Patent ID: 7548829

Claim:
A measuring method for a hand-held pulse laser distance measuring device ( 1 ), the measuring method comprising the steps of: providing a light detector ( 14 ) configured for detecting a measurement pulse ( 6 ) reflected from a measurement object ( 4 ), for detecting a reference pulse ( 7 ), and for generating a mixing pulse train by mixing the measurement pulse ( 6 ) with a local oscillator pulse train whose repetition frequency differs from the repetition frequency of the measurement pulse ( 6 );and providing a microcontroller ( 2 ) with a superimposition module ( 5 ) and an algorithm ( 3 ) which controls the microcontroller ( 2 ) and which serves to calculate and display to a user, from the hand-held pulse laser distance measuring device, in step ( 10 ), a distance (X) to a measurement object ( 4 ) by the superimposition module ( 5 ) using a time difference (τ) between the measurement pulse ( 6 ) and reference pulse ( 7 ), wherein during the calculation step ( 10 ) the measurement of the distance (X) is stored in the microcontroller ( 2 ), wherein the calculation of the distance (X) from the time difference (τ) is preceded by a superimposition step ( 11 ) using the superimposition module ( 5 ) which superimposes a plurality of repeated pulse trains which are repeated with a trigger frequency f TRIGGER to the mixing pulse train from the light detector ( 14 ), and wherein the trigger frequency f TRIGGER lies in the following frequency range at an interference frequency f INT = 120 Hz: 0.7 · 2 2 · m - 1 · f INT < f TRIGGER < 1.3 · 2 2 · m - 1 · f INT , ⁢ where ⁢ ⁢ m = 1 , 2 , 3 , … ⁢ ; thereby the distance (X) is calculated and displayed with protection from any interference by light emitted from an external artificial light source by compensating for the interference from the light emitted from the external artificial light source and arriving at the hand-held pulse laser distance measuring device.