A 64 x 64-Pixels Digital Silicon Photomultiplier Direct TOF Sensor With 100-MPhotons/s/pixel Background Rejection and Imaging/Altimeter Mode With 0.14% Precision Up To 6 km for Spacecraft Navigation and Landing

This paper describes a 64×64-pixel 3-D imager based on single-photon avalanche diodes (SPADs) for long-range applications, such as spacecraft navigation and landing. Each 60-μm pixel includes eight SPADs combined as a digital silicon photomultiplier, a triggering logic for photons temporal correlation, a 250-ps 16-b time-to-digital converter, and an intensity counter, with an overall 26.5% fill factor. The sensor provides time-of-flight and intensity information even with a background intensity up to 100 MPhotons/s/pixel. The sensor can work in imaging (short range, 3-D image) and altimeter (long range, single point) modes, achieving up to 300-m and 6-km maximum distance with <;0.2-m and <;0.5-m precision, respectively, consuming less than 100 mW.