1. The combined epoch count can be seen in two places in the Points Screen: First, the Processed Point Information screen (the screen that allows you to select RTK or PPK) or under Additional Information under Edit Point.
2. That is the Confidence and Consistency.
3. I believe it is because the average position was not originally intended to be a true average. I believe it was putting the result in the most probable location, which would be the center of the region of overlap of the two error ellipses. Imagine two skinny ellipses, one oriented vertically, one horizontally, overlapping each other in such a way that the center is outside of the overlapping area. I believe we were determining the center of the overlapping area. This has been changed and is now a weighted mean.
4. The HRMS and VRMS are statistical estimates (not guarantees) of the likelihood that a coordinate is within a particular tolerance. We report a confidence level of 95%, which is also referred to as 2-sigma. The software estimates, based on the observed standard deviation of the observation and modeled accuracies of the receiver by the manufacturer, that a point has a 95% chance of being within whatever the HRMS and VRMS values are. The 3DRMS is a Pythagorean result of the two. Horizontally the error estimate is not a circle as HRMS would imply. It is an ellipse. The error ellipse has a major axis (a) and a minor axis (b). It also has a rotation (theta).
5. In the report, we see the vector length, the horizontal error estimate of the vector, the error estimate for the vertical difference of the vector, the 3D (Pythagorean of Hz and Vt), the length of the major semi-axis (from center to edge), the length of the minor semi-axis (center to edge). I'm not sure about the ratio. Perhaps
@Vladimir Prasolov can answer that. The final column is the direction of the major axis of the ellipse.
6. Probably the easiest way that I can visualize an error ellipse is looking at a compass and tape measurement. The compass has an error and the tape has an error. Let's measure a line due North at 100'. How close are we at the end of that line to being due North, 100'? At a 100 feet, the tape may have a +/-0.10 foot we'll say. The compass has a potential error of +/-0.5° which at 100 feet is +/-0.9'. So we can estimate that our point that we've measured is somewhere within an ellipse that has a semi-major axis of 0.9' that is oriented E-W (90° perpendicular to the direction of the measurement) and has a semi-minor axis of 0.1'. If we made the measurement at an azimuth of 45°, then the semi-major axis azimuth would be 135° This assumes that the compass observation was using sound procedures (no magnetic interference) and that the tape measurement was made with a horizontal measurement and the tape wasn't bent. If the procedures aren't good, then our estimate is out the window. The same is true for GPS. If the RTK solution was a bad fix, the statistical estimate falls apart, or if the observation was under canopy, then the statistical estimates are less reliable, because part of the error estimate is based on the spread of the collected epochs and part is based on modeled accuracy of the receiver. If the model isn't based on the same conditions as the observation, then there is a loss of reliability. This is why we have comparisons in our adjustments for a priori and a posteriori error estimates. This compares the results of "How much error do I think I might have?" and "How much error does the adjustment suggest that I have?"
I'm still learning too. If anyone finds any explanation I've made to be incorrect or woefully incomplete (I'm trying to keep it somewhat simple) feel free to correct me.