23 September 1994 Performance test and initial results obtained with a chirped laser radar with optoelectronic chirp generation and signal demodulation
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Abstract
Scanning objects in an extended scene or large architectural structures, i.e., building, bridges, etc., is an essential task for numerous applications. In this paper we present the concept of a chirped laser radar with a range of up to 100 m and a design resolution of 3 (DOT) 10-5 realized with an optoelectronic signal processor. The scanning signal is a 1 microsecond(s) long chirped pulse with 100 MHz bandwidth, centered at 300 MHz. This signal is generated by a voltage controlled oscillator that is driven by a direct digital synthesizer (DDS). The DDS facilitates the generation of a signal of the required quality. We present the design concept of an external optronic modulator (OM) consisting of two Bragg cells, capable of intensity modulation of incoherently superimposed laser radiation of different wavelengths. The properties of the chirp signal are used on the OM. The return signal is analyzed via an optoelectronic signal processor that measures the time delay between the target signal and the reference signal. The optoelectronic signal processor consists of two Bragg cells and has two different output channels. Both channels evaluate the time delay of the two signals from the compressed pulses. In this paper we present the evaluation of both channels. First experimental results indicate that the signal analysis gives a resolution of 5 (DOT) 10-4. The evaluation of the second channel is not entirely completed yet. We present experimental results achieved with the radar using a single laser diode, which is intensity modulated by variation of the diode current, and scanning of co-operative targets.
© (1994) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Hubertus A. Luebbers, Jan Michael Mrosik, and Christo G. Stojanoff "Performance test and initial results obtained with a chirped laser radar with optoelectronic chirp generation and signal demodulation", Proc. SPIE 2271, Industrial Applications of Laser Radar, (23 September 1994); doi: 10.1117/12.188142; https://doi.org/10.1117/12.188142
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