BACKGROUND OF THE INVENTION 
     This invention generally relates to a system for requesting roadside assistance from a vehicle at any location. More specifically, this invention relates to a system and method for controlling the activation of a roadside assistance request system. 
     The widespread use of cellular telephones has provided advantages to vehicle owners in that they are able to place telephone calls from their vehicle. This can be especially advantageous in the event that roadside assistance is needed. Under such circumstances, however, the caller must be able to describe where they are and what type of assistance is required. Systems have been developed that utilize cellular telephone communication networks and are specifically designed for requesting roadside service from a vehicle. 
     Existing systems have several shortcomings and drawbacks, however. For example, in various emergency situations, cellular telephone or other mobile communication networks may be unreliable, unavailable or prohibitively expensive. Further, the increased popularity of cellular telephones tends to cause cellular networks to become congested, which may interfere with placing a timely emergency request. Another disadvantage associated with existing systems is that they do not provide sufficient control systems to avoid inadvertent, inaccurate or mistaken assistance requests. 
     This invention provides a system that avoids the shortcomings and drawbacks of the prior art. A system designed according to this invention activates a vehicle assistance request upon the push of a single button. Upon activation, the location of the vehicle, vehicle speed and direction information, vehicle identification, and the type of assistance requested is transmitted through a mobile data communications network to a dedicated monitoring center for handling such requests. Once a request signal is received at the monitoring center, vehicle coordinates, which are determined through a global positioning system, are converted to the closest street address and nearest intersections to the vehicle location. After the vehicle location, vehicle identification, subscriber information and the type of assistance requested is determined, an operator dispatches the appropriate service provider. Since the service is requested through the push of a single button, it is important to provide a system and methodology for minimizing inadvertent or mistaken service requests. 
     SUMMARY OF THE INVENTION 
     In general terms, the method associated with this invention for controlling a vehicle assistance request system that has a transmitter for transmitting a data communication request signal from a vehicle location to a monitoring center remote from the vehicle includes four basic steps. First, a request signal is generated at the vehicle location that indicates that an assistance request should be initiated. The request signal is generated by pressing an activation button on an operator interface module, which can be mounted inside the vehicle or can be a remote key fob. The amount of time that the button is pressed is determined, which corresponds to the amount of time that the request signal is generated. Next, a determination is made whether the amount of time that the request signal is generated is at least as long as a pre-selected minimum time period. Then, an assistance request is initiated at the remote location when the amount of time that the request signal is generated is at least as long as the pre-selected time period. An assistance request is terminated when the amount of time that the request signal is generated at the vehicle location is less than the pre-selected minimum time period. 
     One embodiment for operating a vehicle assistance request system designed according to this invention includes a housing that is supported on the vehicle. The housing preferably is located in the passenger compartment of the vehicle where it is easily accessed by the driver of the vehicle. A plurality of activation buttons are supported on the housing for activating the transmitter to transmit a request signal from the vehicle to a remote location. Each of the activation buttons has a unique, designated request function. A moveable cover that is movably supported on the housing is moveable between a first position where the cover prevents the activation buttons from being pressed and a second position where the cover is away from the buttons such that they can be pressed by a user of the system. A timer times an amount of time that any of the activation buttons are pressed. A communication link between the activation buttons and the transmitter includes a controller that controls whether the transmitter transmits a signal based upon the amount of time determined by the timer. The transmitter only transmits a request signal when one of the activation buttons has been continuously pressed for a minimum amount of time. 
     In the preferred embodiment, the moveable cover is a clear plastic plate that is supported on the housing and is slidable between the position where it covers the buttons and where the buttons are exposed. Also in the preferred embodiment, the controller controls the transmitter such that it transmits a request signal only when one of the activation buttons has been continuously pressed for at least three seconds. 
     In another embodiment, an assistance request button is incorporated into a remote key entry member, or key fob. Now a user can request emergency assistance from outside the vehicle, preferably, a minimum activation time is also used with the key fob. 
     The various features and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the presently preferred embodiment. The drawings that accompany the detailed description can be described as follows: 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic illustration of a vehicle assistance request system. 
     FIG. 2 is a schematic illustration of selected components of a vehicle assistance request system. 
     FIG. 3A is a diagrammatic illustration of an operator interface module designed according to this invention. 
     FIG. 3B is a cross-sectional view along line  3 B— 3 B of FIG.  3 A. 
     FIG. 4 is a flow chart diagram illustrating the method associated with this invention. 
     FIG. 5 is a schematic illustration of an embodiment of this invention including a remote activation button. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1 schematically illustrates a vehicle roadside assistance request system or emergency response network  20 . A vehicle  22  includes an onboard assistance request system  24 . The request system  24  includes a controller unit  26  and an operator interface module  28 . The operator interface module  28  preferably is located within the passenger compartment of the vehicle such that it is easily accessed by the driver of the vehicle. The control unit  26  includes a computer that handles all signal processing at the vehicle location as will become apparent in the following description. 
     An antenna  30  facilitates communication of the system  24  with a global positioning network  32 . A variety of global positioning technologies are available and operative, and can be accessed by a system designed according to this invention. State of the art global positioning system technologies generally have excellent availability and location accuracy capabilities. Typical global positioning systems can provide vehicle location information to an accuracy within 100 meters of the actual location 95% of the time and within 300 meters 100% of the time. Vehicle location typically is determined within 40 meters of the actual location. A system designed according to this invention preferably includes averaging and screening algorithms that utilize and enhance the raw global positioning system data. 
     Another antenna  34  is utilized to transmit and receive data communication signals, which preferably are in a Mobitex format, to a remotely located antenna  36  that is coupled to a Mobitex tower  38 . Significantly, this signal transmission is distinct from and does not rely on cellular telephone communication networks. The Mobitex tower  38  is connected through dedicated transmission lines  40  to a request monitoring center  42 . The request monitoring center  42  includes appropriate devices for facilitating the handling of various service requests and enabling operators to dispatch the appropriate roadside service. 
     FIG. 2 schematically illustrates selected components of the system  20 . The controller  26  of the vehicle assistance request system  24  is schematically divided into two portions. A main processing unit or control system module  44  includes electronics that provide power conditioning, power management and integration logic for communications with the global positioning system, the Mobitex communications and the operator interface module  28 . The control unit  44  processes, for example, the information obtained through the global positioning network  32  and the desired service request sought by the user through the operator interface module  28 . 
     A Mobitex transceiver  46  is coupled with the control unit  44 . The Mobitex transceiver  46  can be a commercially available unit. The Mobitex transceiver  46  is primarily responsible for transmitting a data communication link signal to the Mobitex tower  38  where it is then transferred on to the request monitoring center  42 . The transceiver  46  also receives signals sent from the request monitoring center  42 . 
     FIG. 3A diagrammatically illustrates an operator interface module  28  designed according to this invention. The module  28  includes a housing  50  that preferably is mounted within the vehicle passenger compartment in a position where it is readily accessible by the driver of the vehicle. A plurality of activation buttons  52 ,  54  and  56  are provided to enable a user of the system to press a single button to initiate a vehicle assistance request. Each of the buttons has a dedicated assistance request function associated with it. In the illustrated example, the button  52  initiates a police assistance request, the button  54  initiates a medical assistance request and the button  56  initiates a roadside repair or tow truck service request. The button  60  provides a clear function for clearing or cancelling a previously sent request. 
     Since a request is sent from the vehicle to the remotely located request monitoring center  52  upon pressing a single button, it is important to provide a way of avoiding inadvertent service requests or mistaken service requests. Accordingly, a system designed according to this invention most preferably includes a cover  58  that is mounted onto the housing  50  such that it is slidable in the direction of the arrow  59 . The cover  58  preferably is slidable between a first position where it covers the buttons  52 ,  54  and  56  and a second position where the buttons are accessible by a user. In the preferred embodiment, the cover  58  is made from a clear plastic material such that the buttons and status lights are visible even when the cover is placed over them. The cover  58  preferably is mounted onto the housing  50  through slots  62  so that it can be moved from side to side (according to the drawing) between the position where it protects the buttons from being pressed and the position where the buttons are accessible. The slots  62  are best shown in FIG.  3 B. 
     The operator interface module  28  preferably also includes light emitting diodes  64 , which could be other indicator devices, to indicate the various functions and status of the system  24 . The system preferably also includes a siren for emitting audible warning signals and an operating button  66 , which enables a user to turn off the siren at any given time. A speaker  68  preferably is also provided in order to enable the user to receive audible signals via the operator interface module  28 . 
     In addition to the cover  58 , the system  24  preferably includes electronic hardware or computer software that prevents inadvertent assistance request signals from being sent. According to the presently most preferred embodiment, in order to initiate an assistance request, one of the buttons  52 ,  54  or  56  must be pressed and held for a minimum of three consecutive seconds. A timer unit, which is preferably a portion of the controller  44 , monitors the amount of time that the activation buttons are pressed. If the activation button is not pressed for the minimum amount of time, then no assistance request signal is transmitted by the transceiver  46 . 
     It is important to note that the terms “timer” and “timer unit” as used in this specification refer generically to a hardware or software implementation of the timing feature. In the presently most preferred embodiment, the monitoring of whether an activation button has been appropriately pushed is accomplished through software programming of the controller  44 . Those skilled in the art will understand how to develop appropriate code, given this specification. 
     To further reduce the incidence of undesirable requests being made, a clear button  60  is provided. If a user has sent a request signal inadvertently, within a pre-selected amount of time after sending that signal, it is possible to clear or cancel the request. This is accomplished by pressing the clear button  60  and holding it in 
     The key fob  70  preferably includes three activation buttons. A first button  78  enables the user to lock or unlock the doors of the vehicle and to activate or deactivate a vehicle security system, for example. An assistance request activation button  80  is provided that, when pressed for at least three continuous seconds, will initiate a police assistance request through the system  24 . The key fob preferably includes dedicated electronics or software to determine whether the button  80  is pressed long enough. Once that determination is made, the key fob sends an RF signal to the receiver  76 . 
     The key fob provides a significant advantage in allowing a person to call for immediate police assistance even if they are not inside the vehicle. A clear function button  82  preferably is also provided on the key fob  70  to enable a user to clear an accidental call that may have been made. The clear button  82  preferably must be held for a minimum of three seconds before a request cancellation will be initiated. Also, a clear function preferably is only initiated when the clear button is appropriately pressed within a pre-selected time period from the time that the request is made. 
     The press and hold function of a system designed according to this invention is effective to minimize the occurrence of inadvertent or mistaken vehicle assistance requests. Further, the movable cover  58  provides additional assurance in preventing accidental requests from being made through the operator interface module  28 . 
     The foregoing description is exemplary rather than limiting in nature. Variations and modifications to the disclosed embodiment will become apparent to those skilled in the art that do not depart from the purview and spirit of this invention. Accordingly, the scope of this invention is to be determined only by studying the appended claims.
A vehicle assistance request system includes a device and methodology for preventing inadvertent or mistaken assistance request calls. The system enables a vehicle driver to request roadside assistance with a single push of a button on a user interface module inside the vehicle or a remote, portable key fob. The data communication signal that is generated when the button is pushed communicates location information and the type of assistance that is needed to a dispatcher of the appropriate services. The system includes a timer function that requires that a user press a request button for a minimum time period before a request is initiated. Also provided is a protective shield, which further ensures that a request button is not pushed inadvertently.