Method and device for determining a distance from an object

1. A method for determining a distance from an object, comprising:

emitting an emission light beam from a light emitter;

receiving a reception light beam at a light receiver, wherein the reception light beam arises as a result of reflection of the emission light beam at the object; and

determining the distance on the basis of a propagation time of the emission and reception light beams;

wherein the emission light beam is amplitude-modulated with a rectangular-waveform modulation signal;

wherein the modulation signal has a multiplicity of rectangular pulses which occur in a multiplicity of groups; and

wherein the groups occur at varying temporal intervals with respect to one another and have changing numbers of rectangular pulses,

wherein the rectangular-waveform modulation signal is generated as a binary rectangular-waveform modulation signal via a digital circuit,

wherein at least one of a computational specification of values and a table of values, which represents three modulation signals, is stored in the digital circuit, and by which the digital circuit generates the binary pulse sequence that is fed as the binary rectangular-waveform modulation signal to the light emitter.

2. The method according to claim 1 , wherein the temporal intervals change periodically.

3. The method according to claim 1 , wherein the number of rectangular pulses per group changes periodically.

4. The method according to claim 1 , wherein the modulation signal is generated by addition of a first rectangular-waveform modulation signal having a first modulation frequency and a second rectangular-waveform modulation signal having a second modulation frequency, wherein the first modulation frequency is large relative to the second modulation frequency.

5. The method according to claim 4 , wherein a third rectangular-waveform modulation signal having a third modulation frequency is furthermore added to first and second rectangular-waveform modulation signals, wherein the second and third modulation frequencies differ from one another, and wherein the first modulation frequency is also large relative to the third modulation frequency.

6. The method according to claim 5 , wherein the second and third modulation signals have substantially identical pulse amplitudes.

7. The method according to claim 4 , wherein the first modulation signal has a larger pulse amplitude than the second modulation signal.

8. The method according to claim 1 , wherein the rectangular pulses of the modulation signal have a substantially identical pulse amplitude.

9. The method according to claim 1 , wherein the rectangular-waveform modulation signal is generated as a binary rectangular-waveform modulation signal with the aid of a digital circuit.

10. The method according to any of claim 1 , characterized in that the rectangular-waveform modulation signal is generated from at least two sinusoidal signals having a different frequency, wherein the sinusoidal signals are in each case amplified and amplitude-limited.

11. The method according to claim 1 , wherein the propagation time of the emission and reception light beams is determined on the basis of a phase difference of the modulation signal in the emission light beam and in the reception light beam, wherein there is measurement of the phase angle of the modulation signal in the emission light beam as to the light emitter.

12. A device for determining a distance from an object, comprising:

a light emitter for emitting an emission light beam;

a light receiver for receiving a reception light beam, wherein the reception light beam arises as a result of reflection of the emission light beam at the object; and

an evaluation unit for determining the distance of the object on the basis of a propagation time of the emission and reception light beams;

wherein the emission light beam is amplitude-modulated with a rectangular-waveform modulation signal; and

wherein the modulation signal has a multiplicity of rectangular pulses which occur in a multiplicity of groups;

wherein the groups occur at varying temporal intervals with respect to one another and have different numbers of rectangular pulses

wherein the evaluation unit includes a digital circuit generating the rectangular-waveform modulation signal as a binary rectangular-waveform modulation signal,

wherein at least one of a computational specification of values and table of values, which represents three modulation signals, is stored in the digital circuit, and by which the digital circuit generates the binary pulse sequence that is fed as the binary rectangular-waveform modulation signal to the light emitter.

13. The device according to claim 12 , wherein the light emitter include a laser diode, and wherein the binary rectangular-waveform modulation signal drives the laser diode of the light emitter.

14. The device according to claim 12 , wherein the digital circuit for generating the binary rectangular-waveform modulation signal is a field programmable gate array (FPGA).

15. The device according to claim 12 , wherein the evaluation unit includes a microprocessor that reads digitized reception data from the light receiver and determines a distance between a laser scanner and the object on the basis of the digitized reception data.

16. The device according to claim 15 , wherein the microprocessor is communicatively coupled to the digital circuit for generating the binary rectangular waveform modulation signal, and wherein the microprocessor receives phase information for the binary rectangular-waveform modulation signal for determining propagation time.