Mobile locator system

A locator system comprises a locator device, a control center, a workstation and a computerized interface. The control center and the locator device are configured to communicate via cellular and pager signals.

BACKGROUND OF THE INVENTION
 The present invention relates to mobile locator systems. More specifically,
 the present invention relates to a mobile locator system which employs
 pager and cellular communication, and provides user interface through a
 network such as the internet.
 Various mobile locator systems are known. These systems have been used for
 a range of different applications. One such application, for example, is
 stolen vehicle recovery. In order to recover stolen vehicles, a mobile
 unit is placed in a hidden location in a vehicle and adapted to become
 active when a vehicle security system detects a theft.
 Once engaged, the mobile unit begins acquiring location information
 typically by acquiring position signals from a global positioning
 satellite system. The mobile unit then communicates the information to a
 control center which maps the information and also attempts to notify the
 vehicle owner in order to verify that a theft has indeed occurred. Upon
 verification, the control center notifies the authorities and provides
 position information for the stolen vehicle.
 Such conventional mobile locator systems include two components, a locator
 device and a command center.
 The locator device usually comprises a position determination system, and a
 communication system coupled to the position determination system for
 communicating the position of the locator device as determined by the
 position determination system. The position determination system has taken
 various forms in the past. Known locators have employed various ground
 based navigational systems such as LORAN-C and other forms of LORAN
 navigation. Additionally, the position determination systems have more
 recently begun employing satellite navigation from the NAVSTAR system or
 GLONASS system or both.
 The communication systems employed by locator devices have ranged from
 radio communication, such as UHF, to cellular communication.
 The command centers used in mobile locator systems have traditionally
 communicated directly with the locator device via RF or cellular
 communication. Although cellular communication uses radio-frequency
 communication, it does so on very specific frequencies and through
 specific networks. Thus, it is listed separately to denote the different
 nature of cellular communication from traditional RF communication.
 The approaches of the prior art are limited. First, traditional approaches
 are costly, and employ either cellular communication which is relatively
 expensive, or dedicated radio communications, which is also costly. Even
 where inexpensive radios are used to communicate the position information,
 the effective range of such inexpensive radios severely limits the
 location system. Finally, if users wish to interact with the control
 center, they generally must be onsite, or within the local calling area of
 the command center, lest they accumulate substantial long distance
 telephone charges.
 SUMMARY OF THE INVENTION
 A locator system comprises a locator device, a communication station, a
 control center, and a computerized interface. The communication station
 communicates with the locator device. The control center is coupled to the
 communication station through a network. The computerized interface
 resides at the control center, and the locator system provides
 bi-directional communication between the communication station and the
 locator device via the computerized interface and through the computer
 network.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
 FIG. 1 is a block diagram of a mobile locator communication system 10 in
 accordance with the present invention. FIG. 1 illustrates Global
 Positioning System (GPS) satellite 12 (which represents a satellite-based
 positioning system such as NAVSTAR or GLONASS), satellite communication
 system 14, cellular communication towers 16, public switched telephone
 network 18, satellite uplink station 20, cue paging network 22, control
 center 24, global network 26, customer station 28, and switch 30. FIG. 1
 also illustrates locator device 32 which is installed in, for example, a
 semi tractor or trailer. It should be noted at the outset that while FIG.
 1 illustrates GPS satellite 12, other suitable positioning systems could
 also be used such as LORAN.
 In the embodiment shown in FIG. 1, locator device 32 is implemented as a
 fleet tracking device for tracking a fleet of semi tractors or trailers.
 In that embodiment, each of a plurality of locator devices 32 are
 installed in a semi tractor or trailer. Each of the locator devices
 receives GPS information from GPS satellite 12. Device 32 is adapted to
 determine its own position based upon signals received from GPS satellite
 12. As described in greater detail with respect to FIG. 2, locator device
 32 includes a cellular transceiver and modem, a control circuit which
 includes control electronics, a GPS receiver, a pager, and other suitable
 accessories, such as appropriate cabling and power connections, and
 antennae. Locator device 32 may also optionally include an operator
 interface, such as a message display, or an operator input device which
 receives inputs from an operator associated with locator device 32.
 Control center 24 includes modems 34, router 36, paging server 38,
 communication server 40, MIN tracking circuit 42, data manager 44, data
 base 46, GIS server 48, mail server 50, and global network and customer
 interface server 52. Customer station 28 is preferably connected to
 control center 24 for bi-directional communication either through a
 dedicated pipe 54, through a direct telephone line 56, or through global
 network (such as the internet) 26. Customer workstation 28 may simply be a
 personal computer. The personal computer may optionally be required to
 have internet access, and an internet browser, or a modem.
 Paging server 38 is connected to modems 34 and data manager 44.
 Communication server 40 is connected to modems 34, to data base 46 and
 data manager 44. MIN tracking circuit 42 is connected to router 36 and
 data base 46. Mail server 50 is connected, through global network 26, to
 station 28, and also to data manager 44. Web server 52 is coupled to data
 base 46 and data manager 44, and also to station 28. Further, GIS server
 48 is coupled to data base 46 and web server 52.
 When control center 24 tracks the location device 32, the location device
 32, in a preferred embodiment, periodically receives location information
 from GPS satellite 12 and stores a location indicated by that information.
 Location device 32 also, in the preferred embodiment, periodically
 transmits that location information to control center 24 via a cellular
 data transmission through cellular network 16, PSTN 18, and modems 34. The
 information is received by communication server 40 and provided to data
 base 46, where it is stored for further processing. Any other information
 received from locator device 32 is also transferred by communication
 server 40 to data base 46 for further processing.
 In order to view, or generate reports based on, the location information, a
 customer at station 28 accesses web server 52. Web server 52 receives the
 requested location information from data base 46. GIS server 46 receives
 the latitude and longitude signals and generates a textual description of
 the location, based upon those signals and provides that textual
 description to data base 46 where it is stored in a location associated
 with that particular locator device 32. In addition, GIS server 48
 provides web server 52 with maps based on the position information
 requested by the customer at station 28. The maps are generated also in
 accordance with the location information which is being retrieved, and
 which is stored in data base 46. Thus, web server 52, as will be described
 with reference to later figures, provides a customer interface to the
 customer which includes a textual description of the location, along with
 the longitude and latitude coordinates, as well as maps of the requested
 location. The customer can request additional detailed location
 information, which is described later in the specification, by requesting
 web server 52 to access that information and present it in usable customer
 interface format to the customer.
 In addition, the information periodically received by locator device 32 may
 include other items of data (which will be described in detail later in
 the description) such as alarm conditions, or a request by the operator of
 locator device 32 to send a message to a particular customer at a
 particular workstation 28. In that case (i.e., when the data received from
 locator device 32 requires some action on behalf of the control center)
 communication server 40 stores the data in data base 46, and provides an
 indication to data manager 44 that action needs to be taken. Data manager
 44 places that request in a queue, based upon its priority, and then
 executes that transaction in due course.
 For instance, where the operator of locator device 32 requests that a
 message be sent to a customer, communication server 40 receives the data
 indicative of the message, and stores that data in data base 46.
 Communication server 40 then provides data manager 44 with an indication
 that a message needs to be sent to a particular customer, and indicates to
 data manager 44 the location of that message in data base 46. Data manager
 44 then, in due course, retrieves the message to be sent to the customer,
 and controls web server 52, or mail server 50 (as desired) to initiate
 communication with the customer at station 28, and to send the desired
 message.
 In communicating with locator device 32, control center 24 can communicate,
 on its own behalf or on behalf of an administrator residing at control
 center 24, or on behalf of a customer residing at station 28. For example,
 if a customer wishes to send the operator of locator device 32 a message,
 that customer obtains access to web server 52, and requests web server 52
 to receive the message and store it in data base 46. Web server 52 then
 indicates to data manager 44 that a message must be sent. Data manager 44
 executes that transaction in due course by accessing the data indicative
 of the message, and the destination of the message, from data base 46, and
 then controlling communication server 40 or paging server 38 (whichever is
 desired) to initiate communication with locator device 32 through modems
 34. Web server 52 typically receives from the customer at station 28 some
 indication as to whether the customer wishes to communicate with locator
 device 32 by a page or by a cellular communication. Web server 52 provides
 this information to data manager 44 (either directly or through data base
 46) and data manager 44 contacts locator device 32 accordingly.
 In one preferred embodiment, group communication with a plurality of
 locator devices 32 is accomplished through paging. This can be done in a
 highly efficient manner at very low cost. By contrast, where a specific
 voice or data communication is to go to only one locator device 32, and
 the customer wishes to initiate bi-directional communication, the cellular
 network may be better suited for that type of communication.
 In another preferred embodiment, the message received from locator device
 32 may request that control center 24 communicate with a customer at
 station 28 via e-mail. In that instance, communication server 40 receives
 the body of the message and stores that data in data base 46.
 Communication server 40 then notifies data manager 44 that an e-mail must
 be sent. Data manager 44 executes that transaction in due course, by
 retrieving the data from data base 46 and providing it to mail server 50
 which causes an e-mail to be sent to station 28. The customer at station
 28 may also communicate with locator devices 32 by e-mail, in the reverse
 order.
 Additionally, communication system 10 preferably provides control center 24
 with access to various cellular overhead signals via switch 30. Such
 signals are known in the art, and typically are required to ensure system
 synchronization. For example, cellular transceivers generally transmit
 registration signals to cellular communication systems in which they are
 operating. The purpose of such signals is generally to inform the cellular
 communication system that the cellular transceiver is within the range of
 the cellular communication system. However, because control center 24 has
 access to the overhead signals of the cellular communication system,
 control center 24 is able to know which mobile locator device 32 is within
 range of which particular cellular communication system, and determine a
 general location of locator device 32, at a very low cost.
 As is also known in the art, cellular communication systems communicate
 with one another in a standardized manner generally called an SS7 signal
 employing an IS41 protocol. Typically, the registration signal transmitted
 by a cellular transceiver is received by a non-home cellular communication
 system, and such information is transmitted to the home cellular system
 through the SS7 signal. Thus, the combination of control center 24 having
 access to the cellular communication system, and the SS7 signal coupling
 the cellular communication system to various other cellular communication
 systems, allows control center 24 to approximate locations of all mobile
 locator devices 32 without incurring any significant cost.
 This is done by router 36 receiving the overhead information from switch
 30. Switch 30, in turn, receives the information from the cellular network
 to which it is coupled. Router 36 transmits the information to MIN
 tracking circuit 42 which decodes and deciphers the mobile identification
 number (MIN) and posts this to data base 46.
 This leads to an additional benefit. MIN tracking circuit 42 is configured
 to monitor the proximity of the locator device 32 based on the overhead
 information received. If, in adjacent or closely proximate monitoring
 intervals, locator device 32 indicates that it is in two different and
 distant locations (cell sites); MIN tracking circuit 42 can interpret this
 as indicating that device 32 has been tampered with. For instance, it is
 impractical that a locator device could register with a cellular
 communication system in one location such as Oregon and 15 minutes later
 register with another very distant cellular communication system in
 Florida. Thus, in this instance, fraud detection and control is provided
 to some extent.
 Additional fraud protection is also provided by MIN tracking 42. For
 example, MIN tracking circuit 42 is configured to monitor the usage
 profile of each locator device 32, and compare that to the profile which
 MIN tracking circuit 42 has seen before for that locator device 32. For
 example, if the user of locator device 32 is initiating a very large
 amount of cellular communications with locator device 32, and that is
 inconsistent with the prior usage profile for that particular locator
 device 32, MIN tracking circuit 42 flags this as a potential fraudulent
 usage. In addition, MIN tracking circuit 42 is configured to monitor
 calling patterns associated with each particular locator device 32. In
 that embodiment, MIN tracking circuit 42 monitors the time at which calls
 are normally made by the operator of locator device 32. If that calling
 pattern is abnormal, or inconsistent with a prior calling pattern (for
 example, if a large number of calls are being made at an odd hour of the
 day, and the operator of that particular locator device 32 typically makes
 calls only every eight hours, or so) MIN tracking circuit 42 also flags
 this as a potential fraudulent usage of that particular locator device 32.
 The access of control center 24 to cellular communication system overhead
 also allows control center 24 to take action based upon low cost star code
 calls received by the cellular communication system from mobile locator
 device 32. Star codes, as is known in the art, are generally very low cost
 communications which are virtually universally recognized by all cellular
 communication systems and generally are passed through at very little
 charge. Often, a star code call is a type of phone call from a cellular
 transceiver to a cellular communication system itself to perform various
 functions. However, the access of control center 24 to cellular
 communication system overhead allows control center 24 to monitor star
 code calls emanating from mobile locator device 32 and to take specific
 action in response.
 Thus the unique interaction between control center 24 and the cellular
 communication system allows proximity location of mobile locators devices
 at very low cost. Further, some limited fraud detection and control is
 provided. Finally, the ability of mobile locators to add data to or
 customize registration interaction with cellular communication systems,
 and utilize star codes, provides some limited low cost cellular massaging.
 In operation, control center 24 can communicate with locator device 32
 either through paging, or through cellular communication. This provides a
 great deal of functionality. Control center 24 essentially uses these
 lines of communication to gather data from location device 32, and to
 communicate with one or more of locator devices 32. The particular
 communication between locator device 32 and control center 24 can be for
 any number of reasons. For example, control center 24 may wish to simply
 receive position information from locator device 32 to update its data
 base and to track locator device 32. Control center 24 may also, however,
 wish to initiate a one-way or two-way voice or data communication with
 locator device 32, or an operator or user residing in the vicinity of a
 locator device 32. Further, control center 24 may initiate a communication
 with locator device 32 based upon a prompt or request from a customer at
 customer station 28. The combination of cellular communication, and paging
 communication, allows transactions required for tracking and generating
 reports related to a plurality of locator devices 32 to be performed in a
 highly efficient manner.
 FIG. 2 is a more detailed block diagram of locator device 32. In the
 preferred embodiment, locator device 32 preferably includes cellular
 transceiver 58 (which also preferably includes a cellular modem) and
 antennae 60. Locator device 32 also preferably includes a plurality of
 sensors 0-N, GPS receiver 62, controller 64, pager module 66, message
 display 68, and voice handset 70. Locator device 32 also includes either a
 power source, or a connector for connecting to a power source
 (collectively referred to as a power supply 72). It should also be noted
 that most of the items are optional, such as sensors 0-N, message display
 68 and voice handset 70.
 However, in one preferred embodiment, sensors 0-N are provided. Those
 sensors are placed on items to be sensed in the proximity of locator
 device 32. For example, sensors 0-N may be placed on a semi tractor or
 trailer to sense various aspects of the tractor or trailer and provide an
 output indicative of the sensed parameters to controller 64. In one
 preferred embodiment, a door sensor is provided on the trailer or
 passenger door of the truck and provides an indication to controller 64 as
 to whether the door is open or closed. In another preferred embodiment, a
 switch is placed on the dash board, or in another accessible location in
 the cab of the truck, which is usually accessible by the driver and which
 can be actuated to provide a panic alarm input to controller 64. Such a
 switch would be actuated by the driver during, for instance, a robbery.
 Further, volume sensors can be placed in a trailer. Such sensors are
 preferably sonic-based sensors mounted on the ceiling of the trailer. The
 sensors provide an indication to controller 64 as to the load then being
 carried by the trailer. In other words, the array of sensors is arranged
 along the ceiling of the trailer, from front to back, and senses whether a
 load is being carried in a corresponding part of the trailer. The sensors
 provide outputs indicating how full the trailer is. These, and other
 sensors, can be implemented in locator device 32.
 Controller 64 can perform any number of functions based on that
 information. For example, controller 64 may preferably simply store the
 trailer volume sensor information until control center 24 interrogates
 locator device 32. At that time, controller 64 operates locator device 32
 to transmit the volume information such that control center 24 receives
 and maintains a record as to the volume of the load then being carried by
 that particular trailer. In addition, controller 64 can initiate
 communication with control center 24 based on the inputs from sensors 0-N.
 This can be accomplished in any desired hierarchy.
 Locator device 32 also preferably includes pager module 66. Pager module 66
 is configured to receive pager information transmitted by control center
 24. Pager module 66 demodulates and provides data signals indicative of
 the pager information to controller 64. As with the other various inputs,
 controller 64 can be configured to perform any desired function based on
 the information received.
 GPS receiver 62 is configured, with an appropriate antenna, to receive the
 GPS information from GPS satellite 12. GPS receiver 62 receives this
 information and transmits information signals to controller 64 indicative
 of the GPS signals received. Controller 64 preferably stores this
 information in an associated memory (either integral with controller 64,
 or separate therefrom) and provides the information to control center 24
 upon request.
 Message display 68 and voice handset 70 are preferably provided for
 communication with the operator of the locator device 72. In other words,
 if locator device 72 is to be used other than simply to track the location
 of an object, but is instead used to also accomplish interactive
 communication or one-way communication with the operator, message display
 68 and voice handset 70 are provided. In the preferred embodiment, message
 display 68 is simply a liquid crystal display (LCD) (or other suitable
 display) which is capable of displaying messages to the operator. Message
 display 68 may also be associated with an input mechanism, such as push
 buttons or scroll buttons, by which the operator of locator device 32 can
 acknowledge receipt of the displayed messages, or can initiate limited
 one-way communication with control center 24.
 In other words, in one preferred embodiment, message display 68 is provided
 with scroll buttons and send buttons. In that instance, the operator of
 locator device 32, after receiving a message on message display 68, can
 scroll through a number of preprogrammed messages and send one of those
 messages in response to the received message. In an alternative
 embodiment, a keypad or keyboard (or membrane-type keypad or other
 suitable input device) is provided along with message display 68. In that
 embodiment, the operator of locator device 32 can compose free form
 messages and send those back to control center 24.
 Voice handset 70 is preferably a typical voice handset which is configured
 to receive voice transmission from the operator of locator device 70 and
 transmit information signals to controller 64 indicative of the voice
 input received. Voice handset 70 is also suitable for receiving
 information signals from controller 64 which are indicative of voice
 signals received by cellular transceiver 58, and providing an audible
 voice output based on the signals received. In this way, two-way voice
 communication can be accomplished between locator device 32 and control
 center 24 via the cellular network and the PSTN network.
 Power supply 72 can take any number of forms. For example, power supply 72
 may include a solar panel, batteries, a battery charger (which can be
 tethered to the engine of the semi trailer in which locator device 32 is
 mounted) or can simply be a connection device for connecting locator
 device 32 to a power supply on board the truck in which locator device 32
 is mounted. Any other suitable configurations can also be implemented as
 power supply 72.
 As described above, web server 52 is used to interface with customers at
 customer station 28. The customer interface actually resides on web server
 52. Therefore, in order to access control center 24, or communicate with
 any of its locator devices 32, the customer must proceed through server
 52.
 In the preferred embodiment, once accessed by a customer, server 52
 provides a log-in screen, such as that illustrated in FIG. 3.
 The customer interface in FIG. 3 as used in the internet connection
 embodiment of the present invention is created by interactions between web
 server 52 and internet access software such as Netscape.RTM.. For example,
 upon gaining access to control center 24 for the first time, web server 52
 provides the internet access software with a series of commands preferably
 in hyper-text markup language (HTML) and, JAVA, or other appropriate
 programming language to create the interface. Likewise, user interaction
 with the user interfaces is preferably provided to web server 52 in the
 form of appropriate commands, preferably HTML.
 The customer interface illustrated in FIG. 3 requests that the customer
 enter certain information, such as a company number (in field 71)
 associated with a customer, and an employee password (in field 73) which
 maintains some degree of security in accessing control center 24. After
 the customer has logged in via customer station 28, server 52 assigns a
 session number to that communication, and then tracks and logs information
 and items which are transacted during that session. This information is
 written to data base 46 (in FIG. 1) and is correlated to that particular
 customer's company number. Information which is used in creating a session
 number includes the time that the session was initiated, the particular
 customer initiating the session, and the items accomplished during the
 session.
 Upon entering the appropriate company number and employee password, the
 customer is given a number of options including a manage accounts option
 (by clicking on bar 75), a manage groups option (by clicking on bar 77),
 an edit preprogrammed messages option (by clicking on bar 79), and a
 log-in option (by clicking on bar 81). These options are discussed, in
 order, below.
 Once the user is validly logged in, and if the user selects the manage
 account option in FIG. 3, by clicking on bar 75, the user is presented
 with a second user interface screen, such as that illustrated in FIG. 4.
 The user is then allowed to either view and scroll through the current
 user list (displayed in field 83) which lists users authorized to use the
 system, or to delete those users. In the preferred embodiment, the ability
 is also provided for the customer to add new users. In that case,
 information is entered in the new user information box 85, such as the
 name and user password of the new user, as well as the new user's e-mail
 address. Also, the operator is allowed to assign certain functionality
 which can be executed by the new user by selecting and deselecting certain
 functions in box 87. For example, the find and mapping functions allow the
 user to locate various of its locator devices 32, and to view maps
 associated with the location. The message function allows the user to send
 and receive messages to the various locator devices 32, and the reports
 and settings functions allow the user to generate and view reports, and to
 change various settings in its particular customer configuration.
 If, in FIG. 3, the user chooses the manage groups option by clicking on bar
 77, the user is presented with another user interface, such as that
 illustrated in FIG. 5. One preferred feature for enhancing the efficiency
 of the system is the ability to arrange the various locator devices 32
 associated with any given customer, into groups, or to at least provide
 the customer with that option. Therefore, the user interface illustrated
 in FIG. 5 allows the user to arrange its particular locator devices 32
 into groups. The user is allowed to view the current groups in field 89,
 add groups, erase groups, generate reports associated with each of the
 groups, and update the groups and various information associated with the
 groups, simply by clicking on the appropriate portions of the user
 interface screen. The configuration and use of groups is discussed in
 greater detail below.
 If, in FIG. 3, the user selects the edit preprogrammed messages option by
 clicking on bar 79, the user is provided with yet another user interface
 screen, such as that illustrated by FIG. 6. To simplify communication
 between any particular user or dispatcher at station 28, and drivers or
 operators associated with locator devices 32, a number of preprogrammed
 message capabilities are provided. For instance, preprogrammed messages
 can be provided for driver initiated messages, driver responses, or
 messages from the dispatcher to the driver. In the instance in which
 preprogrammed messages are used, the dispatcher may simply select a
 preprogrammed message to be sent (as will be described later with respect
 to FIG. 7) and server 52 posts transaction data to data base 46 and
 indicates to data manager 44 that a transaction needs to be executed. At
 an appropriate time, data manager 44 accesses the transaction data stored
 in data base 46. That transaction data preferably includes the desired
 locator devices which need to be accessed, and the message data to be sent
 to those particular locator devices, along with a chosen path for sending
 the data (i.e., pager or cellular communication). Data manager 44 then
 accesses the necessary paging or communication server 38 or 40 to
 accomplish the communication.
 The driver then receives the message on the message display 68 (shown in
 FIG. 2) associated with the particular locator device 32. The driver then
 preferably has the option, as described with respect to FIG. 2, to scroll
 through the preprogrammed messages (either the driver initiated messages
 or driver responses shown in FIG. 6) and send one of those messages back
 to the dispatcher through control center 24. In any case, FIG. 6 provides
 the dispatcher with the capability of adding to, subtracting from, or
 editing the preprogrammed messages available to the driver and to the
 dispatcher.
 Once appropriate log-in information is received on the interface
 illustrated by FIG. 3, and if no further log-in options are requested, the
 operator can click on log-in bar 81 to continue interaction with control
 center 24. Server 52 provides the dispatcher or user at station 28 with
 the ability to access information associated with its particular locator
 devices 32. In doing so, server 52 generates yet another customer
 interface, such as that illustrated by FIG. 7.
 FIG. 7 shows that the first customer interface to be presented by server 52
 is one which shows a fleet overview. The fleet overview illustrates all
 locator devices (in this instance semi tractor or trailer trucks) 101 on a
 nationwide map 103 illustrated in an upper portion 97 of the interface
 screen. On the upper left hand corner of the interface illustrated in FIG.
 7, the dispatcher is provided with the ability to find a specific locator
 device 32, by either entering a number in field 91 or a driver name for
 that truck in field 93. If that information is entered, the particular
 truck number, driver name, location (by approximate address), last contact
 date and time, current speed, and current cellular telephone number, is
 illustrated for the particular driver on the right hand side of map 103.
 Also, in the fleet overview interface, the last messages received by the
 members of the fleet are displayed below the map 103 in a data field 99,
 along with the date and time of the message, the location from which the
 message was transmitted and the alarm configuration, and alarm status, of
 each truck.
 FIG. 7 also illustrates that the dispatcher is provided with the option to
 find or filter through various groups of locator devices 32 using group
 field 95 and bars 76 and 78. In other words, the operator can select among
 a number of the groups defined in FIG. 5, and can have only that group
 displayed on the map 103.
 As briefly discussed above, a highly configurable feature of the present
 invention is the ability to create groups and subgroups of mobile
 locators. Thus a user has the ability to create functional subgroups
 within the total group of mobile locators for which the user has access.
 With respect to fleet management systems, one such appropriate subgroup
 may be delivery trucks while another appropriate subgroup would be
 over-the-road transports. As another example, a mobile locator system
 embodied in a vulnerable persons management system can have different
 subgroups comprising children and elderly persons.
 The grouping technique is implemented with an efficient pager protocol.
 Each pager has a specific, unique, identification and a group code. Thus,
 when control center 24 is to communicate with an entire group, potentially
 consisting of thousands of mobile locators, only one pager communication
 signal need be broadcast.
 FIG. 7 allows the user to obtain additional information about the fleet as
 well. By clicking on the alarm configuration information in field 105 for
 a given truck, the particular alarm profile for any given locator device
 32 can be viewed. This is illustrated by a user interface, such as that
 illustrated in FIG. 8. As shown, the particular truck number and driver
 are identified in field 99, along with all the dates and times that alarm
 conditions were conveyed to control center 24. Also, the type of alarm is
 expressly illustrated, and the location of the truck at the time that
 alarm was sent is also illustrated.
 By clicking on the message information in field 107 (of FIG. 7) for a given
 truck, the dispatcher can view the message history for any given truck
 number or driver. This is illustrated by a user interface such as that
 shown in FIG. 9. It should be noted that, in the preferred embodiment, the
 messages as displayed on the screen are color coded to indicate whether
 the messages have been completed, just sent, sent but not confirmed, not
 yet sent (because they could not be completed), or are scheduled to be
 sent, but have not yet been sent. In one preferred embodiment, the
 message, the date and time of creation and completion, and the sender are
 all illustrated.
 The operator can also obtain location profile information for locator
 devices illustrated in FIG. 7 by clicking on location information in field
 109 for any given truck. FIG. 10 illustrates one preferred customer
 interface which is provided by server 52, and illustrates the location
 profile of any given locator device 32. As shown in FIG. 10, an enlarged
 map section 100 is provided which highlights the particular truck being
 viewed. The location profile is set out in data field 99 and includes the
 location and time that each particular location fix was taken, the speed
 of locator device 32 at that time, the heading of the locator device, and
 the specific location, given in terms of approximate address. With this
 information, the progress or movement of any particular locator device 32
 can be quickly and efficiently tracked.
 FIG. 11 illustrates one preferred embodiment of an operator interface which
 is provided to the dispatcher when a particular truck number is entered in
 truck number field 91. At that point, the upper portion 97 of the
 interface illustrates the truck ID in field 102, the driver name in field
 104, and any groups to which the particular truck and driver belong, in
 field 106. The dispatcher is then given the option to select the scope of
 the search used to locate that particular truck. The search can be
 narrowed to a given city which is entered in field 108, and a radius about
 that city given in field 110, along with an indication as to whether the
 operator is inquiring whether the truck is inside or outside of that
 radius, indicated by field 112. Also, at the bottom of the operator
 interface, in data field 99, the fleet overview data information is
 preserved.
 FIG. 11 also illustrates a number of icons which provide the user with
 certain functions, including map icon 80, message icon 82, reports icon
 84, settings icon 86 and help icon 88.
 Once the particular truck identified in FIG. 11 is located, the dispatcher
 is provided with the option of sending a message. This is done by simply
 clicking on the message icon 82. In response, server 52 provides the
 dispatcher with another interface, such as that shown in FIG. 12, which
 includes an indication of the preprogrammed messages associated with that
 particular locator device 32. This information is illustrated in field 114
 in the upper portion 97 of the interface. The dispatcher is also provided
 with a field 116 in which to enter a free form text message which is to be
 sent to that particular locator device 32. In addition, the dispatcher is
 provided with the option of prioritizing the message. In field 118, the
 dispatcher can indicate that the message is to be delivered now, or
 deferred and sent in the normal course of operation of control center 24.
 FIG. 13 illustrates an operator interface provided by server 52 to the
 dispatcher at station 28 when the dispatcher clicks on the reports icon
 84. The truck ID number, driver name and group fields 102, 104 and 106,
 respectively, remain unchanged. However, the operator is provided with the
 ability to choose the type of report to be generated by entering that
 type, or scrolling to that type, in field 120. The operator is then
 provided with the ability to limit the chronological extent of the report
 by entering a start date in field 122, and by entering the number of days
 to report in field 124. The priority of sorting (either by truck or by
 date) can also be selected by the dispatcher in field 126. Further, the
 form of delivery of the report can also be selected by the dispatcher in
 field 128. In that field, the dispatcher can select whether the report is
 to either be delivered to the dispatcher's screen, or e-mailed as a text
 file which can be imported into a document currently being generated by
 the dispatcher.
 FIG. 14 illustrates an operator interface which is presented by server 52
 to the dispatcher at station 28 when the dispatcher selects the settings
 icon 86. The upper portion 97 of the interface is configured to illustrate
 the driver name in field 130 and the trailer type in field 132. The
 location interval field 134 is configured to illustrate the time between
 position fixes which that particular location device 32 will take. In
 other words, controller 64 (shown in FIG. 2) will automatically receive,
 from GPS receiver 62, location information from satellite based global
 positioning system 12. Controller 64 stores that information so that the
 dispatcher can review a certain level of historical data which is
 indicative of the path of locator device 32 over a predetermined prior
 period of time. In FIG. 14, the interval between such position fixes is
 indicated at 15 minutes. This is selectable by the dispatcher.
 FIG. 14 also illustrates that the lower data field 97 in the interface
 depicts the call-in schedule for that particular location device 32. In
 other words, controller 64 can be configured to use cellular transceiver
 58 to automatically initiate communication with control center 24. During
 such communications, a typical transaction is for controller 64 to
 download position information, and thus update data base 46 in control
 center 24 with the most recent position information stored by controller
 64. Controller 64 can be configured to automatically initiate such
 communication, on periodic intervals, or at any time during a day or week.
 The data field 97 shown in FIG. 14 illustrates a call-in schedule (to the
 nearest half hour) when the particular locator device 32 will
 automatically initiate such communication. Of course, this schedule can be
 altered by the dispatcher. In a preferred embodiment, the dispatcher
 simply places the cursor over any of the squares in the schedule and
 clicks on the square in order to activate or de-activate a call-in at that
 particular time.
 FIG. 15 illustrates the remainder of the settings first illustrated in FIG.
 14. By using the arrows on the far right of the interface, and scrolling
 downward, the dispatcher can view the remainder of the settings for that
 particular locator device 32.
 A variety of different alarms are illustrated in field 138. A more detailed
 list of alarms will be discussed later in the specification. The lower
 portion 140 of the interface illustrated by FIG. 15 indicates certain
 settings which can be incorporated into locator device 32 for the cellular
 communication capability of locator device 32. For example, voice settings
 illustrated in FIG. 15 allow the dispatcher to set a personal and
 corporate monthly allotment for cellular charges which can be incurred by
 any particular locator device 32. In addition, a corporate personal
 identification number (PIN) can be inserted which allows the operator of
 locator device 32 to charge cellular communications to the corporate
 account, only if the PIN is known, and input into the phone prior to such
 communications. The voice settings also allow the dispatcher to increase
 both the corporate and personal allotments allowed for any particular
 locator device 32.
 Field 140 also illustrates a call restriction list. This list includes
 fields for receiving a list of telephone numbers. The dispatcher can then
 configure the locator device 32 such that it allows the operator to
 initiate cellular communication with any other number, with only the
 numbers on the call restriction list, or with any number but those on the
 call restriction list.
 FIG. 16 illustrates an operator interface which is presented by server 52
 to station 28 in response to the operator clicking on help icon 88. The
 interface illustrated in FIG. 16 allows the dispatcher to receive help. A
 number of exemplary help subjects are listed in FIG. 16. Of course, any
 number of other suitable help subjects can be provided as well.
 Table 1 is a list of common communications between control center 24 and
 locator device 32. The call now command is issued by control center 24 to
 initiate an exchange of messages between control center 24 and locator
 device 32. Upon initiating that message, and upon receipt of that message
 by locator device 32, all messages, including everything that is waiting
 to be sent to the control center 24 from locator device 32, is exchanged.
 Locator device 32 also determines whether any mail is waiting to be sent
 to it, and that mail is received. The call now command can be configured
 such that locator device 32 calls in to control center 24 immediately upon
 receipt of the message, or first obtains a location (GPS) fix and then
 calls in to control center 24.
 The request alarm report command is issued by control center 24. In
 response, locator device 32 provides a report on the status of all alarms
 currently attached to locator device 32. This information is placed in an
 output message queue by controller 64 of locator device 32, where it is
 delivered at the next time that the locator device is in contact with
 control center 24.
 The send alarm command is received by locator device 32 and is used to
 populate an alarm code table at locator device 32. The alarm code table
 holds the alarm code which is returned to control center 24 when an alarm
 is activated.
 The alarm switch on and alarm switch off commands are issued by control
 center 24 and cause locator device 32 to enable a particular alarm switch
 (upon receipt of the alarm switch on command) or disable the designated
 alarm (when the alarm switch off command is received). When the alarm
 switch on command is received, and that particular switch is already
 enabled, locator device 32 sends back an alarm message immediately,
 corresponding to that alarm switch.
 One type of alarm is a tamper alarm. This alarm when enabled creates an
 alarm condition when tampering of some fashion is detected. This type of
 alarm has particular applicability to fleet management systems where it is
 desirable that a trailer not be tampered with through the majority of its
 travel or when unhooked from a tractor.
 Also, the alarms themselves can be enabled and configured and used in
 conjunction with one another to provide higher level alarm type functions.
 For example, a mobile locator system which is embodied in a fleet
 management system may allow a trailer to be loaded without creating an
 alarm condition. However, once the trailer leaves a zone of loading, a
 tamper alarm is enabled which creates an alarm condition if the trailer is
 tampered with while en route. However, as the trailer approaches its
 destination, and travels within a zone of unloading, the tamper alarm may
 be automatically disengaged to allow simple and efficient unloading
 without tripping the tamper alarm.
 The battery alarm on and battery alarm off commands enable locator device
 32 to enable and disable the battery alarm. When the battery alarm is
 enabled, the locator device 32 monitors the level of battery power being
 supplied to it. If the battery output drops below a threshold level, then
 an alarm message is sent to control center 24 immediately. In the
 preferred embodiment, once a successful low battery alarm has been sent to
 control center 24, no other low battery alarms are sent until locator
 device 32 detects that it is again out of a low power situation.
 The 911 alarm on and off commands enable and disable the 911 alarm on
 locator device 32. When this alarm is enabled, locator device 32 records
 when the driver or operator of locator device 32 makes a 911 call on
 handset 70. As soon as the driver hangs up handset 70, the locator device
 32 sends a 911 alarm to the control center 24 to indicate that a 911 call
 was placed.
 The movement alarm on and movement alarm off commands enable and disable
 the movement alarm. When the movement alarm is enabled, locator device 32
 monitors its own movements to determine whether it has moved more than a
 specified distance, each time it takes a GPS fix. The distance can be
 modified by the dispatcher. Specifically, a movement alarm is configured
 to become active when mobile locator device 32 detects that mobile locator
 device 32 itself has moved a preselected distance while the movement alarm
 is engaged. Through communication between control center 24 and mobile
 locator device 32, the mobile locator system is capable of enabling or
 disabling such movement alarms and configuring the amount of permissible
 movement which is allowed before the movement alarm becomes active.
 After the movement alarm is enabled, mobile locator device 32 acquires a
 first and second position from the GPS system. After acquiring the second
 position, the mobile locator device 32 determines the distance between the
 original location (as stored during the first position acquisition) and
 the second position acquired. After calculating the displacement from the
 original position, mobile locator device 32 determines whether the
 distance traveled is greater than the radius allowable. If mobile locator
 device 32 has traveled an unacceptable distance (i.e., displacement is
 greater than the radius allowable), an alarm condition is set. If,
 however, the displacement is less than the acceptable radius, then no
 alarm condition is set. If the movement alarm continues to be enabled then
 locator 32 acquires another position. This process continues.
 Another alarm of general applicability to mobile locator system 10 is a
 proximity alarm. This type of alarm is essentially a complement of the
 movement alarm. Specifically, when the proximity alarm is enabled, it
 creates an alarm condition when mobile locator device 32 determines that
 mobile locator device 32 itself is within a preselected distance from a
 preselected position. Preferably, control center 24 causes mobile locator
 device 32 to enable the proximity alarm. After enabling the alarm, mobile
 locator device 32 is caused to acquire its position. Mobile locator device
 32 then determines the distance between the acquired position, and a
 target position. Next, mobile locator device 32 compares the distance
 between the acquired position and the target position with a minimum
 allowable radius which was received by mobile locator device 32 during
 enablement. If mobile locator device 32 is unacceptably proximate the
 target coordinates, an alarm condition is set. If, however, mobile locator
 device 32 is not unacceptably proximate the target coordinates, then no
 alarm condition is set. Similar to the movement alarm the proximity alarm
 ends upon being disabled.
 The set mode command allows locator device 32 to be set to one of a number
 of modes. When locator device 32 is ON, that indicates that the entire
 system is powered and is constantly running. When locator device 32 is in
 a SLEEP mode, that indicates that all of the components of locator device
 32 are off, except the pager module 66, and any alarm switches associated
 with locator device 32. In the SLEEP mode, locator device 32 still
 services its call-in schedule, during which it initiates communication
 with control center 24 to provide position information and exchange other
 suitable information. In that embodiment, locator device 32 wakes itself
 up periodically to initiate such communication. Also, in the SLEEP mode,
 if control center 24 wishes to initiate communication with locator device
 32, control center 24 pages locator device 32. Page module 66 then
 initiates a power-up sequence to power-up the remainder of locator device
 32 so that full communication can be accomplished between locator device
 32 and control center 24.
 In the DEEP SLEEP mode, locator device 32 is completely powered down,
 except that pager module 66 is cycled on and off in accordance with a
 predetermined power budget which the operator wishes to meet. In other
 words, of power has been removed from locator device 32 (such as the semi
 trailer ignition being turned off, or when locator device 32 is untethered
 in a semi trailer), the operator may wish to meet a very low power budget.
 Thus, everything on locator device 32 is turned off, except that pager
 module 66 is periodically cycled on and off to save power. In the DEEP
 SLEEP mode, locator device 32 still recognizes any alarm conditions based
 on 0-N sensor alarm inputs.
 In the OFF mode, locator device 32 is turned off completely.
 Locator device 32 is preferably controlled among the various modes
 according to the parameters set out in Table 3. A mode number (1-5) is
 given on the left hand side of Table 3. The four parameters (external
 power, internal battery, time and action) are given along the top of Table
 3. The external power parameter indicates that locator device 32 is
 receiving power from an external source (such as the semi tractor
 battery). The internal battery parameter indicates that locator device 32
 is only receiving power from an internal battery, or that the ignition to
 the semi tractor is turned off so that no alternator power is being
 provided. The time parameter indicates a number of hours (or other
 suitable time interval) during which locator device 32 will stay in the ON
 state even after external power (such as the ignition) is turned off, and
 before it enters the SLEEP mode. The action, if yes, indicates that
 locator device should call control center 24 prior to going into the SLEEP
 mode, so that control center 24 knows that locator device 32 is sleeping.
 If no, the action indicates that locator device 32 need not call in before
 going to sleep.
 Therefore, as indicated by Table 3, when external power is applied, locator
 device 32 can be configured to be ON, OFF, or in SLEEP mode. When only
 internal power is applied, locator device 32 can be configured to be in
 SLEEP mode, in DEEP SLEEP mode, ON or OFF. The number of hours for the
 transition in mode (from the mode associated with external power applied
 to the mode associated with internal power only) can be programmed, and
 the action (whether locator device 32 will be required to call in prior to
 going to sleep) can also be configured in accordance with modes 1-5.
 The GPS interval command indicates how often locator device 32 is to store
 a position fix.
 The call if LD inside/outside a circle command allows the dispatcher to
 configure the locator device to see whether locator device 32 is inside a
 circle defined by the latitude, longitude and radius parameters provided
 to locator device 32, or whether it is outside such a circle.
 The change voice handset call allotment command allows the dispatcher to
 set two allotments for each locator device 32. These allotments can be
 reset automatically after a particular time has passed. The increment
 voice handset call allotment allows the dispatcher to either subtract or
 add minutes to a current call allotment by programming in a negative, or
 positive, increment number into the locator device 32. The external power
 attached alarm on/off commands enable and disable an alarm which indicates
 when power is detached from locator device 32. If the alarm is enabled,
 locator device 32 sends an alarm immediately to let control center 24 know
 that it has been unhooked from its power source.
 The change NAM command allows a dispatcher to change the phone number of
 the particular transceiver 58 in locator device 32.
 The change calling sequence command allows the dispatcher to configure
 locator device 32 to make a predetermined number of calls, and to change
 the timing when locator device 32 automatically calls control center 24.
 In other words, if a first call to control center 24 is unsuccessful, the
 dispatcher can configure the number of calls which locator device 32 is to
 attempt to make, and the timing between those calls, in an effort to
 initiate communication with control center 24.
 The SID specific system selection command allows a SID specific selection
 list to be set. Whenever locator device 32 is making a call within one of
 the SID systems on the list, locator device 32 switches from its normal
 A-side operation to B-side operation for that particular call.
 The set SLEEP cycles command allows the dispatcher to set the schedules for
 the GPS receiver 62, and cellular transceiver 58 in locator device 32 when
 locator device 32 is in a SLEEP mode. Thus, the schedules for receiving
 position fixes and communicating those position fixes to control center 24
 can be configured.
 The NVRAM purge command allows the dispatcher to have locator device 32
 purge all NVRAM. This command erases all information that is kept by
 locator device 32, including all scripts, any scheduled events, and all
 saved location fixes, etc. This command is typically issued in order to
 completely reprogram locator device 32.
 The set pager groups command allows the administrator to configure locator
 device 32 to be in one of a number of pager groups. The group list is held
 in memory by locator device 32. When a page is received, locator device 32
 examines the pager group list contained therein, to see whether it should
 respond to the page. The set pager groups command allows the administrator
 to change the group list stored by locator device 32.
 The display preprogrammed message command can be appended to another
 communication. This causes locator device 32 to look up a corresponding
 preprogrammed message in memory, and display that message on message
 display 68 for observation by the operator. The display free form message
 command causes locator device 32 to pass the text message received to
 message display 68 for observation by the operator.
 The change voice call numbers command allows the administrator to change
 the numbers illustrated in the call restriction list set out in FIG. 15.
 The change system selection options command causes locator device 32 to
 select a system (A or B) to be used based on the setting passed by this
 command. In the normal operating mode, locator device 32 uses the A side
 for all communications, but switches to the B side for out of bounds calls
 when the current A side SID is listed in the SID specific selection table.
 The set preprogrammed messages command allows the administrator to set new
 preprogrammed messages, such as those set out in FIG. 6.
 The send new script command sends new features to locator device 32 which
 can be implemented on a device.
 The erase all scripts command causes locator device 32 to erase all scripts
 then in memory.
 The request AMPS configuration causes locator device 32 to return to
 control center 24 a list of the AMP configuration then held by locator
 device 32 (i.e., the ESN, NAM1, NAM2 and current system selection mode).
 The request SID list command causes locator device 32 to return the SID
 list then contained in its memory. The request pager group BIT MASK
 command causes locator device 32 to return the current pager groups listed
 in its memory. The request preprogrammed message list command causes
 locator device 32 to return all of the pre-programmed messages contained
 in its memory, and the request call restriction causes locator device 32
 to return the call restriction list and the current restriction modes then
 contained in its memory.
 The communications test response command is primarily used for
 installation. This causes locator device 32 to step through a
 predetermined call sequence and respond to control center 24, so that the
 installer is notified that the installation has been successful.
 The request script dump command causes locator device 32 to send back to
 control center 24 all of the current scripts then running in memory.
 The set pager cycle command and the set cellular SLEEP power cycles command
 configure the pager and cellular transceiver for SLEEP and DEEP SLEEP
 modes.
 The change AMPS PIN behavior mode allows the administrator to change or
 disable the lock and unlock sequence used by locator device 32 in making
 cellular communications.
 The request schedule strings command causes locator device 32 to return to
 control center 24 a list of all schedules which locator device 32 is then
 configured to meet.
 The request and clear NVRAM commands causes locator device 32 to either
 provide control center 24 with a listing of its NVRAM contents, or causes
 locator device 32 to clear its NVRAM contents, respectively.
 The set 111 phone number command is a feature which allows a customer or
 user of locator device 32 to quickly initiate communication with control
 center 24, by dialing a predetermined number string (such as 111). This
 command translates that number into a phone number which is associated
 with control center 24.
 The set diagnostic number bank allows the administrator to configure
 locator device 32 to send back a given set of diagnostic information with
 each cellular phone call.
 Table 2 illustrates the preferred messages which travel from locator device
 32 to control center 24. The message confirmation operation sends back a
 message confirmation to the control center 24 for every message that is
 received by locator device 32. A serial number associated with the
 incoming message is duplicated in a message header of the message
 confirmation, and a status field is set to show whether the command was
 recognized and processed accordingly.
 The location bread crumb (bread crumb being position information, including
 date and time of location fixes) message holds the location information
 associated with the locator device 32. It also contains all of the bread
 crumb information stored in memory.
 The driver pre-programmed message is generated to carry a pre-programmed
 message from location device 32 to control center 24. This message is also
 used when a driver (or user of locator device 32) replies to a message
 which is sent to him from control center 24.
 The alarm message and alarm status are sent to control center 24 to
 indicate that an alarm condition exists, or to indicate the status of any
 particular alarm being carried.
 The call record message is generated whenever a cellular phone call is
 initiated, or answered, at locator device 32. This message is generated
 for all voice and data calls. The message includes the date and time the
 call is initiated, the duration of the call, the cellular system in which
 the call was made or received, and the location of the locator device 32
 when the call was made or received.
 All of the messages which start with the term return in Table 2 simply
 indicate information which is returned in response to a request from
 control center 24, as described with respect to Table 1.
 The perform communications test message is a request from locator device 32
 for the control center 24 to complete a communications test. In response,
 control center 24 pages locator device 32. When locator device 32 receives
 the responsive page, it displays a confirmation on message display 68.
 Before the perform communications test message is sent, an installer is
 preferably required to input a truck identification number into which he
 is installing locator device 32.
 The notification of state change message is generated by locator device 32
 and notifies the control center 24 when locator device 32 changes from an
 awake to SLEEP or SLEEP to awake mode. This is preferably only generated
 when a parameter is set in locator device 32 requesting that it be
 generated. Control center 24 preferably utilizes this information in
 determining whether device 32 is likely to be asleep or awake when control
 center 24 is attempting to call it.
 In one preferred embodiment, the pager messages can be any suitable
 messages from control center 24 to locator device 32. However, a number of
 those messages are particularly suitable for pager messages. For example,
 the call now message identified with respect to Table 1, the display
 pre-programmed message command, the activation of certain alarms, the
 setting of modes in locator device 32, the communications test response
 message identified with respect to Table 1, and the communications test
 response indicated in Table 2. Other information is also particularly well
 suited to pager communication. For example, where control center 24
 desires to know whether locator device 32 is inside or outside a certain
 circle, such a message is well suited to pager communication. In addition,
 group communications are also particularly well suited to pager
 communication. This is because the pager communication is a very low cost
 means of broadcasting a message to any number of locator devices 32.
 Where, for example, control center 24 desires to know how many trucks are
 within or without a certain radius, control center 24 simply broadcasts
 the message to an entire group, and waits for responses from that group.
 Pager communication significantly reduces the amount of communication
 overhead needed to support the mobile locator system 10 of the present
 invention. Although it may seem counter intuitive that adding means of
 communication (i.e. a pager) would actually simplify communication and
 reduce the communication burden, it should be borne in mind that pager
 communication is currently very efficient and inexpensive as compared to
 cellular communication. The mobile locator system of the present invention
 takes advantage of pager communication in various ways.
 First, pager communication can be used to prompt mobile locator device 32
 to respond with certain types of information such as alarm status, or
 location. In this respect, much of the communication emanating from
 control center 24 to mobile locator device 32 is in the form of highly
 efficient and inexpensive pager communication. Another example of the use
 of pager communication by the mobile locator system 10 of the present
 invention, is when control center 24 addresses a specific mobile locator
 device 32, or a specific group of mobile locators (not shown), to alter or
 change a configuration parameter. Such configuration parameters can
 include the movement alarm, the proximity alarm, a trailer tampering
 alarm, communication configuration parameters, or other appropriate
 parameters.
 Another example of the use of pager communication by mobile locator system
 10 of the present invention, is when control center 24 causes a specific
 mobile locator device 12 or a specific group of mobile locators 12 to
 enter a powered-down state similar to a (e.g., the SLEEP mode). Typically,
 a cellular transceiver operating on its own internal battery power can
 rarely operate in a standby mode for much more than 24 hours. In contrast,
 pagers typically operate for months in a standby mode. Thus, in some
 circumstances, control center 24 may issue a SLEEP command to mobile
 locator device 32 which causes all components of mobile locator device 32
 to shut off, except for the pager component (device 32 may also enter the
 SLEEP mode on its own after a given time period). The pager module 66
 continues to monitor communications emanating from control center 24 to
 determine if an awaken signal is detected. If such an awaken signal is
 detected by the pager component in mobile locator device 32, mobile
 locator device 32 essentially turns back on, thus waking up. This feature
 is highly advantageous because pagers require much less energy while
 receiving or monitoring communications as compared to cellular
 transceivers. In this manner, significant power conservation can be
 achieved which is of the utmost importance in self-powered circumstances.
 Some semi trailers are not provided with power from the tractor unit. Thus,
 when a mobile locator of the present invention is used with such trailers,
 it must rely on self-contained battery power. As such, the mobile locator
 device 32 must conserve power whenever possible. Thus, the power saving
 feature described above becomes highly advantageous.
 One preferred embodiment will now be described further with respect to
 additional potential commercial application. As described above, the
 present invention has particular applicability to vehicle fleet
 management. Similarly, the present invention can be used for tracking and
 auditing truck advertising. Often, truck owners, specifically owners of
 large trucks such as over-the-road transports, will allow advertising
 indicia to be placed on their trucks in exchange for an advertising fee.
 However, determining an appropriate fee can be difficult because various
 trucking routes have vastly different advertising potential. For example,
 a truck route which passes through largely unpopulated areas may have
 little, if any, advertising value at all. In contrast, truck routes
 passing through heavily populated, urban areas, may have very significant
 advertising potential. Thus, the present invention may be used to track
 the routes of various trailers which are equipped with mobile locators of
 the present invention, to determine the location of various mobile
 locators at various times. This historical path data is, in turn,
 cross-referenced with Department of Transportation data to provide a
 measure of advertising effectiveness which corresponds with a probable
 number of people who would see the advertising indicia on a given truck.
 As can be appreciated, the mobile locator system 10 of the present
 invention has many potential uses. The broad applicability of the present
 invention is based primarily upon the high degree of configurability and
 versatility which is provided. For example, as mentioned above, many types
 of alarms can be configured and/or enabled via communication between
 mobile locator device 32 and control center 24. The combination of
 cellular and pager communication provides great flexibility and
 efficiency. In addition, further configuration can be effected by
 configuring various types of subgroups within the main group of mobile
 locators. Also, the ability of users to completely configure all
 preprogrammed messages adds significant configurability to the entire
 system. Thus, the mobile locator system 10 is provided which can be
 configured to precisely match the needs of various applications ranging
 from fleet management systems to locating missing persons.
 Although the present invention has been described with reference to
 preferred embodiments, workers skilled in the art will recognize that
 changes may be made in form and detail without departing from the spirit
 and scope of the invention.