The Research Of Plused Laser Measurement On Automobile Active Anti-Collision

The life style was changed and convenience was brought out with the rapid development of auto industry, however, the traffic security problems were caused at the same time. Automobile active anti-collision system can prevent the accidents actively and effectively, and reduce the direct economic loss caused by the accidents. One key technology of the automobile active anti-collision system is ranging system.Laser distance measurement was choosed by comparing five ranging technologies such as ultrasonic, laser, infrared, imaging system and radar. Plused laser distance measurement was choosed on the basis of comparing phased and pulsed types laser distance measurement. The overall structure of plused laser distance measurement was designed, the three main units of which was designed(including plused laser transmission unit, pulsed laser receiving unit and pulsed laser time-interval measurement unit), the devices or chips and circuit designs of each unit have been completed.In plused laser transmission unit, SPL_PL90 semiconductor pulsed laser diode was choosed to transmit pluse, the corresponding VMOS switch power source was designed, which contained pluse generating circuit, plastic circuit and VMOS output level circuit. The lens of the optical system were selected in the transmission unit. In pulsed laser receiving unit, the lens of the optical system were also selected, C30724E silicon avalanche photodiode was choosed to receive plused laser signal, the high-pressure bias circuit, feedback circuit and signal processing circuit were designed. In pulsed laser time-interval measurement unit, time-to-digital converter TDC-GP2 was choosed to measure time interval, MSP430F149 MCU was choosed to control Laser Diode(LD) and TDC-GP2, the distance value was gained by calculating and displayed by digital tube, the precise measurement of the pulsed laser round-trip interval in the 200m largest measuring distance can be realized.Finally, pluse generating circuit, plastic circuit and high-pressure bias circuit were simulated and verificated by the simulated softwave Multisim10.0, the resultes show that the designed power source can provide 1kHz~10kHz adjustable frequency and 10ns~100ns adjustable narrow pluse, high-pressure circuit can generate 80V power source, high-pressure bias circuit of APD doesn't provide flat voltage without feedback circuit, but it can after adding feedback circuit and reaches the needing power source160V of APD. So the designed circuits meet the design requirements.