ULTRA-WIDE BAND DISTANCE DETERMINATION WITH AN ANGLE-OF-ARRIVAL BASED DISTURBANCE COMPENSATION

Abstract

There is described a ultra-wide band (UWB) communication device, comprising:

i) a UWB antenna, configured to receive a UWB signal from a further UWB communication device, and
ii) a control device, configured to
iia) determine an angle of arrival (β) based on the received UWB signal,
iib) determine a distance between the UWB communication device and the further UWB communication device, and thereby
iic) compensate for a distance determination disturbance using the determined angle of arrival (β).

Further, a UWB communication system and a method of determining a distance are described.

Claims

1-15. (canceled)

16. An ultra-wide band, UWB, communication device comprising: a UWB antenna, configured to receive a UWB signal from a further UWB communication device; and a control device, configured to determine an angle of arrival based on the received UWB signal, determine a distance between the UWB communication device and the further UWB communication device, and thereby compensate for a distance determination disturbance using the determined angle of arrival.

17. The UWB communication device according to claim 16, wherein the distance determination disturbance comprises at least one of an antenna imperfection, a delay, an angle-dependent delay, an angle-dependent group delay.

18. The UWB communication device according to claim 16, wherein the UWB communication device is configured to determine the distance based on a time-based distance measurement.

19. The UWB communication device according to claim 18, wherein the time-based distance measurement comprises at least one of time of flight, ToF, and time difference of arrival.

20. The UWB communication device according to claim 16, further comprising: a further antenna configured to receive a further UWB signal from the further UWB communication device or another UWB communication device, wherein the control device is configured to apply a phase difference of arrival, PDoA, angle determination based on the UWB signal and the further UWB signal.

21. The UWB communication device according to claim 16, further comprising: a device internal measurement device configured to measure an information indicative of the orientation of the UWB communication device, wherein the control device is further configured to determine the angle of arrival using the information indicative of the orientation.

22. The UWB communication device according to claim 21, wherein the device internal measurement device is an inertial measurement unit.

23. The UWB communication device according to claim 21, wherein the control device is further configured to estimate the spatial position of the UWB communication device based on the received UWB signal.

24. The UWB communication device according to claim 23, wherein the control device is further configured to determine the angle of arrival based on a combination of the information indicative of the orientation and the estimated spatial position of the UWB communication device.

25. The UWB communication device according to claim 16, wherein the angle of arrival determination comprises a regulation loop.

26. The UWB communication device according to claim 16, wherein the UWB communication device is at least one of the group which consists of a mobile device, a mobile phone, a transceiver, a circuit, a tag, a key, a token, a smart card.

27. The UWB communication device of claim 16, wherein the UWB communication device and the further UWB communication device are implemented in a UWB communication system, wherein the further UWB communication device comprises a further antenna.

28. The UWB communication device of claim 27, wherein the UWB communication device is a mobile device, and wherein the further UWB communication device is an anchor device.

29. The UWB communication device of claim 28, wherein the anchor device is attached to a target device.

30. The UWB communication device of claim 27, further comprising: a plurality of anchor devices forming a UWB anchor system.

31. The UWB communication device of claim 27, wherein the further antenna is configured to receive a further UWB signal from the UWB communication device or another UWB communication device, wherein the further UWB communication device comprises a further control unit configured to receive a further UWB signal and wherein at least one of the control unit and the further control unit is configured to apply a PDoA angle determination based on the UWB signal and the further UWB signal.

32. A method of determining a distance in a UWB communication system of a UWB communication device with a first antenna and a further UWB communication device with a further antenna, the method comprising: transmitting a UWB signal between the UWB communication device and the further UWB communication device; determining an angle of arrival based on the transmitted UWB signal; determining a distance between the UWB communication device and the further UWB communication device; and compensating for a distance determination disturbance using the determined angle of arrival.

33. A method of determining a distance in a UWB communication system, the method comprising using a determined angle of arrival to compensate for at least one of antenna imperfections and angle-dependent delays in a UWB communication system.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0045] FIG. 1 illustrates a UWB communication system according to an exemplary embodiment of the present disclosure.

[0046] FIG. 2 illustrates a UWB communication device using a phase difference of arrival measurement according to an exemplary embodiment of the present disclosure.

[0047] FIG. 3 illustrates a UWB communication system using an inertial measurement unit according to an exemplary embodiment of the present disclosure.

[0048] FIG. 4 illustrates a UWB communication device using a regulation loop according to an exemplary embodiment of the present disclosure.

[0049] The illustrations in the drawings are schematic. In different drawings, similar or identical elements are provided with the same reference signs.

DESCRIPTION OF THE DRAWINGS

[0050] Before, referring to the drawings, exemplary embodiments will be described in further detail, some basic considerations will be summarized based on which exemplary embodiments of the present disclosure have been developed.

[0051] According to exemplary embodiments of the present disclosure, there is described a method to compensate for the angle-dependent antenna group delay in a UWB-equipped device that includes either a UWB transceiver system that is able to estimate the angle of arrival (AoA) of the incoming signal or a UWB system that comprises an inertial measurement unit (IMU) for estimating its relative orientation and thus also the incoming angle of the signal. i) In case of a two-antenna based transceiver system, the AoA can be estimated based on the phase-difference of arrival (PDoA) of the signal received at the two receiver antennas and then mapped to the relative azimuth and elevation of the transmitter with respect to the coordinate system of the receiver device. ii) In case of a UWB transceiver system including an IMU, the coarse position estimate of the transceiver can be combined with the known device orientation for estimating the azimuth and elevation AoA of the incoming signal. Given these AoA estimates and known angle-dependent antenna group delays for each channel, obtained from an antenna characterization experimental campaign, an azimuth and elevation based antenna delay compensation can be applied that results in more accurate distance estimates.

[0052] According to exemplary embodiments of the present disclosure, the described method can be applied in any UWB system that performs ranging (distance determination) and is able to estimate the angle of arrival (AoA) of the incoming signal, e.g. either using a multi-antenna system or an IMU. The described method can for example be used in the following applications: [0053] Indoor/outdoor navigation systems using UWB ranging. [0054] Indoor/outdoor tracking systems using ranging schemes. [0055] Mobile systems that measure the distance between users, e.g., for social distancing. [0056] Mobile systems to find a user distance or relative position w.r.t. a UWB-equipped object, e.g., smart tags or when using a UWB-equipped smartphone as a controller for IoT devices. [0057] Automotive smart access systems.

[0058] FIG. 1 illustrates a UWB communication system 100 according to an exemplary embodiment of the disclosure. The UWB communication system 100 comprises a UWB communication device 110 with a first antenna 111 and a further UWB communication device 120 with a further antenna 121. In this example, the UWB communication device 110 is a mobile device such as a mobile phone or tag, while the further UWB communication device 120 is a stationary device, for example an anchor device attached to a target device. A UWB communication signal can be transferred between the antenna 111 of the UWB communication device 110 and the further antenna 121 of the further UWB communication device 120. In this example, both directions are possible. The UWB communication device 110 comprises a control unit (e.g. an IC, not shown) configured to determine a distance between the UWB communication device 110 and the further UWB communication device 120. The distance determination is based on a time of arrival measurement of the UWB signal transferred between the UWB communication device 100 and the further UWB communication device 120.

[0059] In this example, device 1 (further UWB communication device 120) uses a non-ideal antenna ant1 (further antenna 121) for UWB communication and distance estimation. Device 2 (UWB communication device 110) uses an ideal antenna ant2 (antenna 111) for UWB communication. Using a two-way ranging (TWR) exchange, a common ranging-based distance estimation technique, the devices 110, 120 can determine the distance between them. While the position of device 1 is static, device 2 changes its position. At pos1 of device 2, device 1 receives the UWB signal emitted by device 2 with the signal angle of arrival β1. When device 2 is at pos2, device 1 receives the UWB signal with the signal angle of arrival β2. If device 2 is at pos1, the physical distance between the devices is distance 1, while at pos2, the physical distance is distance 2. Since device 1 uses a non-ideal antenna, the antenna delay is a function of the incoming signal angle called f_antenna_delay(β), where β is the incoming signal angle compared to the antenna reference axis shown as a dashed line in FIG. 1. Since device 1 uses a non-ideal antenna whose delay depends on the angle of the incoming signal, the position of device 2 with respect to the position of device 1 changes the direction of the signal, thereby affecting the distance determination (distance determination disturbance).

[0060] This issue is solved in the present disclosure by i) determining an angle of arrival β based on a received UWB signal, and ii) determining the distance between the UWB communication device 110 and the further UWB communication device 120, while compensating for a distance determination disturbance such as an (angle-dependent) delay and an antenna imperfection, using the determined angle(s) of arrival β1, β2.

[0061] FIG. 2 illustrates a UWB communication device 110 or a UWB communication system 100 using a phase difference of arrival measurement according to an exemplary embodiment of the present disclosure. In particular, there are applied at least two antennas, each receiving an incoming UWB signal. While the distance L between the two antennas is known, a distance Δl is calculated based on the phases of a received UWB signal and a received further UWB signal.

[0062] According to a first option, there is provided a UWB communication device 110 with multiple antennas. Thus, the UWB communication device 110 comprises a further antenna 112 configured to receive the further UWB signal from the further UWB communication device 120 or another UWB communication device 130. The control device of the UWB communication device 110 is configured to apply a phase difference of arrival, PDoA, angle determination based on the UWB signal and the further UWB signal.

[0063] According to a second option, there is provided a UWB communication system 100 with the UWB communication device 110 comprising the antenna 111 and the further UWB communication device 120 comprising the further antenna 121. The further antenna 112 is configured to receive a further UWB signal from another UWB communication device 130. The control unit and/or the further control unit is configured to apply a PDoA angle determination based on the UWB signal and the further UWB signal.

[0064] FIG. 3 illustrates a UWB communication system 100 using an inertial measurement unit according to an exemplary embodiment of the present disclosure. The UWB communication system 100 comprises the UWB communication device 110 (here device 1) comprising a device internal measurement device, being an inertial measurement unit 115, coupled to the UWB system (control unit). Said unit 115 is configured to measure an information indicative of the orientation of the UWB communication device 110, for example based on the earth magnetic field. The UWB communication system 100 further comprises an anchor system 101 containing four anchor devices 120 130, 140, 150. Each anchor device comprises a respective UWB antenna 121, 131, 141, 151. UWB signals are transmitted between the UWB communication device 110 and the respective anchor devices 120, 130, 140, 150, in this example in both directions.

[0065] Based on the time of arrival of these UWB signals, distances can be estimated. The control device of the UWB communication device 110 is configured to estimate the spatial position of the UWB communication device 110 based on the received UWB signals using a ToA measurement method. The control device (or a further control device of one of the anchor devices) is further configured to determine the angle of arrival β based on a combination of the information indicative of the orientation and the estimated spatial position of the UWB communication device 110. The information indicative of the orientation of the UWB communication device 110 can be transferred to the anchor devices by UWB communication or by an out-of-band channel.

[0066] FIG. 4 illustrates a UWB communication device 110 using a regulation loop 160 according to an exemplary embodiment of the present disclosure. The UWB communication device 110 applies the IMU unit 115 based angle of arrival determination described in FIG. 3 above. In order to improve the angle determination, a feedback loop is implemented. The difference between the last two position estimates (based on the orientation and the coarse position estimate of the UWB communication device) is compared to a predefined threshold. If the position estimate difference is below the threshold, the compensated device position can be further applied (report compensated device position). If the position estimate is, however, above the threshold, a counter is incremented, and a further regulation round is performed.

[0067] In this specification, embodiments have been presented in terms of a selected set of details. However, a person of ordinary skill in the art would understand that many other embodiments may be practiced which include a different selected set of these details. It is intended that the following claims cover all possible embodiments.

REFERENCE NUMERALS

[0068] 100 UWB communication system [0069] 101 Anchor system [0070] 110 UWB communication device [0071] 111 Antenna [0072] 112 Further antenna (same device) [0073] 120 Further UWB communication device [0074] 121 Further antenna [0075] 130 Other device, anchor device [0076] 140, 150 Anchor devices [0077] 131, 141, 151 Antennas [0078] 160 Regulating loop