Patent Publication Number: US-2009231189-A1

Title: Vehicle tracking and security using an ad-hoc wireless mesh and method thereof

Description:
FIELD OF THE INVENTION 
     The present invention relates to vehicle tracking and security devices, and more specifically, to an automatic tracking and security system which provides location information and security information of a mobile unit, using a wireless ad-hoc mesh network. 
     BACKGROUND OF THE INVENTION 
     With every passing year, there is an increasing movement of goods, personnel and assets from one place to another. It is often desired that location information be available while the goods, personnel or assets are in transit. For instance, a shipping service provider may want to keep track of a fleet of vehicles and more specifically, keep track of packages in the fleet of vehicles. In cases of theft of vehicles, vehicle owners may want to track down the vehicle and apprehend a thief. Personal vehicle owners may also want to track their vehicles for assurance that a driver is at a designated location and is following a prescribed route. The location information may also be desired for tracking personnel, for instance, security personnel deployed in an emergency situation may be tracked using the location information. 
     Tracking solutions provide location information to track a desired object. Typical tracking solutions include a Geo-Positioning System (GPS) which uses the location information beamed from GPS satellites for tracking purposes. The GPS uses known techniques such as triangulation for arriving at the location information with a fair amount of accuracy. Automated Vehicle Locating (AVL) is one such tracking solution for remote vehicle tracking and monitoring. Automated vehicle Locating (AVL) uses the GPS for arriving at the location information. A vehicle is equipped with an AVL device for receiving signals from the GPS satellites. A GPS receiver in the AVL device determines the vehicle&#39;s current location, speed and direction in which the vehicle is heading. This data may then be stored or directly transmitted to a central monitoring station (also known as an operating center). 
     For providing on-demand information, the tracking solutions require the GPS receiver to be in an activated condition constantly, for tracking the satellites. This results in substantial drain of battery power. Further, switching on the GPS receiver on-demand results in delay in computing the location information as the GPS receiver takes a long time to locate and tune into the GPS satellite and then to process the computations required to extract the parameters for computing the location information. Also, the accuracy for the GPS system is reduced under heavy tree cover, or even indoors as the GPS receiver cannot locate the required number of satellites for triangulation and subsequent computation of the location information. 
     Typical tracking solutions use a combination of GPS and Global System for Mobile communications (GSM) for tracking purposes. However, such tracking solutions require large capital and operating cost as every node has to be embedded with a GSM module. Moreover, the cost of sending a Short Message Service (SMS) for every location information, security information and control message, adds to the high operating cost. Other tracking solutions make use of satellite communications and fixed wireless communication techniques. However, such tracking solutions entail enormous costs as they involve reserving satellite channel/radio channel and expensive equipment to be attached to each and every unit being tracked. 
     Further, devices such as the GPS receivers are expensive and have high working cost. Moreover, the working of such devices is complex which proves a hindrance in effective working and requires huge capital investments during hardware or a software upgrade. 
     Cost-effective solutions, such as those providing means for storing tracking data inside the AVL device, and to be downloaded later via RS232 by connecting the AVL device to a personal computer (PC) are available. However, such systems do not provide on-demand location information. 
     Further, such tracking solutions do not provide any means to inform or provide notification to a concerned entity in case of events such as a theft of a unit being tracked or a detected intrusion. Moreover, such tracking solutions fail to respond to an occurrence of such events and as such provide no security. 
     Based on the problems mentioned above with regard to the tracking solutions, there exists a need for a system that provides on-demand location information of a unit to an end user requesting the location information. Further, the system needs to reduce the time to compute the location information and provide the location information in a cheap and efficient manner. Moreover, the system needs to provide means for notification to the end user of an occurrence of a situation and/or provide means to secure the unit being tracked 
     Also, what is needed is a system that provides on-demand location information in a power-efficient manner. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide on-demand notification of a location of a mobile unit and/or occurrence of a situation, to an end user. 
     Another object of the present invention is to reduce the time involved in the computation of the location of the mobile unit. 
     Yet another object of the present invention is to provide an automatic tracking and security system that has low power consumption. 
     Still another object of the present invention is to provide an automatic tracking and security system which is cost-effective and does not involve large capital and operating cost. 
     Yet another object of the present invention is to provide an automatic tracking and security system which provides means to secure the mobile unit being tracked. 
     In view of the foregoing disadvantages inherent in the prior art, the general purpose of the present invention is to provide an automatic tracking and security system providing a notification to an end user, using a wireless ad-hoc mesh network to include all the advantages of the prior art, and to overcome the drawbacks inherent therein. The automatic tracking and security system comprises a plurality of mobile nodes and the one or more fixed nodes configure a wireless ad-hoc mesh network. The wireless ad-hoc mesh network is in operative communication with the central monitoring station. The central monitoring station calculates a GPS assistance data and provides the GPS assistance data to the plurality of mobile nodes using the wireless ad-hoc mesh network. The plurality of mobile nodes compute a location data using the GPS assistance data received over the wireless ad-hoc mesh network. The plurality of mobile nodes may also include one or more security modules. The one or more security modules sense occurrence of a situation and provide situation data. The location data and/or the situation data is dynamically routed over the wireless ad-hoc mesh network from the mobile node to the central monitoring station. The central monitoring station automatically processes the location data and/or the situation data and provides the notification to the end user. The notification may comprise location of a mobile node and/or the occurrence of the situation. The notification may be provided to the end user in response to request for the notification by the end user. Thus the automatic tracking and security system provides the notification of location of a mobile node and/or the occurrence of the situation to the end user, on-demand. 
     Further, the plurality of mobile nodes do not have to locate and tune to a GPS satellite to compute the location data, as they receive the GPS assistance data from the central monitoring station. This greatly reduces the time required to compute the location data. Moreover, as the central monitoring station provides the GPS assistance data, a GPS receiver in each of the plurality of mobile nodes need not be kept in a constantly activated mode to track the GPS satellites. The GPS receiver can be switched off and activated only when the location data is desired. In such a case, the GPS receiver wakes up, receives the GPS assistance data and calculates the location data. Thus, the GPS receiver may be switched off and may be activated only when the location data is desired, resulting in substantially lowering power consumption. 
     The wireless ad-hoc mesh network is capable of adapting itself to failure of at least one of the plurality of mobile nodes and the one or more fixed nodes. The wireless ad-hoc mesh network is also capable of determining new mobile nodes and/or fixed nodes and integrating them in the wireless ad-hoc mesh network. This provides the necessary flexibility to the automatic tracking and security system, as the the wireless ad-hoc mesh network. Further, the wireless ad-hoc mesh network precludes laying expensive cables, making modifications to the existing set-up or embedding each mobile node with a GSM module. This results in substantially lower cost. Moreover, operating cost is also reduced as the location data is dynamically routed over the wireless ad-hoc mesh network precluding the need to send SMS messages. 
     In one aspect of the present invention, the automatic tracking and security system is capable of sending control messages from the end user of the automatic tracking and security system to the mobile node being tracked and may modify the state of the mobile node. For instance, in case of theft of a vehicle, the automatic tracking and security system may immobilize an ignition of the vehicle, thereby securing the vehicle. 
     These together with other aspects of the present invention, along with the various features of novelty that characterize the invention, are pointed out with particularity in the claims annexed hereto and form a part of this disclosure. For a better understanding of the invention, its operating advantages, and the specific objects attained by its uses, reference should be made to the accompanying drawings and descriptive matter in which there are illustrated exemplary embodiments of the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The advantages and features of the present invention will become better understood with reference to the following detailed description and claims taken in conjunction with the accompanying drawings, wherein like elements are identified with like symbols, and in which: 
         FIG. 1  is a block diagram of an automatic tracking and security system, in accordance with various embodiments of the present invention; 
         FIG. 2  is a block diagram of a mobile node, in accordance with an embodiment of the present invention; 
         FIG. 3  is a block diagram of a fixed node, in accordance with an embodiment of the present invention; 
         FIG. 4  is a block diagram of a central monitoring station, in accordance with an embodiment of the present invention; 
         FIG. 5  illustrates a message structure of a Location Request data packet, in accordance with an embodiment of the present invention; 
         FIG. 6  illustrates a message structure of a GPS Assistance data packet, in accordance with an embodiment of the present invention; and 
         FIG. 7  illustrates a message structure of a GPS Tracker data packet, in accordance with an embodiment of the present invention; 
         FIG. 8  is a flow diagram illustrating a method for providing notification to an end user of an automatic tracking and security system, in accordance with an embodiment of the present invention. 
     
    
    
     Like reference numerals refer to like parts throughout the description of several views of the drawings. 
     DETAILED DESCRIPTION OF THE INVENTION 
     The exemplary embodiments described herein detail for illustrative purposes and are subject to many variations in structure and design. It should be emphasized, however, that the present invention is not limited to a particular automatic tracking and security system, as shown and described. It is understood that various omissions and substitutions of equivalents are contemplated as circumstances may suggest or render expedient, but these are intended to cover the application or implementation without departing from the spirit or scope of the claims of the present invention. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The terms “a” and “an” herein do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item. 
     The present invention provides a system and a method for providing location information and security information of a mobile unit, using a wireless ad-hoc mesh network. The system comprises a plurality of mobile nodes, one or more fixed nodes and a central monitoring station. The plurality of mobile nodes and the one or more fixed nodes configure a wireless ad-hoc mesh network. The wireless ad-hoc mesh network is in operative communication with the central monitoring station. The central monitoring station calculates a GPS assistance data and provides the GPS assistance data mobile nodes compute a location data using the GPS assistance data received over the wireless ad-hoc mesh network. The plurality of mobile nodes may also include one or more security modules. The one or more security modules sense occurrence of a situation and provide situation data. The location data and/or the situation data is dynamically routed over the wireless ad-hoc mesh network from the mobile node to the central monitoring station. The central monitoring station automatically processes the location data and/or the situation data and provides a notification to the end user. The notification may comprise location of a mobile node and/or the occurrence of the situation. The notification may be provided to the end user in response to request for location information and/or security information by the end user. 
       FIG. 1  is a block diagram of an automatic tracking and security system (hereinafter referred to as system  100 ), in accordance with various embodiments of the present invention. The system  100  includes a plurality of mobile nodes such as mobile node  102 , one or more fixed nodes such as fixed node  104  and a central monitoring station  106 . The one or more fixed nodes  104  configure a fixed mesh network. The plurality of mobile nodes  102  and the fixed mesh network of the one or more fixed nodes  104  configure a wireless ad-hoc mesh network. The central monitoring station  106  operably communicates with the wireless ad-hoc mesh network. 
     Referring to  FIG. 2 , is a block diagram of a mobile node  102  (of the plurality of mobile nodes  102  shown in  FIG. 1 ), in accordance with an embodiment of the present invention. The mobile node  102  includes a tracking unit  202  and one or more security modules, such as security module  204 . The tracking unit  202  comprises a microprocessor  206 , a memory  208 , a battery  210 , a network interface  212 , an assisted GPS receiver  214 , and an input/output (I/O) interface  216 . The microprocessor  206  is capable of executing programmable instructions for performing operations of the tracking unit  202 . The operations of the tracking unit  202  may include, but are not limited to, handling requests for a notification and reception of a control data. The microprocessor  206  may take a form of an integrated chip that has all the components of a microprocessor, i.e., a central processing unit (CPU), a random access memory (RAM), a read only memory (ROM), and timer circuits. Alternatively, the microprocessor  206  may be implemented as a software program. The memory  208  is capable of storing the necessary programmable instructions and data structures located on the tracking unit  202 . The memory  208  may take the form of a memory card, memory stick, compact flash, and the like. 
     The battery  210  supplies power to the tracking unit  202 . The battery  210  may take the form of a non-rechargeable battery or a rechargeable battery. Examples of the non-rechargeable battery may include, but not limited to, an alkaline battery and a zinc-chloride battery. Examples of the rechargeable battery may include, but not limited to, a lead-acid based battery, an absorbed glass mat (AGM) based battery, a Nickel Cadmium battery and a Nickel Metal Hydride battery. Further, suitable electrical circuits and electrical connections may be provided to enable functions, such as recharging of the battery  210  by using, for example, solar energy, a DC power input, and the like. 
     The mobile node  102  communicates with the other mobile nodes  102  and fixed nodes  104  using the network interface  212 . More specifically, the network interface  212  couples the mobile node  102  to the wireless ad-hoc mesh network, the wireless ad-hoc mesh network configured by the plurality of mobile nodes  102  and one or more fixed nodes  104 . A request for the notification sent by the central monitoring station  106  to the mobile node  102  over the wireless ad-hoc mesh network is received by the mobile node  102  using the network interface  212 . The network interface  212  also serves as an interface for transmitting the location data and/or the situation data to the central monitoring station  106  over the wireless ad-hoc mesh network. Further, the network interface  212  may also serve as an interface for receiving a control data from the central monitoring station  106  dynamically routed over the wireless ad-hoc mesh network. The network interface  212  may include a wireless transceiver to couple the mobile node  102  with the wireless ad-hoc mesh network. An example of the wireless transceiver may be a low power/low range Radio Frequency (RF) transceiver, and the like. 
     The central monitoring station  106  provides a GPS assistance data to the mobile node  102  over the wireless ad-hoc mesh network. The one or more fixed nodes  104  in the wireless ad-hoc mesh network receive the GPS assistance data sent by the central monitoring station  106 . The one or more fixed nodes  104  broadcast the GPS assistance data over the wireless ad-hoc mesh network. The mobile node  102  receives the GPS assistance data from the one or more fixed nodes  104  over the wireless ad-hoc mesh network using the Assisted-GPS (A-GPS) receiver  214 . The A-GPS receiver  214  computes the location data using the GPS assistance data. The computed location data is then dynamically routed over the wireless ad-hoc mesh network from the mobile node  102  to the central monitoring station  106 , using the network interface  212 . The A-GPS receiver  214  may include the necessary programmable instructions for performing operations like computing the location data. 
     Further, the A-GPS receiver  214  goes through a periodic sleep/wake-up cycle to conserve power. The A-GPS receiver  214  wakes up at periodic intervals and receives the GPS assistance data broadcast over the wireless ad-hoc mesh network and computes the location data. As the A-GPS receiver  214  receives the GPS assistance data for calculation of the location data, time required for the computation of the location data is greatly reduced as it does not need to track GPS satellites and tune to a GPS satellite to receive location information, which adds to the time required to compute the location data. Moreover, as the A-GPS receiver  214  may be switched OFF and activated only when the location data is desired, substantial reduction in power consumption is achieved. 
     In accordance with an embodiment of the present invention, the end user of the system  100  may send the request for the notification to the central monitoring station  106 . The request for the notification may include location information of a mobile node  102  desired by the end user. The central monitoring station  106  dynamically routes the request for the notification to the respective mobile node  102 . The central monitoring station  106  also provides the GPS assistance data to one or more fixed nodes  104  which dynamically route the GPS assistance data to the mobile node  102 . On receiving the request for the notification, the A-GPS receiver  214  wakes up from a sleep mode and computes the location data using the GPS assistance data. The computed location data is dynamically routed over the wireless ad-hoc mesh network from the mobile node  102  to the central monitoring station  106 , which then processes the location data and provides the notification to the end user of system  100 . 
     In accordance with an embodiment of the present invention, the mobile node  102  communicates directly with the central monitoring station  106  using the  106  to the mobile node  102  is received by the mobile node  102  using the network interface  212 . Moreover, the mobile node may also receive the GPS assistance data directly from the central monitoring station  106  using the network interface  212 . Further, the network interface  212  may also serves as an interface for transmitting the location data and/or a situation data to the central monitoring station  106 . 
     The tracking unit  202  communicates with the security module  204  using the input/output interface  216 . The input/output interface  216  constantly monitors the security module  204  for receiving the situation data. Further, the input/output interface  216  also serves as an interface for transferring the control data from the tracking unit  202  to the security module  204 . A wired connection or a wireless link couple the input/output interface  216  of the tracking unit  202  to the security module  204 . Examples of wired connection may include cables, electric wires, and the like. Examples of the wireless link may include an optical, an infra-red, a low power radio frequency (RF) transceiver, and the like. 
     The security module  204  may be in a form of a security device such as sensor, for example, a motion sensor, a vibration sensor, an impact sensor, a pollution sensor, a temperature sensor, a humidity sensor, an imaging device, and the like. One or more of the security modules  204  may be installed at various locations in the mobile node  102 . As used herein, the mobile node  102  may be in a form of any object capable of movement such as but not limited to a vehicular unit like a personal vehicle, a cargo truck and the like. In accordance with an embodiment of the present invention, the mobile node  102  may be personnel carrying a mobile tracking unit such as tracking unit  202 . The mobile node  102 , in this case, does not include the security module  204 . Moreover, the tracking unit  202  may be a portable hand-held unit. 
     The security module  204  senses the mobile node  102  for occurrence of a situation and provides the situation data to the tracking unit  202  coupled with the security module  204  on sensing the occurrence of the situation. Examples of situation may include, but are not limited to a completion of a periodic interval for checking fuel gauge or tire pressure and the like; a broken door or window; detection of tampering with the one or more security modules  204 , and presence of intruder in the premise. Examples of situation data may include: fuel gauge readings; tire pressure information; alert data such as a siren or an alarm bell indicating an intrusion in a premise; theft or tampering of the one or more security module  204 ; and the like. 
     The central monitoring station  106  receives the location data and/or the situation data from the mobile node  102 . Examples of the location data may include a latitude and longitude co-ordinates of the mobile node  102  or other location indicators of the mobile node such as a city or street name and the like. The central monitoring station  106  automatically processes the location data- and/or the situation data and provides the notification to the end user of the system  100 . The notification may be sent in the form of a pop-up on the end user&#39;s personal computer, a Short Message Service (SMS), a Multimedia Message Service (MMS), a text message or a video call on the end user&#39;s mobile phone, and the like. The end user of the system  100  may be a subscriber (vehicle-owner, security personnel, and the like) to the system  100 , or any person suggested by the subscriber of the system  100 . The notification may be sent to the end user on a variety of communication networks including wireless networks, power-line networks, fixed wireless networks, wired networks, cellular networks such as GSM/GPRS/3G/CDMA, and similar communications networks. 
     The mobile node  102  communicates wirelessly with other mobile nodes  102  and one or more fixed nodes  104  using the network interface  212  in the tracking unit  202 . Using the network interface  212 , the mobile node  102  may function as a receiver, a repeater, and a transmitter to the other mobile nodes  102  and the one or more fixed nodes  104 , thereby creating a communication network, more specifically the wireless ad-hoc mesh network comprising the plurality of mobile nodes  102  and one or more fixed nodes  104 . 
     The wireless ad-hoc mesh network has self-healing characteristics, i.e., the wireless ad-hoc mesh network is capable of adapting itself to failure of one or more of the mobile nodes  102  and/or one or more fixed nodes  104 . For example, during transmission of the location data and/or the situation data, if one or more of the mobile nodes such as the mobile node  102  fails, then the wireless ad-hoc mesh network removes such a failed mobile node  102  and defines an alternate path for dynamically routing the location data and/or the situation data to the central monitoring station  106 . Additionally, failed mobile nodes  102  or failed fixed nodes  104  may be integrated into the wireless ad-hoc. 
     Further, the wireless ad-hoc mesh network has self-creating and self-determining characteristics i.e., the wireless ad-hoc mesh network is capable of determining newly added mobile nodes, integrating the newly added mobile nodes (such as the mobile node  102 ) into the wireless ad-hoc mesh network, and updating existing paths for dynamically routing the location data and/or the situation data to the central monitoring station  106 . In accordance with an embodiment of the present invention, the wireless ad-hoc mesh network defines a route based on a shortest reliable path algorithm, for dynamically routing the location data and/or the situation data at a given point of time. 
     In accordance with an embodiment of the present invention, the central monitoring station  106  may send the control data to the one or more security modules  204  over the wireless ad-hoc mesh network. Examples of control data include immobilizing an ignition, locking doors, sounding an alarm for notifying security personnel in given premise, reset of the security module  204  or control, execute control action, and the like. The control data may be sent by the central monitoring station  106  with or without the suggestion of the end user. 
     The wireless ad-hoc mesh network configured by the plurality of mobile nodes  102  and one or more fixed nodes  104  therefore support bi-directional communication between the central monitoring station  106  and the mobile nodes  102 . 
     It will be evident to a person skilled in the art that the mobile node  102  may include the requisite electrical circuits and connections to connect the tracking unit  202  and its components such as the microprocessor  206 , the memory  208 , the battery  210 , the network interface  212 , the assisted GPS receiver  214 , and the input/output (I/O) interface  216 ; and the security module  204 . Further, the network interface  212 , the A-GPS receiver  214  and the input/output interface  216  may include interfaces with requisite connections to transmit/receive data such as the location data, the situation data and the control data. 
     Further, the components of the tracking unit  202  such as the microprocessor  206 , the memory  208 , the battery  210 , the network interface  212 , the assisted GPS receiver  214 , and the input/output (I/O) interface  216 , may be implemented as a hardware module, software module, firmware, or any combination thereof. 
       FIG. 3  is a block diagram of a fixed node  104 , in accordance with an embodiment of the present invention. The fixed node  104  comprises a processor  302 , a memory  304 , a storage  306 , a broadcast interface  308 , a first transceiver  310  and a second transceiver  312 . The processor  302  is capable of executing programmable instructions for performing operations of the fixed node  104 . In accordance with an embodiment of the present invention, the processor  302  is a hardware module such as a microcontroller or such other integrated chip for executing operations of the fixed node  104 . In accordance with another embodiment of the present invention, the processor  302  may be implemented as a software module. Preferably, the memory  304  is a random access memory or other type of dynamic storage device, sufficient to hold the necessary programming and data structures located on the fixed node  104 . 
     The storage  306  provides the fixed node  104  with a means for storing information such as information required for dynamic routing of the location data, situation data and/or the control data. Examples of the storage  306  may include a fixed and/or a removable storage such as tape drives, floppy discs, removable memory cards, or optical storage. 
     The broadcast interface  308  may be a wireless transceiver such as a radio frequency (RF) modem, GSM modem, or PSTN modem, or a GPRS modem capable of broadcasting a GPS assistance data received from the central monitoring station  106  to the plurality of mobile nodes  102  over a wireless ad-hoc mesh network configured by the plurality of mobile nodes  102  and the one or more fixed nodes such as fixed node  104 . The fixed node  104  broadcasts the GPS assistance data to the plurality of mobile nodes  102  over the wireless ad-hoc mesh network, at regular intervals at a specified broadcast frequency. In accordance with an embodiment of the present invention, the fixed node  104  constantly broadcasts the GPS assistance data to the plurality of mobile nodes  102  over the wireless ad-hoc mesh network, at the specified broadcast frequency. 
     The first transceiver  310  serves as an interface for the fixed node  104  to communicate with the plurality of mobile nodes  102 . The request for notification received from the central monitoring station  106  may be forwarded to the mobile node  102  over the wireless ad-hoc mesh network, using the first transceiver  310 . Further, the computed location data from the mobile node  102  transmitted over the wireless ad-hoc mesh network is received by the fixed node  104 , using the first transceiver  310 . The fixed node  104  communicates with other fixed nodes  104  and/or the central monitoring station  106  in the fixed mesh network using the second transceiver  312 . The location data and/or situation data may be dynamically routed over to one or more fixed nodes  104  or to the central monitoring station  106  using the second transceiver  312 . Examples of the first transceiver  310  may include low power/low range radio frequency (RF) modems, GSM modems, PSTN modems, GPRS modems, and the like. The second transceiver  312  may include interface for communicating with the central monitoring station  106  wirelessly or using a wired connection. Examples of second transceiver  312  for the wireless connection may include low power/low range radio frequency (RF) modems, GSM modems, PSTN modems, GPRS modems and the like. The second transceiver  312  may include interface for coupling the fixed node  104  to a wired connection such as a world wide web, a power line connection, a Wide Area Network (WAN), and the like. 
     In accordance with an embodiment of the present invention, the fixed node  104  uses multiple frequencies for communication purposes such as a frequency each for broadcasting the GPS assistance data, for communicating with the plurality of the mobile nodes  102  and for communicating with other fixed nodes  104 . Examples of fixed node  104  may include a cellular base station for cellular networks such as GSM/GPRS/3G/CDMA networks, a wireless router, and the like. 
     In accordance with an embodiment of the present invention, the fixed node  104  acts as an aggregator unit performing functions such as collecting, storing and forwarding the location data and/or the situation data over the wireless ad-hoc mesh network to the central monitoring station  106  or directly relaying the location data and/or the situation data to the central monitoring station  106 . In this case, the fixed node  104  gathers the location data and/or the situation data from one or more mobile nodes  102 . 
     It will be evident to a person skilled in the art that the fixed node  104  may include the requisite electrical circuits and connections to connect various components such as the processor  302 , the memory  304 , the storage  306 , the broadcast interface  308 , the first transceiver  310  and the second transceiver  312 . Further, the include interfaces with requisite connections to transmit/receive the location data, the status data and/or the control data. 
     Further, the components of the fixed node  104  such as the processor  302 , the memory  304 , the storage  306 , the broadcast interface  308 , the first transceiver  310  and the second transceiver  312  may be implemented as a hardware module, software module, firmware or any combination thereof. 
       FIG. 4  is a block diagram of the central monitoring station  106 , in accordance with an embodiment of the present invention. The central monitoring station  106  includes a host computer  402  capable of processing a location data and/or a situation data and providing a notification to an end user of the system  100 . The host computer may take the form of an assistance server computer comprising a processor  404 , a memory  406 , a storage  408 , a GPS unit  410 , a first transceiver  412 , and a second transceiver  414 . The processor  404  is capable of executing programmable instructions for performing operations of the central monitoring station  106 . In accordance with an embodiment of the present invention, the processor  404  is a hardware module such as a microcontroller or such other integrated chip for executing operations of the central monitoring station  106 . In accordance with another embodiment of the present invention, the processor  404  may be implemented as software module for executing operations of the central monitoring station  106 . Preferably, the memory  406  is a random access memory or other type of dynamic storage device, sufficient to hold the necessary programming and data structures located on the central monitoring station  106 . 
     The storage  408  provides the central monitoring station  106  with a means for storing information such as information required for dynamic routing of the location data, the situation data and/or the control data. The storage  408  may include a database to store information such as the mobile node  102  and a corresponding end user information; dynamic routing tables from one mobile node  102  to another or to one or more fixed nodes  104 ; the security module  204  information such as the type of the security module  204  and the like. Further, the storage  408  may include the requisite software for keeping track of dynamic routing tables controlling data flow in a wireless ad-hoc mesh network configured by the plurality of mobile nodes  102  and one or more fixed nodes  104 . Examples of the storage  408  may include a fixed and/or removable 
     The GPS unit  410  constantly tracks GPS satellites in the sky and calculates a GPS assistance data. The GPS assistance data includes information such as Almanac, Ephemeris, time data and the like. The Almanac includes orbit information of the GPS satellites, clock correction and atmospheric delay parameters, while the Ephemeris includes information such as the position of a satellite in space as a function of time and the like. The GPS assistance data may be dynamically routed over the wireless ad-hoc mesh network from the central monitoring station  106  to the plurality of mobile nodes  102 . The Almanac and the Ephemeris information included in the GPS assistance data enables the plurality of mobile nodes  102  to compute the location data in substantially reduced time as the A-GPS receiver such as the A-GPS receiver  214  explained in conjunction with  FIG. 2 , need not track the GPS satellites for receiving such information. 
     The first transceiver  412  may be a wireless transceiver such as a radio frequency (RF) modem, or a GSM modem, or a PSTN modem, or a GPRS modem capable of establishing communication between the central monitoring station  106  and one or more fixed nodes such as fixed node  104 . Further, the first transceiver  412  may be capable of establishing communication between the central monitoring station  106  and the plurality of mobile nodes  102 . In accordance with an embodiment of the present invention, the central monitoring station  106  receives the location data and/or the situation data from one or more fixed nodes  104  using the first transceiver  412 . The GPS assistance data to be sent to the plurality of mobile nodes  102  may be relayed by the central monitoring station  106  to the one or more fixed nodes  104  using the first transceiver  412 . The one or more fixed nodes  104  may then broadcast the GPS assistance data over the wireless ad-hoc mesh network to the plurality of mobile nodes  102 . 
     The central monitoring station  106  automatically processes the location data and/or the situation data. The automatic processing of the location data may include checking the authenticity of origin of the location data by performing actions such as Cyclic Redundancy Check (CRC); generating a notification including location of a mobile node embedded in Geographic Information System (GIS) maps depicting terrain information to provide visual representation of the location data and the like. Further, the automatic processing of the situation data may include checking the authenticity of origin identifying the type of information included in the situation data such as but not limited to a status information of fuel gauge, tire pressure and the like or an alarm signal; and generating the notification of an occurrence of the situation. The notification including the location of the mobile node  102  and/or the occurrence of the situation may then be provided to an end user using the second transceiver  414 . 
     The second transceiver  414  also serves as an interface for receiving request for the notification from the end user. Further, the second transceiver  414  may receive an instruction from the end user in response to the notification sent by the central monitoring station  106 . The central monitoring station  106  may further automatically process the instruction sent by the end user which may include, checking the authenticity of origin of the instruction by performing actions such as the Cyclic Redundancy Check (CRC); identifying the type of information included in the instruction such as securing the mobile node  102 , generating an alarm signal; identifying the security module  204  by matching the origin of the instruction and the end user information stored in the storage  408 ; and generating a control data to be relayed to the security module  204  using the first transceiver  412  over the wireless ad-hoc mesh network. The second transceiver  414  in this case may use a cellular interface such as a GSM/GPRS/3G/CDMA connection to notify the end user by sending a short message service (SMS), a multimedia message service (MMS), a text message, a video clip, a world wide web and the like. 
     In accordance with an embodiment of the present invention, the central monitoring station  106  may generate the control data on receiving the situation data, based on a pre-defined situation. The pre-defined situation may include receiving instruction from the end user, a situation response defined by the end-user, typical situation responses such as notifying the security personnel in case of an intrusion, and the like. The central monitoring station  106  dynamically routes the control data over the wireless ad-hoc mesh network to the security module  204 . 
     In accordance with an embodiment of the present invention, the wireless ad-hoc mesh network dynamically routes the location data and/or the situation data to the central monitoring station  106  at fixed frequency such as 433 Megahertz (MHz) or at Industrial, Scientific and Medical (ISM) unlicensed radio frequency bands (2.4 Gigahertz). In accordance with another embodiment of the present invention, the ad-hoc mesh network dynamically routes the location data and/or the situation data to the central monitoring station  106  using typical frequency hopping techniques. 
     In accordance with an embodiment of the present invention, the mobile node  102  dynamically determines the next mobile node to route the location data and/or the situation data. In accordance with an embodiment of the present invention, the central monitoring station  106  updates existing routes for dynamic routing of the situation data and the mobile node  102  routes the situation data based on dynamic routing tables provided by the central monitoring station  106 . The central monitoring station  106  updates the existing routes by keeping a track of the mobile nodes  102  and the fixed nodes  104  added or removed from the network. 
     The host computer  402  may further include a CPU monitor  416  for monitoring the health of the processor  404 . The central monitoring station  106  may also include an external power supply unit  418  to supply power for the operation of the host computer  402  and especially the GPS unit  410 . 
     It will be evident to a person skilled in the art that the central monitoring station  106  may include the requisite electrical circuits and connections to connect the processor  404 , the memory  406 , the storage  408 , the GPS unit  410 , the first transceiver  412 , the second transceiver  414 , the CPU monitor  416  and the external power supply unit  418 . 
     Further, the components of the central monitoring station  106 , i.e., the processor  404 , the memory  406 , the storage  408 , the GPS unit  410 , the first transceiver  412 , the second transceiver  414 , the CPU monitor  416  and the external power supply unit  418 , may be implemented as a hardware module, software module, firmware or any combination thereof. 
     In accordance with an embodiment of the present invention, the central monitoring station  106  and its components may be implemented as a software program residing in a high end server computer comprising internet connectivity having a public IP address for GPRS, a telephone connectivity for PSTN, and a mobile phone for GSM data call. 
     The end user of the system  100  may request location information The request for the notification is received by the system at the central monitoring station  106  using the second transceiver  414 . The central monitoring station  106  automatically processes the request for the notification and routes the request for the notification to the corresponding mobile node  102  over the wireless ad-hoc mesh network in the form of a notification request data packet. In addition to the request for the notification, the notification request data packet comprises information for routing the notification request data packet over the wireless ad-hoc mesh network. The transmission of data packets over the wireless ad-hoc mesh network may be governed by methodologies that include, but are not limited to, guaranteed delivery, frequency hopping and the like. The notification request data packet along with its components will be explained in conjunction with  FIG. 5 . 
       FIG. 5  illustrates a message structure of a notification request data packet  500  in accordance with an embodiment of the present invention. The notification request data packet  500  includes the following fields, a packet ID  502 , a destination device ID  504 , a notification request  506  and a CRC Hash  508 . The packet ID  502  serves to uniquely identify the notification request data packet  500 , thereby avoiding duplicity in its reception and transmission. The destination device ID  504  serves to uniquely identify the mobile node  102  to which the notification request  506  is addressed by the central monitoring station  106 , based on the request for the notification provided by an end user of the system  100 . 
     The notification request  506  includes the actual bytes of the request for notification provided by the end user of the system  100 . The request for the notification may include request for a location of a mobile node  102  or a request for status of a mobile node  102 . The CRC Hash  508  serves to validate the authenticity of the source of the notification request data packet  500 . Further the CRC Hash  508  includes the Cyclic Redundancy Bits for error correction and correct decoding of the notification request  506 . 
     In one exemplary embodiment, the end user of the system  100  desiring a location of a mobile node places a request for a notification with the central monitoring station  106 . The central monitoring station  106  automatically processes the request for the notification and dynamically routes the request for the notification in the form of notification request data packet  500 . The notification request data packet  500  may be routed over a wireless ad-hoc mesh network such as the wireless ad-hoc mesh network (explained in conjunction with  FIG. 2 ) to the mobile node  102 . At every hop in the wireless ad-hoc mesh network, the mobile node  102  or the fixed node  104  may first ascertain the uniqueness of the notification request data packet  500  using the packet ID  502 . Once the uniqueness is ascertained, the mobile node  102  or the fixed node  104  may determine the next hop for the notification request data packet  500  using the destination device ID  504 . The process continues till the notification request data packet  500  reaches the mobile node  102  whose location data was desired. The mobile node  102  in this case decodes the location request using the CRC Hash  508  to decode the request for the notification included in the notification request data packet  500  and computes the location data using the GPS assistance data. 
     In accordance with an embodiment of the present invention, the number of bytes in the notification request data packet  500  may vary and as such equal the number of bytes corresponding to the information contained in the data packet  500 . In an alternative embodiment, the number of bytes in the notification request data packet  500  may be a fixed number. 
       FIG. 6  illustrates a message structure of a GPS Assistance Broadcast data packet  600 , in accordance with an embodiment of the present invention. The GPS Assistance Broadcast data packet  600  includes the following fields, a packet ID  602 , a time stamp  604 , an Almanac  606 , an Ephemeris  608  and a CRC Hash  610 . The packet ID  602  serves to uniquely identify the GPS Assistance Broadcast data packet  600 , thereby avoiding duplicity in its reception and transmission. The time stamp  604  includes date and time (accurate to the order of milliseconds) information. The time stamp  604  aids in calculating and predicting the position of GPS satellites in conjunction with the Almanac  606  and the Ephemeris  608 . As explained in conjunction with  FIG. 4 , the Almanac  606  includes the orbit information of the GPS satellites, clock correction and atmospheric delay parameters while the Ephemeris  608  includes information such as the position of a satellite in space as a function of time. 
     The CRC hash  610  includes the Cyclic Redundancy Bits for error correction and correct decoding of the GPS Assistance Broadcast data using the time stamp  604 , the Almanac  606  and the Ephemeris  608 . 
     In one exemplary embodiment, the central monitoring station  106  calculates the GPS assistance data using the GPS unit as explained in conjunction with  FIG. 4 . The GPS assistance data is routed to one or more fixed nodes  104  for broadcasting the GPS assistance data over the wireless ad-hoc mesh network to the plurality of mobile nodes. The fixed node  104  broadcasts the GPS assistance data over the wireless ad-hoc mesh network in the form of the GPS Assistance Broadcast data packet  600 . The A-GPS receiver such as the A-GPS receiver  214  in the mobile node  102  wakes up on receiving the notification request data packet such as the notification request data packet  500  and receives the GPS Assistance Broadcast data packet  600 . On ascertaining the uniqueness of the GPS Assistance Broadcast data packet  600  using the packet ID  602 , the mobile node uses the CRC Hash  610  to correctly decode the time stamp  604 , the Almanac  606  and the Ephemeris  608 . The A-GPS receiver  214  then calculates the location data using the time stamp  604 , the Almanac  606  and the Ephemeris  608 . 
     In accordance with an embodiment of the present invention, the number of bytes in the GPS Assistance Broadcast data packet  600  may vary and as such equal the number of bytes corresponding to the information contained in the GPS Assistance Broadcast data packet  600 . In an alternative embodiment, the number of bytes in the GPS Assistance Broadcast data packet  600  may be a fixed number. 
       FIG. 7  illustrates a message structure of a GPS Tracker data packet  700 , in accordance with an embodiment of the present invention. The GPS Tracker data packet  700  includes the following fields, a packet ID  702 , a mobile unit ID  704 , a location data  706 , an input/output data  708  and a CRC Hash  710 . The packet ID  702  serves to uniquely identify the GPS Tracker data packet  700 , thereby avoiding duplicity in its reception and transmission. The mobile unit ID  704  serves to uniquely identify the mobile node  102  whose location data  706  is being provided to the end user in the GPS Tracker data packet  700 . The location data  706  contains actual bytes containing the location data of the mobile node  102 . Examples of location data may include latitude and longitude co-ordinates of the mobile node  102 , geographical location such as a name of a city, a street, and the like. The input/output data  708  may include situation data of an occurrence of a situation sensed by one or more security modules such as the security module  204  or status information of the security modules  204 . The status information of the security modules  204  may include ON/OFF status of the security modules  204  or fuel gauge meter reading or sensed tired pressure and the like, corresponding to each security module  204 . 
     The CRC hash  710  includes the Cyclic Redundancy Bits for error correction and correct decoding of the location data  706  and the input/output data  708  in the GPS Tracker data packet  700 . 
     In one exemplary embodiment, A-GPS receiver such as the A-GPS receiver  214  in the mobile node  102  calculates the location data  706  in accordance with the National Marine Electronics Association (NMEA) guidelines. The mobile node  102  then transmits the location data  706  along with the input/output data  708  over the wireless ad-hoc mesh network to the central monitoring station  106  in the form of the GPS tracker data packet  700 . The central monitoring station  106  on receiving the GPS Tracker data packet  700  automatically processes the location data  706  and the input/output data  708 . The central monitoring station  106  accordingly provides a notification to the end user of the system  100 . 
     In accordance with an embodiment of the present invention, the number of bytes in the GPS Tracker data packet  700  may vary and as such equal the number of bytes corresponding to the information contained in the GPS Tracker data packet  700 . In an alternative embodiment, the number of bytes in the GPS Tracker data packet  700  may be a fixed number. 
       FIG. 8  is a flow diagram illustrating a method for providing a notification to an end user, in accordance with an embodiment of the invention. The method initiates at step  802  on the reception of a request for notification such as notification request data packet  500  by the mobile node such as mobile node  102  from a central monitoring station such as central monitoring station  106 . The end user of the system  100  provides the request for notification to the system  100  and is received by the system  100  at the central monitoring station which then relays the request to the mobile node. At step  804 , one or more security modules such as security module  204  sense the mobile node for an occurrence of a situation and provide situation data to be sent to the central monitoring station. At step  806 , a central monitoring station provides GPS assistance data to the mobile node over a wireless ad-hoc mesh network configured by a plurality of mobile nodes and one or more fixed nodes such as the fixed node  104 . At step  808 , the mobile node computes a location data using the received GPS assistance data. The A-GPS receiver such as A-GPS receiver  214  in the mobile node receives the GPS assistance data and calculates the location data. At step  810 , the location data and/or the situation data is dynamically routed over the wireless ad-hoc mesh network from the mobile node to the central monitoring station. At step  812 , the central monitoring station automatically processes the location data and/or the situation data. At step  814 , the central monitoring station provides a notification to the end user. At step  816 , the method ends when the end user of the system receives the notification from the central monitoring station. 
     The end user on receiving the notification may send instruction to the central monitoring station. The central monitoring station may then generate control data based on the instruction received from the end user. Alternatively, the central monitoring station may generate the control data based on some pre-defined situation. For instance, the pre-defined situation may be detection of an intrusion, or sensed tampering with the one or more security modules and the like. The central monitoring station may then route the control data over the wireless ad-hoc mesh network to the one or more security modules. The one or more security modules may then respond on the basis of the control data received from the ad-hoc mesh network. The response may include immobilizing the ignition, sounding an alarm bell to notify the security personnel or any such person suggested by the end user and the like. 
     In accordance with an exemplary embodiment of the present invention, an automatic tracking system for tracking vehicles such as the mobile node  102  is provided. An end user of the automatic tracking system requests a location of a vehicle. The request for the location of the vehicle is received at a central monitoring station such as central monitoring station  106 . The central monitoring station routes the request to the vehicle whose location information was desired by the end user, over a wireless ad-hoc mesh network formed by a plurality of vehicles (each vehicle is fitted with transceivers for communication purposes) and one or more fixed nodes such as fixed node  104 . The A-GPS receiver such as the A-GPS receiver  214  in the vehicle wakes up on the reception of the request by the vehicle, and receives a GPS assistance data being broadcast over the wireless ad-hoc mesh network. A GPS unit such as the GPS unit  410  in the central monitoring station constantly tracks GPS satellites and computes the GPS assistance data. The GPS assistance data is provided by the central monitoring station to the one or more fixed nodes which broadcast the GPS assistance data over the wireless ad-hoc mesh network to be received by the A-GPS receivers in the vehicles. The location data computed by the A-GPS receiver includes the location information of the vehicle. The location data is dynamically routed over the wireless ad-hoc mesh network from the vehicle to the central monitoring station. The central monitoring station automatically processes the location data, which may include providing a visual representation of the location information using the location data received from the vehicle. The central monitoring station then provides the location of the vehicle to the end user. 
     Further, to secure the vehicles in events such as theft or intrusion, the vehicles may be fitted with one or more security modules such as security module  204 . For instance, the vehicle may be fitted with an impact sensor for doors and windows, speed sensor and the like. The one or more security modules may detect an occurrence of a situation such as intrusion and provide situation data. This situation data along with the location data may be routed over the wireless ad-hoc mesh network from the vehicle to the central monitoring station. The central monitoring station automatically processes the situation data and the location data to identify the vehicle, the vehicle owner and type of situation and such other information, and notifies the appropriate personnel of the occurrence of the situation along with location information. The end user may then send instruction to the central monitoring station to be relayed to the one or more security modules, such as immobilizing the ignition, thereby securing the vehicle. The automatic tracking information thereby provides on-demand vehicle location information and also provides means for securing the vehicle. 
     In accordance with an another exemplary embodiment of the present invention, the system  100  and the automatic tracking system explained above, include direct communication between the mobile node  102  (such as the vehicle) with the central monitoring station. The plurality of mobile nodes  102 , configure a wireless ad-hoc mesh network for dynamic routing of the location data, the situation data and/or the control data. The central monitoring station in this case broadcasts the GPS assistance data to the plurality of mobile nodes for the computation of the location data. The computed location data is dynamically routed over the wireless ad-hoc mesh network to the central monitoring station, which then provides a notification to an end user. 
     The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and its practical application, and to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omissions and substitutions of equivalents are contemplated as circumstances may suggest or render expedient, but these are intended to cover the application or implementation without departing from the spirit or scope of the claims of the present invention.