Apparatus and method for measurement of the reception time of a pulse

• US 8,995,577 B2
• Filed: 04/14/2009
• Issued: 03/31/2015
• Est. Priority Date: 04/22/2008
• Status: Active Grant

• Current Assignee: RIEGL Laser Measurement Systems GmbH
• Original Assignee: RIEGL Laser Measurement Systems GmbH
• Inventors: Ullrich, Andreas, Pfennigbauer, Martin, Schubert, Walter, Zierlinger, Wolfgang, Hofbauer, Andreas, Ederer, Gerhard
• Primary Examiner(s): Haider, Syed
• Application Number:
  US12/989,009
• Publication Number:
  US 20110038442A1
• Time in Patent Office: 2,177 Days
• Field of Search: 375/215, 375/340, 375/372
• US Class Current: 375/340
• CPC Class Codes: G01S 7/40 Means for monitoring or calibrating
• CPC Class Codes: G01S 7/4052 by simulation of echoes
• CPC Class Codes: G01S 7/4082 using externally generated reference signals, e.g. via remote reflector or transponder
• CPC Class Codes: G01S 7/497 Means for monitoring or calibrating
• CPC Class Codes: G01S 7/52004 Means for monitoring or calibrating short-range imaging G01S7/5205

Abstract

Apparatus for measurement of the reception time of a pulse in a receiving system, which contains at least one receiving channel with a non-linear transmission response, which receiving channel produces at its output a received signal, having a memory, in which the received signals of reference pulses with a predetermined different amplitude are available as reference signals with respect to a time scale, and having an evaluation device, which is connected to the receiving system and to the memory and compares a received signal with each reference signal with a variant time offset in order to determine that reference signal and that time offset for which the comparison discrepancy is a minimum, and outputs this time offset as the reception time with respect to the time scale.

Claims

1. An apparatus for measurement of a reception time of a pulse in a receiving system including at least one receiving channel with a nonlinear transmission response, which receiving channel supplies a received signal at its output the apparatus comprising:

a memory in which at least two received signals of at least two reference pulses with predetermined different amplitudes are stored as at least two reference signals with respect to a time scale, wherein the reference signals are generated from a training and calibration sweep of the reference pulses, and

an evaluation device connected to the receiving system and to the memory, wherein the evaluation device is configured to compare the received signal from the receiving channel with each reference signal of said at least two reference signals using a different time offset each in order to determine that reference signal and that time offset for which the comparison deviation is a minimum, and is configured to output this time offset as the reception time with respect to the time scale.

3. The apparatus according to claim 1, wherein at least one of the receiving channels is analogue in nature and the memory and the evaluation device are digital, an analogue/digital converter being present at the output of the receiving channels.

4. The apparatus according to claim 3, wherein the reference signals are present in the memory in a high first time resolution,

that the received signal from the receiving channel of the pulse is sampled with a low second time resolution, and

that the evaluation device varies the time offset in the resolution steps of the high first time resolution.

5. The apparatus according to claim 4, wherein the first time resolution is in the order of picoseconds and the second time resolution is in the order of nanoseconds.

6. The apparatus according to claim 1, wherein the time scale is universal time.

7. The apparatus according to claim 1, wherein the time scale is referenced to an emission time of the pulse from a transmitting system in order to obtain a transit time from the time offset.

8. The apparatus according to claim 1, wherein the memory additionally contains, for each reference signal, the amplitude of the associated reference pulse, and the evaluation device outputs the amplitude of that reference pulse which is associated with the determined reference signal as the amplitude of the pulse.

9. The apparatus according to claim 1, wherein for the measured reception time, the evaluation device also outputs the associated comparison deviation as an indication of a quality of the measurement.

10. The apparatus according to claim 1, wherein the apparatus comprises at least one sensor which measures and supplies at its output, as a form of further received signal, an operating state of one or more receiving channels,

that the memory contains such further received signals of the reference pulses as further reference signals, and

that, during the comparison, the evaluation device also compares a further received signal of this kind with the further reference signals and includes it in determining the comparison deviation.

11. The apparatus according to claim 1, further comprising at least one sensor which measures an operating temperature of one or more receiving channels,

that the memory contains reference signals for various operating temperatures and

that the evaluation device determines therefrom, if necessary by means of interpolation or extrapolation, and uses in the said comparison, the reference signals valid for the respective current operating temperature.

12. The apparatus according to claim 1, wherein the determination of the minimum comparison deviation is carried out using a least squares method.

13. The apparatus according to claim 12, wherein the memory also contains weighting values for the reference signals, which weighting values are incorporated into the least squares method.

14. At least one of a laser range finder and a laser scanner with the apparatus according to claim 7, wherein the pulse is a laser pulse.

2. An apparatus for measurement of a reception time of a pulse with high dynamic range in a receiving system including at least two parallel receiving channels of differing sensitivity for one pulse, which receiving channels supply at their outputs a set of time-parallel received signals for said one pulse comprising:

a memory in which at least two sets of received signals of at least two reference pulses with predetermined different amplitudes are stored as at least two reference sets with respect to a time scale, wherein the reference signals are generated from a training and calibration sweep of the reference pulses, and

an evaluation device, which is connected to the receiving system and to the memory, is configured to compare the set of time-parallel received signals with each reference set of said at least two reference sets using a different time offset in order to determine that reference set and that time offset for which the comparison deviation is a minimum, and is configured to output this time offset as the reception time with respect to the time scale.

29. The apparatus according to claim 2, wherein the receiving channels are analogue in nature and the memory and the evaluation device are digital, an analogue/digital converter being present at the output of the receiving channels.

30. The apparatus according to claim 29, wherein the reference sets are present in the memory in a high first time resolution,

that the received signals from the receiving channels of the pulse are sampled with a low second time resolution, and

that the evaluation device varies the time offset in the resolution steps of the high first time resolution.

31. The apparatus according to claim 30, wherein the first time resolution is in the order of picoseconds and the second time resolution is in the order of nanoseconds.

32. The apparatus according to claim 2, wherein the time scale is universal time.

33. The apparatus according to claim 2, wherein the time scale is referenced to an emission time of the pulse from a transmitting system in order to obtain a transit time from the time offset.

34. The apparatus according to claim 2, wherein the memory additionally contains, for each reference set, the amplitude of the associated reference pulse, and the evaluation device outputs the amplitude of that reference pulse which is associated with the determined reference set as the amplitude of the pulse.

35. The apparatus according to claim 2, wherein for the measured reception time, the evaluation device also outputs the associated comparison deviation as an indication of a quality of the measurement.

36. The apparatus according to claim 2, wherein the apparatus comprises at least one sensor which measures and supplies at its output, as a form of further received signal, an operating state of one or more receiving channels,

that the memory contains such further received signals of the reference pulses as further reference signals and

that, during the comparison, the evaluation device also compares a further received signal of this kind with the further reference signals and includes it in determining the comparison deviation.

37. The apparatus according to claim 2, further comprising at least one sensor which measures an operating temperature of one or more receiving channels,

that the memory contains reference sets for various operating temperatures and

that the evaluation device determines therefrom, if necessary by means of interpolation or extrapolation, and uses in the said comparison, the reference sets valid for the respective current operating temperature.

38. The apparatus according to claim 2, wherein the determination of the minimum comparison deviation is carried out using a least squares method.

39. The apparatus according to claim 38, wherein the memory also contains weighting values for the reference sets, which weighting values are incorporated into the least squares method.

40. At least one of a laser range finder and a laser scanner with the apparatus according to claim 33, wherein the pulse is a laser pulse.

51. The method according to claim 38, wherein predeterminable weighting values for the reference sets are incorporated into the least squares method.

15. A method for measuring a reception time of a pulse in a receiving system including at least one receiving channel with nonlinear transmission response, which receiving channel supplies a received signal at its output, the method comprising:

providing at least two received signals of at least two reference pulses of predetermined different amplitudes as at least two reference signals relative to a time scale, wherein the reference signals are generated from a training and calibration sweep of the reference pulses,

comparing, by an evaluation device, the received signal from the receiving channel with each reference signal of said at least two reference signals using a different time offset each in order to determine that reference signal and that time offset at which the comparison deviation is a minimum, and

outputting this time offset as the reception time with respect to the time scale.

17. The method according to claim 15, wherein:

the reference signals are provided in a high first time resolution, the received signal being sampled with a low second time resolution and during comparison, the time offset is varied in the resolution steps of the high first time resolution.

18. The method according to claim 17, wherein a reference signal to be provided is generated by using a plurality of reference pulses of the same kind, which are time-offset in the resolution steps of a high time resolution, their received signals being sampled with a low time resolution and combined in a meshed manner to form the reference signal.

19. The method according to claim 18, wherein the combined reference signal is brought to an even higher time resolution by insertion of interpolation values.

20. The method according to claim 17, wherein the high first time resolution is in the order of picoseconds and the low second time resolution in the order of nanoseconds.

21. The method according to claim 15, wherein the time scale is universal time.

22. The method according to claim 15, wherein the time scale is referenced to an emission time of the pulse from a transmitting system in order to obtain a transit time from the time offset.

23. The method according to claim 15, further comprising:

for each reference signal, the amplitude of the associated reference pulse is provided and that the amplitude of that reference pulse which is associated with the determined reference signal is output as the amplitude of the pulse.

24. The method according to claim 15, wherein for the pulse, at least one further received signal is obtained from an operating state of at least one receiving channel, compared with further reference signals previously obtained in this manner for reference pulses, and included in determination of the comparison deviation.

25. The method according to claim 15, wherein the reference signals are provided for various operating temperatures, and that therefrom, if necessary by means of interpolation or extrapolation, are determined those reference signals which are valid for the particular current operating temperature.

26. The method according to claim 15, wherein the determination of the minimum comparison deviation is carried out using a least squares method.

27. The method according to claim 26, wherein predeterminable weighting values for the reference signals are incorporated into the least squares method.

28. The method according to claim 22, wherein the pulse is a laser pulse in a laser range finder or laser scanner.

16. A method for measuring a reception time of a pulse of high dynamic range in a receiving system comprising at least two parallel receiving channels of differing sensitivity for one pulse, which receiving channels supply at their outputs a set of time-parallel received signals for said one pulse, the method comprising:

providing at least two sets of received signals of reference pulses of predetermined different amplitudes as at least two reference sets relative to a time scale, wherein the reference signals are generated from a training and calibration sweep of the reference pulses,

comparing, by an evaluation device, the set of time-parallel received signals with each reference set of said at least two reference sets using a different time offset each in order to determine that reference set and that time offset at which the comparison deviation is a minimum, and

outputting this time offset as the reception time with respect to the time scale.

41. The method according to claim 16, wherein:

the reference signals are provided in a high first time resolution,

that the received signal is sampled with a low second time resolution and

that, during comparison, the time offset is varied in the resolution steps of the high first time resolution.

42. The method according to claim 41, wherein a reference set to be provided is generated by using a plurality of reference pulses of the same kind, which are time-offset in the resolution steps of a high time resolution, their received signals being sampled with a low time resolution and combined in a meshed manner to form the reference set.

43. The method according to claim 42, wherein the combined reference set is brought to an even higher time resolution by insertion of interpolation values.

44. The method according to claim 41, wherein the high first time resolution is in the order of picoseconds and the low second time resolution in the order of nanoseconds.

45. The method according to claim 16, wherein the time scale is universal time.

46. The method according to claim 16, wherein the time scale is referenced to an emission time of the pulse from a transmitting system in order to obtain a transit time from the time offset.

47. The method according to claim 16, further comprising:

for each reference set, the amplitude of the associated reference pulse is provided and that the amplitude of that reference pulse which is associated with the determined reference set is output as the amplitude of the pulse.

48. The method according to claim 16, wherein for the pulse, at least one further received signal is obtained from an operating state of at least one receiving channel, compared with further reference signals previously obtained in this manner for reference pulses, and included in determination of the comparison deviation.

49. The method according to claim 16, wherein the reference sets are provided for various operating temperatures, and that therefrom, if necessary by means of interpolation or extrapolation, are determined those reference sets which are valid for the particular current operating temperature.

50. The method according to claim 16, wherein the determination of the minimum comparison deviation is carried out using a least squares method.

52. The method according to claim 46, wherein the pulse is a laser pulse in a laser range finder or laser scanner.