Inertial position conversion

A first glance onto trial data

Receiver clock synchronization

With the data acquired the following logic was applied to derive the offset and drift of each receiver:

After we choose G9 to be our reference receiver we now get values for the three offsets

over the flight time or distance flown. We have selected two aircraft 4006DB and 49516C that were both on a pretty Southbound track. The result is shown in the two graphs below.

We have drawn the offset for each plotted position over the latitude. The scope is the entire 2 minutes of the trial as both aircraft were seen during the full period.

Compared to station G9 station P5 has a pretty steep drift which equals about 17,000 clocks or 875 µs/min, while R1 and MC have a much smaller drift and almost the same drift value. To have a better view onto their drift the resolution is enhanced in the second graph:

The resulting drift for both R1 and MC is about 2,500 clocks or 125 µs per minute.

Remark: a high drift value does not describe a malfunction. Drift values are just relative to a randomly selected other box and they depend on the crystal accuracy and the prevailing environmental conditions, especially the temperature.

In addition to the drift we have observed the following basic offset values at the beginning of the recording (as hexadecimal values):

For any box and any flight we can now adjust the received clock value to a clock value as if the receiver would behave as box G9: