3D Imaging with CMOS Single-Photon Detector Arrays for Space Applications: Ground-Based Measurements and Irradiation Tests

An increasing and heterogeneous number of applications is requiring precise awareness of the environment through image sensors, spanning from autonomous driving to gaming or industrial control. In many of these applications, and in particular in the field of space navigation, rendez-vous and landing with high relative velocity instrument-target, the requirements in terms of robustness and frame rate make the objective quite challenging. One of the imaging techniques which can be chosen as a solution is direct time-of-flight (DTOF), and an interesting technology able to respond to the implementation needs is represented by CMOS single-photon avalanche diodes (SPAD), with specialized processing circuitry enabling the integration of smart features. With this configuration, a light pulse is emitted to the scene, and its back-reflected echo is detected by the single-photon device, while the CMOS circuit implements the “stopwatch” function needed to measure the time-of-flight. In this paper, the sensor realized in [1] is employed in a light detection and ranging (LiDAR) system able to realize both 3D imaging and single-point distance measurement, and its performance to generate Digital Elevation Map in real-time is assessed in a ground-based measurement test. At the same time, a first proton irradiation test is performed for the evaluation of robustness in space environment.