Indoor altitude determination in location tracking devices using barometric pressure data

Abstract

A tracking device 200, for determining position, comprises a pressure sensor for sensing ambient air pressure, a temperature sensor for sensing ambient temperature, a satellite positioning system, suc

Description

The present application relates generally to a tracking device for determining the location of an object or person, and more specifically to a system and method for utilizing satellite positioning, wireless communication, and computing technology to accurately track and monitor the movement of the object or person in real-time. BACKGROUND ART The US20120072110A1 shows a pressure sensor can be implemented on a network device to minimize vertical positioning errors of the network device in an indoor environment. The US20120290253A1 shows a method for determining a height, i.e. elevation above ground level, at which a communication device having an electronic processor and a sensor is located may include obtaining a reference height of a first location, the reference height being a known height relative to ground level, the reference height having a corresponding reference pressure; obtaining, with the sensor, a pressure measurement at a second location; and calculating, with the electronic processor, a height at the second location based on the pressure measurement, the reference height, and the reference pressure. The US9671224B2 reveils methods and systems for determining the elevation of tracked personnel or assets, trackees, that can take input from mounted sensors on each trackee, including barometric, inertial, magnetometer, radio frequency ranging and signal strength, light and GPS sensors, external constraints, including ranging constraints, feature constraints, and user corrections, and terrain elevation data. These approaches present limitations. PROBLEM STATEMENT This application addresses the problem of determining the position of a tracking device accurately and efficiently when the tracking device is indoor The application provides a device and method for determining the relative position of a tracking device using ambient air pressure and ambient temperature information. The tracking device includes a pressure sensor for sensing ambient air pressure and a positioning means for determining the position of the tracking device(usually a 2D position with latitude and longitudes when indoor), wherein the positioning means comprises a radio-wave based positioning system. The radio-wave based positioning system can be a satellite positioning system, and the tracking device can - as an option only - be a wearable device. A tracking device data exchange unit is provided for transmitting and receiving data, for example using an Internet protocol or other protocols that use bidirectional data transmission, wherein the tracking device can transmit the ambient temperature information, the ambient air pressure information, and the position and / or an altitude information to an observing device. Using an Internet protocol makes the device easy to build and reliable in operation. A relative height position information between a tracking device and an observing device is obtained by the following steps: - determining a tracking device position information, a tracking device ambient temperature information, and a tracking device ambient air pressure information, - determining an observing device position information and an observing device ambient air pressure information, - determining a relative position information from the tracking device position information, from the tracking device ambient air pressure information, from the observing device ambient air pressure information, from the observing device position information, and from the tracking device ambient temperature information. Embodiments of the invention are associated with various advantages and / or technical effects. The tracking device utilizes a pressure sensor to accurately sense ambient air pressure, allowing for precise position determination. The observing device uses both the tracking device ambient air pressure and the observing device ambient pressure information to determine the relative height position of the tracking device, resulting in a more reliable and robust tracking system. The tracking device reduces overhead by using a pressure sensor to sense the ambient air pressure and leverage on the observing device’s pressure sensor for relative height calculation, eliminating the need for additional equipment or systems. The tracking device offers controllability as it includes a data exchange device for transmitting / l real time information , enabling precise positioning calculations. The tracking device provides mobility as it can be easily carried or worn due to its compact and wearable design, and it ensures accurate positioning by providing the tracking device ambient air pressure. Used together with the observing device ambient pressure information, this results in improved accuracy of the determined position. In a development, the ambient pressure information comprises a further ambient air pressure measured by the observing device which can also be called “reference device”. The ambient pressure information in the tracking device for determining a position includes a further ambient air pressure measured by the reference device, ensuring that the position determination is based on accurate and up-to-date data. By incorporating a reference device to measure the further ambient air pressure, the reference device enhances the precision and reliability of the position determination process. The inclusion of the further ambient air pressure measured by a reference device allows for real-time adjustments and updates to the position determination, improving the overall tracking accuracy. In a development, the ambient pressure information comprises a further ambient air pressure retrieved from a database. The ambient pressure information in the observing device for determining a position can include a further ambient air pressure retrieved from a database, providing a wide range of reference data for accurate position determination. By retrieving the further ambient air pressure from a database, the device eliminates the need for additional sensors or devices, simplifying the tracking system and reducing costs. The use of a database for the ambient pressure information allows for easy access to historical and real-time data, enabling accurate position determination even in dynamic environments. The position determination In the observing device includes altitude information determined based on the ambient air pressure, providing a comprehensive understanding of the tracking device’s position. In a development, the tracking device further comprises a radio-wave based positioning system for determining position information. The use of a radio-wave based positioning system allows for accurate determination of position information, enhancing the overall tracking capabilities of the device. The inclusion of a satellite positioning system ensures global coverage, enabling the tracking device to be used in various locations around the world. The ability of the positioning device to determine position using at least the position information enhances the accuracy and reliability of the tracking device. In a development, the radio-wave based positioning system is a satellite positioning system. The inclusion of two-dimensional position information provides precise location data, allowing for accurate tracking and monitoring of the device. In cases where the radiowave based positioning system provides a three-dimensional position information, pressure difference based altitude tracking according to the application can help to improve determining the position of the tracking device by using redundancies from the two independently produced altitude information. The use of a wearable device as the tracking device offers convenience and portability, allowing for easy and continuous tracking of the user. The tracking devic”s capability for indoor positioning enables tracking and monitoring even in environments where GPS signals may be weak or unavailable. The use of a satellite positioning system ensures global coverage, allowing the tracking device to be used in various locations around the world. The positioning devic”s capability to determine position using at least the position information enhances the accuracy and reliability of the tracking device. In a further development, the tracking device further comprises a temperature sensor for measuring an ambient temperature, and the relative position information can be further improved based on the temperature. The application presents an approach to indoor determination in location tracking devices using comparative barometric pressure data. Elimination of GPS Dependency: One advantage of some embodiments of the application is their independence from a reliable GPS signal indoors for altitude determination, which becomes ineffective indoors due to signal obstructions. Some embodiments of the application offer a solution that is not reliant on GPS, providing accurate indoor altitude information. Enhanced Versatility in Wi-Fi Positioning: Some embodiments of the application provide height information within indoor environments even if the building has undergone specialized configuration and extensive data collection efforts. The application then offers increased versatility. It even enables general-purpose tracking without the need for such complex preparations, making it a more practical choice for various applications. Mitigation of Air Pressure-Based Inaccuracies: Some embodiments of the application employing air pressure-based height measurements improve inherent inaccuracies. These inaccuracies can stem from the fluctuating atmospheric pressure, even in fixed locations. To attain better accuracy, it is possible to leverage on near-real-time pressure differential information. . Some embodiments of the application address this by providing accurate height data without relying on impractical, building-specific pressure fixes. Practical Height Verification: Even in scenarios where absolute height is ascertainable at a reference point, e.g. a ground level landmark, some embodiments of the application provide current pressure data at that reference point. This improves realistic height verification against the reference point. The application provides practical and accurate height determination. In summary, the application offers substantial advantages by addressing the challenges associated with indoor altitude determination, including GPS dependency, the complexity of Wi-Fi positioning, inaccuracies in air pressure-based measurements, and difficulties in height verification. These advantages render the subject matter of the application a practical and versatile choice for a wide range of tracking applications in indoor environments. The proposed technology uses the absolute air pressure data from a user's smartphone as a basic reference point. By comparing this reference data with the pressure data from the tracking device, the system can accurately derive the relative vertical position of the tracking device within a given building or environment, achieving a remarkable level of accuracy down to the centimeter level. More importantly, since this is relative height information in near real-time, it simplifies a person searching for target tracked device / person size. This method not only improves indoor height determination but also provides users with an accurate and meaningful indoor height metric. In doing so, it significantly enhances the overall utility of location-tracking devices by enabling users to determine the vertical location of a device with unprecedented accuracy. In today’s urban landscapes, the ability to accurately track moving people, assets, or pets within multi-story structures such as office buildings, shopping malls, and apartment complexes has become increasingly important. This is especially true in scenarios such as locating a missing person with dementia or tracking valuable assets. The application provides latitude and longitude data, and elevation or floor-level information. As a result, users do not need to spend hours searching for a person or an asset across multiple floors. The application is highly effective and provide accurate elevation data indoors by not only relying solely on elevation sensors. Since both the searcher and the target could be in dynamic motion, it is even more advantageous to have the relative altitude information between the two to make the search more effective. The application uses comparative air pressure data. Because the difference in air pressure between different heights within the same building is both predictable and consistent, some embodiments of the application, when combined with GPS or indoor Wi-Fi location systems, can pinpoint positions in a three-dimensional manner. This provides users with a comprehensive understanding of the vertical position of a tracked object or individual. Whether it’s first responders trying to locate a person inside a building, users searching for misplaced items, or any scenario where vertical positioning is critical, some embodiments of the application addresses a need in the marketplace. The application provides: 1. Comparative pressure data for accurate altitude tracking: To solve the problem where individual air pressure sensor data can be measured, but it is not possible to derive an accurate height position from that, some embodiments of the application combine the use of the pressure sensor in a hardware tracking device and a companion phone app to obtain an accurate comparative pressure data difference. This, combined with optional temperature sensor information in one or both devices, can result in accurate height calculation in some embodiments of the application, so that the user can use the phone to see exactly how many meters that hardware device is either above or below the current user.. 2. Comparative Calibration: to provide accurate comparative pressure data for altitude calculation. The system requires the report of both the user's phone and the location tracking device at the same location at almost the same time. The difference between the readings is recorded and used as an offset, ensuring that both devices have a common baseline in pressure reading, 3. Event-driven data collection: Unlike systems that may collect data continuously, some embodiments of the application operate on an event-driven basis. The tracking device is designed to track and register noticeable changes in air pressure and update the cloud with this data. At the same time, the phone is programmed to retrieve its current pressure reading when the user attempts to determine the altitude difference, ensuring near realtime accuracy. 4. User-centric design: Recognizing the importance of the user experience, the system displays altitude differences in an intuitive manner, using numerical values in meters and a graphical user interface that indicates upward or downward movement. 5. Environmental Adaptability: The system is designed to provide optimal results in open airflow environments, demonstrating its adaptability to different environments while recognizing the limitations of controlled pressure or temperature environments. By addressing the technical challenges of indoor altitude sensing and providing a solution that is both innovative and user-centric, some embodiments of the application stands out as a novel contribution to the field of location tracking. Some embodiments of this technology have the ability to accurately measure pressure differences between two devices in near real time. This concept opens up a number of potential applications and enhancements: 1. Device-to-Device Tracking: The technology isn't limited to phone-to-device configurations. It can be extended to track between phones, provided both have a pressure sensor, or even between devices. This flexibility allows for various tracking scenarios, from personal devices to industrial equipment. 2. Group altitude tracking for smartphones: Consider a scenario where a group of smartphone users want to determine their relative heights within a building. Once all phones are calibrated to a standard pressure sensor reading, accurate height differences can be inferred, provided they are in the same vicinity. This can be particularly useful in scenarios such as emergency evacuations, team building exercises, or guided tours of multi-level structures. 3. Mixed group tracking: Consider a situation where assets or individuals equipped with a mix of trackers and phones are scattered throughout a building. By designating a device or phone at ground level as a reference point (after calibration), the system can track the relative vertical positions of the entire group. This provides not only the height difference between group members, but also in relation to the reference device 300 positioned at a fixed level. Further features of the application are described in the following with reference to Fig. 7: - Some embodiments of the application provide a complete solution, the left is a hardware tracker device with embedded pressure and temperature sensor, it also has GPS / WIFI and cellular connectivity. The right is a companion app to the hardware device that can run on any compatible phone (a phone with a barometer sensor, and optional temperature sensor). - Hardware tracker device can be attached to the person / asset / pet user wants to track. - When user is searching for the device, first the GPS / WIFI / Cellular system will provide the standard 2D position information that will help the searcher to come close to the device in latitude / longitude perspective. - Then the pressure difference information from hardware tracker to phone will help to provide meaningful altitude difference (further improved by temperature information from tracker and / or phone). Further Advantages of Some embodiments of the application: Elimination of Specialized Building Setup: Unlike traditional methods such as GPS or wifi positioning, which require special setup for each building, Some embodiments of the application operate effectively in generic indoor environments without the need for building-specific configurations. Accurate Indoor Elevation: While pressure sensing is currently considered the best option for accurate indoor elevation, Some embodiments of the application offer a more robust solution compared to existing methods in this field. Reference Device 300-Free Approach: Unlike other methods, some embodiments of the application do not rely on the impractical placement and maintenance of reference pressure devices in every building. Users are not burdened with the task of searching for reference devices, making the process simpler and more user-friendly. Real-Time Relative Height: With Some embodiments of the application, users searching for a tracked device do not need to guess the real-time relative height, as it dynamically calculates the height difference between embodiments of the application, their device (e.g., a smartphone) and the target device. This real-time feedback enhances accuracy and convenience. No Ground-Level Reporting Requirement: Unlike in existing methods, some embodiments of the application don't require the target-tracked device to report its pressure reading location when it's on the ground floor or any known reference point. This eliminates the need for manual interventions and ensures continuous tracking. Reduced Time Lag: Traditional time-based tracking methods may suffer from time lag between embodiments of the application readings due to pressure changes over time. Some embodiments of the application minimize this issue, providing near real-time height tracking with minimal setup, reducing inaccuracies caused by time delays. Seamless User Experience: As users approach the target device, some embodiments of the application update the height display dynamically, creating a seamless and intuitive tracking experience. This feature enhances user satisfaction and usability. In summary, some embodiments of the application offer advantages, providing a more accurate, user-friendly, and efficient solution without the need for specialized building configurations or reference devices. Dynamic Pressure Reference Point: Some embodiments of the application offer an advantage by incorporating a dynamic pressure reference point through the user's smart device, such as a smartphone. This enables real-time determination of the target-tracked device's height relative to the user. Real-Time Height Calculation: Some embodiments of the application utilize the real-time air pressure readings obtained from both the user's carrying device and the target-tracked device. This precise comparison allows for accurate determination of the target device's height relative to the user's position, even while the user is in motion. No Building-Specific Setup Required: Some embodiments of the application excel by not necessitating any prior setup within the building where tracking is required. This eliminates the need for building-specific configurations, making it applicable for use in a wide range of indoor environments. Scalability in Urban Environments: In the context of a general people / item tracking system, the inherent impracticality of performing setup procedures in every building across a city is resolved by the application. This scalability ensures that Some embodiments of the application can be effectively deployed in urban settings where such an extensive setup would not be easily feasible. BRIEF DESCRIPTION OF DRAWINGS The present disclosure is illustrated by way of example and not limited in the accompanying figures in which like reference numerals indicate similar elements. Embodiments of the application will now be described with reference to the attached drawings: Figure 1 shows a house with a tracking device and a reference device; Figure 2 shows a tracking device according to the application; Figure 3 shows an observing device according to the application; Figure 4 shows a communication between a tracker device and an observing device to the application; Figure 5 illustrates the initial calibration of the embodiment of Fig. 4; Figure 6 illustrates the ongoing measurement with the embodiment of Fig. 4; Figure 7 illustrates a further embodiment of the application. DETAILED DESCRIPTION Fig. 1 shows a house 100 with a tracking device and a reference device Figures 1 and 2 show a tracking device 200 for determining a position. The tracking device 200 includes a pressure sensor 210 for sensing ambient air pressure, a receiving device 220 for receiving ambient pressure information, and a positioning system 230 for determining the position of the tracking device 200. The ambient pressure information can be obtained from a pressure sensor 210. The tracking 200 device may also include a radio-wave based positioning system, such as a satellite positioning system, for determining a tracking device position information. The position information can be two-dimensional. The tracking device can be provided as a wearable device and it can be configured for indoor positioning. Additionally, the tracking device 200 may include a temperature sensor 220 for measuring temperature, which can be used to determine the position and / or altitude information. Figure 3 shows an observing device 300, also called “reference device” for determining a relative position of the tracking device 200. The reference device 300 includes a pressure sensor 310 for sensing ambient air pressure and a positioning device 330 for determining the position of the reference 300 device. The ambient pressure information can be obtained from the reference device 300 itself or retrieved from a database. The position of the tracking device 200 including an altitude information is determined based on the ambient air pressure of the tracking device 200 and of the observing device 300. The reference device 300 may also include a radio-wave based positioning system, such as a satellite positioning system 330, for determining position information. The position information can be two-dimensional. The reference device 300 can be a wearable device and can be configured for indoor positioning. Additionally, the reference device 300 may include a temperature sensor 320 for measuring temperature, which can be used to determine the position and / or altitude information of the tracking device 200. Fig. 4 shows a communication between an observing device B and a target device A according to the application. Figure 4 shows a schematic representation of an observing device B for determining a position. The observing device B includes a pressure sensor 310 for sensing ambient air pressure, a data exchange device 350 for receiving ambient pressure information, and a positioning device 330 for determining the position of the observing device B using at least radio-wave based positioning system. The ambient pressure information can be obtained from the reference device B itself or retrieved from a database. The position is determined including an altitude information based on the ambient air pressure. The tracker device A also includes a radio-wave based positioning system, such as a satellite positioning system, for determining position information. Fig. 5: illustrates the initial calibration of the embodiment of Fig. 4 and it shows a schematic representation of a tracking device A for determining a position. The tracking device A includes a pressure sensor 210 for sensing ambient air pressure, an optional temperature sensor 220 for receiving ambient temperature information, and a positioning means 230 for determining the position of the tracking device A, using at least radio-wave based positioning system. The air pressure and positioning information is send to observing device B for intial calibration. Observing device B first ensure the information send from device A is within close proximity in terms of time and location, it then records the pressure reading difference between observing device pressure sensor 310 and tracking device pressure sensor 210. This difference is recorded for use in future measurements as the calibration data for pressure difference between 210 and 310. Fig. 6: illustrates the ongoing measurement with the embodiment of Fig. 4. The device A sends out new pressure, temperature and / or position (2D or 3D position) data. Device B, typically a smartphone, receives this pressure, temperature and position (2D or 3D position) data from device A and compares its internal reference pressure with the pressure received from device A. Device B then displays the location data that it has received from device A, together with a relative height difference that has been derived from the pressure difference, optionally taking into account temperature information from the device A and / or from the device B. Fig. 7 illustrates a further embodiment of the application. Figure 7 shows a schematic diagram of a tracking device 200 on the left for determining a position. The tracking device 200 includes a pressure sensor for sensing ambient air pressure, and a positioning device for determining the position of the tracking device. The tracking device 200 also includes a radio-wave based positioning system, such as a satellite positioning system, for determining position information. The positioning device is configured to determine the position using at least the position information. The tracking device 200 can be a wearable device and can be configured for indoor positioning. In one example as shown in the Figures 4, 5, and 6, the process is carried out as follows: 1. the tracking device A with pressure sensor A is moving in the building, it sends out the ambient pressure sensor data and ambient temperature data when it changes the position. That selective sending of data can save battery life. 2. phone B(observing device) user checks the tracking device A location, 3. phone B’s own pressure sensor B is being used to read the phone B’s position's ambient air pressure 4. a phone B app compares the phone B’s ambient pressure data and - optional -temperature data with the tracking device A’s ambient pressure data and - optional -temperature data 5. utlising the above information, the phone B calculates the height difference between the phone B and the tracking device A. 6. the phone B shows to user in real time how many meters the tracking device A is above or below the phone B position. If the tracking device detects an air pressure of 100100 Pa and the phone user who is looking for the tracker, has a phone pressure reading of 100300 Pa (assume in Singapore, at 25 degrees Celsius), one can be confident that the user is about 17 meters below the tracker. The phone's 100300 Pa pressure reading does give an estimate of its absolute altitude above sea level, but this estimate can be tens of meter off, making the absolute altitude number meaningless, In the following, further embodiments are described by means of an itemized list of features combinations: 1. A tracking device for determining a position, the tracking device comprising - a pressure sensor for sensing ambient air pressure, - a positioning system, also called positioning means, for determining the position of the tracking device. 2. Tracking device according to item 1, wherein the altitude information is given in terms of discrete levels, because of digitizing the readings of the pressure sensor. 3. Tracking device according to one of the preceding items, wherein the tracking device further comprises a radio-wave based positioning system for determining position information. 4. Tracking device according to item 3, wherein the radio-wave based positioning system is a satellite positioning system, Wi-Fi positioning system, or Bluetooth positioning system. 5. Tracking device according to one of items 3 or 4, wherein the positioning device is configured for determining the position using at least the position information, however that position information is enhanced by the additional ambient air pressure reading. 6. Tracking device according to one of items 3 to 5, wherein the position information is or comprises a two-dimensional position information. 7. Tracking device according to one of the preceding items, wherein the tracking device is a wearable device. 8. Tracking device according to one of the preceding items, wherein the tracking device is configured for indoor positioning. 9. Tracking device according to one of the preceding items, wherein the tracking device further comprises a temperature sensor for measuring an ambient temperature, and wherein the position and / or an altitude information if determined based on the ambient temperature. 10. Method for determining a position of a tracking device, the method comprising the following steps: - determining a tracking device position information, and a tracking device ambient air pressure information, - determining an observing device ambient air pressure information, - determining a relative position information from the tracking device position information, from the tracking device ambient air pressure information, and from the observing device ambient air pressure information. 11. Method for determining a position of a tracking device according to item 10, further comprising the step of determining an observing device position information, wherein the step of determining a relative position information is using the observing device position information. 12. Method for determining a position of a tracking device according to item 10 or claim 11, further comprising the step of determining an observing device ambient temperature information, wherein the step of determining a relative position information is using the observing device ambient temperature information. 13. Method for determining a position of a tracking device according to one of items 10 to 12, further comprising the step of determining a tracking device ambient temperature information. 14. Method for determining a position of a tracking device according to item 13, wherein the step of determining a relative position information is using the tracking device ambient temperature information. 15. Method according to one of items 13 to 14, wherein the observing device pressure information comprises an ambient air pressure retrieved from a database. 16. Method according to one of items 13 to 15, wherein the observing device pressure information is determined including an altitude information determined based on the ambient air pressure. 17. Method according to one of items 10 to 16, wherein the altitude information is given in terms of discrete levels. 18. Method according to one of items 10 17, wherein the position of the tracking device is further determined using position information obtained from a radio-wave based positioning system. 5 19. Method according to item 18, wherein the radio-wave based positioning system is a satellite positioning system. 20. Method according to one of items 10 to 19, wherein the ambient pressure information is received from a smartphone. 10 21. Method according to one of items 10 to 20, wherein the position information is or comprises a two-dimensional position information. In short words, the tracking device transmits the ambient temperature information, the 15 ambient air pressure information, the position and / or the altitude information to an observing device. All items above can be combined with each other, in any order and / or selection. Reference numbers list 100 House 5 101 First Level 102 Second Level 103 Third Level 104 Fourth Level 200 tracking device 10 210 pressure sensor, pressure sensing means 220 optional temperature sensor 230 positioning system, positioning means 250 tracking device data exchange unit 300 observing device (used as a reference device, it can be a smartphone) 15 310 pressure sensor, pressure sensing means 320 optional temperature sensor 330 optional positioning system 350 observing device data exchange unit

Claims

1. A tracking device (200) for determining a position, the tracking device comprising- a pressure sensor (210) for sensing ambient air pressure,- a temperature sensor (220) for sensing ambient temperature,- a positioning means (230) for determining the position of the tracking device(200),- a tracking device data exchange unit (250) for transmitting and receiving data, wherein the positioning means (230) comprises a radio-wave based positioning system in the form of a satellite positioning system, wherein the tracking device is provided as a wearable device, and wherein the tracking device transmits ambient temperature information, ambient air pressure information, and the position.

2. Method for determining a relative position information between a tracking device and an observing device, wherein the method comprises the following steps:- determining a tracking device position information, a tracking device ambient temperature information, and a tracking device ambient air pressure information,- determining an observing device position information and an observing device ambient air pressure information,- determining a relative position information from the tracking device position information, from the tracking device ambient air pressure information, from the observing device ambient air pressure information, from the observing device position information, and from the tracking device ambient temperature information.

3. Method according to claim 2, wherein the observing device pressure information comprises an ambient air pressure retrieved from a database.

4. Method according to claim 2 or claim 3, wherein the observing device pressure information is determined including an altitude information determined based on the observing device ambient air pressure.

5. Method according to one of claims 2 to 4, wherein the altitude information is given in terms of discrete levels.

6. Method according to one of claims 2 to 5, wherein the position of the tracking device is further determined using position information obtained from a radio-wave based positioning system.5 7. Method according to claim 6, wherein the radio-wave based positioning system is a satellite positioning system.21

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