Abstract:
Methods and apparatus are provided for configuration a single remote fob to be fully operational with different vehicles such as more than one vehicle within a vehicle fleet. In particular, the method and apparatus implements functional transmitter identification and synchronization to allow for dynamic authentication and configuration of the key fob with the last vehicle with which it was successfully passively authenticated.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 61/940,283 filed on Feb. 14, 2014. The entire disclosure of the above application is incorporated herein by reference. 
     
    
     TECHNICAL FIELD 
       [0002]    The present disclosure generally relates to vehicles having passive entry, passive start functionality, and more particularly relates to a method for configuring a passive entry, passive start key to operate one of a plurality of designated vehicles. 
       BACKGROUND 
       [0003]    Vehicles equipped with passive entry, passive start (PEPS) functionality are known in the art. With conventional PEPS systems one or two keyless fobs are associated with a given vehicle. Such PEPS vehicle systems generally include a body control module or BCM in the vehicle which is operable to lock and unlock the vehicle doors, release the truck latch, start-up and turn off the engine, honk the horn and other auxiliary vehicle functions. The body control module is also operable to communicate with the keyless fob to activate these vehicle functions. 
         [0004]    These PEPS system communicates in one of two modes. In a first mode, a passive command is communicated between the keyless fob and the BCM as a low frequency or LF signal such that a passive entry is enabled simply by lifting the door handle or a passive start is enable by pushing a start button on the instrument panel. Such passive commands require the keyless fob to be in close proximity with the BCM. In a second mode, an active command is communicated between the keyless fob and the BCM as a radio frequency or RF signal such that an active lock/unlock or a remote engine start is enabled by pushing a button on the keyless fob. Such active commands may be carried out when the keyless fob is a substantial distance from the BCM. 
         [0005]    For security reasons, the keyless fob and the BCM are statically configured and permanently assigned transceiver IDs which only enable one or two keyless fob to operate a specific vehicle. In other words, remote keyless functions, whether passive or active, are supported on one and only one vehicle. As such, the procedure of associating a new keyless fob with a particular vehicle is complicated and time-consuming. Likewise, PEPS-equipped vehicles in a commercial or police fleet require a specific keyless fob for each vehicle in the fleet. As such, a fleet driver is limited to use the specific fleet vehicle for his or her keyless fob and no fob variant exists that allows other vehicles within the fleet to be operated with that particular keyless fob. 
         [0006]    Accordingly, it is desirable to develop a simple, quick and secure manner for associating a keyless fob with a BCM in a PEPS-equipped vehicle. In addition, it is desirable to allow a single PEPS keyless fob to be fully operational (passive commands, active commands and immobilizer functions) on more than one vehicle. Furthermore, other desirable features and characteristics of the present disclosure will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and this background. 
       SUMMARY 
       [0007]    A method is provided for dynamically configuring a PEPS system to be fully functional to issue passive and active commands upon passive authentication of the keyless fob with the BCM in a given vehicle selected from a fleet of vehicles. 
         [0008]    In accordance with a disclosed method, a remote fob is authenticated for use with a body control module in at least one of a plurality of vehicles. In an embodiment a passive challenge function is initiated in a first vehicle selected from the plurality of vehicles. A vehicle identifier is issued from the body control module of the first vehicle to the remote fob in response to the passive challenge function. A functional transmitter identifier is issued from the remote fob to the body control module of the first vehicle in response to the remote fob receiving the vehicle identifier. The functional transmitter identifier is generated using the vehicle identifier and a stored transmitter identifier of the remote fob. The functional transmitter identifier is compared with at least one authenticated identifier stored in the body control module of the first vehicle. Radio frequency communication is enable between the body control module of the first vehicle and the remote fob when the functional transmitter identifier matches the at least one authenticated identifier. A wakeup command may be exchanged between a body control module in the first vehicle and the remote fob prior to issuing the vehicle identification from the body control module. 
         [0009]    The remote fob may be authenticated for use with a body control module in a second vehicle from the plurality of vehicles. A second passive challenge function is initiated in a second vehicle selected from the plurality of vehicles. A vehicle identifier is issued from the body control module of the second vehicle to the remote fob in response to the passive challenge function. A functional transmitter identifier is issued from the remote fob to the body control module of the second vehicle in response to the remote fob receiving the vehicle identifier, wherein the functional transmitter identifier is generated using the vehicle identifier and a stored transmitter identifier of the remote fob. The functional transmitter identifier is compared with at least one authenticated identifier stored in the body control module of the second vehicle. Radio frequency communication is enable between the body control module of the second vehicle and the remote fob when the functional transmitter identifier matches the at least one authenticated identifier. 
         [0010]    A PEPS system is also provided with dynamic configuration of a remote fob with a BCM in a given vehicle selected from a fleet of vehicles upon passive authentication of the system components. In accordance with a disclosed system, a remote fob includes circuitry configured to receive a vehicle identifier issued from the body control module of a first vehicle in response to a passive challenge function and issue a functional transmitter identifier to the body control module of the first vehicle. The functional transmitter identifier is generated using the vehicle identifier and a stored transmitter identifier of the remote fob. The functional transmitter identifier is compared with at least one authenticated identifier stored in the body control module of the first vehicle, and radio frequency communication is enable between the body control module of the first vehicle and the remote fob when the functional transmitter identifier matches the at least one authenticated identifier. 
         [0011]    Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    The present invention will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and 
           [0013]      FIG. 1  is a block schematic showing a PEPS system having a BCM and a set of keyless fobs; 
           [0014]      FIG. 2  illustrates a vehicle fleet which may be authenticated to one of several keyless fobs; 
           [0015]      FIG. 3  is a schematic illustration showing authentication of a keyless fob with a fleet vehicle; and 
           [0016]      FIG. 4  is a flowchart showing an authentication process for a keyless fob with a fleet vehicle. 
       
    
    
     DETAILED DESCRIPTION 
       [0017]    The following detailed description is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Furthermore, there is no intention to be bound by any theory presented in the preceding background or the following detailed description. 
         [0018]    With reference  FIG. 1 , a vehicle  8  having a passive entry, passive start (PEPS) system  10  is schematically shown to include a body control module or BCM  12  that is operable to a door lock function  14  for locking and unlocking the vehicle doors, a trunk release function  16  for unlatching the truck lock, an engine start function  18  for starting the engine, and a horn function  20  for honking the horn. The BCM  12  may be configured to operate other auxiliary vehicle functions, e.g., seat heaters, vehicle lights, seat position, etc. The PEPS system  10  and in particular the BCM  12  is operable to wirelessly communicate with a keyless fob  22  for activating certain vehicle functions. Both the BCM  12  and the keyless fob  22  have data memory—BMC memory  24  and fob memory  26  respectively—which are used to store system identification information and synchronization information for enabling PEPS system functionality. 
         [0019]    The BCM  12  includes circuitry  28  which is capable of wirelessly communicating with circuitry  30  in the keyless fob  22 . Circuitry  28 ,  30  are conventional for current PEPS systems and capable of communicating in at least two modes. In a first passive mode, a passive command is communicated between the BCM  12  and the keyless fob  22  as a low frequency or LF signal. As used herein an LF signal is generally known in the art to be a data signal having a carrier frequency in the range of 30-300 kHz and typically on the order of about 125 kHz. Passive commands require the keyless fob  22  to be in close proximity with the BCM  12 . In response to a passive challenge the BCM  12  interrogates or polls the area immediately around the vehicle using the LF signal to detect the keyless fob  22 . When the keyless fob  22  receives and authenticates the polling signal, the key fob  22  will transmit a passive command signal to the BCM  12  for performing a particular function. Typically, passive challenges include a passive entry command for unlocking a door that is enabled by lifting the door handle, a passive trunk release that is enabled by pushing a trunk release button or a passive start command for starting the engine when a start button on the instrument panel is push. 
         [0020]    In a second active mode, an active command is communicated between the keyless fob  22  and the BCM  12  as a radio frequency or RF signal. As used herein an RF signal is generally known in the art to be a data signal having a carrier frequency in the range of 300-500 MHz. Active commands are issued in response to pushing a button on the keyless fob  22 . Typically, the active commands include an active lock command for locking a door, an active unlock command for unlocking the door, an active remote start command for starting the engine, an active trunk release command for opening the trunk and an alert command for repeatedly honking the horn. Because the active commands are issued as an RF signal, they may be carried out when the keyless fob  22  is a substantial distance from the BCM  12 . 
         [0021]      FIG. 2  illustrates a plurality or fleet of vehicles  8 . 1 ,  8 . 2 ,  8 . 3 ,  8 . 4 , each having a PEPS system  10  as described above. A plurality of keyless fobs  22 . 1 ,  22 . 2 ,  22 . 3   22 . 4 ,  2  may be dynamically configured with the BCM  12  of a given vehicle  8  selected from a fleet of vehicles  8 . 1 ,  8 . 2 ,  8 . 3 ,  8 . 4 , using passive authentication of the PEPS system  10 . The BCM  12  in each of the vehicles  8 . 1 ,  8 . 2 ,  8 . 3 ,  8 . 4  is calibrated with a unique vehicle ID or VID in BCM memory  24 , and each keyless fob  22 . 1 ,  22 . 2 ,  22 . 3 ,  22 . 4  is calibrated with a unique stored transmitter ID or STID in fob memory  26 . The VID and STID are used to dynamically configure a functional transmitter ID or UID in the keyless fob  22  which corresponds with a UID calibrated in the BCM  12  of every fleet vehicle. In this way, conventional remote keyless entry functionality can be securely performed on the BCM  12  in last vehicle with which the keyless fob  22  was successfully authenticated. 
         [0022]    With reference now to  FIGS. 3 and 4 , the passive authentication process will now be described in which an attempted operation of the PEPS system  10  in the passive mode executes an authentication process for pairing a BCM  12  with a keyless fob  22 . To initiate the process, an LF wakeup command is exchanged from the BCM  12  of vehicle  8  to keyless fob  22  as represented at block  302 . As presently preferred, the LF wakeup command for fleet applications is a 4 byte command that includes a 2 byte wakeup pattern and a 2 byte VID referred to as a 2+2 fleet pattern. The 2 byte wakeup pattern may be a generic vehicle wakeup pattern or a unique fleet wakeup pattern configured for a specific set of vehicles. As presently preferred, the keyless fob  22  will also have a fleet enable flag stored in fob memory  26  which is used to determine when a 4 byte conventional wakeup pattern (i.e., for non-fleet vehicles) is enabled and when a 2+2 fleet pattern described above is enabled. 
         [0023]    In response to a passive challenge (i.e., passive commands received by the BCM  12 ), the BCM  12  issues its VID to the fob  22  as shown at block  304 . The fob  22  generates and returns a functional transmitter ID or UID to the BCM  12  as shown at block  306 . The UID is generated based on the VID from the BCM  12 , STID of the fob  22  and a passive command code. The BCM  12  compares the UID with a list of authenticated UIDs stored in BCM memory  24  as shown at block  308 . If the UID does not match one of the authenticated UIDs, then the keyless fob  22  has not been properly configured for the fleet vehicle  8  and the fob  22  is not authorized to operate the PEPS system  10 . The PEPS system control returns to execute the LF wakeup command at block  302 . 
         [0024]    If the UID matches one of the authenticated UIDs, then the keyless fob  22  has been properly authenticated for the fleet vehicle  8  and the fob  22  is authorized to operate the PEPS system  10  of that vehicle as shown at block  310 . Upon authentication of the keyless fob  22 , the circuitry  28  in the PEPS  10  is updated for responding to active commands from the circuitry  30  in keyless fob  22 . The VID is also stored in the fob memory  26  at block  310  for allowing the keyless fob  22  to track which vehicle it was last used for passive challenges and for enabling the active command functionality between specific BCM-keyless fob combinations. The fob memory  26  has a user data block for storing various vehicle data such as tracking of the last vehicle accessed by the UID, vehicle odometer, etc. As presently preferred, the fob memory  26  is enabled to store such user data for the last two fleet vehicles used. 
         [0025]    At this point, the UID is used to enable the authenticated keyless fob  22  for issuing active commands to the authenticated BCM  12  based on button pushes on the keyless fob  22  at block  312 . Subsequently passive challenges may be used to execute a passive command at block  314  and to dynamically configure a functional synchronization counter as shown at block  316  and further described below. The BCM memory  24  has a transmitter data block for storing the transmitter ID for several (e.g. the last eight) passively-authenticated keyless fobs  22 . The BCM memory  24  also has a sync_counter data block for storing the synchronization counter for the last eight transmitter IDs. 
         [0026]    With specific reference to  FIG. 3 , data structure  100  represents the data issued from the remote fob  22  to the vehicle  8  and includes a wakeup byte  102 , a header byte  104 , response value  106 , a functional transmitter ID  108 , miscellaneous data  110  (such as a battery status for the fob  22 ) and a checksum byte  112 . Similarly, data structure  200  represents the data issued from the BCM  10  to the fob  22  and includes a wakeup byte  202 , a wakeup pattern  204  (such as a generic 4 byte pattern or a 2+2 fleet enabled pattern), a header/command byte  206 , a zone detect byte  208 , a random challenge  210  and the remainder of the vehicle ID  212 . 
         [0027]    Additional functions may be implemented when the fleet enable flag is set for the PEPS system  10 . For example, when a new passive challenge for a driver door function—door unlock, door lock, door opening/ajar—the UID in the fob  22  may reset to be 2 bytes of its unique ID (STID) and 2 byte of the VID at block  318 . In this way the keyless fob  22  can be authenticated to the vehicle with which the “driver” is interacting. As presently preferred, the passive challenge reset may be limited to opening the driver side door to prevent modifying the expected operation of a “passenger” with a separate fleet-enabled keyless fob. When the keyless fob  22  receives a new passive challenge for a driver door function, the current functional synchronization counter is modified to equal a random challenge value received. The challenge value is then used to provide a method for authenticating passive operation as well as synchronizing vehicle  8  and fob  22  without adding additional data bytes in transmission or requiring a secondary communication event. 
         [0028]    When the BCM  12  receives a response from a new passive challenge for a driver door function, it will compare the received UID with the valid Transmitter IDs stored within memory. If the Transmitter ID is not already present, it will store the received UID into the least recently used ID memory location and update the RF receiver associated with circuitry  28  as needed at block  310 . Storage of the UID is required to identify which transmitters are valid for actively controlling the vehicle and to maintain smart filtering of RF receiver. 
         [0029]    When the BCM  12  receives a response from a new passive challenge for a driver door function, it will compare the received UID with the valid Transmitter IDs stored within memory  24 . If the Transmitter ID is not already present, it will store the transmitted challenge value as the Synchronization Counter for the applicable Transmitter ID. This allows for automatic synch counter update without additional data transmissions between the BCM  12  and the keyless fob  22 . 
         [0030]    As presently preferred, the calibration programmed into keyless fob  22  may include a fleet function flag which is used to determine whether the keyless fob  22  will actively work with only one vehicle or dynamically update to operate the last passively accessed vehicle. This function allows for single keyless fob design to be used in multiple ways—namely for fleet users, for single end users, and for replacement of the original fobs, thereby reducing warranty due to customer confusion with dynamic mode. 
         [0031]    An encrypted fleet secret key may also be calibrated into the BCM  12  such that the decrypted value can be programmed into the keyless fob  22  during key learning. This functionality allows for unique secret keys for police fleets versus non-police fleet or between different law enforcement fleets as needed. 
         [0032]    A fleet enable function may also be supported as a calibration in the BCM  12  which, during key learning, identifies whether BCM Random Secret Keys and Wakeup Patterns which are to be programmed into the keyless fob  22  or if fleet secret key, fleet wakeup pattern, and fleet enable will be programmed into the keyless fob  22 . Once programmed into the keyless fob  22 , the fleet enable flag will be used to determine 2+2 byte or 4 byte wakeup pattern and functional transmitter ID definition. This functionality also reduces part numbers and keyless fob complexity by allowing common keyless fobs to be used as either fleet or master keys. 
         [0033]    A single “Master Secret Key” may be used for programming of OEM specific keyless fobs with additional unique, random secret keys allows keys to be reused/reprogrammed to additional or different vehicles in the future. This functionality reduces the impact of keys inadvertently swapped at the plant or subsequent vehicle service procedures. 
         [0034]    Lastly, user data such as odometer, VIN, key number, programming event data, etc. are cipher written to the keyless fob memory  28  with value encryption. Software within the keyless fob  22  will, upon writing, decrypt the data and store the plain read version of the data within memory configured as Plain Read/Denied Write. Additional keyless fob software delaying between decrypt cycles may also be used for maintaining security of user data while allowing use of a common OEM Master Secret Key in all keys. 
         [0035]    While at least one exemplary embodiment has been presented in the foregoing detailed description of the invention, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the invention in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing an exemplary embodiment of the invention. It being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope of the invention as set forth in the appended claims.