US 2009/0021721 A1 · Hand-held laser distance measuring device with a pulse reflection mixing method

Abstract

A hand-held laser distance measuring device (1) with pulse reflection mixing includes a control device (2) for calculating the distance (D) to a measurement object (3) over at least one determinable periodic, with a pulse repetition frequency (f), time difference (τ) between a measurement pulse (4) reflected at the measurement object (3) and a reference pulse (6) of an optically emitted transmitting pulse (7) traveling over a reference distance (5) within the device, a local oscillator (8) for generating the transmitting pulse (7) at the pulse repetition frequency (f), at least one delay circuit (9a, 9b) which can be controlled by the control device (2), is arranged between the local oscillator (8) and a light detector (10) and/or a light transmitter (12), and generates a delay between the scanning pulses (11) and the transmitting pulses (7) in order to scan the measurement pulse (4) and the reference pulse (6).

Claims13

Dependent claims

A hand-held laser distance measuring device with pulse reflection mixing, comprising a control device (2) for calculating a distance (D) to a measurement object (3) over at least one determinable time difference (τ) between a measurement pulse (4) reflected at the measurement object (3) and a reference pulse (6) of an optically emitted transmitting pulse (7) traveling over a reference distance (5) within the device, the time difference (τ) being periodic with a pulse repetition frequency (f);

a local oscillator (8) for generating the transmitting pulse (7) at the pulse repetition frequency (f);
and at least one delay circuit (9a, 9b) which can be controlled by the control device (2), is arranged between the local oscillator (8) and at least one of a light detector (10) and a light transmitter (12), and generates a delay between scanning pulses (11) and the transmitting pulses (7) in order to scan the measurement pulse (4) and the reference pulse (6).

A measurement method for a hand-held laser distance measuring device (1), comprising the following steps:

the calculation step (18) for calculating the distance (D) from at least one time difference (τ) between measurement pulses (4) and the reference pulses (6) by an algorithm of a control device (2);
within the calculation step (18), at least one transit time determining step (19) for determining the time difference (τ) between the measurement pulses (4) and the reference pulses (6);
within this transit time determining step (19), a plurality of scanning steps (20) in which the measurement pulses (4) and reference pulses (6), which are received by the light detector (10) and are periodic in a pulse repetition frequency (f), are scanned directly at the light detector (10) with scanning pulses (11) of precisely this pulse repetition frequency (f) and by which the scanning results are acquired from the control device (2);
the step of variably controlling a delay between the scanning pulses (11) and the transmitting pulses (7) by the control device (2) with the delay circuit (9a, 9b);
and the step of calculating the time difference (τ) between the measurement pulses (4) and the reference pulses (6) in a prioritized transit time determining step (19) from precisely the time delays associated with the successful scanning events.

2 more elements

Dependencies are inferred from the claim text.

Hand-held laser distance measuring device with a pulse reflection mixing method

Life of this patent

Hand-held laser distance measuring device with a pulse reflection mixing method

Life of this patent

Abstract

Claims13