(a) & (b). RTI plots of Event 20100415_051949 before and after the H-ICS processing with normalized SNR indicated by the colour bar. (c) The light curves of three receivers: A, B and C. (d) The spatial imaging results shown in the 3D X–Y–Z domain and its 2D projections with time (s) given by the colour bar. As shown in the left-bottom plot (the X-Y plane) in (d), this event has two components: the initial Z > 88 km component (event 1) exhibits a range-rate ν_f = ∼9 km s⁻¹ while the vector velocity ν ≈ [−16.0 −11.0 −9.0] km s⁻¹, and its magnitude |ν| ≈ 21.5 km s⁻¹ at a zenith angle θ ≈ 65.3°. The relative mean-square error (e) of the fitted line is ∼0.003%. The second event (event 2) exhibits a range-rate ν_f = 9.5 km s⁻¹ while the velocity ν ≈ [−18.4 −12.2 −9.9] km s⁻¹, and its magnitude |ν| ≈ 24.2 km s⁻¹ at a zenith angle θ ≈ 66°. The relative mean-square error (e) of the fitted line is ∼0.981%. Note the head-echo interference or beat pattern and that no flaring is seen. As discussed in the text, the early part of this net event appears to be a separate and likely unrelated event.