Fig. 1

a Newtonian aperture as seen from the front, with a simulated insect trajectory marked in orange. b Illustration of the telescope imaging from above, showing that two adjacent QPD elements receive light from slightly different directions. c Raytracing of the FOV of two adjacent detector elements, where the eastern FOV is marked in green and the western FOV is marked in red. Positions where the fields overlap are marked in yellow. d Simulated signals from point scatterers transiting the probe volume from east to west with a speed of 1 m/s at different distances. The ranging parameters τ and Δt are shown in blue