Patent Application
20110090041
The present invention relates to the monitoring of mobile and remote endpoint devices over a very large area of service.
Asset management is a critical part of any business entity engaged in the transfer of raw or finished goods. It is important to carefully manage re-supply of raw materials to ensure that the manufacturing or service element of an industry does not halt and to carefully manage transportation of finished goods to minimize inventory held for sale. Those companies that do not optimize manufacturing and materials handling are at a significant disadvantage.
The proliferation of location based services, devices, and methods in the past decade is a testimony to the market need for an effective means for locating and managing remote assets that are fixed or mobile. There exist several methods for collecting remote data wirelessly, including terrestrial and satellite based communications systems. The problem arises in collecting data from assets that do not have readily available power, such as cargo trailers, rail, and remote fixed assets such as pipelines, shear sensors, and the like.
The uncertainty associated with raw materials and finished goods in transit presents a problem in asset management. Companies generally operate with an element of uncertainty as to the exact time of delivery or location of pending delivery for products and raw materials in transit. Unforeseen conditions impacting the arrival of truck, rail, or other vessel deliveries are impossible to predict and difficult to model. Real-time information about materials in transit can be used to forecast deliveries, schedule manpower and other materials, and predict finished goods inventory supply.
The transportation industry suffers from in-transit cargo theft and loss. Loss of cargo happens in a wide variety of ways, from employee/driver theft to the organized capture of entire fleets of trailers and rail-cars. The transportation industry has been struggling to limit loss through radio communication means. The cellular telephone industry has enabled a host of communications products that are making an impact. These products provide many functions such as standard voice communication, data services, and real-time position reporting and status of vehicle operations such as speed, temperature, or brake conditions.
Conventional solutions typically rely on cellular communication systems or satellite communication systems. Existing technology solutions that rely on cellular coverage are generally not ubiquitous in coverage. Cellular coverage may be adequate for urban and major interstate routes but becomes unreliable in rural or sparsely populated regions. Additionally, a cellular network implemented primarily for voice communications is a poor solution for rail or vessel data communication. Also, as cellular technology advances, the protocols have transitioned from analog to digital and now to tri-band Global System for Mobile Communication (GSM). Thus, some communication systems developed only a few years ago are already obsolete.
Cellular communication asset management systems are inherently two-way in nature and thus require continuous line power for operation. This type of system does not operate effectively on battery power without periodic reconnection to line power such as an automotive power system.
Satellite based communication systems mitigate some of the problems associated with cellular asset management devices. For instance, satellite modems are not limited to the service coverage area of cellular telephone corridors. Instead, the area of service is related to the satellite system selected for use and thereby solves the problem of rural and vessel coverage.
Satellite asset management systems are preferred if the communication system can provide adequate information bandwidth to support the application requirements. Generally, satellite asset management systems are the successors of cellular systems and offer broadband feature sets such as Internet and voice over Internet-Protocol. Broadband satellite services are typically expensive and generally prone to communication failures due to weather and obstruction. Most asset management systems which utilize broadband satellite must package broadband services such as voice or Internet in order to justify the cost of the data bandwidth, even though the information for asset management is generally low-bandwidth in nature. This drives the cost of satellite-based asset management systems up.
The transmit power required to communicate to geo-stationary satellites imposes power system problems for a remote asset management device. Existing satellite asset management systems generally must incorporate transmit power amplifiers of up to 10 Watts to adequately operate. As most satellite communication systems impose tightly controlled spectral masks, digital communication systems must incorporate linear or nearly linear (Class A or Class AB) power amplifier architectures to prevent spectral re-growth. As a result, the transmit device must be designed to produce up to 10 Watts with amplifier architectures which are typically only 40% efficient. This creates difficult design limitations which require sufficient line power or high-density bulky battery systems to function.
Most satellite-based asset management systems use satellite architectures that are duplex in nature. In order to send data over a satellite, the remote device must generally negotiate a data channel. Even if the data is only one-way in nature, the communication modem must contain both receive and transmit capability to implement this negotiation. Remote asset management devices must both listen and transmit in order to facilitate data transfer to and from a remote device.
Both cellular and two-way satellite asset management systems require available line power or extensive battery systems to operate. Even existing systems equipped with low power operational states must utilize excessive power to manage two-way communications as well as transmit with sufficient energy to operate within the communications infrastructure.
Existing asset management devices are generally located on the tractor-cab of the truck, train, or vessel. This serves to locate the cargo while the load is attached. Unfortunately, when a load such as the trailer, rail-car, or barge is disconnected, the important information that provides value for asset management is lost. Trailers that get dropped-off by a driver may become lost for hours or days, resulting in the total loss of perishable loads or missing deadlines for non-perishable loads. Thus, inventory management becomes difficult and highly labor intensive to minimize misplaced loads.
Rail-car tracking systems generally lag in capability behind truck tracking systems. Since rail-cars remain on class 1 lines, the owners typically know when the rail-cars have passed checkpoints using barcode or visual identification systems. However, once the rail-cars are placed on class 2 or class 3 lines there is generally no real-time tracking. Additionally, customers often use rail-cars as temporary storage to delay offloading goods and maintain an average amount of storage of goods at the cost of the rail-fleet owner. Rail-fleet owners have a difficult time assessing demurrage charges because they may not know if the rail-car has been offloaded on schedule or where the rail-car is currently located. As a result, the only solution generally applied is to add new cars to the fleet to satisfy logistic problems of moving goods.
Barge and vessel owners generally are dependent on river pilots and deep-sea vessel operators for the location of goods using voice communication only. As such, commodity traders usually maintain a staff of logistics personnel to voice-track products as they are moved. A radio-telemetry product that works without a cellular infrastructure and without the requirement of available power can thus dramatically reduce the reliance of pilots and logistics staff.
There is thus an unmet need in the art for an asset management device that operates on an internal battery and provides years of service, utilizes satellite communication with a world-wide footprint, integrates Global Positioning Satellite service (GPS) providing world-wide location determination, utilizes remote configuration, and which provides for external data such as alarms and raw user data, enabling sophisticated endpoint monitoring.
It is a first object of this present invention to enable simplex transmitters for remote configuration through the use of an external interface, which can be a wired or a wireless interface such as a short-range radio transceiver interface. The present invention provides a system and method whereby the introduction of an external interface is extremely power efficient while providing utility of function. The present invention also provides a system and method whereby use of the external interface is extremely power efficient, and does not significantly impair the overall service life of the battery operated remote asset management device.
The introduction of an external interface introduces many new utilities as well as overcomes a significant shortcoming of the prior art. Since a simplex satellite transmitter is one-way, it is dependent on internally or locally initiated stimuli to engage alternate functional modes. For example, since it is not possible to talk to a remote asset management device that is field deployed, it is impossible to instruct such a device to alter a report schedule or initiate an extended low power state. Thus, it is an additional object of the present invention to provide an external interface to provide configuration, sensor monitoring, group detection and control, and long-range detection and control of host satellite asset management devices. The addition of the external interface, operating in a power efficient mode, serves to overcome deficiencies in the art.
The foregoing and other advantages and features of the present invention will become more apparent from the detailed description of exemplary embodiments of the invention given below with reference to the accompanying drawings.
Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views, preferred embodiments of the present invention are described.
Enclosure 102 depicts the physical enclosure of the asset management device. Internal to the enclosure 102 is a battery 107 used to power the location determination device 103. The location determination device 103 may be any means in the art for ascertaining the location of the endpoint device. For example, the location determination device 103 may derive the location using inertial navigation, barcode scan for waypoints, radio telemetry for fixed waypoints, or satellite data. Once the location has been ascertained by a location determination function, the location information is transmitted using a satellite transmitter 104 to the satellite system 105. This transmission function may be accomplished using any number of satellite communications means, such as a simplex satellite transmitter. Simplex communication as known in the art is a form of one-way communication that provides for a transmit or a receive path between two network components. The efficiencies of a simplex one-way satellite transmitter may be utilized to send data to a satellite constellation for relay to a ground receiver or network. The data may be distributed from the receiver gateways to end users using a variety of other terrestrial communication networks, such as the Internet. Battery 107 is a power source local to the device and provides power to the remote asset management device.
The embodiment of the present invention as shown in
In
Remote asset management device 202 includes a host interface controller 206 which performs several functions that add utility to the endpoint device. The primary function of the host interface controller 206 is power management. Thus, the host interface controller 206 can contain an algorithmic engine capable of enabling and disabling the functional blocks of the remote asset management device 202. The host interface controller 206 can therefore connect the battery 207 of the remote asset management device 202 to the GPS receiver 203, the satellite transmitter 204, and the short-range transceiver 208 to perform power management functions as necessary, such as disabling all functionality to set the unit 202 into a low power state. While in a low power state, the host interface controller 206 will use a variety of means to resume active power mode to perform the asset management function.
The current embodiment of the present invention can include external interfaces 309 used to bridge the communication between the controller 307 and any combination of external alarms, configuration devices, or communications devices. Additionally, the present invention may also include an optional power input 310 used to extend or replace the internal battery 306 function.
The short-range radio transceiver can be power managed to prevent undue degradation of service life through exhaustion of battery 306.
Data may be generated by the controller or received from remote sensors or data interfaces via the wired serial interface or over the wireless short-range transceiver interface 308.
Additionally, it is an object of the present invention to utilize a wireless external interface to enable use of wireless sensors, thus removing the need to install connecting wiring.
Alternatively, the sensor may be loosely bound, enabled to communicate to any asset management device 503, 504 in range of the transceiver link 506, 507. In this mode, the sensor may be portable between asset management devices 503, 504. Examples of the utility provided would be a sensor affixed to a palette or mobile load that is transferred between trailers, each tagged with an asset management device 503. The portable sensor would therefore acquire any suitable asset management device 503 and thus relay data to the data satellite 502 while in transit. Other similar applications exist where the sensor must be portable.
The asset management device 503 may also support a multiplicity of wireless sensors. The current embodiment can support many wireless sensors as each sensor can contain a unique identification data term. The protocol implemented in one embodiment of the present invention supports up to 32 unique sensors, allowing for many palettes of cargo tagged with portable sensors to be monitored by one asset management device 503. Each sensor such as 506 or 507 would logically connect to a given asset management device 503 and use that device 503 to relay sensor data to the data satellite network 502.
The configuration tool 505 can be used to configure the sensors 506, 507 for operation either at time of deployment or subsequently in field use. The configuration tool 505 can configure an asset management device 503 as described previously by initiating a communication link and acting as a slave device. The configuration tool 505 can configure a sensor 506, 507 by initiating a communication link while acting as a master device with a reserved identification code that the sensors detect. Under normal operation the sensor monitors the master communications node of the asset management device, but can also detect the presence of the unique identification code of the configuration tool 505, and upon determining a tool is present could slave to the configuration tool 505. The configuration tool 505 could then configure the operational setting of each sensor 506, 507 and then release them to re-acquire the asset management device serving as the master communications node for that sensor network. Alternatively, a local stimulus to the sensor such as a switch or magnet activated relay switch could trigger the sensor 506 to engage configuration mode with the configuration tool 505.
Another object of an embodiment of the present invention is to provide for automated monitoring and configuration of asset management devices and sensors through the use of a gateway device 605 as depicted in
The gateway device 605 may be configured to locally monitor a region, such as a depot service yard, and to detect the presence of assets as they arrive in the yard. Upon such detection, the gateway device 605 can alter the configuration of any or all detected assets. Such configuration changes may be a change in reporting, internal functions such as motion detection, mapping, frequency, or any other operational function local to the asset management device 603. It may also instruct the asset management device 603 to enter a low power state, thus reducing the power utilization and data messaging to the data satellite network 602. The gateway device 605 may also instruct the asset management device 603 to engage a low power state while in the presence of the gateway communications link, and then automatically resume operation upon detection of removal from the gateway device 605. In this way, the asset management device 603 can engage a low power mode and then resume normal reporting functions when the asset management device is relocated away from the gateway device 605.
The gateway device 605 may be used in a stand alone operation for managing short-range transceiver equipped assets 603 within a local region. Alternatively, the gateway device 605 could include a long-range communications function 608 to enable remote communications between the gateway device 605 and a remote controller. A gateway device 605 equipped with a long-range communications means may be connected to a local network containing local controllers or other gateway devices. In such a way, the effective range of the short-range transceiver could be extended through the use of a multiplicity of gateway devices communicating over a local network in order to more effectively provide short-range transceiver capability over an expanded range of service. A local controller function also connected to the network could manage each gateway device 605 to properly manage the remote asset management devices 603, 604 and sensors 606, 607 within range of the collective gateway devices. This controller function could reside in either a stand alone controller, or in one or more of the gateway devices 605 themselves acting as a network master.
Similarly, the long-range communications interface 608 could interface to a distant network, interfacing the gateway device 605 to a distant controller or network of controllers. The long-range communications interface can be a dedicated hard-wired line, public or private telephone, Internet, long-range wireless such as cellular, RF data link, satellite, or other similar means. The gateway device 605 can be controlled by a distant controller monitoring and controlling the operations of the asset management devices 603, 604 in range of the gateway device 605. The distant controller can be an asset management device with an external interface in various embodiments of the present invention.
Another embodiment of the present invention provides for public or shared use of widely distributed gateway devices 705, each networked using the long-range communications means of each gateway device 705 in each gateway region 706, 707 over a long-range network 708 to a distant controller 709. In this embodiment, an asset manager could distribute posted commands for specific assets to a multiplicity of widely distributed gateway devices 705. Upon detection of the presence of the desired asset via the short-range transceiver link to any gateway device 705, the gateway device 705 can effect a change of configuration in the remote asset, and subsequently report the change to the central controller and asset manager. In such an embodiment, multiple asset managers could use the same network and same distributed gateway devices 705, accessing shared or unique sets of endpoint assets to gain widely distributed access to mobile assets. In such a way, gateway devices 705 widely distributed but networked using their intrinsic long-range communications means could act as a back-channel communications means not present in simplex communications. By intelligently selecting locations for networked gateway devices 705 such as truck stops, rail yards, interstate crossings, and high density asset nodes, the asset management device of the present invention becomes capable of receiving reconfiguration commands abroad for the majority of operating devices of a fleet.
Since each local network can operate with encryption, it is possible to use the gateway networks in a public manner. Gateway regions may be established and connected into a central network controller for use by a multiplicity of separate users or companies to collectively gain broader regional coverage than attainable using privately installed networks. Gateways 705 that are used in this manner can use the encryption keys tied to specific master identifications to access their own local master networks over any installed public gateway device 705.
For example, customers that install their gateway devices 705 to manage their own depot storage regions may connect to a public network accessible through a web-site over the Internet. Other companies similarly enrolling in the approach could add their gateway regions to the public network, such as interstate weigh stations and truck stops. Both companies may post commands at all connected gateway devices to perform specific functions for a unique master identification device upon detection. Once the local network master is in range of any of the public gateway devices, the gateway will use the customer supplied encryption key, secured by the network controller as private to the customer, and access the local network master to perform the specified function. In this way, the introduction of other gateway devices to the public network enables broader and broader control access to mobile asset management devices. The same architecture discussed as private using
As depicted in the embodiment of
Another embodiment of the present invention enables extensions of range for the short-range transceiver function through the use of repeat enabled gateway devices.
This capability provides utility for assets that are disadvantageously positioned, such as stacked or loaded in the holds of ships or strung in lines such as loaded on a train. The repeater capability allows for a gateway device 906 or devices to stay in positive communications contact with the distributed asset 903, 904 management devices. The protocol of the short-range transceiver function incorporates repeat level data to ensure that repeated messages eventually terminate and thus a repeater will not continue to repeat a repeated message. Similarly, multiple repeaters can be used to further extend the effective range and provide multiple paths for data flow to provide better network integrity.
In embodiments of the present invention, the addition of a wireless interface to the short-range transceiver of the asset management tool provides powerful enhancements to existing functions and enables new capabilities. In order for the short-range transceiver function to work properly, it is necessary for the power utilization to be minimized in order to preserve the service life of the battery operated endpoint asset management devices and sensors. An efficient and innovative protocol is implemented in the present invention that enables the functions described herein while minimally impacting the battery life of the asset management device. The protocol described below causes a degradation of the product life of a few months over 8 years of service and requires approximately 10 uA of average current draw on the primary battery.
Each local network is managed by a network master. The asset management device serves as the local network master in one embodiment of the present invention. Network slaves are devices that communicate only with the network master. Slave devices in the present invention are typically sensors, but can be asset management devices in various embodiments of the present invention. A key aspect in the present invention is that sensors are intelligent, performing the prescribed sensing function and using the network master most often as a communications conduit to the data system, which is a satellite system in one embodiment of the present invention. The network master predominately provides for the easy acquisition of slave devices.
To accomplish these goals, the network master as depicted in
LEADER: data term used by the receiving device (network slave) to detect a message start.
MASTER ID: data term specific and unique to a network master device. This is the electronic serial number (ESN) of the asset management device.
CONTROL REGISTER: contains a set of data terms used to manage the local network. The Network Master Idle Message Control Register 1202 is further described in
CNTRL/Type: a term denoting the device type acting as a network master.
CNTRL/Carton Manifest: a term denoting the network master holds a shipping carton data manifest in memory (used in product manufacturing packaging and shipping).
CNTRL/D: a term denoting the network master holds data in a local data store for collection by external network controller such as a repeater or gateway device.
RF Sequence Number: a term that enumerates the specific time window allocated to the Network Master Idle Message. The network master increments this sequence number between 0 to 31 and then repeats the sequence indefinitely. The range of sequence numbers is not critical to the operation of the method. 32 individual time slots can be used in one embodiment of the present invention to facilitate up to 32 different slave devices per network master. Each slave device may seize an available RF sequence number Time Division Multiple Access (TDMA) slot for responding to the master idle message and predominately use this slot for all communications to the network master. Optionally, a slave device may simply attempt to communicate on any channel time slot.
DITHER: a term that denotes the time period till next Network Master Idle Message. The messages generally occur periodically and are modified slightly with a randomization term to prevent adjacent network masters from locking and jamming each other.
ECRC: or checksum (CRC) term is a data validation term used to qualify the data integrity of the message for the receiver.
The network master repeatedly transmits the Network Master Idle Message, modifying the RF Sequence number. Following transmission of the message, the network master listens for any slave device to send a message as depicted on timeline expansion 1003. If no slave device message is detected, the network master resumes low power or sleep mode. The typical duty cycle for active versus inactive is 1:1000. The precise duty cycle is a tradeoff between response time for a slave device and battery live of the master device.
A slave device monitors the idle messages of the network master. When it needs to communicate to the master, it will respond in the time window immediately following the master idle message as shown in 1003. Optionally, in one embodiment of the present invention there is a subsequent acknowledgement from the master to the slave immediately following the slave response. If implemented, this acknowledgement confirms the message was received by the master device.
The network slave device transmits data to the network master using a Network Slave Response Message 1005 protocol. This message contains one or more of the following data terms:
LEADER: data term used by the receiving device (network master) to detect a message start.
MASTER ID: a repeat of the master ID received. This is the electronic serial number (ESN) of the master asset management device.
SLAVE ID: data term specific and unique to a network slave device. This is the electronic serial number (ESN) of the slave device.
CONTROL REGISTER: contains a set of data terms used to manage the local network. The Network Slave Response Message Control Register 1204 is further described in
CNTRL/TX: a term instructing the network master to relay the information in a subsequent transmission to the data satellite network or short-range transceiver interface. This term is set to no-transmit for supervisory and data log type messages.
CNTRL/DEV TYPE: a term denoting the device type acting as a network slave.
CNTRL/GPS: a term that instructs the network master to perform a GPS function, and/or pass payload verbatim, and/or then replace a specific field of data in the payload with location data prior to transmission or data store.
CNTRL/D: a term instructing the network master to store data for collection by an external network controller such as a repeater or gateway device.
RF Sequence Number: a term that enumerates the specific time window allocated to the Network Master Idle Message. The network master increments this sequence number between 0 to 31 and then repeats the sequence one or more times. The range of sequence numbers is not critical to the operation of the method. 32 individual time slots were chosen for the present embodiment to facilitate up to 32 different slave devices per network master. Each Slave device may seize an available RF sequence number Time Division Multiple Access (TDMA) slot for responding to the master idle message and predominately use this slot for all communications to the network master, or alternatively simply attempt communication on any time receive window of the master device. The method for timeslot selection can be established during Slave setup mode.
Payload: a term that contains sensor or remote slave data to be acted upon by the network master. The payload field is further defined for use in the asset management device to include specific sensor types, data logging functions, data relay, and location determination commands.
CRC: or Cyclic Redundancy Checksum (CRC) term is a data validation term used to qualify the data integrity of the message for the receiver.
Two types of slave devices are supported, bound or unbound. Additionally, a slave device can operate in one of three modes, acquire, track, and alarm. In acquire mode, the slave device listens for all Network Master Idle Messages observable.
If a bound sensor in acquire mode detects and decodes the message, it will confirm that the Master ID matches the master ID configured in the sensor, and thus the sensor has found the master it is logically bound with. If the Master ID does not match the configured term, it ignores the message and continues monitoring additional messages. Upon detection of the appropriate Network Master Idle Message, the slave will transmit to the network master with a Network Slave Response Message 1005 time coincident to the network master listen interval. The slave device can then transition from acquire mode to track mode. The network master may optionally be configured to engage a function upon determination of a lost sensor or slave device that fails to report in a specified period of time. For example, the network master may send a data message to the satellite data network notifying the detection of a lost sensor. This enables a security notification for a locally disabled sensor such as a door switch.
In track mode, the sensor will resume a low power state coincident with the master low power state and awaken each master sync message to track and stay in sync with the network master. The slave need not transmit each wake interval, but merely track to follow the randomized Dither parameters. If the slave misses a sync message, it merely resumes acquire mode. The slave will periodically transmit a supervisory message to the network master to keep the master from timing out and transmitting a lost sensor message, if the function is enabled.
If a sensor determines it is time to perform the designed function, such as detection of an door open, a temperature alarm, or a wired input alarm, the sensor will engage alarm mode. In this mode the sensor will initiate a Network Slave Response Message on the next TDMA window coincident with the RF Sequence number detected when the unit engaged tracking mode, or alternatively simply transmit in the receive time window following any master idle message.
An unbound sensor operates as a bound sensor except that it will engage any network master available, ignoring the Master ID field match that the bound sensor performs. Unbound sensors operate as slave devices that can relay sensor data through any conduit available, generally with the purpose of relaying to the satellite data network the sensor data independent of the asset management device used. Examples of use for unbound sensors include cargo tags, security switches, industrial data sensors etc. In each of these cases, the sensor data itself is the valuable item, and the asset management device used to relay this data is relatively unimportant. The data may be relayed to the satellite data network or a local recipient via the short-range transceiver interface. Additionally, the data may be logged to local data storage 311 of the asset management device.
A sensor may remain in track mode until it is time to perform a transmit function and then wait until the desired RF Sequence number occurs, or it may remain totally dormant, then engage acquire mode to initiate a data transmission. If a sensor is logging or monitoring data or is monitored by the system for a lost sensor, it is usually configured to remain in track mode, generating periodic supervisory messages to the network master. If a sensor is very infrequently used, it is probably dormant, and will acquire only upon sensor event. In this case the acquisition cycle would appear as depicted in the embodiment of
When the sensor event occurs coincident to 1103 in the diagram, the sensor engages listen mode waiting to hear the next master idle message 1101 with an embedded RF sequence number (4 in the case of the diagram). Decoding the transmitted master idle message, the sensor may notice another sensor transmitting in the slot or simply not successfully complete the communication link through active acknowledgement on the Slave Response fail. The sensor may reschedule a second attempt, noting the DITHER term, denoting the next event window and resuming low power mode to awaken at the end of the sleep interval. On waking, the sensor may again fail to finish the communication exchange as depicted, and again reschedule for the next time window. The sensor would continue this process until it successfully communicates 1104 with the network master with the successful slave response message 1105.
A similar approach is used for sensors that are experiencing difficulty in reliably communicating as determined by a CRC test. The sensor would simply track to the next available slot and operate within that TDMA sequence number slot. In this way, high densities of sensors and masters will dynamically adjust to operate correctly, with the network master merely monitoring and collecting data. The network master sets up the structure for sensors to adjust and collects data from any TDMA slot without priority or weight of position. This pushes down the network management to sensors that are equipped with a mechanism to automatically adjust and acquire communication channels of the master.
Data security remains a concern over any communication link, especially wireless links. The short-range transceiver interface can incorporate three levels of encryption in the master idle messages 1004 and the network slave response messages 1005. The encryption is designed to allow for friendly (owner devices) and foreign (other party's devices) cooperation without enabling misuse of the communication link.
The lowest level of encryption is disabled. Disabled encryption allows for any person to observe, configure, or copy the communication of a given local network. A network operating without encryption allows for any sensor to operate over any network manager in bound or unbound modes.
The next level of encryption is moderate. Moderate encryption, as depicted in 1004, uses an encryption key that scrambles the data following the leader. The encryption key is generally provided to a given user of the network hardware. All master and slave devices will use the same key allowing all devices of a given user (friendly) to operate together and ignore any other similar devices (foreign) of another party. This prevents unbound sensors of a user from using a foreign master to relay data over the data satellite network (and also the battery usage associated with the master function). Moderate encryption allows for the detection of communication in a local region but not the interpretation of the communication. The CRC checksum could be redundantly encrypted (ECRC) as shown in 1004 or un-encrypted (CRC) as shown in 1005.
The last level of encryption is high. High encryption scrambles all the data of the message including the leader. As with moderate encryption, only friendly devices have access to the communication network. But unlike moderate encryption, high encryption mode makes it impossible for a foreign observer to detect or intercept communications in a local region. Without the encryption key, the operation of the network is undetectable.
The short-range transceiver interface as described above is also suitable for use with other slave devices such as configuration tools, data logging interfaces, gateway, and repeater devices. Configuration tools can initiate a communication link with a master device by connecting as a slave device and then passing a payload command that engages configuration mode. Similarly, configuration tools can initiate a communication link with a slave device by connecting as a master device with a pre-defined master ID of a configuration tool. Slave devices within range of the configuration tool would receive the configuration master idle message and abort following any previously bound network master and rebind to the configuration tool. The tool then communicates the desired configuration changes and releases the slave to resume operation with the specified network master.
Gateway devices can similarly connect to master and slave devices within range of the short-range transceiver link. The embodiment of
Operating as slave devices, a gateway device can link to any network master and effect configuration changes and pass and collect data. Operating as a network master, the gateway device can connect to a slave device and effect configuration changes and pass and collect data.
A repeater is a gateway device that connects to a local network master to relay data from that network to a nearby gateway using a short-range transceiver interface. Time line 1303 represents the operation of a repeater in collecting data from a local network master. The repeater device monitors the master idle messages 1308 and notes the presence of the CNTRL/S flag 1309 indicating the master is holding data that can be collected. The repeater device then delays a randomized time interval 1310 and initiates a dialog with the network master by issuing a slave response message 1311 with the Type field of the Control Register denoting Transparent Modem. The network master and repeater device engage a point-to-point communications link 1312 where the gateway retrieves the held information, clearing the CNTRL/S flag of the network master. The network master resumes sending periodic idle messages 1313 with the CNTRL/S flag cleared.
The repeater then changes modes and becomes a new local network master 1314, transmitting the Idle message with a CNTRL/S flag set. The repeaters also incorporate use of the Repeat Level term to either bit-mask by installed repeater instance or by incrementing count to ensure the message will not be repeated indefinitely. Subsequent repeaters or gateways, can pull the data from the repeater operating as a master. In this way, slave response messages stored in a local network masters may propagate through repeaters to distant gateway devices for collection.
A gateway monitors all network masters 1304, including the repeater operating in slave mode. Upon the detection of a CNTRL/S bit in either a network master or a repeater 1314, the gateway will delay a random time interval 1315 before responding with a slave response message 1316 to engage transparent modem mode and retrieve the data 1317. Once the data has been retrieved from a repeater, it will resume slave mode 1319, again searching for data to retrieve.
Similarly, a local network master may perform the logical functions of a repeater by alternating as a master and a slave to another nearby master. In this mode of operation, a group of network masters may collectively network to build a bridge for local sensor and other master data to hand off data to a regionally configured gateway or fixed repeater.
In yet another embodiment of the present invention, a local device may incorporate both master and slave operation to serve as a local repeater to extend the range of a sensor to a local master. This type of a device has value for sensors that are disadvantageously placed relative to the monitoring master, such as sensors inside metal containers with the associated master outside the container. A single local repeater can penetrate the metal enclosure using a master node on the inside to monitor sensors inside the container, and using a slave node on the outside that communicates to the local asset management master device. The local repeater simply incorporates both communication methods to monitor the slaves that would otherwise not be operable to the local network master. In this case, the local repeater may use a unique identification or it could simply mimic the identification of the local master to the slaves.
The local network master may be configured to redundantly store to local data storage any transmitted data satellite message, setting the CNTRL/S term. In this way, messages that may be dropped by the simplex satellite network are augmented through gateway devices, often later as the device comes within range of a gateway or repeater. The data through the gateway may be collected using a long-range communication link and merged with data collected from the data satellite system to create a more complete set of data.
Similarly, gateways, repeaters, or configuration tools could monitor the CNTRL/M and/or CNTRL/U flags to detect and retrieve data created by the asset management device itself or remote users who uploaded data for storage. A logistics manager may seal a container with an asset management device affixed, then upload user data to storage data for later retrieval at container destination. The destination manager could monitor the idle message of the local master and detect it by using the CNTRL/U flag if user data exists for extraction and review.
Repeaters can retrieve data from a local network master upon detection of a CNTRL/S flag after a random delay of several Idle message cycle intervals. This delay allows a time window where any local gateway will have ample opportunity to be the first to retrieve data directly from a network master. The repeater can randomize the Idle Sequence TDMA slot to minimize the probability that multiple repeaters will attempt to retrieve data from a local network master at the same Idle Sequence TDMA interval. The delays in retrieving the data from a local network master are relatively small compared to the standard time to resolve a GPS location determination. Gateway devices differ from repeaters in that they contain computation controllers, typically microprocessor based and custom algorithms and software to perform a variety of functions.
The ability of embodiments of the present invention to establish private or public networks to control battery powered remote simplex asset management devices is unique. Other two-way type devices do not incorporate a wireless architecture that will support battery operation, let alone provide for the additional capability of supporting wireless sensors. The present invention discussed herein provides utility in container security, rail, marine, fixed and mobile security, trailer tracking and more on a global scale, operable using batteries for years of service.
Many of the algorithmic operations and functions described herein may be implemented using a conventional general purpose computer or microprocessor programmed according to the teachings of the present invention, as will be apparent to those skilled in the art. Appropriate software can readily be prepared by programmers of ordinary skill based on the teachings of the present disclosure as will be apparent to those skilled in the art.
A general-purpose computer may be used to implement the method of the present invention, wherein the computer housing houses a motherboard which contains a CPU, memory (e.g., DRAM, ROM, EPROM, EEPROM, SRAM, SDRAM, and Flash RAM), and other optional special purpose logic devices (e.g., ASICS) or configurable logic devices (e.g., GAL and reprogrammable FPGA). The computer also includes plural input devices, (e.g., keyboard and mouse), and a display card for controlling a monitor. Additionally, the computer may include a floppy disk drive; other removable media devices (e.g. compact disc, tape, and removable magneto optical media); and a hard disk or other fixed high density media drives, connected using an appropriate device bus (e.g., a SCSI bus, an Enhanced IDE bus, or an Ultra DMA bus). The computer may also include a compact disc reader, a compact disc reader/writer unit, or a compact disc jukebox, which may be connected to the same device bus or to another device bus.
As stated above, the system includes at least one computer readable medium.
Examples of computer readable media are compact discs, hard disks, floppy disks, tape, magneto optical disks, PROMs (e.g., EPROM, EEPROM, Flash EPROM), DRAM, SRAM, SDRAM, etc. Stored on any one or on a combination of computer readable media, the present invention includes software for controlling both the hardware of the computer and for enabling the computer to interact with a human user. Such software may include, but is not limited to, device drivers, operating systems and user applications, such as development tools. Computer program products of the present invention include any computer readable medium which stores computer program instructions (e.g., computer code devices) which when executed by a computer causes the computer to perform the method of the present invention. The computer code devices of the present invention can be any interpretable or executable code mechanism, including but not limited to, scripts, interpreters, dynamic link libraries, Java classes, and complete executable programs. Moreover, parts of the processing of the present invention may be distributed (e.g., between (1) multiple CPUs or (2) at least one CPU and at least one configurable logic device) for better performance, reliability, and/or cost.
The invention may also be implemented by the preparation of application specific integrated circuits or by interconnecting an appropriate network of conventional component circuits, as will be readily apparent to those skilled in the art. Numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.
This application is a continuation-in-part of U.S. application Ser. No. 10/656,133, filed on Sep. 8, 2003, which is herein incorporated by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 11480793 | Jul 2006 | US |
| Child | 12962848 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 10656133 | Sep 2003 | US |
| Child | 11480793 | US |
