Abstract:
At least first and second geofences are established. The first geofence provides for indicating to an operator of a vehicle a limit to the territorial extent of a permitted operational area for the vehicle. The second geofence limits the territorial extent of a permitted operational area for the mobile platform, typically by limiting the mobility of the mobile platform. The first and second geofences are located with respect to one another and the permitted operational area so that with movement through the limits of the permitted operational area, the mobile platform encounters the first geofence no later than it encounters the second geofence.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Technical Field 
         [0002]    The invention relates to geofencing for vehicles, and more particularly, to providing multiple geofences to allow nested, virtual regions and staggered responses to geofence violations. 
         [0003]    2. Description of the Problem 
         [0004]    A geofence may be defined in part as a virtual spatial boundary. Geofences are a byproduct of the marriage of mobile, inexpensive telecommunications platforms and data processing systems. While not dependent upon global positioning systems in theory, their accuracy is greatly enhanced by making use of global positioning systems to provide accurate and precise determination of the location of the mobile platform. A geofence is manifested in programmed responses of a data processing system installed on the mobile platform responsive to changes in the platform&#39;s position. Typically the positions which produce a given set of responses define a contiguous region. The edges of the region become a virtual boundary or geofence. The spatial location of a geofence, that is the limits of region, have commonly been established by selecting a point feature, which may be a point defined by latitude and longitude, and then defining either a radius, or lengths for the major and minor axes through the point, to establish a boundary around the point. 
         [0005]    United States Pat. Appl. Pub. 2005/0159883 described a method and system relating to geofences which described various irregularly shaped geofences and distinguished between what it termed a geofence object and a geofence area (See generally paragraphs [0067-9] of the reference). The geofence object is described as enclosed by a geofence, and the geofence area encloses, in addition to the geofence object, a “hysteresis buffer area” outside and surrounding the geofence object. Responses to movement across the fence appear to require clearing the hysteresis area. Conceptually the publication seems to provide that the geofence has depth. 
       SUMMARY OF THE INVENTION 
       [0006]    According to the invention there is provided a system and method for controlling geofences for a mobile platform. At least first and second geofences are established. The first geofence provides for indicating to an operator of the mobile platform a limit in territorial extent of a permitted operational area for the mobile platform. The second geofence limits the territorial extent of a permitted operational area for the mobile platform, typically by limiting the mobility of the mobile platform. The first and second geofences are located with respect to one another and the permitted operational area so that with movement through the limits of the permitted operational area, the mobile platform encounters the first geofence no later than it encounters the second geofence. Usually the first geofence will circumscribe the territorial extent of the permitted operational area. Sometimes the permitted operational area surrounds the first and second geofences with the area within the second geofence being nested within the first geofence. 
         [0007]    Additional effects, features and advantages will be apparent in the written description that follows. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself however, as well as a preferred mode of use, further objects and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings, wherein: 
           [0009]      FIG. 1  is a map of a geographic region on which a geofence may be raised. 
           [0010]      FIG. 2  is a graphical illustration of an irregular region which is both itself a set of nested regions defined by geofences and which includes nested, geofenced regions. 
           [0011]      FIG. 3  is a block diagram schematic of a control system for a mobile platform which enables implementation of the staggered or tiered geofences of the present invention. 
           [0012]      FIG. 4  is a flow chart of an algorithm for establishing nested geofences. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0013]    Referring now to  FIG. 1 , vehicles  11 (A),  11 (B),  11 (C) . . .  11 ( n ) travel on the road network  12  in the region  10 . The vehicles  11  may include cars or trucks. Some or all of the vehicles  11  include suitable equipment that enables them to receive the global positioning information broadcast by a global positioning satellite constellation  50  and thus are mobile platforms with respect to which a geofence may be raised. Geofences (not shown) may be erected on region  10  through interaction of data processing equipment on board the vehicles with positioning data, or by response of a central control facility  40  to which the positioning data is reported. Each vehicle may be programmed with individual sets of responses so that the geofences applied to each vehicle are unique to that vehicle both as to location and as to the character of the responses. 
         [0014]    Referring to  FIG. 2 , a geofence may be based on an irregular polygon, a circle, a regular rectangle, or a combination of these shapes. In the present invention the responses which occur upon crossing a virtual boundary are “tiered” or “staggered”, to produce the effect of multiple boundaries, and to allow the nesting of regions. The mobile platform may be enclosed by a geofence (or geofences) or it may be limited to an area outside a zone defined by one or more geofences. Staggered responses are implemented by the use of nested geofences and directed to achieving any number of objectives. It may be considered desirable by an operator to prevent operation of commercial vehicles outside of a zone, but to warn drivers of the vehicles when they are approaching limits of the permitted operational area. Hence a first geofence may be used to produce a warning and a second geofence may be used to disable the vehicle. In other circumstances an operator may wish to make a zone a “no-stop” zone, but to permit transit through the area. Staggered responses may or may not be used depending upon the context. 
         [0015]    In  FIG. 2  a variety of regions have been defined by geofences including region or operational area  200  in which operation of a vehicle (not shown) is not inhibited. While the permitted operational area is shown as one contiguous region, it might comprise two or more non-contiguous regions connected by zones which permit transit but not stopping. Considering first a basic outer limit to vehicle operations, geofences  202  and  204  define limits on operation of a mobile platform  250 . Upon crossing geofence  202  the driver of the vehicle is warned that the vehicle is approaching its permitted operational limit and at geofence  204  the programmed responses which define that limit come into play. These may include shutting down the vehicle, or imposing an extremely low speed limit on the vehicle. There is no reason why areas which are operationally restricted cannot be nested within a permitted region such as region  200 . Such a situation is illustrated by geofences  208 ,  210 , where a warning is issued upon crossing geofence  208  from region  200  toward geofence  210  and the vehicle is operationally restricted upon passing into the area defined within geofence  210 . It is also possible to provide a operationally fully restricted zone such as enclosed by geofence  212 , or an operationally partially restricted zone such as enclosed within geofence  206 , either with or without warning zones. A partially restricted zone may allow vehicle operations through the zone without prolonged stops. A zone such as zone  206  could be used to link otherwise non-contiguous operational areas. It is conceptually possible for two geofences to merge for a portion of their lengths, but they are not permitted to cross so that first tier responses would occur after second tier responses as a vehicle left the non-inhibited, operational area  200 . 
         [0016]    Referring particularly to  FIG. 3 , a block diagram schematic of a control system  109  for a vehicle illustrates systems used to implement the invention at an operational, physical level. Control system  109  includes an electrical system controller (ESC)  111 , or equivalent, which may be taken to serve as a supervisory controller over the control system. Control system  109  further includes a plurality of relatively autonomous controllers or operators may include local data processing and programming and are typically supplied by the manufacturer of the controlled component. These controllers include the transmission controller  140 A, the engine controller  115  and the gauge controller  117 . There may also be generic, programmable controllers, these are particularly used to carry out operator defined tasks though they are not limited to such functions. The assignee of the present application markets generic controllers for controller area network applications, termed Remote Power Modules, which can be readily programmed from an external diagnostic port  136  or by the electrical system controller  111  in response to particular hardware attached to the remote power module. Possible examples of such controllers in control system  109  are the door operator controller  102 A for door  18 , a parking brake actuator  103 A for the parking brake  103  and the lighting controllers  106 A,  107  for the flashers  106  and interior lights  24 . 
         [0017]    The common data bus  110  is typically a serial data link  110  constructed as a twisted pair cable. It is typically externally accessible via a diagnostic port  136 . Although the autonomous controllers handle many functions locally and may be capable of functioning without reference to ESC  111 , they exchange data with ESC  111  and can receive operational direction from ESC  111  over the data bus  110 . Bus  110  typically operates in accord with a protocol such as the Society of Automotive Engineers (SAE) J1939 protocol relating to controller area networks (CAN). 
         [0018]    In an SAE 1939 compliant CAN, data buses may be private or public. A system topology will generally provide that the generic controllers are connected to a private bus and the dedicated controllers are connected to a distinct public bus. The ESC  111  is then connected to both buses and acts as a bridge between the buses. The general principal here is that generic controllers are typically used to provide customer specific functions, and use an customized communication set, which is not understandable by the dedicated controllers. This requires the ESC  111  to handle translation between the buses where a controller on one bus is required to respond to events being reported on the other bus and to allow data exchange between dedicated and generic controllers. The details of such a system are not relevant to the present invention and data bus  110  may be taken to be a conflation of public and private buses. 
         [0019]    Typically any function which can be carried out by a generic controller may also be carried out by the electrical system controller (ESC)  111 , provided output ports are available for connection of operational hardware to the ESC. The functions of the hazard light  106  flasher controller  106 A, the controller  107  for the interior lights  24 , or a controller actuator  103 A for the parking brake  103  may be implemented as programming on ESC  111 , or as programmed generic controllers which ESC  111  communicates with over bus  110 . 
         [0020]    A geofence is manifested as preprogrammed responses of the vehicle control system occurring with changes in vehicle position which alter vehicle operation in a way not conforming to normal operation. However, a geofence does not mandate any specific response and accordingly a geofence, in the sense of the invention, may be manifested as selected subsets of possible vehicle responses. In the preferred embodiment of the invention there are two tiers of responses, the first a warning issued to the driver and the second some limit on vehicle operation. Implementing limits on vehicle operation necessary involves vehicle operational variables and system controllers. For example, violation of the limits on the operational area for a vehicle may be manifested by limiting vehicle speed. A vehicle will have a sensed parameter measurement device such as a speed sensing device  121 , which provides a signal indicating the vehicle&#39;s speed. A navigation system  131  provides the geographic location of the vehicle  10 . The navigation system is conventionally supplied by a Global Positioning System (GPS) device that takes an external input from a satellite such as the commercially available LORAN system. The navigation system  131  may alternatively be a dead reckoning system without an external input or a combination of an external system and an internal to the vehicle dead reckoning system from the speed sensing device and other sensed parameter measurement devices. When the ESC  111  determines from the navigation system  131  that the vehicle is outside its permitted operational area it can limit engine  121  output to allow a maximum speed as reported by the speed sensing device. In the alternative, or in addition to these effects, the hazard flasher control  106 A may be invoked for flasher  106  operation. 
         [0021]    In the broader sense then, basic operations typically include providing for activation of geofence warning devices and operational inhibition for the vehicle in response to violation of geofences. The operating variable of vehicle position triggers all responses. The ESC  111  may be programmed to operate all, one, or some of the devices used for inhibiting the vehicle&#39;s operation or for warning an operator. Upon crossing a first tier geofence ESC  111  can cause gauge controller  117  to issue an audio warning over an audio/visual input/output device  119  on the vehicle dash panel. Upon the vehicle reaching the limits of its operational area the ESC  111  inhibits vehicle operation. It will be understood that the responses to violation of a geofence are flexible being limited only by reasonable prudence. 
         [0022]    Referring to  FIG. 4 , a high level flow chart illustrates system operation. Beginning at step  300 , program execution moves to determination as to whether geofences are active. If YES the program continues to determination as to whether one or two tiers of responses are provided (step  304 ). If one response tier is provided step  306  is executed to determine if the mobile platform (vehicle) has passed a geofence requiring full response to the incursion. If not program execution simply loops to step  302 . If YES, first (if provided/applicable) and second tier responses are applied to the vehicle and maintained as long as the vehicle remains out of bounds (the program loops back to step  306 ). 
         [0023]    If multiple tiers of responses to incursions into warning and prohibited zones are provided, than program execution following step  304  follows the “2” branch to step  308  where it is determined if the vehicle has passes a first tier geofence. If NO, than no response is required and the program loops to step  302 . If YES, the first tier responses are executed and the program moves to step  306  to determine if the platform has violated a second tier geofence. 
         [0024]    Those skilled in the art will now appreciate that alternative embodiments of the invention can exist. While the invention is shown in one of its forms, it is not thus limited but is susceptible to various changes and modifications without departing from the spirit and scope of the invention.