US 5,671,190 AGranted

Method and device for measuring the distance of an object from an ultrasonic transmission/reception unit

AssigneeSiemens Aktiengesellschaft

InventorsNils Kroemer, Martin Vossiek

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Abstract

The method makes it possible, in particular, to measure distances which lie within the ambiguity zone of the ultrasonic transmission/reception unit. The ultrasonic transmission/reception unit comprises a single ultrasonic transducer which is operated in pulse-echo mode. The time t.sub.e1 of the first received echo is initially determined. If this time lies outside the double dead time 2t.sub.T, then the measurement is unambiguous and the propagation time of the sound, which is proportional to the difference between the ultrasonic transmission/reception unit and the object, is output. Otherwise, the propagation time of the sound is determined from the difference between the arrival times of two successive multiple echoes from the same object.

Claims10

Dependent claims

A method for measuring the distance of an object from an ultrasonic transmission/reception unit, comprising the steps of:

emitting an ultrasound pulse from an ultrasonic transmission/reception unit toward an object whose distance from the ultrasonic transmission/reception unit is to be measured and thereby producing multiple, successive ultrasound echoes from said object;
registering a time t.sub.e1 at which a first of said ultrasound echoes from said object is registered at said ultrasonic transmission/reception unit;
and
if said first of said ultrasound echoes is registered at said ultrasonic transmission/reception unit within a predetermined time interval after emission of said ultrasound pulse, registering a time t.sub.e2 at which a second of said ultrasound echoes from said object following said first of said ultrasound echoes is received at said ultrasonic transmission/reception unit, and determining said distance of said object from said ultrasonic transmission/reception unit from a time difference t.sub.e2 -t.sub.e1.

1 more element

A device for distance measurement comprising:

a pulse generator which emits a pulse;
an ultrasonic transmission/reception means, supplied with said pulse, for emitting an ultrasound transmission signal directed at an object whose distance from the ultrasonic transmission/reception means is to be measured, said object producing multiple, successive ultrasound echoes by interaction with said ultrasound transmission signal and said ultrasound echoes being received by said ultrasonic transmission/reception means;
a timer, supplied with said pulse, which emits an enable signal at a predetermined time following said pulse;
gate means, having inputs respectively connected to said timer and to said ultrasonic transmission/reception means and having an output, for gating ultrasound echoes through to said output of said gate means when said enable signal is present;
a pulse former supplied with said ultrasound echoes from said gate means which forms respective echo signal pulses therefrom;
and
counter means, connected to said pulse former, for counting each echo signal pulse and means for determining a distance of said object from said ultrasonic transmission/reception means from a number of echo signal pulses counted by said counter means.

4 more elements

Dependencies are inferred from the claim text.