  Space coronagraphs are projected to detect exoplantes that are at least 1e10
times dimmer than their host stars. Yet, the actual detection threshold depends
on the instrument's wavefront stability and varies by an order of magnitude
with the choice of observation strategy and post-processing method. In this
paper the authors consider the performance of the previously introduced
observation strategy (dark hole maintenance) and post-processing algorithm
(electric field order reduction) in the presence of various realistic effects.
In particular, it will be shown that under some common assumptions, the
telescope's averaged pointing jitter translates into an additional light source
incoherent with the residual light from the star (speckles), and that jitter
"modes" can be identified in post-processing and distinguished from a planet
signal. We also show that the decrease in contrast due to drift of voltages in
deformable mirror actuators can be mitigated by recursive estimation of the
electric field in the high-contrast region of the image (dark hole) using
Electric Field Conjugation (EFC). Moreover, this can be done even when the
measured intensity is broadband, as long as it is well approximated by an
incoherent sum of monochromatic intensities. Finally, we assess the performance
of closed-loop vs. open-loop observation scenarios through a numerical
simulation of the Wide-Field Infra-Red Survey Telescope (WFIRST). In
particular, we compare the post-processing factors of Angular Differential
Imaging (ADI) with and without Electric Field Order Reduction (EFOR), which we
extended to account for possible telescope rolls and the presence of pointing
jitter. For all observation parameters considered in this paper, close-loop
dark hole maintenance resulted in significantly higher post-processing
accuracy.
