A wide dynamic range laser rangefinder with cm-level resolution based on AGC amplifier structure

► AGC technology applied both in the pre-amplifier and the post-amplifier. ► Big receiver bandwidth achieved with 3cm single-shot precision. ► Large dynamic range achieved with 100ps time walk error. ► Simplicity of this system is superior to previous laser rangefinder. A pulsed time-of-flight (TOF) laser rangefinder with a pulsed laser diode and an avalanche photo diode (APD) receiver is constructed and tested. Trigged by an avalanche transistor, the laser diode can emit a periodic pulse with rise time of ∼2ns. A new structure with auto gain control (AGC) circuits both in the pre-amplifier and the post-amplifier is presented. Through this technology, not only the dynamic range of the receiver is extended, but also the walk error of timing discriminators is reduced. Large measurement range from 5m to 500m is achieved without any cooperative target. The single-shot precision is 3cm for the weakest signal. Compared with previous laser rangefinders, the complexity of this system is greatly simplified.