Method and arrangement for target seeking
First Claim
1. Method for searching for targets, where an instrument emits an electromagnetic radiation and searches for a target reflector by detecting if reception takes place of a received electromagnetic radiation reflected from the target reflector back to the instrument, characterized in that in the radiation direction of the electromagnetic radiation, the following procedural steps take place after one another:
- a. polarization of the electromagnetic radiation;
b. polarization modulation of the polarization direction of the electromagnetic radiation through alternately changing it;
c. polarization of the electromagnetic radiation;
wherein at least one of the procedural steps mentioned under points a) to c) is performed near to the target reflector (11); and
checking of the detected reflector is performed by testing if the received radiation changes alternately at the same rate as the modulation of the polarization direction, and only accepting a target which gives different signal strengths for the received radiation at said rate.
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Accused Products
Abstract
The invention relates to a method and arrangement for target seeking, where a rotatable instrument emits an electromagnetic radiation and automatically searches for a target reflector by detecting whether reception occurs of electromagnetic radiation received by the target reflector and reflected back to the instrument. In the beam path of the electromagnetic radiation, polarization of the electromagnetic radiation, polarization modulation of the polarization direction on the electromagnetic radiation by alternately changing it, and polarization of the electromagnetic radiation take place in sequence. At least on of these steps is performed at the target reflector. Checking of the detected reflector is carried out by testing if the received radiation changes at the same rate as the modulation of the polarization direction. Only targets are accepted which give different signal strengths at said rate for the received radiation.
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Citations
10 Claims
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1. Method for searching for targets, where an instrument emits an electromagnetic radiation and searches for a target reflector by detecting if reception takes place of a received electromagnetic radiation reflected from the target reflector back to the instrument, characterized in that in the radiation direction of the electromagnetic radiation, the following procedural steps take place after one another:
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a. polarization of the electromagnetic radiation; b. polarization modulation of the polarization direction of the electromagnetic radiation through alternately changing it; c. polarization of the electromagnetic radiation; wherein at least one of the procedural steps mentioned under points a) to c) is performed near to the target reflector (11); and
checking of the detected reflector is performed by testing if the received radiation changes alternately at the same rate as the modulation of the polarization direction, and only accepting a target which gives different signal strengths for the received radiation at said rate. - View Dependent Claims (2, 3)
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4. Target seeking arrangement for a rotatable instrument comprising a unit (12) which emits a beam, a detector unit (15) which is arranged to detect reception of a radiation received and reflected back from a target reflector (11) to the instrument, characterized by
a. a polarization modulating arrangement (14; - 14'"'"';
40;
43;
45) arranged in the beam path of the radiation, controllable to alternately change the polarization direction of the radiation;b. at least one polarization arrangement (10,13;
10,13'"'"';
41,42;
44;
46,47) with a fixed polarization so placed in the beam of the radiation that the beam passes through the polarization arrangement both before and after the polarization modulating arrangement;c. whereby at least one of the above mentioned arrangements is placed by the reflector (11); d. a control unit (31) which controls the polarization modulating arrangement alternately between different opposing polarizations; e. an evaluation circuit (25-31) connected to the detector unit (15) and arranged to accept a target reflector which gives different degrees of reflection for said different polarizations. - View Dependent Claims (5, 6, 7, 8, 9, 10)
- 14'"'"';
Specification