INDOOR POSITIONING SYSTEM UTILIZING BEAMFORMING WITH ORIENTATION- AND POLARIZATION-INDEPENDENT ANTENNAS
20180191079 ยท 2018-07-05
Inventors
- John T. Apostolos (Lyndeborough, NH)
- William Mouyos (Windham, NH)
- James D. Logan (Candia, NH)
- Sean Joseph (Windham, NH, US)
Cpc classification
H01Q7/00
ELECTRICITY
H01Q9/16
ELECTRICITY
G01S5/28
PHYSICS
H01Q21/24
ELECTRICITY
G01S5/0268
PHYSICS
G01S5/20
PHYSICS
H01Q19/32
ELECTRICITY
G01S3/14
PHYSICS
International classification
H01Q19/13
ELECTRICITY
H01Q9/16
ELECTRICITY
Abstract
Orientation-independent antennas and associated beamforming circuits, to provide polarization-independent determination of position. An Indoor Positioning System (IPS) may utilize beacon or tag devices equipped with orientation-independent antennas to determine the location of nearby objects. The system can exist in many different customizable configurations, sometimes utilizing orientation-independent antennas embedded in smartphones that serve as beacon or tag devices. The devices, systems and methods described herein may be used for an IPS in a residential setting, a commercial setting (like a department store), an event or workplace, or an industrial setting.
Claims
1. A directional antenna apparatus comprising: a pair of crossed dipole elements; a loop element; and combining circuits to produce an output proportional to at least one of azimuth or elevation of a radiated signal, the output independent of both orientation of the apparatus and polarization of the radiated signal.
2. A position detection system comprising a beacon device or tag device that use the antenna of claim 1 for reception and/or transmission of wireless signals.
3. An indoor positioning system comprising: a beacon device for receiving a wireless signal from a tag device using an orientation independent antenna for receiving the wireless signal, the wireless signal having been transmitted from the tag device using a directional antenna.
4. A directional antenna apparatus for use within an indoor environment, comprising: an orientation-independent antenna array located at a known height from a floor; combining circuits to produce an output proportional to azimuth and elevation of a signal radiated from a remote device; and a processor, for using the azimuth, elevation, and known height information to locate the remote device in three dimensions.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] The description below refers to the accompanying drawings, of which:
[0008]
[0009]
[0010]
[0011]
[0012]
[0013]
[0014]
[0015]
DETAILED DESCRIPTION OF AN ILLUSTRATIVE EMBODIMENT
Indoor Positioning System (IPS) Using Orientation-Independent Antennas
[0016]
[0017] The beacon 102 may in turn be connected via wireless or wired connection to a processor 110 that accesses one or more databases 112. The databases may derive and/or maintain information such as unique identification (UID) numbers for the tags 104 or their associated users, maps of the location in which the system 100 is placed, and other information such as analytics derived from collected location data. The databases 112 may be accessed by other devices 114 such as a laptop computer to display and analyze the data collected by system 100. Processor 110 and databases 112 may be partially or wholly contained within beacon 102.
[0018] Of note is that beacon 102 and/or tags 104 include scanning directional antennas that may focus radiate energy in steerable beams 103, 105. The use of scanning directional antennas enables the distance between the beacon 102 and tags 104 to be increased as compared to implementations that instead use fixed omnidirectional antennas. It should also be noted that the tags 104 and their respective antennas may be disposed in various orientations with respect to the surrounding area. For example, tag 104-2 is laying horizontally on a table, but tag 104-3 is attached to an object in a person's pocket, and is laying in a generally vertical direction. Tag 104-1 is in some other location, such as in a person's hand, and is thus positioned at some other unknown angle.
[0019] The use of directional antennas also increase security of system 100 as interference from unknown devices 102, 104 may be attenuated.
[0020]
[0021]
[0022]
[0023] The radiating elements 2120 may have various physical configurations and may be tuned in particular ways. For example, rectangular patch elements may be folded over onto or near the front and back faces in a u shape to conform to the edges of housing 2115. In that configuration, the radiating elements circumscribe a volume that not only encompasses a space along the edge of the housing, but also encompasses a space that reaches into the body of the device 2100.
[0024] In some arrangements as shown in
[0025] The X,Y,Z axes shown in
[0026] In one aspect, the horizontal component H may be suppressed by the cylindrical antenna element 300 if the diameter versus height ratio of the cylinder 302 is relatively large. In one example for operation at 2400 MHz, bandwidth of 200 MHz, a quality factor Q of 12 in a
[0027]
[0028] A second hybrid power combiner 402, which is a difference, or 180 combiner provides an output signal
DB= sin()
and a third 180 hybrid 403 provides
AC= cos()
The outputs of combiners 402, 403 feed a 90 quadrature hybrid 404 to produce a signal,
V=e.sup.j
proportional to the azimuthal angle.
[0029] A phase detector 406 can determine a phase difference 406 between signals V.sub. and V thus provides the azimuthal angle, . A hybrid divider 407 determines the ratio between them, to produce an output proportional to the elevation angle .
[0030] Another implementation shown in
H cos
Hybrid combiners 602, 604 are 180 combiners that provide both a sum and difference output. The 180 hybrid combiners 602, 604, quadrature combiner 606, and combiner 608, arranged as shown, produce signals:
V cos
V sin
H cos
H sin
Ve.sup.j
and
He.sup.i
As shown in the equations of
[0031] In one implementation, the tags 104 may be smartphones. In that implementation, as per
[0032] It can now be understood that both types of orientation-independent antenna arraysthe cylindrical element arrays shown in
[0033] In one use case, the detected angle of arrival happens to be parallel to two of the sides of the smartphone housing (due north or due south), or happens to coincide with a centerline axis of the cylindrical array implementation. In that instance, the two sets of beams generated by the line arrays on the two sides that are parallel to that direction (that is, line arrays 2101 and 2103 shown in
Indoor Positioning System Options and Use Cases
[0034] The functions described above are obtained by packing an orientation-independent antenna or some other similar antenna in a single device to provide position and/or direction finding.
Scanning Rates:
[0035] In some implementations, the antenna array 160 associated with the beacon 102 may be scanned at a rate that is different than the rate at which the antenna 300 associated with the tag 104 is scanned. Different procedures may be used to determine which device scans at the higher rate, while the other device scans or is incrementally stepped at a slower rate.
Inclinometer Alignments to Directional Array:
[0036] An inclinometer, if available in the beacon 102 or tag 104, may provide some additional information as to the orientation of the X, Y, and Z axes with respect to a reference, such as the earth's magnetic field. That information may be used to simplify the processing needed to determine elevation and azimuth.
Ranging Techniques
[0037] The distance between beacon 102 and tag 104 may be determined by any known ranging techniques. In one example, range can be determined using time difference of arrival (TDOA) using a cooperative protocol that places the tag 104 in a transponder mode, and having the beacon 102 emit a narrow ranging pulse (on the order of a few nanoseconds wide). The range can then be estimated by measuring the delay of the resulting response from the tag 104. Other methods are possible, for example, if the cellular, WiFi, Bluetooth, or other wireless protocols in use provide Receive Signal Strength Indication (RSSI) outputs.
[0038] In other implementations, the beacon 102 and tag 104 may not necessarily operate a cooperative ranging protocol. In that instance, range may still be determined by operating individual circular subarrays 1600 of array 160 or end fire arrays 2101, etc. in a stereoscopic or triangulation mode. For example, a first circular subarray 1600-1 may be placed in a scanning mode and locate a first angle of arrival 1 for a tag 104. A second circular subarray 1600-2 may also be placed in a scanning modebecause subarray 1600-2 is at a slightly different position, it may detect a signal from tag 104 at a second angle of arrival 2. A crossover point between line vectors 1 and 2 determines a location for tag 104.
[0039] Thus, in one implementation, for tags 104 operating a cooperative protocol, the beacon 102 may selectively use the directional forwarding/time of flight mode to determine position. However, for tags 104 that do not operate a cooperative protocol, the beacon may switch to a mode that uses stereoscopy/triangulation to locate the tags 104.
A Single Orientation-Independent Antenna Tag:
[0040] A single orientation-independent antenna tag 104 may actively scan for neighboring beacons 102 using its directional capabilities. This scanning will incur approximately 5% more energy consumption to do than to simply broadcast omni-directionally like most traditional Bluetooth low energy systems do. The orientation-independent antenna beamforming directional scanning region may be focused in the direction it is scanning, and thus have a relatively narrow, or pencil beam shape. This directional scanning may, for example, have approximately 25% more range than an omni-directional scan, allowing for more active positioning to take place, and reducing interference.
[0041] In some implementations, the orientation-independent antennas 160, 300 or 2100 may scan quadrant by quadrant in 45 degree or 90 degree intervals. Upon coming into contact with an orientation-independent antenna array (a beacon 102) or another orientation-independent antenna equipped device 104, such as a smartphone, the orientation-independent antenna tag 104 and the new signal may both orient themselves through scanning to maximize signal strength between the two. At this point the orientation-independent antenna's position relative to the new signal may be determined to within about 1% by the smartphone or beacon using time of flight, signal strength, and/or directional information stored by the orientation-independent antenna from an inclinometer. This relative location can either be used directly by an orientation-independent antenna equipped smartphone user (with an arrow pointing in the direction stating the distance away the object is) or can be converted to absolute positional data by the beacon. Assuming the building has been mapped in some way or another and the beacons location in the building has been tied to that map, the absolute location of that orientation-independent antenna can be determined, not just its location relative to the beacon/smartphone signal. These capabilities come at a low cost to manufacture. In some implementations, the orientation-independent antenna can operate at a unique frequency using a unique waveform so it does not interfere with other signals such as Bluetooth, Wi-Fi, or other signals.
Multiple Orientation-Independent Antenna Tags:
[0042] A similar process my occur with multiple orientation-independent antenna tags 104 as for a single orientation-independent antenna tag 104; they may come into contact with one another while scanning and form a constellation of relative positions by communicating between themselves. Once one of those relative positions is tied to an absolute location by a beacon 102 or orientation-independent antenna equipped smartphone, all of the other relative locations in contact with the absolute orientation-independent antenna may also be resolved to absolute locations using the same process.
Beacons:
[0043] As shown in
Orientation-Independent Antenna in a Smart Device:
[0044] An orientation-independent antenna embedded in a smart mobile device (smartphone or laptop) works largely the same as an orientation-independent antenna tag 104, but unlike most orientation-independent antenna embedded tags (like a TV remote or a keychain), a smart device is capable of giving feedback directly to the user. This means when an orientation-independent antenna embedded smart device enters an orientation-independent antenna constellation it can give the user information about the objects nearby it. A map could be displayed, marked with waypoints (like pins on a map) for orientation-independent antenna objects and labeled based off of a Unique Identification (UID). Additionally, when no predefined map is readily available, the orientation-independent antenna smart device can act as a sort of compass, pointing the phone in the direction of the orientation-independent antenna objects and giving the user angle and distance information.
Orientation-Independent Antenna Adjustment Based Off of Previous Smartphone or Beacon Interactions:
[0045] If an orientation-independent antenna equipped device 102, 104 frequently makes connections with smart devices or beacons in a specific direction, the devices may alter their scanning pattern(s) in order to intelligently scan areas where it is more likely to pick up a signal. This means if an object is in one corner of a home (for example), and a beacon 102 only ever finds connections by pointing west, it will spend far more of its time searching in that direction, making it even easier to detect tags 104.
Intelligent Scanning Rates:
[0046] One design consideration for an orientation-independent antenna-based IPS system is the directional scanning rate of each orientation-independent antenna equipped object 102, 104. If two objects scan around themselves at the exact same rate it is possible they may never come into contact with each other even if they are within range. To counteract this issue, orientation-independent antenna scanning rates may be variable. Low energy objects such as tags 104 with small batteries may scan at a slow rate. Beacons 102 could scan at a much higher rate (and with more smooth adjustments rather than scanning quadrant by quadrant) because of their energy source (a wall plug). Smart devices (such as a phone or laptop) using orientation-independent antennas may also utilize a variable scan rate. The smartphone orientation-independent antenna may scan at a higher rate than tags 104, similar to a beacon, however such a smart device may scan at a lower rate than the beacon 102 itself to allow nearby beacons to improve detection.
Usage of IPS System in Various Settings:
Residential Setting
[0047] In a residential setting the orientation-independent antenna can be used as an object detection apparatus for other orientation-independent antenna equipped objects throughout the house. A single stationary orientation-independent antenna equipped device with access to an electrical outlet (a beacon 102) or a smartphone equipped with an orientation-independent antenna may be sufficient in order to locate any object within their range. The beacon or smartphone are not necessarily doing the actual mapping of the house, as this could be accomplished by one of the various home mapping technologies currently available. However, mapping could also be completed by using a stationary orientation-independent antenna device in tandem with a smartphone.
[0048] 1. Stationary Orientation-Independent Antenna with Access to Wall Outlet: [0049] One of these residential beacon orientation-independent antennas 102 could be placed somewhere in the house. Embedded in an Amazon Alexa or Google Home or similar devices would be one preferred option. This orientation-independent antenna device could give information regarding the location of other orientation-independent antenna equipped devices in the house. In the example of an Amazon Alexa the user could ask where are the car keys and the Alexa could respond with in the living room. One additional feature to this residential setup is that a map of the home could be utilized to bind the constellation of orientation-independent antenna devices 104 (generated as the devices in the house come into contact with one another and each determine their relative location, as described previously) to the physical world. This could be a picture of a floor plan, a map generated by currently available home mapping technology, a map generated by the user as a drawing, or a map generated using other orientation-independent antenna devices and a smartphone equipped with an orientation-independent antenna.
[0050] 2. Using a Mobile Device with an Orientation-Independent Antenna: [0051] In a home without an orientation-independent antenna beacon 102 but with orientation-independent antenna tags 104, location data could still be used by an orientation-independent antenna equipped smartphone. The phone may detect nearby orientation-independent antenna equipped devices and create a constellation map of these for the user. This information might still be relative positional data, but because the user would be holding the orientation-independent antenna equipped phone, they could still use the constellation around them to find the object they want. Essentially, because the smartphone user knows where they themselves are and they know the relative position (distance and angle) of the nearby orientation-independent antennas, they can tie the orientation-independent antenna constellation to the familiar real world position of the devices around them.
[0052] 3. Using Both to Map the House: [0053] When a user has access to both an orientation-independent antenna equipped beacon 102 and an orientation-independent antenna equipped mobile device 104 the user can create a map of the house. This map would help tie the relative location of the orientation-independent antenna device constellation to the real world position of those objects in the house. This process would be initiated by the user on the smartphone. They would start at the entrance to the home and pace the perimeter of the house. Because the orientation-independent antenna beacon 102 is stationary and can track orientation-independent antenna tags or mobile device(s) 104, the user may create an outline of their home. Additionally software could be implemented to label the various rooms of this user created map, allowing for even greater ease in locating orientation-independent antenna tags 104 in the house.
[0054] 4. on the go: [0055] Even when in a car or out in the world an orientation-independent antenna equipped system can still work as a limited IPS system. For example; assume a user drives their car out for a picnic. The user then forgets their keys in the field where they had the picnic. The user backtracks to near where they believe they lost their keys and tries to locate them using an orientation-independent antenna equipped smartphone. If the keys have an orientation-independent antenna tag in the chain and are within range the phone can tell the user the distance and angle the keys are from the user. This can be used as a sort of compass directing the user back to their keys. This system can also be used to make sure a user doesn't lose their keys in the first place. The keys and phone could be set to notify the user if they become a certain range apart from one another.
Commercial Setting
[0056] In a Commercial setting the orientation-independent antenna equipped devices may be used in an indoor mapping system in order to determine positional data. A single stationary orientation-independent antenna beacon may be all that is necessary for positional tracking as long as all objects that need to be tracked are within its range. There are various different ways the orientation-independent antenna based IPS can be used in a commercial setting. The beacon 102 can be used to track materials throughout a store. The beacon 102 can also track orientation-independent antenna equipped mobile devices 104 moving throughout its range. The beacon can even track non cooperative sources such as non-orientation-independent antenna equipped Bluetooth devices using its ranging techniques described elsewhere. This permutation of the IPS could also tie very closely into available mapping software. One conceivable use of this could be a user with a shopping list. Assuming the objects are tagged when the user enters the store, an app like Google maps could be overlaid with collected data to create an optimum path to get to all of the objects on their list as quickly as possible. Additionally, if the objects are tagged the user could be charged directly through their phone when they leave the store without having to check out.
[0057] 1. Beacon and Orientation-Independent Antenna Based Smartphone (and Orientation-Independent Antenna Equipped Objects): [0058] When a beacon 102 is in a store it can track the location of all smart device users with orientation-independent antennas 104 within the range of the beacon through the previously described methods. This can be used to communicate with the orientation-independent antenna mobile devices 104 so users can determine their own location within a store. For example, in a shopping mall a user could find their precise location within the mall by checking their phone rather than having to find a mall map kiosk. This map the users are presented with can be used as an advertising space for stores as well. Users could see what stores are nearby and receive recommendations for what is on sale right on the map. This system could also work in a single store like a Home Depot. The user could be told by the beacon their own position in the store and also see waypoints (like a pin on a map) of objects within the store equipped with orientation-independent antennas. This could be used as a searchable catalog so that a user could simply Google maps search, for example, duct tape in the store and be presented with a pin on the map of the store for the aisle and bay location of the duct tape. This could work as additional ad space with specific tape manufacturers purchasing advertisement(s) for their stocked brand to show up as the users first search result.
[0059] 2. Beacon and Non-Cooperating Bluetooth or Other Signals: [0060] For big-data and consumer-trends purposes data could also be collected from consumers not trying to utilize the orientation-independent antenna indoor positioning system. If a store owner installed a beacon 102 even if no users were interested in connecting with the orientation-independent antenna indoor positioning system, some data could be recorded. For example, standard Bluetooth or WiFi signals transmitted by a phone may be positionally tracked by orientation-independent antenna beacons 102 through the use of stereoscopy. This data could be used by store owners in order to optimize the experience of consumers in the store. This could be done by opening more registers in response to the number of people in the store or determining superior aisle structuring based off of consumer movement data.
[0061] 3. Beacon and Cooperating Legacy Devices (Like Bluetooth): [0062] Assuming a user was interested in connecting with the indoor positioning system, they could use the system even if their device wasn't equipped with an orientation-independent antenna. In one example, as long as they allow a Bluetooth connection with the beacon 102 they could be given exact positional data from the beacon. This information could be collected by the beacon as described in the previous scenario and the user can be identified by their Bluetooth UID. The user could then indicate they were in the store and interested in using the IPS (by opening the app) and the app would connect their positional data to them.
Event Setting
[0063] In an event setting like a trade show or an amusement park, the orientation-independent antenna based IPS is also useful. The system would function somewhat similarly to how it functions in a commercial setting; with a beacon 102 set up somewhere at the event and users 104 being tracked. The additional functionality for events could be using orientation-independent antenna tags 104 to create waypoints for certain booths or rides. Being able to look at an interactive park/event map on a smartphone would also give the opportunity to present users with more advertisements for specific booths, rides, or events the event would like to promote by annotating the map. In a theme-park like environment, the IPS would also make a great child tracker. Many child devices have GPS capabilities so parents can roughly keep track of their child's location, but in a setting like an amusement park, those rough GPS-based estimates may not be accurate enough if a child goes missing. Being able to precisely keep track of a child's position using the IPS can be achieved with the parent and child device once they have allowed their devices to be visible to one another on the map through permissions. A child would not even necessarily need to have a smartphone, but may only need an inexpensive orientation-independent antenna tag 104 set up to only transmit positional data to the parent/user device. This would be sufficient to keep track of child's position without revealing it to strangers.
Industrial Setting
[0064] In an industrial setting such as a warehouse or system of warehouses there are already many different types of package tracking systems. An orientation-independent antenna based positioning system can work similarly to other package tracking systems, or build off of them, while also offering the additional functionality of displaying the packages as waypoints or pins on a map for employees. Many automated systems have a drawback of being difficult to navigate for humans. Robots can find packages just fine, but if an issue pops up, a human needs to look through a database of countless packages to find it. By generating a map with packages listed as waypoints, employees would not have to deal with databases and could simply be presented with a map having waypoints to locate the product they need to find.
Retail Setting without Direct Line of Sight
[0065]
[0066] To this end, one or more orientation-independent antennas are place in or near a ceiling. In an acquisition mode, the orientation-independent antenna can be controlled to scan over the entire floor with a directional, narrow beam. The beam may be relatively narrow such as 45 degrees. Individual cell phone users such as 1 and 2 are isolated and located within the beam width of the orientation-independent antenna.
[0067] Accurate elevation angle, azimuth angle and polarization of the incident plane wave are then determined using the polarization independent algorithms described in the above-referenced patent application. Since the cell phone users 1 and 2 are located on the floor, theta (), phi (), and H are all that are needed to determine location in three dimensions of line of sight targets such as user 2.
[0068] Targets such as user 1, which are not in a direct line of sight to the orientation-independent antenna, may be hidden by a row of shelves. The acquisition of energy by the orientation-independent antenna from target user 1 may be due to a reflection off of an adjacent line of shelves.
[0069] In one approach, with the cell phone operating a cooperative protocol that reports receive signal strength back to the orientation-independent antenna, that information for beams emitted in different directions by the orientation-independent antenna (or from different orientation-independent antennas) may resolve position ambiguities (such as by selecting the strongest received signal).
[0070] However, an estimate of the location of target 1 can also be made by using geometric ray tracing, physical optics ray tracing or using an electromagnetic modeling program such as High Frequency Electromagnetic Field Simulation (HFSS) software available from ANSYS, Inc. of Canonsburg, Pa. The high accuracy provided by the orientation-independent antenna direction of arrival algorithms enhances the result of these ray tracing methodologies. These schema typically require an accurate representation of the geometry of the store with its fixtures, walls, shelves, etc.
[0071] In some implementations, a last known position of user 2 may also be used to resolve ambiguities.
[0072] Another scheme involves calibrating the entire store by having a staff person walk through all the aisles/product locations with a cell phone, transmitting a signal to the orientation-independent antenna array. A data base of target location versus orientation-independent antenna measurement of theta and phi can then be created. Thus, for each acquisition and measurement event during store hours, there will be a corresponding unique target location.
[0073] If scattering of the target electromagnetic waves is polarization dependent (i.e. cell phone orientation), then as the calibrating person walks through the store, three orthogonal polarizations in the x,y,z directions can be generated. The data base, for each target location, will then have three components of incident plane wave information from the orientation-independent antenna, (theta, phi, polarization), for each of the three x,y,z target polarization vectors. The data base containing these three vectors for all the target locations thus calibrated can then be correlated against the received vector (theta, phi, and polarization) from the orientation-independent antenna for each acquisition and measurement event during store hours. The maximum correlation indicates which target location is valid.
[0074] The ray tracing methodologies may also take into account polarization since the orientation-independent antenna array measures the polarization of the incident wave.