Method and apparatus for impulse radio transceiver calibration

• US 20030076879A1
• Filed: 09/17/2002
• Published: 04/24/2003
• Est. Priority Date: 09/17/2001
• Status: Active Grant

• Current Assignee: Humatics Corporation
• Original Assignee: Time Domain Corporation (Humatics Corporation)
• Inventors: Langford, David W., Troutman, Dennis L.
• Granted Patent: US 7,230,980 B2
• Time in Patent Office: Days
• US Class Current: 375/219
• 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 13/76 wherein pulse-type signals are transmitted

Abstract

A method for calibrating an impulse radio distance measuring system comprising an impulse radio transceiver by conducting a pulse through a transmit receive switch to an antenna, receiving return energy which has been discharged across the transmit receive switch, determining a time of arrival of the return energy. The return energy is comprised of two distinct pulses, one of which represents discharge of the transmit switch as the original pulse travels to the antenna, the second represents energy reflected from the antenna and again discharged across the transmit receive switch while the switch is in the transmit position. The timing of the un-reflected energy is determined then the timing of the reflected energy relative to the un-reflected energy is determined through auto-correlation of the time domain scan of the received composite waveforms.

Claims

1. A method for calibrating an impulse radio distance measuring system, said distance measuring system comprising an impulse radio transceiver, comprising the steps of:

a. conducting a pulse through a circuit, said circuit comprising a switch and an antenna;

b. receiving a return energy, said return energy being discharged across said switch;

c. determining a time of arrival of said return energy; and

f. converting said time of arrival to a distance.

2. The method of claim 1, wherein said return energy comprises an un-reflected energy and a reflected energy, said reflected energy being reflected by said antenna.

3. The method of claim 2, wherein said step of determining a time of arrival further comprises measuring a first time of arrival of said reflected energy.

4. The method of claim 3, wherein said measuring a first time of arrival comprises the steps of:

1) measuring a second time of arrival, said second time of arrival being a time of arrival of said un-reflected energy;

2) measuring a differential time, said differential time being the difference between arrival of said reflected energy and said un-reflected energy; and

3) summing said second time of arrival and said differential time.

5. The method of claim 4, wherein said step of measuring a second time of arrival comprises finding the occurrence of a leading energy excursion of said un-reflected energy.

6. The method of claim 5, wherein said differential time is measured by autocorrelation.

7. An impulse radio transceiver apparatus for calibrating an impulse radio distance measuring system comprising:

a. a pulser configured to generate pulses having an ultra wideband frequency characteristic;

b. a switching means coupled to said pulser, said switching means comprising a transmit position;

c. an antenna means coupled to said switching means;

d. a scanning receiver responsive to said switching means;

e. a control processor having at least one input, said at least one input being coupled to said scanning receiver, said control processor being adapted to determine a time of arrival of a return energy, said return energy being discharged from said switching means, and to convert said time of arrival into a distance.

8. The impulse radio transceiver apparatus of claim 7, wherein said return energy comprises an un-reflected energy and a reflected energy, said reflected energy being reflected from said antenna.

9. The impulse radio transceiver apparatus of claim 8, wherein said control processor is adapted to determine said time of arrival by finding a leading edge of said un-reflected energy.

10. The impulse radio transceiver apparatus of claim 9, wherein said control processor is adapted to determine time of arrival by measuring a time differential between arrival of said reflected energy and said un-reflected energy.

11. The impulse radio transceiver apparatus of claim 10, wherein said time differential is measuring by auto-correlation.

12. A method for calibrating an impulse radio distance measuring system, said distance measuring system comprising an impulse radio transceiver, comprising the steps of:

a. conducting a pulse through a transmit circuit;

b. determining a time of arrival of a return energy, said return energy being discharged from said transmit circuit.

13. The method of claim 12, wherein said return energy comprises a reflected energy, said reflected energy being reflected from an antenna coupled to said transmit circuit, and an un-reflected energy.

14. The method of claim 13, wherein said step of determining said time of arrival comprises determining a first time of arrival, said first time of arrival being the time of arrival of said reflected energy.

15. The method of claim 14, wherein determining a first time of arrival comprises determining a second time of arrival of said un-reflected energy and determining a differential time, said differential time being the difference in time of the arrival of said un-reflected energy and said reflected energy.

16. The method of claim 15, further comprising the step of converting said time of arrival into a distance.