Location system

• US 8,934,579 B2
• Filed: 07/02/2010
• Issued: 01/13/2015
• Est. Priority Date: 07/10/2009
• Status: Active Grant

• Current Assignee: Ubisense Incorporated (IQGeo Group Plc)
• Original Assignee: Ubisense Incorporated (IQGeo Group Plc)
• Inventors: Ward, Andrew Martin Robert
• Primary Examiner(s): PATEL, DHAVAL V
• Application Number:
  US13/383,075
• Publication Number:
  US 20120163421A1
• Time in Patent Office: 1,656 Days
• Field of Search: 375/145, 375/149, 375/340
• US Class Current: 375/340
• CPC Class Codes: G01S 13/0209 Systems with very large relative bandwidth, i.e. larger than 10 %, e.g. baseband, pulse, carrier-free, ultrawideband
• CPC Class Codes: G01S 13/765 with exchange of information between interrogator and responder
• CPC Class Codes: G01S 13/878 Combination of several spaced transmitters or receivers of known location for determining the position of a transponder or a reflector G01S13/874 takes precedence
• CPC Class Codes: G01S 5/14 Determining absolute distances from a plurality of spaced points of known location
• CPC Class Codes: G01S 7/003 Transmission of data between radar, sonar or lidar systems and remote stations

Abstract

A receiver for receiving a signal, the signal conforming to a protocol such that the signal comprises a synchronising portion and a data portion, each portion comprising pulses located in respective time slots, the time offsets between successive time slots being defined by the protocol, the receiver comprising: a detector configured to detect a first pulse and a second pulse of the synchronising portion; a comparison module configured to compare the time offset between the first and second pulses to a corresponding time offset defined by the protocol so as to determine the relationship between the detected time offset and the corresponding time offset; a determination module configured to determine expected times of arrival of the time slots of the data portion using the determined relationship and the time offsets defined by the protocol; and a data reader configured to read data conveyed in the data portion at the expected times of arrival.

Claims

1. A receiver for receiving a signal, the signal conforming to a protocol such that

the signal comprises a synchronising portion and a data portion, each portion comprising pulses located in respective time slots, the time offsets between successive time slots being defined by the protocol, the receiver comprising:

a replica pulse generator configured to generate first and second replica series of pulses, each pulse offset from the next by a time e, and each series being offset from the next by a time f, where f is not an integer multiple of e;

a mixer configured to mix the replica series with the received signal and output the mixed signal to a detector;

the detector configured to detect a first pulse and a second pulse of the synchronising portion, the detector being configured to detect a pulse of the received signal if that pulse is input to the mixer coincident with a pulse of the replica series;

a comparison module configured to compare the time offset between the first and second pulses to a corresponding time offset defined by the protocol so as to determine the relationship between the detected time offset and the corresponding time offset;

a determination module configured to determine expected times of arrival of the time slots of the data portion using the determined relationship and the time offsets defined by the protocol; and

a data reader configured to read data conveyed in the data portion at the expected times of arrival.

2. A receiver as claimed in claim 1, wherein the detector is configured to detect the first and second pulses by detecting a first group of pulses comprising the first pulse and a second group of pulses comprising the second pulse, and wherein the comparison module is configured to compare the time offset between the first and second pulses to a corresponding time offset defined by the protocol by comparing the time offset between the first group of pulses and the second group of pulses to the corresponding time offset defined by the protocol.

3. A receiver as claimed in claim 1, wherein the data reader is configured to read data by virtue of the omission of pulses from one or more of the time slots in the data portion.

4. A receiver as claimed in claim 1, further comprising a signal processor configured to process the signal so as to determine the time-of-arrival of one or more of the pulses.

5. A receiver as claimed in claim 1, wherein the comparison module is configured to compare the time offset between the first and second pulses to a corresponding time offset defined by the protocol by:

determining the offset between a first replica series of pulses that coincides with the first pulse and a second replica series of pulses that coincides with the second pulse; and

comparing the determined offset to the corresponding offset defined by the protocol.

6. A receiver as claimed in claim 1, wherein the replica pulse generator is configured to refine the time e so as to generate a pulse of the replica series of pulses at each of the expected times of arrival of the time slots of the data portion.

7. A receiver as claimed in claim 1, further comprising an integrator configured to integrate successive pulses of the data portion, the data reader being configured to read the integrated data output from the integrator.

8. A receiver as claimed in claim 1, the receiver being a part of a location system for estimating the location of a transmitter of the signal by means of the receiver.

9. A receiver as claimed in claim 2, wherein the data reader is configured to read data by virtue of the omission of pulses from one or more of the time slots in the data portion.

10. A receiver as claimed in claim 2, further comprising a signal processor configured to process the signal so as to determine the time-of-arrival of one or more of the pulses.

11. A receiver as claimed in claim 3, further comprising a signal processor configured to process the signal so as to determine the time-of-arrival of one or more of the pulses.

12. A receiver as claimed in claim 5, wherein the replica pulse generator is configured to refine the time e so as to generate a pulse of the replica series of pulses at each of the expected times of arrival of the time slots of the data portion.