Method and system for movement state detection of a sensor device

Abstract

A method at a sensor device, the method comprising: calculating a value of an objective function based on at least one sensor of the sensor device; determining that the value of the objective function is within a defined threshold range for a defined period of time, thereby finding an in-flight state for the sensor device; and shutting down transmission of a radio from the sensor device based on the in-flight state.

Description

[0001] Divisional application

[0002] This application is a divisional application of Chinese patent application No. 201980024657.2, filed on April 9, 2019, entitled "Method and System for Detecting the Motion State of a Sensor Device". Technical Field

[0003] This disclosure relates to the transport of goods, and more particularly to sensor devices for the transport of goods. Background Technology

[0004] During cargo transportation, sensor devices can be attached to shipping containers. Such containers may include vehicles, shipping containers, cargo boxes, airline containers, consumer baggage, and other options. Sensor devices can be used for fleet management, cargo monitoring, cargo status detection, and other purposes.

[0005] The sensor device can be equipped with a variety of sensors or be able to communicate with a variety of sensors. Examples of such sensors may include, but are not limited to, position sensors such as Global Navigation Satellite System (GNSS) sensors, accelerometers, gyroscopes, temperature sensors, light sensors, door opening sensors, Automatic Dependent Surveillance-Broadcast (ADS-B) receivers, and other options. A communication system on the sensor device can allow sensor data to be transmitted from the sensor device to a network-based server.

[0006] However, if the container was intended for air transport, it is important that the sensor devices know when the container is in the air so that communication functions on the sensor devices can be turned off. In particular, the U.S. Federal Aviation Administration (FAA) has regulations prohibiting the operation of communication equipment while an aircraft is in flight. Similar regulations exist in other jurisdictions. Attached Figure Description

[0007] This disclosure will be better understood with reference to the accompanying drawings, in which:

[0008] Figure 1 This is a block diagram illustrating an example sensor device;

[0009] Figure 2 It is shown that it is used for Figure 1 A block diagram illustrating an example environment for the operation of the sensor device;

[0010] Figure 3 It is a state diagram of the sensor device and the transitions between states;

[0011] Figure 4 This is a diagram illustrating the transition from a stopped state.

[0012] Figure 5 is a process graph from a flying state transition;

[0013] Figure 6 is a process graph from a ground moving state transition;

[0014] Figure 7 is a plot of the objective function value when using ground transportation to transport a shipping container associated with a sensor device;

[0015] Figure 8 is a plot of the objective function value when transporting a shipping container associated with a sensor device in flight; and

[0016] Figure 9 is a block diagram of an example computing device that can be used in accordance with embodiments of the present disclosure. DETAILED DESCRIPTION

[0017] The present disclosure provides a method at a sensor device, the method comprising: calculating a value of an objective function based on at least one sensor of the sensor device; determining that the value of the objective function is within a defined threshold range for a defined period of time, thereby discovering an in-flight state for the sensor device; and shutting down transmission of a radio from the sensor device based on the in-flight state.

[0018] The present disclosure also provides a sensor device comprising: a processor; and a communication subsystem, wherein the sensor device is configured to: calculate a value of an objective function based on at least one sensor of the sensor device; determine that the value of the objective function is within a defined threshold range for a defined period of time, thereby discovering an in-flight state for the sensor device; and shut down transmission of a radio at the communication subsystem from the sensor device based on the in-flight state.

[0019] The present disclosure also provides a computer readable medium for storing instruction code that, when executed by a processor on a sensor device, causes the sensor device to: calculate a value of an objective function based on at least one sensor of the sensor device; determine that the value of the objective function is within a defined threshold range for a defined period of time, thereby discovering an in-flight state for the sensor device; and shut down transmission of a radio at a communication subsystem from the sensor device based on the in-flight state.

[0020] In the transportation of shipping containers, it is important to determine when a trailer or cargo box is in flight, as under certain conditions, radio transmissions from sensor devices need to be turned off due to FAA regulations or other similar regulations. Existing devices do not provide an accurate estimation of the in-flight state, and it is also difficult to distinguish between the in-flight state and the general moving state. For example, it is difficult to determine whether a sensor device is in flight or moving on a highway. For example, even relying on altitude can not be sufficient to determine whether a container is in flight based on location.

[0021] Accordingly, according to embodiments described below, an algorithm is provided that will detect the in-flight state based on generally available sensor data, such as measurement data from an accelerometer and, in some embodiments, measurement data from a gyroscope sensor.

[0022] For various reasons, sensor systems can be included on vehicles or shipping containers. For example, multiple sensor devices can operate remotely from a central monitoring station to provide remote sensor data to a management or monitoring hub. One sensor system involves a fleet management or cargo management system. In a fleet management or cargo management system, sensors can be placed on trailers, shipping containers, or similar products to provide information about the container to a central station. Such information can include, but is not limited to, the current location of the trailer or shipping container, the temperature inside the shipping container or trailer, operational parameters such as tire pressure, noise level, or engine temperature, the closing of a door on the shipping container or trailer, whether a sudden acceleration or deceleration event occurred, the angle of tilt of the trailer or shipping container, and other data.

[0023] In other embodiments, the sensor device can be affixed to the vehicle itself. As used herein, the term vehicle can include any motorized vehicle, such as a truck, tractor, car, boat, motorcycle, snowmobile, aircraft (such as an airplane, helicopter, dirigible, blimp, etc.), and can further include a trailer, shipping container, or other such cargo moving container, whether or not attached to a motorized vehicle.

[0024] In other embodiments, the sensor device can be affixed to a container for moving an item, such as a shipping box, package, luggage, and other options.

[0025] According to embodiments described herein, the sensor device can be any device or computing apparatus capable of providing data or information from a sensor associated with the sensor device to a central monitoring or control station. The sensor associated with the sensor device can be a physical part of the sensor device, such as a built-in global positioning system (GPS) chipset, or can be associated with the sensor device through short-range wired or wireless communication. For example, the sensor can be a Bluetooth® sensor that communicates with the sensor device through Bluetooth® communication from the sensor to the sensor device. TMLow energy (BLE) signals provide information to the sensor device. In other cases, a camera can be part of the sensor device or can communicate with the sensor device through wired or wireless technology. Other examples of sensors are possible.

[0026] The central monitoring station can be any server or combination of servers remote from the sensor device. The central monitoring station can receive data from multiple sensor devices.

[0027] With respect to Figure 1 A sensor device is shown. However, Figure 1 The sensor device of FIG. 1 is merely an example, and other mobile devices can be used equally well in accordance with embodiments of the present disclosure.

[0028] Reference is now made to Figure 1 which shows an example sensor device 110. The sensor device 110 can be any computing device or network node. Such computing devices or network nodes can include any type of electronic device including, but not limited to, mobile devices such as a smart phone or cellular phone. Examples can also include stationary or mobile devices such as an Internet of Things device, an endpoint, a home automation device, a medical device in a hospital or home environment, an inventory tracking device, an environmental monitoring device, an energy management device, an infrastructure management device, a vehicle or device for a vehicle, a stationary electronic device, and the like.

[0029] The sensor device 110 includes a processor 120 and at least one communication subsystem 130, where the processor 120 and the communication subsystem 130 cooperate to perform the methods of the embodiments described herein. In some embodiments, the communication subsystem 130 can include multiple subsystems, e.g., for different radio technologies.

[0030] The communication subsystem 130 allows the sensor device 110 to communicate with other devices or network elements. The communication subsystem 130 can use one or more of a variety of communication types, including but not limited to cellular, satellite, Bluetooth TM , Bluetooth TM Low Energy, Wi-Fi, Wireless Local Area Network (WLAN), ADS-B, Near Field Communication (NFC), ZigBee, wired connections such as Ethernet or fiber optic, and other options.

[0031] As such, the communication subsystem 130 for wireless communication typically has one or more receivers and transmitters, as well as related components such as one or more antenna elements, local oscillators (LOs), and can include a processing module such as a digital signal processor (DSP). As will be apparent to those of skill in the art of communications, the specific design of the communication subsystem 130 will be dependent on the communication network or communication technology over which the sensor device is to operate.

[0032] If the communication subsystem 130 operates through a cellular connection, a subscriber identity module (SIM) 132 can be provided to allow such communication. The SIM 132 can be a physical card or can be virtual. In some embodiments, the SIM 132 can also be referred to as a universal subscriber identity module (USIM), as an identity module (IM) only, or as an embedded universal integrated circuit card (eUICC), among other options.

[0033] The processor 120 generally controls the overall operation of the sensor device 110 and is configured to execute programmable logic, which can be stored with data using the memory 140. The memory 140 can be any tangible, non-transitory computer-readable storage medium, including but not limited to optical (e.g., CD, DVD, etc.), magnetic (e.g., tape), flash drive, hard drive, or other memory known in the art.

[0034] Alternatively, or in addition to the memory 140, the sensor device 110 can access data or programmable logic from an external storage medium, such as through the communication subsystem 130.

[0035] In Figure 1 embodiments, the sensor device 110 can utilize multiple sensors, which in some embodiments can be part of the sensor device 110 or in other embodiments can be in communication with the sensor device 110. For internal sensors, the processor 120 can receive input from the sensor subsystem 150.

[0036] Figure 1 Examples of sensors in embodiments of the sensor device 110 include a positioning sensor 151, a vibration sensor 152, a temperature sensor 153, one or more image sensors 154, an accelerometer 155, a light sensor 156, a gyroscope sensor 157, and other sensors 158. Other sensors can be any sensor capable of reading or obtaining data that can be useful to the sensor device 110. In other cases, the sensors can be external to the sensor device 110 and communicate with the sensor device using the communication subsystem 130. One such sensor is shown as sensor 160.

[0037] However, Figure 1 the sensors shown in embodiments of the sensor device 110 are examples only, and in other embodiments different sensors or a subset of the sensors shown in FIG. 1 can be used. For example, in one embodiment of the present disclosure, only an accelerometer or gyroscope sensor is provided. Figure 1

[0038] ​Positioning sensors may use positioning subsystems such as Global Navigation Satellite System (GNSS) receivers, which may be, for example, Global Positioning System (GPS) receivers (e.g., in the form of chips or chipsets) for receiving GPS radio signals transmitted from orbiting GPS satellites. The reference to “GPS” here is intended to include both assisted GPS and GPS-assisted systems. Although this disclosure explicitly refers to “Global Positioning System,” it should be understood that the term and its abbreviation “GPS” are broadly used to include any GNSS or satellite-based navigation signal broadcasting system, and therefore will include other systems used worldwide, including the BeiDou (COMPASS) system developed by China, the multinational Galileo system developed by the European Union in cooperation with China, Israel, India, Morocco, Saudi Arabia, and South Korea, Russia’s GLONASS system, India’s proposed Regional Navigation Satellite System (IRNSS), and Japan’s proposed QZSS regional system.

[0039] Alternatively, another positioning subsystem can be used, such as a radio positioning subsystem that uses radio positioning technology to determine its current location. In other words, the location of a device can be determined using triangulation of signals from base stations within range (e.g., for Wireless E911). Wireless Enhanced 911 service enables the geographic location of mobile phones or other wireless devices using radio positioning technologies such as (i) Angle of Arrival (AOA), which requires locating the caller at the point where signals from two towers intersect; (ii) Time Difference of Arrival (TDOA), which uses multipoint positioning similar to GPS, except that the network determines the time difference and thus the distance to each tower; and (iii) Location Signature, which uses a “fingerprint” to store and recall patterns (e.g., multipath) exhibited by mobile phone signals at different locations within each cell. Wi-Fi TM The Positioning System (WPS) can also be used as a positioning subsystem. Radio positioning technology, WPS, and / or ADS-B can also be used in conjunction with GPS in a hybrid positioning system.

[0040] Furthermore, in some embodiments... Figure 1 The sensor device 110 can act as a gateway and can communicate with other sensor devices (not shown) on the trailer, wherein the other sensor devices can act as a hub for a subset of sensors for the vehicle or trailer.

[0041] In one embodiment, communication between the various components of the sensor device 110 can be achieved via an internal bus 170. However, other forms of communication are also possible.

[0042] The sensor device 110 can be affixed to any stationary or portable platform. For example, in one embodiment, the sensor device 110 can be affixed to a shipping container, a truck trailer, a truck cab. In other embodiments, the sensor device 110 can be affixed to any vehicle, including motor vehicles (e.g., automobiles, cars, trucks, buses, motorcycles, etc.), aircraft (e.g., airplanes, unmanned aerial vehicles, unmanned aerial systems, drones, helicopters, etc.), spacecraft (e.g., spaceplanes, space shuttles, space capsules, space stations, satellites, etc.), watercraft (e.g., ships, boats, hovercraft, submarines, etc.), rail vehicles (e.g., trains and trolleys, etc.), and other types of vehicles including any combination of any of the foregoing vehicles, whether currently existing or later created, etc.

[0043] In other examples, the sensor device 110 can be carried by a user.

[0044] Such a sensor device 110 can be a power-limited device. For example, in some embodiments, the sensor device 110 can be a battery-operated device that can be affixed to a shipping container or trailer. Other limited power sources can include any limited power supply, such as a small or direct current generator, a fuel cell, a solar power source, and other options.

[0045] In other embodiments, the sensor device 110 can utilize external power, such as from an engine of a towing vehicle of a towed trailer, from a terrestrial power source such as a plug-in to an entertainment vehicle or from a building power supply, and other options.

[0046] The external power can further allow for recharging of a battery to allow the sensor device 110 to then again operate in a power-limited mode. Recharging methods can also include other power sources, such as but not limited to solar, electromagnetic, acoustic, or vibrational charging.

[0047] Figure 1 The sensor device of the present disclosure can be used in a variety of environments. With respect to Figure 2 One example environment in which the sensor device can be used is shown.

[0048] Referring to Figure 2 , three sensor devices are provided, namely sensor device 210, sensor device 212, and sensor device 214.

[0049] In Figure 2In the example of FIG. 2, sensor device 210 can communicate through cellular base station 220 or through access point 222. Access point 222 can be any wireless communication access point. For example, access point 222 can be a WiFi router or a private router network. Further, the private router network can have a path from an access point name (APN) to a server and in some embodiments can reduce network latency based on the location of the sensor device.

[0050] Further, in some embodiments, sensor device 210 can communicate through a wired access point such as Ethernet or fiber optic.

[0051] Communication can then be over a wide area network such as the Internet 230 and to a server 240 or 242.

[0052] Similarly, sensor device 212 and sensor device 214 can communicate with server 240 or server 242 through one or both of base station 220 or access point 222 and other options for such communication.

[0053] In other embodiments, any of sensors 210, 212, or 214 can communicate through satellite communication technology. This can be useful, for example, if the sensor device is traveling to an area outside of cellular coverage or access point coverage.

[0054] In other embodiments, sensor device 212 can be out of range of access point 222 and can communicate with sensor device 210 to allow sensor device 210 to act as a relay for communication.

[0055] Communication between sensor device 210 and server 240 can be one-way or two-way. Thus, in one embodiment, sensor device 210 can provide information to server 240 but server 240 does not respond. In other cases, server 240 can issue commands to sensor device 210 but data can be stored internally on sensor device 210 until the sensor device reaches a particular location. In other cases, there can be two-way communication between sensor device 210 and server 240.

[0056] In the description herein, server, central server, processing service, endpoint, uniform resource identifier (URI), uniform resource locator (URL), backend, and / or processing system can be used interchangeably. Server functionality generally represents data processing / reporting that is not closely tied to the location of mobile image capture devices 210, 212, 214, etc. For example, a server can be located substantially anywhere so long as the server has network access to communicate with image capture devices 210, 212, 214, etc.

[0057] The server 240 may, for example, be a fleet management centralized monitoring station. In this case, the server 240 can receive information from sensor devices associated with various trailers or cargo containers, providing information such as the location of such cargo containers, the temperature within such cargo containers, system information such as pressure or vibration sensor readings, any abnormal events including sudden deceleration, temperature warnings when the temperature is too high or too low, and other data. The server 240 can compile such information and store it for future reference. The server can further alert an operator. For example, the entry of a vehicle into a restricted geofenced area can provide a warning to the operator.

[0058] Other examples of the functionality of the server 240 are possible.

[0059] In Figure 2 embodiments, the servers 240 and 242 can further access third party information or information from other servers within the network. For example, a data service provider 250 can provide information to the server 240. Similarly, a data repository or database 260 can also provide information to the server 240.

[0060] For example, the data service provider 250 can be a subscription-based service used by the server 240 to obtain current weather conditions.

[0061] The data repository or database 260 may, for example, provide information such as image data associated with a particular location, aerial maps, low latency access point names, virtual SIM information, or other such information.

[0062] The type of information provided by the data service provider 250 or the data repository or database 260 is not limited to the examples described above, and the information provided can be any data useful to the server 240.

[0063] In some embodiments, information from the data service provider 250 or from the data repository of the database 260 can be provided to one or more of the sensor devices 210, 212, or 214 for processing at those sensor devices.

[0064] With the system described above Figure 1 and Figure 2 a cargo monitoring system is enabled. However, as described above, due to FAA regulations or other similar regulations, the sensor device can need to be shut down for wireless transmission for communication when the container or cargo box associated with the sensor device is in flight. Further, the communication functionality should be restored when the container or cargo box is back on the ground or below a certain altitude.

[0065] According to embodiments described below, in one alternative, the sensor device will have access to an accelerometer providing an output. For example, in one case, the sensor device will have access to three accelerometers, one for each of the x, y, and z directions. It is assumed that the signals provided by the accelerometers are always available. Furthermore, in some embodiments below, the sensor device will have access to output from three gyro sensors, one for each of the x, y, and z directions.

[0066] According to a first embodiment of the present disclosure, the sensor device and the cargo box or container associated with the sensor device can be in one of three states. Specifically, referring now to Figure 3 As can be seen in the embodiment of Figure 3 , the sensor device can be in a stopped state 310. In the stopped state, the cargo box or container with the sensor device is stationary. For example, this can be a state in which the cargo box or container is waiting to be loaded onto a vehicle such as a truck or an airplane. It can further include the period in which the airplane is waiting on the runway to taxi or take off. It can further include other cases in which the cargo box or container is stored for shipment, for example in a truck yard or a warehouse. Other examples are possible.

[0067] The sensor device can further be in a flying state 312. The flying state 312 is when the cargo box or container and the associated sensor device are on a flying airplane or aircraft.

[0068] The sensor device can further be in a moving on the ground state 314. The moving on the ground state can include moving in a truck, on a ship, when the airplane is taxiing, and other options, but not moving in a flying airplane or aircraft.

[0069] From the embodiment of Figure 3 , the cargo box or container with the sensor device can start, for example, in state 310. Possible transitions from state 310 include staying in state 310 or transitioning to state 312 or state 314. Transition conditions for transitioning to these states are described below.

[0070] Similarly, from state 312, the sensor device can stay in state 312, or transition to state 310.

[0071] From state 314, the sensor device can stay in state 314 or can transition to state 310. Generally, a transition from state 314 directly to state 312 will not be possible. However, in Figure 3In one embodiment, a state transition from state 314 to state 312 is provided to allow for a rapid transition between state 314 and state 312 in the event that the sensor device is mistakenly detected to be in state 314 when it should be in state 312.

[0072] For example, such state transitions are shown in Table 1 below, which shows the "x" for possible state transitions.

[0073]

[0074] Table 1: State Transitions

[0075] Therefore, as shown in Table 1 above, according to Figure 3 In the state diagram, the state transition from state 312 to state 314 is impossible.

[0076] based on Figure 3 Based on Table 1 above, several observations can be made. First, if the sensor device is in state 312, then for the next state, the sensor device only needs to check whether the state has not changed or whether the state has changed to stop state 310. It is not necessary to check whether the sensor device has changed from state 312 to state 314.

[0077] The second observation is that when the sensor device is in state 312, it is not necessary to check this state at every subsequent sampling time. Instead, detection can be stopped and then resumed after a certain skipped duration.

[0078] The third observation is that if the sensor device is in state 314, which is used for moving ground vehicles, it is necessary to check whether the state has not changed, whether the state has changed to a stopped state 310, or whether the state has changed to a flying state 312. Whenever the sensor device is in state 314, the detection should be performed at each sampling time.

[0079] The fourth observation is that when the sensor device is in state 310, it is necessary to check whether the state has not changed, whether it has changed to state 312 for a moving aircraft, or whether it has changed to state 314 for a moving truck or ground vehicle. Whenever the sensor device is in state 310, a check should be performed at each sampling time.

[0080] In an alternative approach, the state transition can be determined based on a defined objective function f(k). The objective function f(k) is based on at least one accelerometer or gyroscope calculated at each sampling time k.

[0081] In one example, the objective function f(k) is the sum of the moving variances (MV) of the three accelerometers mvACCE(k). This sum is shown in Equation 1 below.

[0082]

[0083] In Equation 1 above, i is equal to 1, 2 and 3 in the x, y and z directions, respectively.

[0084] In another example, f(k) is the weighted sum of the movement variances of the three accelerometers.

[0085] This is as shown in Equation 2 below.

[0086]

[0087] In Equation 2 above, α(i) is a weighting factor for each of the three accelerometer outputs. Different weights can be assigned to the three accelerometer outputs corresponding to the x, y, and z directions, respectively. For example, a larger weight can be given to the x or z direction.

[0088] In yet another embodiment, the objective function f(k) can be the sum of the second differences of the movement variances of the three accelerometers.

[0089] Other examples of the objective function are possible. In this disclosure, the objective function of Equation 1 will be used for illustrative purposes. However, this disclosure is not limited to the use of the objective function of Equation 1.

[0090] In some embodiments described below, the movement variance mvGYRO(k) of three gyroscope sensors may also be used. However, using this movement variance from the gyroscope sensors is optional because the output signals from the gyroscope sensors may not always be available. For example, the gyroscope sensors may only be turned on for a short duration when necessary, and in this case, the movement variance from the gyroscope sensors may only be available when such gyroscope sensors are turned on.

[0091] Starting from state 310

[0092] In the first embodiment, the movement threshold from Equation 1 above can be utilized. At this point, the vehicle can start in state 310 and make a decision regarding the transition.

[0093] In the initial state 310 when the vehicle stops, for time index k, where k is greater than zero, perform the following operation.

[0094] Especially now, for reference Figure 4 It illustrates the process when the sensor device is in a stopped state. Figure 4 The process begins at box 410 and proceeds to box 412, where the value of the objective function f(k) is calculated for the current k.

[0095] Then, the process proceeds to block 420, where a check is made to determine if the calculated value of the objective function from block 412 is less than a first threshold value, denoted as threshold 1. If so, the process then proceeds to block 422, where the state remains in the stopped state.

[0096] The process proceeds from block 422 to block 424, where the value of k is incremented to the next sampling time by setting k = k + 1. The process proceeds from block 424 to block 430 and ends.

[0097] In contrast, from block 412, if the value of the objective function is greater than the first threshold value, the process proceeds to block 440, where a check is made to determine if the value of the objective function is also greater than a second threshold value, denoted as threshold 2, where threshold 2 > threshold 1.

[0098] From block 440, if the value of the objective function is greater than the second threshold value, the process proceeds to block 442, where the state is changed to the ground movement state 314 in the sensor device. Figure 3 The process then proceeds to block 424, where the next detection time period is incremented by one to indicate that a check is made at each sampling period in the ground movement state. The process then proceeds to block 430 and ends.

[0099] In contrast, from block 440, if the value of the objective function is not greater than the second threshold value, this indicates that the value of the objective function is between the first and second threshold values. The process then proceeds to block 450.

[0100] At block 450, a check is made to determine if the value of the objective function falls between the two threshold values continuously and consistently over an extended period of time. In particular, the check is made according to equation 3.

[0101] threshold1 < f(k + i) < threshold2 (3)

[0102] where i in equation 3 is a duration from 1 to n1, where n1 is a positive integer corresponding to a predetermined duration td1.

[0103] From block 450, if the value of the objective function is not between the two threshold values over the extended duration, the process proceeds to block 452. At block 452, the process remains in the stopped state. The process then proceeds to block 424, where the sampling time interval is set to the next sampling time. In particular, as shown at block 424, k = k + 1. The process proceeds from block 424 to block 430 and ends.

[0104] In contrast, if the value of the objective function is between the two threshold values over the extended duration, in one embodiment, the state of the sensor device is changed to the ground movement state 314 described above.Figure 3 The next sampling instant is then set as k = k + n3.

[0105] Optionally, in another embodiment, if the value of the objective function is between the two thresholds for an extended duration, the process proceeds from block 450 to block 454. At block 454, the gyro sensor on the sensor device is turned on to start computing the moving variance of the gyro sensor, denoted as mvGYRO.

[0106] In particular, at block 454, the value of the moving variance of the gyro sensor over an extended period of time, mvGYRO(k+i), is computed. In this case, i is a number from 1 to n2, and n2 is a positive integer corresponding to the predetermined duration td2.

[0107] The process proceeds from block 454 to block 460, where a check is made to determine if the value of the moving variance of the gyro sensor over an extended duration is less than or equal to a third threshold, denoted as threshold3.

[0108] If the value of the moving variance of the gyro over an extended duration is less than or equal to the third threshold, the process proceeds from block 460 to block 462, where the state of the sensor device is changed to the flying state 312 in Figure 3

[0109] The process proceeds from block 462 to block 464, where the sampling can change from every period to a duration of n3. Thus, at block 464, the next sampling instant is set as k = k + n3.

[0110] The process proceeds from block 464 to block 430 and ends.

[0111] Conversely, if the value of the moving variance of the gyro is not consistently and continuously less than or equal to the third threshold for the duration, the process proceeds from block 460 to block 470, where the state is changed to the ground moving state 314 in Figure 3

[0112] The process then proceeds to block 472, where the next sampling instant is set as k = k + nn, where nn is a positive integer greater than or equal to one sampling instant denoting the duration td3.

[0113] The process proceeds from block 472 to block 430 and ends.

[0114] From state 312

[0115] In another case, if the current state is the flying state 312 in Figure 3 ​​Flight status 312 in the middle can be determined according to Figure 5 Make a decision to change your state. Now refer to... Figure 5 .

[0116] Figure 5 The process begins at box 510 and proceeds to box 520, where a check is performed to determine if the value of the objective function is less than a first threshold. If so, the process proceeds from box 520 to box 530, where the state of the sensor device changes as described above. Figure 3 The stop state is 310.

[0117] Then, the process proceeds to box 532, in which the next sampling time is set to k = k + 1.

[0118] The process proceeds from box 532 to box 540 and then ends.

[0119] Conversely, if the value of the objective function is greater than or equal to the first threshold, the process proceeds from box 520 to box 550, in which the sensor device remains in the same state, i.e., the flight state.

[0120] The process proceeds from box 550 to box 552, where the next sampling time is set to k = k + n3.

[0121] The process proceeds from box 552 to box 540 and then ends.

[0122] Starting from state 314

[0123] In another scenario, the previous state of the sensor device could be as described above. Figure 3 Ground mobile vehicles are classified as state 314. In this case, regarding… Figure 6 The process used to determine state transitions is shown.

[0124] Figure 6 The process begins at box 610 and proceeds to box 620, where an examination is performed to determine whether the value of the accelerometer's movement variance remains consistently and continuously between two thresholds over the extended duration. Figure 6 The embodiment shows an extended duration with mvACCE(k+i), where i is an integer between 1 and n1.

[0125] If the objective function value is determined at box 620 to be between two thresholds over the duration, the process proceeds to box 630, where the state changes as described above. Figure 3 Flight status 312.

[0126] The process proceeds from box 630 to box 632. In box 632, the next sampling time is set to k = k + n3, where n3 is an integer representing the duration.

[0127] The process proceeds from box 632 to box 640 and then ends.

[0128] Instead, starting from box 620, if the value of the objective function is not between the two thresholds during the duration, the process proceeds to box 650. At box 650, a check is performed to determine whether the accelerometer's movement variance is less than a first threshold during the duration, where the duration is represented by i, and i is a value from one to n1.

[0129] If the objective function at box 650 is less than the threshold over the duration, then the process proceeds from box 650 to box 652, where the state changes as described above. Figure 3 The stop state is 310.

[0130] The process proceeds from box 652 to box 654, where the next sampling time is set to k = k + 1.

[0131] The process proceeds from box 654 to box 640 and then ends.

[0132] Conversely, starting from box 650, if the value of the objective function is not less than a first threshold over a duration, the process proceeds to box 660, where the sensor device can remain in its current state.

[0133] The process proceeds from box 660 to box 662, where the next sampling time is set to k = k + 1.

[0134] The process proceeds from box 662 to box 640 and then ends.

[0135] In the above Figure 4 to Figure 6 In some embodiments, if the state transition is to flight state 312, the sensor device's wireless electronic systems are shut down to ensure compliance with aviation regulations. In some embodiments, a notification may be transmitted to network elements prior to shutting down the radio, indicating that the sensor device is transitioning to flight state and that radio transmissions are being shut down.

[0136] Alternative Algorithm

[0137] Although the above Figure 4 The determination of state transitions includes the movement variance of the gyroscope sensor; however, in a first alternative embodiment, the determination can be based solely on the accelerometer without using the gyroscope sensor. In this case, multiple thresholds can be defined, namely threshold 1, threshold 2, threshold 3, and threshold 4.

[0138] In this case, the objective function f(k) is defined as a weighted sum of the variance of movement of the three accelerometers. For example, Equation 2 above can be utilized.

[0139] In Equation 2, a(i) is the weight given to the variance of movement of each of the three accelerometers. In one example, more weight can be given to the X and Z directions than to the Y direction.

[0140] In the case where the objective function f(k) is greater than a threshold 1 (which can be a takeoff threshold and typically has a larger value) and the objective function f(k+i) is greater than a threshold 2, where threshold 2 < threshold 1 for i = 1,... K1 (a takeoff confirmation window), the in-flight state can be declared.

[0141] If it is determined that the sensor device is in flight, the landing state is declared when the objective function f(k) is greater than a threshold 3 and f(k+i) is less than a threshold 4 for i = 1,... K2 (a landing confirmation window).

[0142] In one example, K1 can be a relatively small value and thus have a small latency of determination, while K2 can be a larger value because it is more important to quickly turn off the radio, while it is typically acceptable to turn on the radio with a larger latency but with a more accurate estimate.

[0143] In one embodiment, to further distinguish a vehicle in motion from moving in the air, a second objective function is defined according to Equation 4 below.

[0144]

[0145] In Equation 4 above, x and y represent the magnitude of the accelerometer in the x and y directions, respectively. If the value of f1(k) is greater than a fifth threshold, denoted as threshold 5, during the takeoff confirmation window, or the average over a predetermined window is greater than threshold 5 during the takeoff confirmation window, the "in flight" state is determined. Otherwise, the "moving on the ground" state is determined.

[0146] In another example, to avoid false alarms in flight, after determining that the sensor device is in flight, the algorithm can periodically retest whether the objective function f(k) is greater than threshold 2 during the takeoff confirmation window.

[0147] After determining the in-flight state, in one embodiment, all communications except for the communication between the accelerometer and the sensor device are turned off in order to conserve battery power. The accelerometer is used to determine whether a landing event has occurred. Prior to disabling such communications, in one embodiment, a notification can be sent to a network element such as a fleet management server.

[0148] In another embodiment, after the in-flight status is determined, all irrelevant functions, such as functions for door opening or closing detection, etc., can be turned off.

[0149] In yet another alternative, the algorithms can be combined. For example, in one embodiment, at least two "in-flight" detection methods can be combined, where in addition to any of the above embodiments, the second method can include monitoring ADS-B messages corresponding to the aircraft or flight engine. The sensor device can then select the most conservative indication of the "in-flight" status to turn the radio off or on.

[0150] Moving variance

[0151] In the above, the moving variance can be determined by various techniques. One example is described below with respect to a first order infinite impulse response (IIR) filter. In this case, the moving variance of a real sequence X = {x k}, k = 1, 2,..., n can be computed as s = {s k}, k = 1, 2,..., n.

[0152] For the first time interval, in other words, k = 1, the following equations 5a and 5b apply.

[0153]

[0154]

[0155] In this case, the moving variance is represented in equation 6 as

[0156] s1= 0 (6)

[0157] For k > 1, then equations 7a and 7b apply.

[0158]

[0159]

[0160] In this case, the moving variance is computed according to the following equation 8.

[0161]

[0162] In equations 7a and 7b above, 0 < a < 1 and a is a coefficient of the IIR filter.

[0163] Test

[0164] Using equation 1 and the above Figure 4 to Figure 6In the embodiments described, various tests were performed in the real world. In these tests, the IIR coefficient was set to 0.04. Furthermore, threshold 1 was set to 0.01, threshold 2 was set to 3, and threshold 3 was set to 20.

[0165] also, Figure 4 to Figure 6 In the embodiments, the durations are set to 30, 3, and 300, respectively.

[0166] When the sensor devices associated with the shipping container are traveling on the ground, the results are as follows: Figure 7 The diagram is shown below. In this case, the discovered MV value leads to the sensor device's state being considered as the ground vehicle's movement state throughout the experiment. Therefore, the sensor device's radio remains on.

[0167] In another scenario, the sensor device flies between airports along with the shipping container. The result is as follows... Figure 8 The diagram is shown. As can be seen from line 810, the radio is turned off when a successful in-flight confirmation is made. Furthermore, the radio is turned back on when a landing event occurs.

[0168] Therefore, the above provides a method for determining the state of a sensor device based on an objective function associated with that sensor. Specifically, if the objective function falls between two defined thresholds, this indicates a flight state and the sensor device can therefore shut down its radio.

[0169] Servers such as server 240, 242, or 250 can be any network node. For example, regarding... Figure 9 A simplified server is provided that can execute the above embodiments.

[0170] exist Figure 9 In this embodiment, server 910 includes processor 920 and communication subsystem 930, wherein processor 920 and communication subsystem 930 cooperate to perform the methods of the embodiments described herein.

[0171] Processor 920 is configured to execute programmable logic, which can be stored on server 910 along with data, and Figure 9 In the example, memory 940 is shown. Memory 940 can be any tangible, non-transitory computer-readable storage medium, such as optical (e.g., CD, DVD, etc.), magnetic (e.g., magnetic tape), flash drive, hard disk drive, or other memory known in the art. In one embodiment, processor 920 can also be implemented entirely in hardware and perform logical functions without requiring any stored program.

[0172] Alternatively, or in addition to memory 940, server 910 can access data or programmable logic from external storage media, such as through communications subsystem 930.

[0173] Communications subsystem 930 allows server 910 to communicate with other devices or network elements.

[0174] In one embodiment, communications between various elements of server 910 can be through internal bus 960. However, other forms of communication are possible.

[0175] The embodiments described herein are examples of structures, systems or methods having elements corresponding to the elements of a technology of this application. This written description can enable others skilled in the art to manufacture and use such embodiments having the functionality of the technology of this application. The technology of this application, therefore, is not limited to any specific embodiments described herein, but includes other embodiments that are within the scope of the technology of this application.

[0176] Although operations are depicted in a particular order in the figures, this should not be understood as requiring such order, nor requiring that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing can be employed. Moreover, the separation of various system components in the implementations described above should not be understood as requiring such separation in all implementations, and it should be understood that the described program components and systems can generally be integrated together in a single software product or packaged into multiple software products. In some cases, the functionality can be performed entirely in hardware, and such solutions can be functional equivalents of software solutions.

[0177] Also, techniques, systems, subsystems, and methods described and shown in various embodiments herein can be combined with other systems, modules, techniques, or methods. Other items shown or discussed as separate from other items or uniquely placed can be implemented as parts of the other items or as combined. Other examples of changes, substitutions, and alterations are ascertainable by one skilled in the art and can be made without departing from the spirit and scope of the technology of this application.

[0178] While the above detailed description has shown, described, and pointed out the fundamental novel features of the disclosure as applied to various embodiments, it will be understood that various omissions, substitutions, and changes in the form and details of the system illustrated can be made by those skilled in the art without departing from the spirit of the disclosure. The order of method steps is not necessarily restricted by the order in which they appear in the claims.

[0179] When messages are sent to / from electronic devices, such operations can not be immediate or directly from a server. Messages can be delivered synchronously or asynchronously from a server or other computing system infrastructure that supports the devices / methods / systems described herein. The foregoing steps can include synchronous / asynchronous communications to / from the devices / infrastructure in whole or in part. Further, communications from the electronic devices can be directed to one or more endpoints on a network. These endpoints can be served by servers, distributed computing systems, stream processors, etc. Content delivery networks (CDNs) can also provide communications with the electronic devices. For example, rather than a typical server response, a server can also provide or indicate data for a content delivery network (CDN) to await download by the electronic device at a later time, e.g., a subsequent activity of the electronic device. Thus, data can be sent directly from a server or other infrastructure (e.g., distributed infrastructure or a CDN) that is part of the system or separate from the system.

[0180] Generally, a storage medium can include any or some combination of the following: a semiconductor memory device, e.g., a dynamic or static random access memory (DRAM or SRAM), an erasable and programmable read-only memory (EPROM), an electrically erasable and programmable read-only memory (EEPROM) and flash memory; a magnetic storage medium, e.g., a disk, cartridge or cassette tape; another magnetic medium; an optical medium, e.g., a compact disc (CD) or a digital video disc (DVD); or another type of storage device. Note that the above-mentioned instructions can be provided on one computer-readable or machine-readable storage medium, or alternatively, can be provided on a plurality of computer-readable or machine-readable storage media distributed in a large system having possibly a plurality of nodes. Such computer- readable or machine-readable storage medium or media is (are) considered to be part of an article (or article of manufacture). The article or article of manufacture can refer to any manufactured single component or multiple components. The storage medium or media can be located either in the machine running the machine-readable instructions or located at a remote station which can download the machine-readable instructions over a network for execution.

[0181] In the above description, numerous details are set forth to provide an understanding of the subject matter disclosed herein. However, implementations can be practiced without some or all of these details. Other implementations can include modifications and variations from the details discussed. It is intended that the appended claims cover such modifications and variations.

Claims

1. A method at a sensor device, the method comprising: calculating a value of an objective function at the sensor device, the objective function being a weighted sum of moving variances of three accelerometers at the sensor device, the moving variance of each accelerometer being provided with an independent weighting value; determining that the value of the objective function is greater than a first threshold at a first time instant; finding that the value of the objective function is greater than a second threshold for a first defined period of time after the first time instant, the second threshold being less than the first threshold; based on the determining and the finding, declaring an in-flight state of the sensor device; and based on the in-flight state, shutting down transmission of a radio from the sensor device.

2. The method of claim 1, wherein each of the three accelerometers has a different orientation.

3. The method of claim 1, wherein the moving variances are calculated using a first order infinite impulse response filter.

4. The method of claim 1, wherein the independent weighting value for X direction moving variance and the independent weighting value for Z direction moving variance are higher than the independent weighting value for Y direction moving variance.

5. The method of claim 1, further comprising: determining that the value of the objective function is greater than a third threshold at a second time instant; finding that the value of the objective function is lower than a fourth threshold for a second defined period of time after the second time instant; declaring a landing state of the sensor device; and based on the landing state, reactivating transmission of a radio from the sensor device.

6. The method of claim 5, wherein the second defined period of time is longer than the first defined period of time.

7. The method of claim 1, further comprising verifying the in-flight state using a second objective function that is greater than a fifth threshold, the second objective function being defined as: where x k and y k correspond to the magnitude of the accelerometer in the x direction and the magnitude of the accelerometer in the y direction at time k.

8. The method of claim 1, further comprising: verifying the in-flight state by periodically retesting whether the objective function is greater than the second threshold while the sensor device is in the in-flight state.

9. The method of claim 1, further comprising: disabling functions on the sensor device that are not associated with the determination of the objective function during the in-flight state.

10. A sensor device, comprising: a processor; and a communication subsystem, wherein the sensor device is configured to: calculate a value of an objective function at the sensor device, the objective function being a weighted sum of moving variances of three accelerometers at the sensor device, the moving variance of each accelerometer being provided with an independent weighting value; determine that the value of the objective function is greater than a first threshold at a first time instant; find that the value of the objective function is greater than a second threshold for a first defined period of time after the first time instant, the second threshold being less than the first threshold; declare an in-flight state of the sensor device; and based on the in-flight state, shut down transmission of a radio from the sensor device.

11. The sensor device of claim 10, wherein each of the three accelerometers has a different orientation. ​ 12. The sensor device of claim 10, wherein the movement variance is calculated using a first order infinite impulse response filter.

13. The sensor device of claim 10, wherein an individual weight value for movement variance in an X direction and an individual weight value for movement variance in a Z direction are higher than an individual weight value for movement variance in a Y direction.

14. The sensor device of claim 10, wherein the sensor device is further configured to: determine that a value of the objective function is greater than a third threshold at a second time; find that the value of the objective function is below a fourth threshold for a second defined period of time after the second time; declare a landed state of the sensor device; and reactivate transmission from a radio of the sensor device based on the landed state.

15. The sensor device of claim 14, wherein the second defined period of time is longer than the first defined period of time.

16. The sensor device of claim 14, wherein the sensor device is further configured to verify the in-flight state using a second objective function that is greater than a fifth threshold, the second objective function defined as: where x k and y k correspond to the magnitude of the accelerometer in the x direction and the magnitude of the accelerometer in the y direction at time k.

17. The sensor device of claim 10, wherein the sensor device is further configured to verify the in-flight state by periodically retesting whether the objective function is greater than the second threshold while the sensor device is in the in-flight state.

18. The sensor device of claim 10, wherein the sensor device is further configured to disable functionality on the sensor device that is not associated with determination of the objective function during the in-flight state.

19. A computer-readable medium for storing instruction code that, when executed by a processor on a sensor device, causes the sensor device to: calculate a value of an objective function at the sensor device, the objective function being a weighted sum of movement variances of three accelerometers at the sensor device, the movement variance of each accelerometer provided with an individual weight value; determine that the value of the objective function is greater than a first threshold at a first time; find that the value of the objective function is greater than a second threshold for a first defined period of time after the first time, the second threshold being less than the first threshold; declare an in-flight state of the sensor device; and turn off transmission from a radio of the sensor device based on the in-flight state. ​

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