The present invention relates generally to freight shipping and, more particularly, to a method and apparatus for tracking air cargo.
Freight or cargo is shipped using any of a variety of methods, the method or methods used for any one shipment being selected on the basis of cost, delivery schedule, and pick-up and drop-off locations. Furthermore, if the goods are perishable or fragile, additional shipping precautions may be required.
During shipment, it is extremely difficult and typically very labor intensive to determine the exact location of the goods being shipped. Such tracking often requires multiple communications via phone, fax, e-mail, or other means between the shipper, forwarder, and the various carrier personnel. Location determination may even require physically searching a cargo storing warehouse, trucking warehouse, airport cargo terminal, or other location.
Shipment tracking is complicated by a number of factors. First, a variety of parties typically handle a piece of cargo during shipping, the parties potentially working for multiple independent companies. For example, a single shipment may require handling by multiple trucks and/or trucking companies and utilize multiple airline flights and/or airline companies. Additionally, a variety of cargo handlers/loaders are required to move the cargo between trucks/flights/carriers, staging areas, and temporary storage locations. Second, there are often last minute changes in shipping, for example due to a piece of freight being off-loaded from a scheduled flight in order to make room for a more valuable or time sensitive piece of freight. Such changes are typically made at the discretion of the carrier without notifying either the shipper or the forwarder. In this situation the shipper or forwarder may not be aware of the change until the freight does not arrive on the scheduled flight or at the expected time. As a result, the shipper is likely to expend additional time attempting to locate the delayed freight.
A number of carriers have attempted to provide improved tracking information by allowing at least some of the larger forwarders to directly view their loading manifests, for example via a Web site. Although this approach can provide some tracking information, it requires carriers to accurately update the status of cargo at each step of cargo movement. As a consequence, this approach is labor intensive and thus costly. Additionally, the cargo status may not be updated at each step, for example, the carrier may only update the status when the cargo actually is loaded or unloaded from a plane, not when the cargo is simply moved from a storage facility to a loading site. Lastly, as cargo status information relies on human operators inputting the data, the data may be incorrect or delayed.
Some shipping integrators have begun to use bar code tracking as a means of providing cargo tracking. Typically each piece of cargo is immediately tagged with a bar code upon receipt by the integrator. Then at each step of shipping, the handler scans the bar code, thereby immediately logging the location of the cargo as well as the time that the bar code was scanned into a manifest readable by the shipper via a Web site or other means. Although this approach reduces the risk of human error through the use of bar codes, the approach is still labor intensive as human operators are required to input the data. Additionally, the provided information is still only as accurate as the last bar code scan.
Accordingly, what is needed in the art is a system that autonomously tracks cargo during shipping, providing the shipper and/or forwarder with accurate, timely, cargo status. The present invention provides such a system.
An autonomous cargo tracking system and method of using same are provided. The system is comprised of a communication and sensor unit that is affixed to the container to be tracked, a ground system that coordinates communications between the unit and the users, and one or more satellite systems that provide communication capabilities as well as position information. The system can operate either as a unidirectional system or as a bi-directional system. As a unidirectional system data is sent either directly to the users or, more preferably, sent indirectly to the users via the ground system. As a bi-directional system users are able to both request and receive data from the unit, either directly or indirectly through the ground system. Preferably users communicate with the ground system using an Internet Web site.
According to the invention, a position sensing and communication (PSC) unit is affixed to or integrated into a shipping container, shipping pallet, cargo net, or cargo unit load device (ULD). The PSC unit provides a means of communicating with a ground system and determining location coordinates. Additionally, the PSC unit can include one or more sensor modules that can be used to provide additional information such as environmental conditions, container status, rate and/or direction of movement, etc. Once activated, the identity of a specific PSC unit is linked to or associated with the specific cargo to which it is coupled.
The PSC unit, using a GPS satellite constellation or other means, obtains position coordinates in response to a triggering event, the type of triggering event depending upon the configuration of the PSC unit and/or the system. Triggering events include detected movement, detected movement meeting preset criteria, a change in a predefined environmental condition (e.g., humidity, vibrational level, pressure, temperature, etc.), lapsing of a preset time period, and/or when polled by the ground system or a user.
In the preferred embodiment position coordinates, once determined, are sent to a ground system for translation into user recognizable locations, the translated coordinates provided either textually (i.e., as a location description) or graphically (i.e., as a map with a location indicator). The ground system sends the location information to a user, either in response to a request for the information by the user or automatically according to a predefined set of rules.
Preferably the communication portions of the PSC unit are placed in standby mode when the container and the associated PSC unit are loaded into the cargo bay of an aircraft, thus insuring that the unit does not interfere with the aircraft""s avionics systems. In one embodiment, container loading is determined on the basis of the container being raised more than five feet, as determined by an on-board accelerator module, and at a rate commensurate with a cargo loader. Preferably container loading is verified, for example by comparing the container""s coordinates with an airport data base. In an alternate embodiment, container loading is determined by monitoring the electromagnetic spectrum of its surroundings, specifically monitoring for the radiated emissions of the aircraft power supply which are most prevalent at 400 Hertz. In another alternate embodiment, the PSC unit includes a RF detector designed to detect non-aircraft originating RF signals, the receipt of which is interrupted when the container and PSC unit are loaded into the aircraft. In yet another alternate embodiment, the PSC unit""s sensor module emits one or more pulses of radiation, preferably ultrasonic radiation, and monitors the return of the radiation. The timing of the return can be used to detect the proximity of adjacent surfaces, such as the walls of the aircraft.
A further understanding of the nature and advantages of the present invention may be realized by reference to the remaining portions of the specification and the drawings.