Diode laser range finding system, design and construction aspects

number: 
888
إنجليزية
Degree: 
Author: 
Rana Mohammed Taha Al-Bayyati
Supervisor: 
Dr. Fareed F. Rasheed
year: 
2004
Abstract:

The present work, represents design and manufacture of the main elements of the laser range finder, by using a diode laser with a wavelength 904nm that includes: - • Laser transmitter. • Laser receiver. • Range circuit processing. At the first stage, laser transmitter circuit was designed and manufactured; which consists of the oscillator circuit and the driver circuit. MOSFET technology was used in the driver circuit to ensure the operation of the circuit with high frequency, which is reaches 4MHz. Afterwards different measurements and experiments were conducted to specify of the laser diode measurement work, type of GaAs Single heterodyne (SH). The threshold current measurement was done, within 3Amp, and then measuring the laser diode operation current that is suitable for the work without resulting into its damage and it was within 10Amp. The laser pulse width was measured and it was within 50nsec. The transmitted power of the laser diode was around 2W. At the second stage of the research, designing and manufacturing of the receiver circuit was done, which includes the amplifier circuit of the avalanche photodiode type of In GaAs, having a high response of the wavelength, concerning the diode laser 904nm, after that the signal is transferred to the range computer circuit to calculate the range which is reached to 1km. Finally, theoretical calculations were performed, concerning the atmospheric effects upon the laser beam for different visibility ranges, regarding the transmitted power to the target and the reflected power from the target and for different reflection coefficient .