The GUI was written before the chip was built and we used it to test the chip's performance. The ULD was written a year later when people asked for a much smaller driver.
Inside the timing budgets are bits to turn on some modes of the chip and how much time to spend of these. VHV is one of the modes. This adjusts for temperature changes. The decision was made in the ULD to only adjust for changes within a +/- 2 degree change per range as it was faster. The GUI allows a much bigger change. But we determined it would be a strange setup indeed that the temp could change that much from range to range, so we 'cheated' a little bit to make the driver smaller.
In Lidar - as in Radar there is a concept of Aliasing. (Google 'Radar Aliasing' if my explanation is lacking.) This is where light from pulse N comes back after pulse N+1 goes out. So a distance of 5M would read 1M if your max range was 4M. To lessen this effect there is a range A with one pulse repetition rate and a range B with a different rate. How long one spends in A and B and VHV and a couple of other things are all tied up in the Timing Budget.
But you shouldn't have to go through the pain of knowing which combinations work and which do not. We did that work for you. And we chose the best numbers. And apparently the designers of the ULD had the benefit of a lot of testing.
Both work.
And before you ask for how to set those numbers, the spread sheet we use is really, really complex. You don't want to get into it.
