Distance measuring device

• US 9,103,669 B2
• Filed: 03/07/2013
• Issued: 08/11/2015
• Est. Priority Date: 03/07/2012
• Status: Active Grant

• Current Assignee: ‎Vectronix AG
• Original Assignee: ‎Vectronix AG
• Inventors: Giacotto, Luca, Tinivella, Riccardo
• Primary Examiner(s): Ratcliffe, Luke
• Assistant Examiner(s): RODRIGUEZ, VICENTE M
• Application Number:
  US13/788,986
• Publication Number:
  US 20130235366A1
• Time in Patent Office: 887 Days
• Field of Search: 356/5.01
• US Class Current: 1/1
• CPC Class Codes: G01C 3/08 Use of electric radiation detectors
• CPC Class Codes: G01S 17/10 using transmission of interrupted, pulse-modulated waves determination of distance by phase measurements G01S17/32
• CPC Class Codes: G01S 7/484 Transmitters
• CPC Class Codes: G01S 7/4865 Time delay measurement, e.g. time-of-flight measurement, time of arrival measurement or determining the exact position of a peak peak detection in noise, signal conditioning G01S7/487

Abstract

An optoelectronic distance measuring device is disclosed. The device has a transmitting unit with a driver stage for emitting optical pulses, a receiving unit for receiving a portion of the optical pulses, said portion being reflected from a target object, and converting it into an electrical reception signal, via a photosensitive electrical component. It also has an analog-digital converter for digitizing the reception signal, and an electronic evaluation unit to ascertain a distance from the target object on the basis of a signal propagation time using the digitized reception signal. The driver stage can be designed so that at least two pulse durations of different length for the optical pulses can be set.

Claims

1. An opto-electronic distance measuring device, comprising:

a transmitting unit having a driver stage for a light source for emitting optical pulses as pulsed-mode-intensity-modulated optical radiation,

a receiving unit for receiving a portion of the optical radiation, said portion being reflected from a target object, and converting it into an electrical reception signal, by means of a photosensitive electrical component,

an analogue-digital converter for digitizing the reception signal, and

an electronic evaluation unit which is configured such that a distance from the target object can be ascertained on the basis of a signal propagation time using the digitized reception signal, wherein the electronic evaluation unit is configured such that the setting of the pulse duration is taken as a basis for using configurable filter to set a bandwidth for the reception signal,

wherein the driver stage is configured such that at least two pulse durations of different length for the optical pulses can be set, and

wherein extension of the pulse duration allows expansion of a distance measurement range, as a maximum ascertainable distance, to be achieved.

2. The distance measuring device according to claim 1, wherein the distance measuring device provides a first mode of operation having a first pulse duration and at least one second mode of operation having a second pulse duration, wherein the first pulse duration is shorter than the second, wherein one of the modes of operation can be selected by a user.

3. The distance measuring device according to claim 1, wherein the transmitting unit is configured such that the pulse duration is set on the basis of an at least coarsely ascertained or estimated distance from the target object, wherein the distance measuring device is configured such that the pulse duration is set to be longer for long distances than for short distances.

4. The distance measuring device according to claim 1, wherein the driver stage is a pulse output stage which is configured such that the pulse duration can be set variably independently of a pulse amplitude of the optical pulses.

5. The distance measuring device according to claim 1, wherein the driver stage has a connectable capacitor for storing a pulse energy, wherein by connecting the capacitor the pulse duration can be set.

6. An observation apparatus having a distance measuring device according to claim 1, the apparatus comprising:

a targeting device for sighting the target object, wherein an optical axis of the targeting device points in the same direction as an optical axis of the distance measuring device, wherein the observation apparatus is configured such that a first mode distance accuracy or a second mode measurement distance of the distance measuring device can be selected using respective different pulse durations.

7. The observation apparatus according to claim 6, which has an automatic mode which is configured such that the variable setting of the pulse duration takes place automatically in accordance with an evaluatability of reception pulses in the reception signal and a signal-to-noise ratio that can be achieved therefor.

15. The distance measuring device according to claim 1, wherein extension of the pulse duration involves reduction of the bandwidth, and wherein extension of the pulse duration involves lowering of an upper cutoff frequency for a low-pass-filter characteristic of the configurable filter.

16. The distance measuring device according to claim 1, wherein the configurable filter is a digital configurable filter to set the bandwidth for a digitized reception signal.

17. The distance measuring device according to claim 5, wherein

a distance threshold being exceeded by the ascertained distance automatically involves extension of the pulse duration in comparison with that for a distance below the distance threshold.

19. The distance measuring method according to claim 15, wherein

the set pulse duration is automatically matched to the ascertained distance, wherein the pulse duration is extended as distance increases.

8. A distance measuring method comprising:

emission of pulsed-mode-amplitude-modulated optical radiation,

reception of a portion of the optical radiation, said portion being reflected from a target object, by means of a photosensitive electrical component which converts the received optical radiation into an electrical reception signal,

digitization of the reception signal by means of an analogue-digital converter, and

ascertainment of a distance from the target object on the basis of a signal propagation time by means of evaluation of the digitized reception signal by means of an electronic evaluation unit, wherein the electronic evaluation unit is configured such that the setting of the pulse duration is taken as a basis for using configurable filter to set a bandwidth for the reception signal,

wherein one of at least two adjustable pulse durations of different length for the optical radiation is selected, which allows a maximum value for the ascertainable distance to be altered, wherein extension of the pulse duration increases the maximum value for the ascertainable distance.

9. The distance measuring method according to claim 8, wherein the distance is ascertained by means of configurable filtering of the reception signal, which filtering is configured in accordance with the set pulse duration such that a bandwidth for the reception signal is matched to the set pulse duration.

10. The distance measuring method according to claim 9, wherein besides the pulse duration being set the pulse amplitude is also set, wherein the pulse duration and the pulse amplitude can each be set independently of one another.

11. The distance measuring method according to claim 8, wherein the pulse duration is set on the basis of the distance, wherein a longer pulse duration is set for a distant target object at a relatively long distance than for a close target object at a shorter distance.

12. The distance measuring method according to claim 8, wherein a selection is made between a first mode accurate measurement with emission of the optical pulses with a shorter pulse duration than in at least one second mode long measurement with emission of the optical pulses with a longer pulse duration than in the first mode.

13. The method of claim 8, comprising:

matching of a pulse duration of an emitted optical transmission signal from the distance measuring device on the basis of an ascertained or ascertainable distance, comprising matching of a bandwidth of a reception signal, which is used for ascertaining the distance, to the pulse duration.

14. A computer program product having program code, which is stored on a non-transitory machine-readable storage medium, embodied by an electromagnetic wave, for carrying out the method according to claim 8, wherein the program code varies a maximum measurement distance of the optoelectronic distance measuring method by setting a pulse duration for optical radiation emitted in pulsed fashion, when the program code is executed in an evaluation unit of an optoelectronic distance measuring device.

18. The distance measuring method according to claim 12, wherein

the bandwidth is decreased towards longer pulse durations.