Originally Posted by
Gysbreght
Hi Hyperveloce,
A couple of questions:
I suppose you used the BFO calibration given in the report. What fixed frequency bias did you use?
I do not use an a priori AES fixed frequency bias (nor 150 Hz, nor a uniform distribution between 150-5 and 150+5 Hz like in the report), in my simulation the AES frequency bias is estimated (along with another parameter via a linear regression) for each simulated flight so that its simulated BFO profile is the closest possible (rms) to the measured BFO profile. The AES fixed bias obtained through this procedure are indeed close to 150 Hz and I get the following probability density function (an histogram actually):
https://drive.google.com/file/d/0B3s...it?usp=sharing
It is not the uniform distribution between 245 and 155 Hz used in the report, 80 % of the estimated freq. biases are between 150 and 155 Hz.
Originally Posted by
Gysbreght
At each arc crossing of the segmented track there is a change of heading. The BFO changes with heading, so at each crossing there are two values of BFO, one for the arriving segment and one for the departing segment. Did you use both?
For this simulation, the reference trajectories are rhumb lines connecting points (constructed under varied constant speed hypothesis) on the varied handshakes:
https://drive.google.com/file/d/0B3s...it?usp=sharing
For each of the reference (non mutated/randomized) trajectories corresponding to each of the ground speed hypothesis (between 320 and 520 kts), the handshakes sample each time the new course taken arriving at a new ping ring. But in its subsequent mutations or crossovers, the relative timing between the trajectory and the hanshakes is also randomized (a handshake can occur slighty before or after the real one/related event on the trajectory).
Originally Posted by
Gysbreght
Assuming that your 'goodness-of-fit' criterion is the root-mean-square of the deviations between the calculated and the measured values of BFO, which speed gave the best fit, and what were the deviations at each point?
The best fit is reached between 400 and 410 kts of ground speed, the goodness of fit I use is not a rms (linked to the 2-norm) but the max gap over the flight (linked to the infinite norm), for the best fit, it is less than 5 Hz for the BFO and less than 0.1° for the angle of elev/BTO.