A high-resolution random-modulation continuous wave lidar for surface detection using a semiconductor laser diode is presented. The laser diode is intensity modulated with the pseudorandom binary sequence. Its enhanced resolution is achieved via interpolation and a novel front-end analog technique, lowering the requirement of the analog-to-digital converter sampling rate and the associated circuitry. Its mathematical model is presented, including the derivation of the signal-to-noise ratio and the distance standard deviation. Analytical and experimental results demonstrate its capability to achieve distance accuracy of less than $2\mathrm{cm}$ within $2.6\mathrm{ms}$ acquisition time, over distances ranging from 1 to $12\mathrm{m}$ . The laser diode emits $1.4\mathrm{mW}$ of optical power at a wavelength of $635\mathrm{nm}$ .