method 400 illustrated in FIG. 4, or the techniques disclosed herein. The HMI 622 may be configured to interact with the other ECUs of the VCS 602 and / or the data processor 612 via the data bus 616 to provide information or input received via the HMI 622 to a corresponding component of the VCS 602 and to present information or output received from the various components of the VCS 602 to the operator or driver of the vehicle.The data processor 612 may include one or more of a microprocessor, microcontroller, programmable logic array, application specific integrated circuit, logic device, or other logic device for processing, inputting, outputting, manipulating, storing, or retrieving data. In embodiments, the VCS 602 may include a general purpose computer programmed with various programming instructions or modules stored in the data storage device 614 (e.g., electronic memory) or elsewhere.The data storage device 614 may include one or more of electronic memory, non-transitory random access memory (e.g., RAM), flip-flops, a computer-writable or computer-readable storage medium, a magnetic or optical data storage device, a magnetic or optical disk drive, a hard disk drive, or other electronic device for storing, retrieving, reading, or writing data. The data storage device 614 stores one or more software program modules or software instructions for execution by the data processor 612.In certain embodiments, the process descriptions or blocks in the figures, such as FIGS. 2-5, may represent modules, segments, or portions of code that include one or more executable instructions for implementing specific logical functions or steps in the process. Within the scope of the embodiments described herein, all alternative implementations are included, wherein functions may be performed out of the order shown or described, including substantially simultaneously or in reverse, depending on the functionality involved, as is known to one of ordinary skill in the art. It should be appreciated that the embodiments described above, particularly any "preferred" embodiments, are possible examples of implementations and are set forth only for a clear understanding of the principles of the invention. Many variations and modifications may be made to the embodiment(s) described above without materially departing from the spirit and principles of the techniques described herein. All such modifications are intended to be included herein within the scope of this disclosure and protected by the following claims.

Claims

A vehicle (104) comprising: a plurality of antennas positioned at locations inside and outside a vehicle cabin (108), each antenna being in wireless communication with an external mobile device (102) and associated with signal strength information; and a central module (110) in communication with the antennas and configured to: identify the antennas with the two strongest signals, and determine that one of the antennas is positioned outside the vehicle cabin (108) and the other antenna is positioned inside the vehicle cabin (108) opposite the first antenna relative to the vehicle cabin (108); and if a difference between the signal strengths of the identified antennas exceeds a threshold, identify that the mobile device (102) is in the same position relative to the vehicle (104) as the first antenna (106a).The vehicle (104) of claim 1, wherein the mobile device (102) is configured to operate as a vehicle key fob capable of remotely controlling a predetermined series of vehicle operations.The vehicle (104) of claim 1, wherein the central module (110) is further configured to: enable a passive start function when the mobile device (102) is located within the vehicle cabin (108); and enable a passive access function when the mobile device (102) is located outside the vehicle cabin (108).The vehicle (104) of claim 1, wherein the plurality of antennas communicate with the mobile device (102) using a short-range wireless communication network.The vehicle (104) of claim 1, wherein the plurality of antennas includes a first antenna (106a) located on the exterior of a front driver side door of the vehicle (104) and a second antenna (106b) located within the front driver side door.The vehicle (104) of claim 5, wherein the plurality of antennas further includes a third antenna (106c) located on the exterior of a front door on the passenger side of the vehicle (104) and a fourth antenna (106d) located within the front door on the passenger side of the vehicle (104).The vehicle (104) of claim 5, wherein the plurality of antennas further includes at least one antenna located adjacent a center console within the vehicle cabin (108), a rear headliner within the vehicle cabin (108), or adjacent a rear tailgate (120) of the vehicle (104).A method comprising: receiving signal strength information associated with a plurality of antennas wirelessly communicating with a mobile device (102), the antennas positioned at locations inside and outside a vehicle cabin (108); identifying a first antenna having a first highest signal strength and a second antenna having a second highest signal strength; and determining a location of a mobile device (102) relative to the vehicle cabin (108) based on the locations of the first and second antennas, determining whether one of the first and second antennas is positioned outside the vehicle cabin (108) and the other of the first and second antennas is positioned inside the vehicle cabin (108); if so, calculating a difference between the first highest signal strength and a signal strength of an opposing antenna positioned opposite the first antenna relative to the vehicle cabin (108); and if the difference exceeds a threshold, identifying that the mobile device (102) is in the same position relative to the vehicle (104) as the first antenna (106a).The method of claim 8, wherein determining a location of a mobile device (102) relative to the vehicle cabin (108) comprises: determining whether both the first antenna (106a) and the second antenna (106b) are positioned within the vehicle cabin (108); and if so, identifying that the mobile device (102) is within the vehicle cabin (108).The method of claim 8, wherein determining a location of a mobile device (102) relative to the vehicle cabin (108) comprises: determining whether both the first antenna (106a) and the second antenna (106b) are positioned outside the vehicle cabin (108); and if so, identifying that the mobile device (102) is outside the vehicle cabin (108).The method of claim 8, wherein determining a location of a mobile device (102) relative to the vehicle cabin (108) further comprises: if the difference does not exceed the threshold, initiating an alternative authorization sequence.The method of claim 11, wherein the alternative authorization sequence includes: causing an active authorization request to be displayed on the mobile device (102); receiving a user-selected command from the mobile device (102) in response to the request; and executing the received command.The method of claim 11, wherein the alternative authorization sequence comprises: causing a reduction in a transmit power level associated with the first antenna and a transmit power level associated with the opposing antenna; identifying that one of the first antenna and the opposing antenna exhibits a greater resultant drop in signal strength; when the identified antenna is positioned outside the vehicle cabin (108), identifying that the mobile device (102) is located outside the vehicle cabin (108); and when the identified antenna is positioned inside the vehicle cabin (108), identifying that the mobile device (102) is located inside the vehicle cabin (108).The method of claim 8, further comprising: enabling a passive start function when the mobile device (102) is located within the vehicle cabin (108); and enabling a passive access function when the mobile device (102) is located outside the vehicle cabin (108).

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