Pair Crossings

An analysis of the crossings was performed to identify those corresponding to pairs of detectors observing the same transit of the drone across the focal plane. Crossings were filtered by grouping those separated by less than 100 ms. This method produced the results shown in the following figures for the flight, where the polarization angle for each crossing is plotted against ctime. Each crossing is represented by a cross marker, and pairs are indicated by dots of the same color. Both plots correspond to f150: the left plot is for FLY696 satp3, and the right plot is for FLY301 satp1. 

Pair identification enabled the analysis of the polarization angle differences between detectors within the same pair. Results from selected example flights are shown below. The absolute polarization angle difference for each identified pair is presented, along with the average absolute difference. It is important to note that the mean was computed excluding pairs with zero difference, as these may result from errors in the method used to calculate each polarization angle. 

Since the objective of this analysis is to determine the uncertainty of results for polarization angle computed from single crossings via the processing of pairs, the same same procedure as he one presented earlier as conducted in all flights for a given band and telescope.  As difference in polarization angles is being treated with the absolute value, the corresponding distribution was assumed to be a half-normal distribution centered in the origin. The respective standard deviation sigma was estimated as the 68.2 percentile.  The corresponding gaussian distribution is plotted aswell.