Abstract:
The present invention provides a system for increasing the reliability of location data received from a container monitoring unit. According to a first embodiment, the system includes a GPS mesh network device to communicate with existing GPS devices and a remote monitoring station which receives data from unit devices applying back-end analysis for determining the most accurate and robust geo-location for each unit. The present invention provides a method to coordinate analysis of data to improve determination of 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. This level of real time asset management translates into greater operational efficiency and performance, cost reductions, and improved safety and security.

Description:
BACKGROUND OF THE PRESENT INVENTION 
     1. Field of the Present Invention 
     The present invention relates to a method for determining the best GPS position data for a cargo container. More particularly, the present invention provides a method for communicating between multiple GPS enabled devices being transported together and applying analysis to find the exact location of a single unit, container or box. 
     2. Description of Related Art 
     Currently, smart container monitoring systems employ GPS transponders to track assets. However, the strength and reliability of the GPS signal can be degraded by many factors. For instance, reliable location data from an automotive GPS may be hampered by metallic features in windshields, such as defrosters or car window tinting films, which can act as a Faraday cage and degrade reception inside the car. Furthermore, man-made electromagnetic interference (EMI) can also disrupt 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. 
     Signal degradation can also occur due to intentional jamming. 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 LI C/A jammer was published in an online magazine. The U.S. government believes that such jammers were used occasionally during the 2001 war in Afghanistan. 
     There are several techniques which are currently employed to address interference. Receiver Autonomous Integrity Monitoring (RAIM) is included in some receivers, to warn if jamming or another problem is detected. Since 2004, the U.S. military has also deployed 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. 
     Despite various technologies available, there is no reliable solution that enables a shipping container to reliably obtain accurate geo-location data when satellite coverage is limited. 
     SUMMARY OF THE PRESENT INVENTION 
     To address the problems and limitations noted above, a system for increasing the reliability of location data received from a smart container monitoring unit is provided. According to a first embodiment, the system includes a GPS mesh network device to communicate with existing GPS devices and a remote monitoring station. The present invention further provides a method to coordinate analysis of data to improve determination of the exact location and status of a tracked container. This increased visibility will enable the customer to pinpoint the real time location of a single box more accurately and efficiently. This level of real time asset management translates into greater operational efficiency and performance, cost reductions, and improved safety and security. 
     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  shows a functional configuration in accordance with an embodiment of the present invention. 
         FIG. 2  shows a functional configuration in accordance with an embodiment of the present invention. 
         FIG. 3  shows a functional configuration in accordance with an embodiment of the present invention. 
         FIG. 4  shows a block diagram of a unit device in accordance with an embodiment of the present invention. 
         FIG. 5  shows a block diagram of the electrical wiring in accordance with an embodiment of the present invention. 
         FIG. 6  shows a block diagram of a sensor control unit in accordance with an embodiment of the present invention. 
         FIG. 7  shows a flow chart diagram of a preferred method in accordance with 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. 
     The terms “program,” “computer program,” “software application,” and the like as used herein, are defined as a sequence of instructions designed for execution on a computer system. A program, computer program, or software application may include a subroutine, a function, a procedure, an object implementation, an executable application, an applet, a servlet, a source code, an object code, a shared library, a dynamic load library and/or other sequence of instructions designed for execution on a computer system. A data storage means, as defined herein, includes many different types of computer readable media that allow a computer to read data therefrom and that maintain the data stored for the computer to be able to read the data again. Such data storage means can include, for example, non-volatile memory, such as ROM, Flash memory, battery backed-up RAM, Disk drive memory, CD-ROM, DVD, and other permanent storage media. However, even volatile storage such a RAM, buffers, cache memory, and network circuits are contemplated to serve as such data storage means according to different embodiments of the present invention. 
     With reference now to  FIG. 1 , a functional configuration in accordance with an embodiment of the present invention will now be discussed. As shown in  FIG. 1 , a cross-sectional view of the deck of a ship  104  is provided on which three smart cargo containers, A-C, are stacked above the ship&#39;s deck  104  and six smart cargo containers, D-I, are positioned below the ship&#39;s deck  104 . Additionally, satellites 1, 3, 5 and 7 and a Remote Monitoring Station (RMS)  100  are illustrated. As further shown in  FIG. 1 , container unit A is in a position to send a signal from its GPS transponder to SAT 1, SAT 3 and SAT 5 only and receive a signal back from SAT 1, SAT 3 and SAT 5 only. In the embodiment as shown, Unit A will determine its location based on the signals received from Satellites 1, 3 and 5, and then will transmit the determined location and data to the RMS  100 . 
     As further shown in  FIG. 1 , container unit F is below the ship&#39;s deck yet is in a position to send a signal from its GPS transponder to SAT 3, SAT 5, and SAT 7 only. For the purposes of this example, Unit F will also determine its location based on the signals received from Satellites 3, 5 and 7 and then will also transmit the determined location and data to the RMS  100 . As also shown in  FIG. 1 , the GPS transponder of the monitoring device of container Unit H which is positioned well below the ship&#39;s deck  104  is only capable of receiving a return signal from satellites 3 and 5. In this position, Unit H will determine its location based on the signals received from satellites 3 and 5 and then will transmit its determination of its location and signal data to the RMS  100 . Preferably, the RMS  100  may receive and collect the data from Units A, F and H and using a multilateration of each satellite signal with respect to the each container unit and the Uplink Time Difference of Arrival (U-TDOA) analysis of the signal from the RMS  100  to each unit to determine the most accurate geo-location of each Unit: A, F and H. After backend analysis is completed, the RMS  100  may transmit the updated and most accurate geo-location of each container to the monitoring unit of each container. 
     Preferably, an RMS may query each unit for geo-location data on a preprogrammed basis and serve to update tracking information to shipping companies and customers on a routinely programmed basis. Also preferably, the RMS may query any or all units for geo-location, status, or updates on a constant, random or as needed basis. 
     With reference now to  FIG. 2 , a functional configuration in accordance with an embodiment of the present invention will now be discussed. As shown in  FIG. 2 , an independent carrier  202 , transporting multiple shipments from different shipping companies is provided. Preferably, each shipping company is responsible for accurately tracking their shipments via a smart container monitoring device capable of sensing, communicating, and processing the status of each container individually. The independent carrier may or may not be responsible for monitoring the status of each container unit or for communicating the status of each container to the RMS  200 . In this example, it is preferred that the monitoring units on each container include a GPS transponder. Also, with reference to  FIG. 2 , it is to be assumed that conditions are prohibiting all but two GPS transponders from receiving satellite signals. Therefore, conditions are such that Unit A is receiving signals from two satellites, 1 and 3, and Unit F is also receiving signals from only two satellites, 3 and 5. Further, for purposes of illustration, container monitoring units B, C, D, and E are shown failing to pick up any signals from any satellites but may respond when queried by the container device of Unit A. In this example, when Unit A queries Units B, C, D, and E for identity and location, these units may respond with their respective identities and location data for each. Further, when Unit A queries Unit F, Unit F preferably responds by identifying itself and providing data regarding its location. 
     As further shown in  FIG. 2 , exemplary container Unit A is signaling to Satellites 1 and 3 but can also transmit to and receive a wireless signal from Cell Tower  14 . In the embodiment as shown, Unit A will preferably determine its location based on the signals received from Satellites 1 and 3, and the location of Cell Tower  14  and then will transmit the determined location and data to the RMS  200 . 
     As further shown in  FIG. 2 , container Unit F is signaling to Satellites 3 and 5 only but can also transmit to and receive a wireless signal from Cell Tower  6 . In the embodiment as shown, Unit F will determine its location based on the signals received from Satellites 3 and 5, and the location of Cell Tower  6  and then will transmit the determined location and data to the RMS  200 . 
     According to a further aspect of the present invention, the RMS  200  may receive and collect the data from Units A and F. Further, RMS  200  may use Uplink Time Difference of Arrival (U-TDOA) analysis to determine the most accurate geo-location of Units A and F. After backend analysis is completed, the RMS  100  may transmit the updated and most accurate geo-location of each container unit. Preferably, Unit A may transmit its geo-location as determined by the RMS to Units B, C, D and E. Also preferably, Units B, C, D, and E will acknowledge receipt and update the geo-location of each unit individually. Also preferably, Units B, C, D, and E may attempt to contact the RMS  200  individually and update the geo-location of each unit as a means of confirming that transmission was successful. 
     Preferably, each container monitor unit, A-F, may be equipped with a GPS Mesh Network device which includes a radar range finder capable of transmitting an RF signal to determine the distance from itself to every other unit monitoring device within a selected range (“pinging”). In response to this pinging, it is preferred that a target container is equipped with an RFIP tag or similar device which produces a response when queried. For example, an RFID tag may be programmed to transmit a distinctly identifiable code or number in response. Based on responsive signals, the controller unit may create a map of the relative locations of all monitored devices and may transmit this data to the RMS  200  for further analysis. 
     With reference now to  FIG. 3 , a functional configuration in accordance with the present invention will now be discussed. As shown in  FIG. 3 , a cross-sectional view of the deck of a ship  304  is provided on which three smart cargo containers, A-C, are shown stacked above the ship&#39;s deck  304  and six smart cargo containers, D-I, are positioned below the ship&#39;s deck  304 . Further, exemplary satellites 1, 3 and 5, and a Remote Monitoring Station (RMS)  300  are illustrated as well. As shown in  FIG. 3 , container unit A is in a position to send a signal from its GPS transponder to SAT 1, SAT 3 and SAT 5 only and to receive a signal back from SAT 1, SAT 3 and SAT 5 only. In the embodiment as shown, Unit A will determine its location based on the signals received from Satellites 1, 3 and 5, and then will transmit the determined location and data to the RMS  300 . 
     As shown in  FIG. 3 , for illustrative purposes, Units B and C are provided as “dumb” containers (i.e. containers without monitoring or communication capabilities). Additionally, Units D, E, F, G, H, and I are shown in a position where they cannot transmit signals due to a Faraday Cage effect caused by the ship&#39;s hull. However, as shown, Unit A can query Units D-1 and serve as a relay node for Units D-I. 
     Within this exemplary environment, it is preferred that Unit A transmits a message to the RMS  300 , it may identify itself, indicate that it is transmitting signals from Units D-I, report that Units D-I are receiving no geo-location signals, and report its data and distance from Satellites 1, 3 and 5. Based on the information received by Unit A from the satellites 1, 3 and 5, Unit A will report its geo-location and request that the RMS  300  verify its location based on its time/distance (T-UDOA) signal to the RMS  300  and its position relative to Units D-I. Preferably, the RMS  300  may verify the position of Unit A based on data from Satellites 1, 3 and 5 and the T-UDOA to Unit A and by comparing its results to Unit A&#39;s geo-location data. If variances in the determined locations are determined to be too large, the system preferably will reinitiate a request for location data. If the resulting geo-location positions are in agreement, Unit A may transmit to Units D-I an accurate geo-location. 
     With reference now to  FIG. 4 , the details of a block diagram in accordance with an embodiment 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 , radar 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. 
     With reference now to  FIG. 5 , a block diagram of the electrical wiring in accordance with an embodiment of the present invention will now be discussed. A microcontroller unit  602  receives input from a charging circuit and battery cells  503 , the status detect sensors  513 , an RFID reader  509 , a Radar Range Finder  501 , a GPS Transponder  511  and variable sensors in suite  507 . The microcontroller unit  602  then assesses all the information and sends out signals to a radio transmitter/transceiver  517 , a sensor log  527 , a remote monitoring station  521 , a GPS tracking system transmitter  519 , an alarm module  515 , and an RFID Manifest  525 . Data from these sensors is processed, stored, and acted upon by the microcontroller unit  602 . 
     Preferably, the sensor unit of the present invention includes circuitry and digital ports to connect to existing electrical and sensor management systems of trailers and containers previously configured with embedded circuitry. In operation, a microcontroller unit  602  is preferably programmed to routinely scan the condition of each sensor to ensure operability. 
     With reference now to  FIG. 6 , it is preferred that the microcontroller unit  602  receives data from the sensor suite  604  and incorporates a microprocessor  606 , a real time clock  618 , a general purpose Input/Output port to support external peripheral control  608 , a Universal Synchronous/Asynchronous Receiver Transmitter (USART)  610 , a Serial Port Interface (SPI)  612 , and memory such as RAM  622 , FLASH memory  620 , and EEPROM  614  as shown. 
     Preferably, the microprocessor  606  used may be a low power, high performance, eight-bit intergrated circuit based on the Motorola HCS08 instruction set. The controller  602  will preferably manage power and host the master date-time clock, communication scheduling and annotation of flash memory records. 
     With reference now to  FIG. 7 , a method in accordance with the present invention will now be discussed. As shown in  FIG. 7 , a first container monitoring unit (CMU) will determine its location via a GSP transponder  701 . Following determining its own location, the CMU of the first container will send out a query of other containers for their identifying information and location  703 . The first container&#39;s CMU may then report the data it has collected to a remote monitoring station (RMS)  705 . In accordance with a further aspect of the present invention, a second CMU from a second container may determine its location by GPS  707  and thereafter query other containers for their identifying information and location data  709 . The second CMU will then preferably report the collected data to the RMS  711  which will further analyze the signals and data. For example, the RMS may use techniques of multilateration and Uplink Time Difference of Arrival (U-TDOA) analysis. 
     After determining and updating the geo-location of the containers, the RMS will transmit this updated geo-location data back to the CMU of the containers  713 . The first and second CMU&#39;s will then preferably relay the updated location data to the other containers  715 ,  717 . Preferably, the RMS will work to continuously track and update container locations and preferably continually relay that information to the shipping companies  719  for real-time asset tracking. 
     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 the like, 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, 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 the 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 data flow 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&#39;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 short, such a data fusion center would preferably provide a consolidated source of information that could be used to assist agencies and shippers 
     The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are to be included within the scope of the following claims.