Hi Liviu, we now carry out parity checking for ADS-B aircraft to ensure that we get the correct ID of the aircraft to minimise the decoding errors we got on previous versions of the software.
For non ADS-B aircraft we carry out checks to ensure that we get two messages with the same hex/callsign combination again for the same reasons. Aircraft only squit in response to an interogation by ground based radar and we recognise that in some areas the radar coverage is not a great as in others and even to get two consecutive messages with the correct squawk/callsign combination received can be difficult/take some time so we allow the user to decide whether to enable squawk validation or not.
When the aircraft do not populate, how many messages are received and do they populate after a time or not at all. Are the ones which are not populating ADS-B equipped or not.
Alan