Patent Application
20140266668
1. Field of the Invention
The invention pertains to apparatus and methods for ensuring the security of shipping containers, and more particularly to security systems having tamper detection features.
2. Description of Related Art
Much of the worldwide commerce in finished goods involves transportation in various kinds of shipping containers, such as those carried on ships, trains, and over-the-road trucks. There is a great need to protect the contents of shipping containers from theft or damage during transit, and many solutions have been proposed to address container security. These solutions may be broadly classified as locking solutions and visibility solutions. Locking solutions involve various ways to secure a container so that it can be opened only under certain conditions (e.g., a person presents a valid pass code; the container has arrived at a designated destination; etc.) Visibility solutions involve various ways to track a container, often in real time, so that users may be alerted if the container has left a prescribed area, deviated from a prescribed route, experienced a delay in scheduled progress, etc. Some solutions involve a combination of both visibility and locking functions.
Shipping containers are often in remote areas and may be unattended for periods of time, so the security devices often include various means of tamper detection. Such means may include load cells, accelerometers, tilt sensors, thermal sensors, etc., along with a communication means by which the security device can alert a central system monitor that tampering may be occurring.
Tamper detection systems are subject to the same fundamental trade-off as any other security system, viz., the need to minimize false positives while avoiding false negatives. If the sensitivity is set too high, false alarms will be generated, whereas if sensitivity is set too low, a tampering event may go undetected.
Objects of the present invention include the following: providing a container security system that can detect tampering; providing a container security system in which one or more tamper sensing mechanisms have variable threshold(s); providing a container security system with improved ability to minimize false positives while avoiding false negatives; providing a container security system with user-adjustable tamper detection settings; providing a container security system with automatically adjustable tamper detection settings; providing a tamper-resistant container security system having reduced power consumption. These and other objects and advantages of the invention will become apparent from consideration of the following specification, read in conjunction with the drawings.
According to one aspect of the invention, a security system for shipping containers comprises:
a system monitor; and,
a device mounted on the shipping container comprising:
According to another aspect of the invention a security system for shipping containers comprises:
a system monitor; and,
a device mounted on the shipping container comprising:
According to another aspect of the invention, a method for monitoring the status of a shipping container comprises:
providing a system monitor;
mounting a device on a shipping container, the device including:
measuring at least one condition of said container;
adjusting at least one parameter of the tamper sensing system; and,
notifying the system monitor if tampering is detected.
The drawings accompanying and forming part of this specification are included to depict certain aspects of the invention. A clearer conception of the invention, and of the components and operation of systems provided with the invention, will become more readily apparent by referring to the exemplary, and therefore non-limiting embodiments illustrated in the drawing figures, wherein like numerals (if they occur in more than one view) designate the same elements. The features in the drawings are not necessarily drawn to scale.
The invention comprises a tamper-detection device and method, which may be part of a larger locking and/or visibility solution for shipping containers. As used herein, the term shipping containers includes standard multimodal containers, custom containers, semi-trailers, trucks, rail cars, and virtually any enclosed, lockable space for containing items to be shipped from place to place. The device will in most cases be able to operate with some degree of autonomy and will in general have an on-board power supply (typically batteries).
The general concept may be illustrated with reference to Applicants' patented locking/visibility solutions described in U.S. Pat. Nos. 8,009,034 and 8,058,985 to Dobson et al., the entire disclosures of which are incorporated herein by reference. In this example, the device is packaged into a robust housing 2 with locking members that engage the locking bars on a shipping container to prevent the container from being opened. The device typically contains a GPS receiver or other means to monitor its position and speed 4, along with a means of communication 3 with a central system monitor 1.
The device further includes a sensor interface to allow the detection of selected events or environmental factors (including but not limited to: tilting, vibration, and tamper switches, air pressure, temperature and humidity sensors, and detectors for hazardous conditions such as the presence of chemical, biological, radiological, nuclear, and explosive agents).
It will be appreciated that the detection of tampering is as complex as the variety of methods that are available to an adversary seeking to attack or disable the device, as illustrated in the following examples.
A key aspect of the present invention is based on Applicants' realization that the performance of the tamper detection system 5 can be greatly improved by incorporating an understanding of how such tampering is likely to be attempted and, more importantly, when tampering is likely or unlikely. As a simple example, physical tampering is extremely unlikely to occur when the container is moving at high speed. At the same time, while the container is moving there will be incidental movements and vibrations that might be comparable in magnitude to what might be a tampering event if the container were initially motionless. Thus, a tamper system using accelerometers with a fixed alarm threshold runs the risk of being too sensitive during transit (false positives) or not sensitive enough when parked (false negatives).
It will be appreciated that, as with many systems involving security and situational awareness, it is often useful to employ several inputs as a further means of distinguishing benign conditions from hostile ones.
An additional benefit to making adjustments to sensor threshold settings based on measured conditions of the container is to conserve battery power. By using measured parameters to determine times when a container is more likely to be tampered with, sensor monitoring times and communication times can be adjusted to reduce the overall amount of battery power the system uses and thus extend battery life.
A further benefit to making adjustments to sensor threshold settings based on measured conditions of the container is to reduce the amount of communication data. By using measured parameters to adjust sensor thresholds and alarm reporting frequency, there can be a cost savings benefit since communications costs are measured in number of bytes of data.
Applicants contemplate that in many instances the tamper sensing system 5 will be part of a larger visibility and locking solution. In such cases, the tamper circuit may be configured not only to alert the remote system monitor or central station, but also to disable the lock 6 from being unlocked. Thus, e.g., if the container is stopped or parked, and tampering is detected, a person will be unable to unlock the container even if a valid unlock code is known.
It will be appreciated that the inventive device 3 may communicate with the remote system monitor 1 using any suitable wireless communication protocol, such as cellular telephone, satellite telephone, radio, or other means as taught in the aforementioned U.S. Pat. Nos. 8,009,034 and 8,058,985. When a locking device 6 is used, communication between the tamper sensing system 5 and the lock may be hard wired or it may use any suitable short-range wireless communication protocol as are well known in the art.
