High-precision pulsed laser ranging using CMOS single-photon avalanche diodes

We demonstrate a μm-scale precision with a direct time-of-flight ranging module consisted of a single-photon avalanche diode (SPAD), a picosecond laser, and a high-resolution time-to-digital converter. A systematic study on factors including the target reflectance, the biased voltage of SPAD, the integration time, and the laser repetition rate is performed and their impact on the ranging precision is investigated. We find that the two parameters, the full-width at half maximum (FWHM) of the collected histogram and the effective integration time, play a deterministic role in ranging precision.