Distributed localization systems and methods and self-localizing apparatus

• US 10,302,737 B2
• Filed: 03/09/2018
• Issued: 05/28/2019
• Est. Priority Date: 03/07/2015
• Status: Active Grant

• Current Assignee: Verity AG
• Original Assignee: Verity Studios AG
• Inventors: Hehn, Markus, Waibel, Markus, D'Andrea, Raffaello
• Primary Examiner(s): Cai, Wayne H
• Application Number:
  US15/917,544
• Publication Number:
  US 20180196120A1
• Time in Patent Office: 445 Days
• CPC Class Codes: G01S 1/024 of beacon transmitters
• CPC Class Codes: G01S 1/20 using a comparison of transit time of synchronised signals transmitted from non-directional antennas or antenna systems spaced apart, i.e. path-difference systems
• CPC Class Codes: G01S 5/0289 of multiple transceivers, e.g. in ad hoc networks
• CPC Class Codes: G01S 5/14 Determining absolute distances from a plurality of spaced points of known location
• CPC Class Codes: G05D 1/101 specially adapted for aircraft
• CPC Class Codes: H04B 1/7163 using impulse radio
• CPC Class Codes: H04W 4/026 using orientation information, e.g. compass
• CPC Class Codes: H04W 4/027 using movement velocity, acceleration information
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks

Abstract

A self-localizing apparatus uses timestampable signals transmitted by transceivers that are a part of a distributed localization system to compute its position relative to the transceivers. Transceivers and self-localizing apparatuses are arranged for highly accurate timestamping using digital and analog reception and transmission electronics as well as one or more highly accurate clocks, compensation units, localization units, position calibration units, scheduling units, or synchronization units. Transceivers and self-localizing apparatuses are further arranged to allow full scalability in the number of self-localizing apparatuses and to allow robust self-localization with latencies and update rates useful for high performance applications such as autonomous mobile robot control.

Claims

1. A method for calibrating ultra wideband (UWB) transceivers in an UWB transceiver network comprising at least a first UWB transceiver, a second UWB transceiver, and a third UWB transceiver, each with at least partially unknown relative positions, the method comprising:

wirelessly transmitting, using at least two of the first, second, and third UWB transceivers, at least two UWB signals;

receiving one or more of the at least two UWB signals at at least two of the first, second, and third UWB transceivers, wherein there are at least three receptions of the at least two UWB signals;

timestamping each of the at least three receptions to generate at least three reception timestamps;

receiving the at least three reception timestamps at a position calibration unit; and

computing, using the position calibration unit, a position of the first UWB transceiver, a position of the second UWB transceiver, and a position of the third UWB transceiver based on the at least three reception timestamps.

2. The method of claim 1, further comprising:

initializing, in the position calibration unit, the positions of the first, second, and third UWB transceivers based on partial knowledge.

3. The method of claim 2, wherein:

the position calibration unit continuously maintains an estimate of the positions of the first, second, and third UWB transceivers;

the initializing comprises initializing a position estimate; and

the computing comprises updating the position estimate.

4. The method of claim 1, wherein:

wirelessly transmitting the at least two UWB signals comprises;

wirelessly transmitting, using the first UWB transceiver, at least one first UWB signal; and

wirelessly transmitting, using the second UWB transceiver, a second UWB signal;

receiving the one or more of the at least two UWB signals at at least two of the first, second, and third UWB transceivers comprises;

receiving one of the at least one first UWB signal at the second UWB transceiver;

receiving one of the at least one first UWB signal at the third UWB transceiver; and

receiving the second UWB signal at the third UWB transceiver; and

timestamping each of the at least three receptions to generate at least three timestamps comprises;

timestamping the reception of the one of the at least one first UWB signal at the second UWB transceiver based on a clock of the second UWB transceiver to generate a first timestamp;

timestamping the reception of the one of the at least one first UWB signal at the third UWB transceiver based on a clock of the third UWB transceiver to generate a second timestamp; and

timestamping the reception of the second UWB signal at the third UWB transceiver based on the clock of the third UWB transceiver to generate a third timestamp.

5. The method of claim 4, wherein the first UWB transceiver comprises a first sensor and wherein the second UWB transceiver comprises a second sensor, the method further comprising:

receiving a first data reading from the first sensor;

receiving a second data reading from the second sensor;

transmitting the first data reading to the position calibration unit; and

transmitting the second data reading to the position calibration unit,

wherein computing the positions is further based on the first data reading and the second data reading.

6. The method of claim 4, further comprising:

wirelessly transmitting, using the third UWB transceiver, at least one third UWB signal prior to the wireless transmission of one of the at least one first UWB signal and prior to the second UWB signal;

wirelessly transmitting, using the second UWB transceiver, a fourth UWB signal prior to the wireless transmission of one of the at least one first UWB signal;

receiving the fourth UWB signal at the first UWB transceiver;

receiving one of the at least one third UWB signal at the first UWB transceiver; and

receiving one of the at least one third UWB signal at the second UWB transceiver,

wherein computing the positions is further based on;

at least one transmission time stamp of the at least one third UWB signal;

a transmission time stamp of the fourth UWB signal;

a known transmission delay between a reception of an UWB signal at the first UWB transceiver and a corresponding transmission of an UWB signal from the first UWB transceiver; and

a known transmission delay between a reception of an UWB signal at the second UWB transceiver and a corresponding transmission of an UWB signal from the second UWB transceiver.

7. The method of claim 1, wherein:

the UWB transceiver network comprises a fourth UWB transceiver with at least a partially unknown position to the first, second, and third UWB transceivers;

wirelessly transmitting, using at least two of the first, second, and third UWB transceivers, the at least two UWB signals comprises wirelessly transmitting, using at least three of the first, second, third, and fourth UWB transceivers, at least three UWB signals;

receiving one or more of the at least two UWB signals at at least two of the first, second, and third UWB transceivers comprises receiving one or more of the at least three UWB signals at at least three of the first, second, third, and fourth UWB transceivers, wherein there are at least six receptions of the at least three UWB signals;

timestamping each of the at least three receptions comprises timestamping each of the at least six receptions to generate at least six timestamps;

receiving the at least three timestamps comprises receiving the at least six timestamps; and

computing the positions comprises computing the positions of the first, second, third, and fourth UWB transceivers based on the at least six timestamps.

8. The method of claim 7, wherein computing the positions of the first, second, third, and fourth UWB transceivers comprises solving a system of hyperbolic equations or a linearized version thereof.

9. The method of claim 1, further comprising transmitting data representative of the positions of the first, second, and third UWB transceivers to a self-localizing apparatus within range of at least one of the first, second, and third UWB transceivers.

10. The method of claim 1, wherein one of the first, second, and third UWB transceivers comprises a sensor configured to detect movement, the method further comprising:

detecting movement of the one UWB transceiver based on a sensor signal from the sensor; and

wirelessly transmitting, in response to detecting movement, information indicating that the one UWB transceiver has moved.

11. The method of claim 1, wherein the first UWB transceiver comprises a first clock, the second UWB transceiver comprises a second clock, and the third UWB transceiver comprises a third clock, the method further comprising synchronizing, using a synchronization unit, the first, second, and third clocks timing offsets or rate errors, the method further comprising:

scheduling, using a scheduling unit, the transmission of UWB signals from the first, second, and third UWB transceivers.

12. The method of claim 11, wherein scheduling the transmission comprises scheduling time division multiple access (TDMA) time slots, wherein the UWB transceiver network comprises an additional UWB transceiver, wherein wireless transmissions of the additional UWB transceiver do not interfere with a particular one of the first, second, and third UWB transceivers, and wherein scheduling the TDMA time slots comprises allocating one TDMA time slot to both the additional UWB transceiver and the particular one of the UWB transceivers.

13. The method of claim 1, further comprising computing, using the position calibration unit, refined positions of the first, second, and third UWB transceivers based on at least two subsequently transmitted UWB signals.

14. The method of claim 1, wherein the computed positions of the first, second, and third UWB transceivers comprise relative positions.

15. An ultra wideband (UWB) system, comprising:

a first UWB transceiver comprising a first clock;

a second UWB transceiver comprising a second clock;

a third UWB transceiver comprising a third clock,

wherein;

at least two of the first, second, and third UWB transceivers are configured to transmit at least two UWB signals; and

at least two of the first, second, and third UWB transceivers are configured to receive one or more of the at least two UWB signals, wherein there are at least three receptions of the at least two UWB signals and wherein each reception is timestamped based on the clock of the receiving UWB transceiver; and

a position calibration unit configured to;

receive the at least three reception timestamps; and

compute a position of the first UWB transceiver, a position of the second UWB transceiver, and a position of the third UWB transceiver based on the at least three reception timestamps.

16. The system of claim 15, wherein:

the first UWB transceiver is configured to wirelessly transmit at least one first UWB signal of the at least two UWB signals;

the second UWB transceiver is configured to;

wirelessly transmit a second UWB signal of the at least two UWB signals;

receive one of the least one first UWB signal; and

timestamp the reception of the one of the at least one first UWB signal based on the second clock to generate a first timestamp of the at least three timestamps; and

the third UWB transceiver is configured to;

receive the second UWB signal;

timestamp the reception of the second UWB signal based on the third clock to generate a second timestamp of the at least three timestamps;

receive one of the at least one first UWB signal; and

timestamp the reception of the one of the at least one first UWB signal based on the second clock to generate a third timestamp of the at least three timestamps.

17. The system of claim 16, wherein:

the first UWB transceiver comprises a first sensor and is configured to;

receive a first data reading from the first sensor; and

transmit the first data reading to the position calibration unit;

the second UWB transceiver comprises a second sensor and is configured to;

receive a second data reading from the second sensor; and

transmit the second data reading to the position calibration unit; and

the position calibration unit is configured to compute the positions further based on the first data reading and the second data reading.

18. The system of claim 17, wherein the first sensor and the second sensor each comprises one of a gravitational force sensor, an electromagnet force sensor, a fluid pressure sensor, a gas pressure sensor, a global positioning signal sensor, and a radio time signal sensor.

19. The system of claim 16, wherein:

the third UWB transceiver is further configured to wirelessly transmit at least one third UWB signal prior to the transmission of the at least one first UWB signal and prior to the second UWB signal;

the second transceiver is further configured to;

wirelessly transmit a fourth UWB signal prior to the wireless transmission of one of the at least one first UWB signal; and

receive one of the at least one third UWB signals;

the first UWB transceiver is configured to;

receive one of the at least one third UWB signal; and

receive the fourth UWB signal; and

the position calibration unit is configured to compute the positions further based on;

at least one transmission time stamp of the at least one third UWB signal;

a transmission time stamp of the fourth UWB signal;

a known transmission delay between a reception of an UWB signal at the first UWB transceiver and a corresponding transmission of an UWB signal from the first UWB transceiver; and

a known transmission delay between a reception of an UWB signal at the second UWB transceiver and a corresponding transmission of an UWB signal from the second UWB transceiver.

20. The system of claim 15, further comprising:

a fourth UWB transceiver comprising a fourth clock, wherein the fourth UWB transceiver has at least a partially unknown position to the first, second, and third UWB transceivers,

wherein;

at least three of the first, second, third, and fourth UWB transceivers are configured to transmit at least three UWB signals;

at least three of the first, second, third, and fourth UWB transceivers are configured to receive one or more of the at least three UWB signals, wherein there are at least six receptions of the at least three UWB signals and wherein each reception is timestamped based on the clock of the receiving UWB transceiver; and

the position calibration unit is configured to determine the positions of the first, second, third, and fourth UWB transceivers based on the at least six timestamps.

21. The system of claim 15, further comprising:

a self-localizing apparatus configured to;

receive UWB signals from the first, second, and third UWB transceivers; and

compute a position of the self-localizing apparatus based on the received UWB signals.

22. The system of claim 15, wherein the computed positions of the first, second, and third UWB transceivers comprise relative positions.