Besides flexibility as well as portability, high accuracy and automation is needed in large volume metrology. Not only these requirements are fulfilled by the Laser Radar, furthermore this non-contact measurement system offers special benefits.
The Laser Radar is an optical, noncontact, polar measurement system, which registers for determining the target’s position in space two angles and one distance. The angles theta and phi are calculated with the established method of using angles encoders, which ideally are mounted orthogonally. But a main difference in respect of other polar measurement systems is the method for determining the range. The evaluation of distance uses the principal of frequency modulation for the transmitted beam. This fact is also reflected in an alternative name for the Laser Radar, namely FMCLR (Frequency Modulated Coherent Laser Radar).
This frequency modulation is realized by using chirps. In the time period of one millisecond the carrier frequency of nearly 200 THz is raised about 100 GHz. Following, in the same while the achieved frequency is again reduced to the carrier frequency of approximately 200 THz. ... mehrBy reiterating the modulation, a triangular-wave is generated. For determining the target’s range the trans-mitted and the received signal are combined as well as a frequency difference is calculated. Knowing the triangular-wave-function the desired range can be deduced from the frequency difference. Accordingly, the target’s position in space is measured.