Abstract:
An apparatus and method for determining real time location of assets by calculating the relative position of a plurality of GPS enabled devices transported together, taking advantage of multiple GPS enable devices being transported together including dual band GPS and averaging location data between US and European GPS data. Additionally, an IMB acts to receive GPS data from multiple devices in a shipment and IMB combines and averages data from both GPS systems to create more liable location determination.

Description:
PRIORITY CLAIM 
     The present invention claims priority to U.S. Provisional Application No. 61/41 1,415, tiled Nov. 08, 2010. No new matter has been added. 
    
    
     BACKGROUND OF THE PRESENT INVENTION 
     1. Field of the Present Invention 
     The present invention relates to a method and apparatus to determine asset location by calculating the relative position of a plurality of GPS enabled devices transported together. More particularly, the present invention derives the most accurate GPS position data to create a real time location system to find the exact location of a single box. 
     2. Description of Related Art 
     In automotive GPS receivers, metallic features in windshields, such as defrosters or car window tinting films, can act as a Faraday cage, degrading reception inside the car. Man-made electromagnetic interference (EMI) can also disrupt or GPS signals. In one well-documented case it was impossible to receive GPS signals in the entire harbor of Moss Landing, Calif. due to unintentional jamming caused by malfunctioning TV antenna preamplifiers. Intentional jamming is also possible. Generally, stronger signals can interfere with GPS receivers when they are within radio range or line of sight. 
     In 2002, a detailed description of how to build a short-range GPS L1 C/A jammer was published in the online magazine. The U.S. government believes that such jammers were used occasionally during the 2001 war in Afghanistan, and the U.S. military claims to have destroyed six GPS jammers during the Iraq War, including one that was destroyed with a GPS-guided bomb. A GPS jammer is relatively easy to detect and locate, making it an attractive target for anti-radiation missiles. 
     Some countries allow GPS repeaters to facilitate the reception of GPS signals indoors and in obscured locations; however, under European Union and U.K. laws, these are prohibited because the signals can interfere with other GPS receivers that receive data from both satellites and the repeater. 
     Various techniques can address interference. One is to not rely on GPS as a sole source. According to John Ruley, “IFR pilots should have a fallback plan in case of a GPS malfunction” Receiver Autonomous Integrity Monitoring (RAIM) is included in some receivers, to warn if jamming or another problem is detected. The U.S. military has also deployed since 2004 their Selective Availability/Anti-Spoofing Module (SAASM) in the Defense Advanced GPS Receiver (DAGR). DAGR detects jamming and maintains its lock on encrypted GPS signals during interference. 
     Real time location systems improve how companies locate, track, and manage high value assets. Modern asset management requires tracking the location of containers and cargo. Currently, various types of Real Time Location Systems (RTLS) such as ISO/IEC 24730-2, Cisco, CCX Wi-Fi, precision GPS and Ultra-Wideband are being used to fit the operational needs of the customer. 
     The present application discloses a method and apparatus designed to increase reliability location data by creating a GPS mesh network device to communicate with existing GPS devices and coordinate data to improve visibility into the exact location and status of assets. This increased visibility will enable the customer to pinpoint the real time location of a single box more accurately and efficiently than the prior art. This level of real time asset management translates into greater operational efficiency and performance, cost reductions, and improved safety and security. 
     SUMMARY OF THE PRESENT INVENTION 
     The object of the present invention is to overcome the shortcomings disclosed in the prior art. The accompanying drawings, which are incorporated in and constitute part of the specification, illustrate various embodiments of the present invention and together with the description, serve to explain the principles of the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an illustrative example of a plurality of different GPS devices within a tractor trailer. 
         FIG. 2  is a schematic diagram of a GPS mesh network communications system according to an embodiment of the present invention. 
         FIG. 3  is an illustrative diagram of a method of determining and mapping the relative distances between monitored elements according to an embodiment of the present invention. 
         FIG. 4  is a block diagram of a preferred embodiment of the present invention. 
         FIG. 5  is a functional configuration of a microcontroller unit according to an embodiment of the present invention. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     For the purposes of promoting an understanding of the principles of the present invention, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the present invention is hereby intended and such alterations and further modifications in the illustrated devices are contemplated as would normally occur to one skilled in the art. 
     With reference now to  FIG. 1 , an illustrative example of a plurality of different GPS devices contained within a tractor trailer will now be discussed. As shown in  FIG. 1 , a plurality of different models of GPS devices are attempting to transmit various signals. For the purposes of example, the GPS devices shown include six Standard GPS devices and three Galileo GPS devices. As further shown in  FIG. 1 , a standard Satellite  108  is provided transmitting to the Standard GPS model devices and a Galileo Satellite  110  is provided transmitting specifically to the Galileo GPS devices  116 . As further shown in  FIG. 1 , a GPS-Mesh Network Device  212  is provided transmitting  112  to the Standard Satellite  108 . 
     As shown in  FIG. 1 , a varying amount of interference is blocking a percentage of the GPS devices within the tractor trailer from successfully transmitting to the satellites. For example, the transmission  106  from a Galileo GPS  116  is not able to penetrate a vertical obstruction. Further, the transmission  102  from a Standard GPS  114  is not strong enough to penetrate the tractor trailer. Additionally, the unsuccessful transmission  104  from another Standard GPS  118  may be caused by atmospheric interference. 
     With reference now to  FIG. 2 , a first preferred method of establishing a GPS mesh communications network system will now be discussed. As shown in  FIG. 2 , an example of a plurality of different GPS devices within a tractor trailer  202  as previously described paragraphs [0023] and [0024] is shown. Within this example, the first step in establishing a GPS Mesh Communications Network  204  is GPS Mesh Network Device  212  successfully transmitting to a satellite to determine location. In the example of  FIG. 2 , the communications is via the Standard Satellite  108 . However, the GPS Mesh Network Device  212  may be alternatively configured to communicate with the Galileo satellite  110  or multiple satellite systems which may be chose based on the quality of reception or other factors. 
     After the GPS Mesh Network Device  212  has determined its location, it sends out a RF ping in all directions to locate all other GPS receivers within the trailer compartment and requests their location data  206 . Once the request for the location data from each GPS device is submitted and received, the GPS Mesh Network Device  212  preferably crosschecks or compares the location data  208 . The GPS Mesh Network Device  212 , using dual band GPS, will average the location data between the Standard U.S. Satellite  108  and the European Galileo Satellite  110 . Finally, the GPS Mesh Network Device  212  will determine the most accurate location data and distribute it back to the other GPS devices in the network  210 . The preferred outcome being a robust confidence in accuracy of the location data. 
     With reference to  FIG. 3 , an illustrative diagram of a method of determining and mapping the relative distances between monitored elements will now be discussed. For the purposes of this discussion, a monitored element is defined as any item, box, package or container having an embedded or attached RFID tag. Preferably, each RFID will transmit a distinctly identifiable code or number. 
     As shown in  FIG. 3  with reference to elements of the GPS Mesh Network Device as described in  FIG. 4 , the GPS Mesh Network Device  212  may send out a first ping  304  which may poll RFID devices and detect measurable responses based on distance and time algorithms. A second ping may be transmitted for polling for responses from RFID tags which may be situated on other planes within the container. Based on the time of the returned signals from the various monitored element, the GPS Mesh Network Device may then calculate the relative locations of each monitored element within the storage area. The controller unit  408  may then create a map of the relative real time location of all monitoring elements within the compartment. This data may be transmitted to a home station  310  via satellite uplink for backend analysis. Additionally, this method can be repeated by multiple GSA Mesh Network Devices to increase the reliability of data. 
     According to an alternative embodiment, the GPS Mesh Network Device  212  may include a range finder  404  which is configured to measure the interior dimensions of a cargo hold. According to further alternative embodiments, the interior dimensions may be determined by other means such as manually measured, acoustically or otherwise. Thereafter, using the determined dimensions of the cargo hold, the GPS Mesh Network Device may send out single ping to the monitored elements. Based on the response time from each monitored unit and the dimensions of the cargo hold, the GPS Mesh Network Device  212  may approximate the relative real time location of each monitored element. Thereafter, the controller unit  408  may create a map of the relative real time location of all monitoring elements within the compartment and transmit the map to a home station  310  via satellite uplink for backend analysis. Further, the relative locations of the monitored elements may be compared with previous measurements to determine whether any shifting or tampering of the contents has occurred. 
     With reference now to  FIG. 4 , the details of a block diagram of the present invention will now be discussed. As shown in  FIG. 4 , a Global Positioning System Mesh Network Device  400  (GPSMND) comprises a GPS receiver  402 , an RFID reader  404 , a range finder  406 , a microcontroller unit  408  and a wireless radio transceiver  410 . The GPSMND may be a stand-alone unit inserted or affixed, either temporarily or permanently, into a compartment, such as a ships hold, freight warehouse, or trailer unit. Preferably, the range finder  406  may employ a radio radar finder technology, but alternatively, may employ alternative technologies that produce accurate measurements between the GPS Mesh Network Device  212  and other GPS devices. For example, other forms of range finder technology may include: laser, radar, sonic or ultrasonic technologies. 
     Processing System 
     With reference now to  FIG. 5 , it is preferred that the microcontroller unit  502  incorporates a microprocessor  504 , a real time clock  518 , a general purpose Input/Output port to support external peripheral control  508 , a Universal Synchronous/Asynchronous Receiver Transmitter (USART)  510 , a Serial Port Interface (SPI)  712 , and memory such as RAM  722 , FLASH memory  520 , and EEPROM  514  as shown. 
     Preferably, the microprocessor  504  used may be a low power, high performance, eight-bit intergrated circuit based on the Motorola HCS08 instruction set. Such a chip, for instance the NCL08 microcontroller, will preferably use an event driven power management technique to reduce power consumption by half compared with alternative microprocessors. The controller will preferably manage power and host the master date-time clock, communication scheduling and annotation of flash memory records. 
     Communication System 
     In accordance with a preferred embodiment of the present invention, the reporting may be made via a wireless connection to a satellite mode to communicate with a satellite system such as Globalstar or Orbcomm. Preferably, such a satellite device will be a device such as the Axxon, AutoTracker, or a customized Orbcomm VHF satellite GPS tracking communications device which may be adapted with Zigbee interface antenna devices to incorporate them into the overall LAN architecture of the security system. These devices include a satellite transceiver, a GPS receiver, a customized Zigbee wireless antenna with a serial (Ax Tracker) or duplex (OrbComm) interface. 
     In accordance with an alternative preferred embodiment of the present invention, the reporting may also be made using a wireless system independent from the satellite system. According to this embodiment, wireless signals may be transmitted to a wireless relay, base station or the like for routing and transmission to a chosen centralized location independent from or in combination with the transmissions made from the satellite system. In accordance with this alternative embodiment, signals may also be received by the communications manager and wireless interface from such external wireless networks as well. 
     According to a preferred embodiment of the present invention, it is preferred that the wireless communications used within the present invention will be based on the Zigbee (IEEE 802.15.4) standard. This standard transmits RF signals in the 2.4 GHz ISM band and operates with low power consumption due to its relatively slower data transmission rate (128 Kpps-250 Kbps). This approach enables additional capacity and flexibility of design through an up to 255 node pico-network. Communications are simplex or duplex in design, meaning that data can be assessed in either a push or pull process. 
     As referred to above, all communications of the present invention may be designed to be duplex or simplex in nature. Further, as needs require, the processes for transmitting data to and from the present invention may be designed to be push or pull in nature. Still, further, each feature of the present invention may be made to be remotely activated and accessed from distant monitoring stations. Accordingly, data may preferably be uploaded to and downloaded from present invention as needed. For example, as detailed above, each system and subsystem of the present invention may be designed to send, receive, report and request information via the wireless and/or satellite systems so as to continually maintain and update the container systems. 
     Additional communications with the communications manager are preferably enabled via industry standard wired interfaces, with communications protocols implemented in firmware for future upgrade. These interfaces preferably will include at least two RS-322 compatible serial ports. These alternate serial ports may assist the communications manager to interface with additional remote sensors as well as other local reader/controllers such as an RFID reader or other devices. 
     Remote Monitoring 
     To support and monitor the dataflow generated by the present invention, it is preferred that users establish a centralized location to collect and analyze data. This central location or “data fusion center” would preferably consolidate all tracking signals, sensor alarms and reports generated by the monitoring systems and provide further context and links with current intelligence. 
     Preferably, such a data fusion center will receive such source information in a variety of formats such as Electronic Data Interchange, XML, E-mail, HTML and flat text files. After receiving such data, the data fusion center preferably would act to process information to identify anomalies. With this data collected and processed, analyst may calculate statistics and probability of detection models used for decision support. 
     In terms of decision making, such a data fusion center would assist agents and shippers in making decisions regarding the status of each container. In short, such a data fusion center would preferably provide a consolidated source of information that could be used to assist agencies and shippers to identify containers quickly and accurately.