Field of the Invention The present invention is directed to wireless communication, and more particularly to asset location and tracking systems.

Background and Summary of the Invention Businesses have an ongoing need to track and inventory assets. This is particularly critical for high-value assets such as in portable communications test equipment used by the telecommunications industry. When valuable equipment is portable, it is susceptible to theft, as well as loss or misplacement. Because such equipment may be used at remote locations outside the premises of the business, conventional security measures such as locking down equipment and guarding against its removal are impractical.

In addition, even where security is not a concern, equipment may be misplaced and not locatable when needed,. even if safely stored on the proper premises, leading to increased equipment costs to ensure an adequate inventory. Also, some equipment may include specialized hardware and software that may have different versions, different update status, and different compatibility for different uses. It may be difficult for an inventory system to monitor the particular characteristics of each item, so that the most appropriate item can be located, or so that deficient items can be efficiently located for updating.

Systems have been proposed to track assets using global positioning system (GPS) signals, with cellular transceivers reporting the assets'locations. While possibly suited for some applications, these are not useful'for areas where GPS signals do not reach, such as the interior of most buildings where many types of assets are most likely to be found.

The present invention overcomes the limitations of the prior art by providing a communication module for an asset to be monitored. The module operates to periodically

receive a signal from a monitoring facility via a first wireless communication system, and in response to the absence of the signal at an expected time, communicating with the module via a. second wireless system. The first system may be a short range system operating inside a limited facility, and the second system may be a cellular phone system. The module may include a global positioning receiver, so that the module may report its location via the second system to the monitoring system when it is taken from the transmission range of the first system.

Brief Descriution of the Drawings Figure 1 is a high-level block diagram showing the environment in which the facility preferably operates.

Figure 2 is a schematic block diagram showing an instrument tracking module according to a preferred embodiment of the invention.

Detailed Description of a Preferred Embodiment Figure 1 shows an asset tracking system 10 operating both intemally to and externally of a user entity's physical facility 12. The facility may be one or more buildings, such as warehouses, or open areas in a limited space, normally private or restricted property controlled by the user. The facility contains a short range wireless communication system having one or more base transceiver stations 14 that are installed in the facility in sufficient numbers and distributed locations to provide full wireless communication coverage for the entire interior of the facility.

Each base station 14 includes a transceiver and antenna 16, and a controller 20. The controllers are connected to a. central computer 22 in the facility, or connected to the components in the facility. The computer 22 is connected to a telecommunication network 24, such as provided by the Internet, an internal network, or a public switched telephone network. A number of equipment assets 26 to be tracked may be located anywhere, inside of or outside of the facility.

As will be discussed below, each of these assets includes a communication module that communicates with the facility transceivers 14, with a cellular network 30 connected to the telecommunication network, and with a satellite-based global position system (GPS) 32. A

monitoring center 34 connected to the network 26 receives and coordinates communications from the asset modules.

The facility's internal wireless communication system is preferably a radio frequency system operating on a 2.4 GHz ISM (Industrial, Scientific, Medical) frequency band designated by the FCC as a license-free band. This provides broadcast and reception range of about 1000 feet, so that larger facilities may require more than one base station. An advantage of this mode is that the low power spread spectrum transceivers do not affect nearby equipment that might otherwise be susceptible to radio frequency energy generated in other modes, such as by cellular transmitters. Depending on the configuration of the facility, more base stations may be required if the space is subdivided into rooms by walls that impede transmission of signals. In alternative embodiments, different frequency bands may be employed. For applications in which the assets are large and generally visible in an open space, visible or infrared line-of-sight transmissions may be used. Such a system is better suited for tracking large equipment such as heavy machinery or large manufactured goods than for the smaller portable electronic assets of the preferred embodiment.

Figure 2 shows a portable electronic equipment asset 26, which includes a tracking communication module 36. The module includes a short range transceiver 40 and associated antenna 42 that communicate with the facility base stations 14 when the asset is in the facility. A cellular transceiver 44 and associated cellular antenna 46 operate to communicate with the cellular system 30 when the asset is outside of the facility. A GPS receiver 50 and associated antenna 52 operate to receive signals from satellites 32, from which the receiver calculates its location.

A controller 54 includes microprocessor circuitry programmed to coordinate communication by each of the above elements, and may be integrated with or connected to other circuitry in the asset. Such integration may be used so that the controller disables or enables the asset function depending on communication status (e. g. disabling the device if taken out of an authorized area by a presumed thief.) The controller may also read information from the device, including asset configuration, identifying number, asset options, software revision level, and

hardware revision level, so that one of the transceivers can report this information to the central system. This permits the system to generate benefits other than security and inventorying. For instance, calibration and updates may be schduled, either centrally, or by a report generated in the asset that a calibration or update is due.

The module includes a dedicated rechargeable battery 56 that powers the module when the asset is disconnected from an external power source. A charger 60 is connected to the device power supply to charge the battery when the device is connected to power for normal operation.

In the preferred embodiment, the short range transceiver 40 includes a 2.4 GHz modem.

The cellular transceiver 44 may essentially consist of CDMA, TDMA, GSM or AMPS cellular telephone circuitry, with an analog modem converting digital signals to and from the controller into analog signals transmissible via cellular transmission. The circuitry of the communication tracking module 36 is shown as having separate components for each function. However, the various functions may integrated onto fewer components to reduce size and cost. Further, the module components may be integrated with other circuitry of the asset, at least in part as a security measure against unauthorized disablement or removal of the tracking circuitry.

Operation The facility central computer 22 operates to regularly poll all assets in the facility to verify their presence. A polling signal is sent out to each of the assets, which reply with identifying information. Alternatively, the system may send out a single call for reports from the assets, which may reply sequentially or simultaneously. The reply may also include location information enabling the asset to be located within the facility, as well as other device status information noted above. Different devices may be polled at different selected intervals, and polling may be conducted automatically, or manually, such as in response to a user's need for a particular type of asset.

Each asset may operate using receipt of the polling signal as an optional"keep alive" signal, so that the asset is disabled if it does not receive the signal. Thus, a device that has been taken from the facility is disabled until it is returned. For devices requiring authorized use outside the facility, an authorization code may be entered to permit operation (this may be

integrated with verification measures associated with remote cellular communication discussed below.) If an asset is removed from the facility so that it is out of communication with the short range wireless system, it may be programmed to respond in several different ways, which may be employed separately or in combination. As noted above, it may disable itself in the absence of a "keep alive"signal.

Preferably, upon removal from the facility, the module responds to the lack of an expected polling signal at a selected time by initiating a cellular telephone transmission to the monitoring center. The call may be delayed any amount of time as needed. For some assets, an immediate call may be appropriate to prevent theft. For other assets routinely taken from the. facility and normally returned within limited time period, a delay may be appropriate (e. g. a checked out municipal bus might not report its location until after the end of the expected shift, so that normal use does not trigger a cellular report, but failure to return promptly does.) The monitoring center may be a central agency serving many different independent users, or which may be on the site of the user, and connected directly to or integrated with the control computer 22.

Either automatically, or upon request by the monitoring authority, the module controller may activate the GPS circuitry to establish the current location of the asset, and transmit this location information to the monitoring center. This permits the asset to be recovered in the event of theft, In typical cases, such as when the asset has been removed as a part of routine business, the location may be checked against expected authorized locations. Such locations may be stored in a database to reflect corridors of authorized transport, remote locations of authorized use and storage, and trip or relocation plans entered in advance by personnel intending to make. authorized transport.

As an altemative to the module automatically initiating cellular communication in the absence of the facility signal, the device may remain passive, so that action must be taken by the tracking computer. Essentially, the system calls the cellular transceiver of the missing asset to receive a report of its whereabouts. This has the disadvantage of requiring the cellular phone to

be powered up fin a receiving mode, depicting batteries. However, conservation measures such as cycling the receiver on only at periodic intervals knows to the system limit power consumption.

In this case, the tracking computer is alerted by the absence of a response to the short range wireless signal in the facility. Consequently, the tracking system may take action to track down the asset. In cases where the asset is expected to be out of the facility for a pre-established period of time (such as if it is checked out for a temporary off-site job), the computer may take no action, unless the device does not return as expected. This strategy is suitable for users having multiple facilities between which assets are transported, where each facility has its own sort range wireless tracking system. In such cases, the computer may allow a grace period for the device to return to a facility, before initiating cellular location efforts. These techniques are also applicable to the active module approach discussed above, in which the module initiates cellular communication in the absence of the facility signal.

Another operating mode provides a. virtual"fence"within which the asset may tolerably be located, and outside of which it is not permitted to be moved. This fence may be preprogrammed into the controller as acceptable location values to be generated by the GPS unit.

When GPS-generated location values depart from the acceptable domain, a cellular reporting call is initiated.

The module may include safeguards that disable the asset if it is kept out of cellular range for more than a selected period of time. For instance, to prevent a thief from secreting and using an asset in a shielded or remote area away from cellular coverage (assuming the absence of a keep-alive system), so that the owner could not located it via the GPS/cellular liuc, the device may be programmed to become disabled. An extended grace may be allowed, so that an authorized user may temporarily use the asset in a remote or shielded location. For extended use away from cellular coverage,. a wired telephone line may be connected. to the module to report location information, and to enable any keep-alive signals to be transmitted from the monitoring center.

Additional functionality may include using the wireless transport to provide software upgrades to the device; provide"data downloads"to the device that may update certain configuration information of the device. Other remote diagnostics could also take place during the connection to the wireless network.

While the above is discussed in terms of preferred and alternative embodiments, the invention is not intended to be so limited. For instance, instead of the two illustrated modes of communication (short range radio frequency and cellular frequencies), other communication modes may be used. These may include email, pager, satellite modes, in addition to other local transmission modes such a. s the optical modes discussed above. The modules may include other security features, such as motion, video and audio sensors that allow transmission of additional information about the environment into which the asset has been taken. Such information may be used to prosecute wrongdoers, and to deter future wrongdoing. Various combinations of the different features above may be employed without departing from the concept of the invention.