Closed sekarchandran closed 6 years ago
It's definitely possible the aircraft broadcast the same message several times in response to different interrogations.
ADSB messages( position -lat,long,altitude, velocity - speed,heading, call sign..) are broadcasted without any interrogation at regular intervals ( one second once) ....correct me if i am wrong ..
I just added some code to display the messages in console continually ....there i noticed that both position and velocity messages are repeated with in some milliseconds interval...same values only time is the different.
I verified the code thoroughly with various ways...in my understanding ..these messages are coming in different times ( different reads ) have you ever noticed that the position and velocity messages repeated ..?
As far as I understand ADSB messages can either be periodical (as is the case with extended squitter) or respond to secondary radar interrogations.
Regardless, unless it can be shown that there truly is a software bug that causes erroneous repeated messages I'll have to close this issue.
as of now i am not having the dongle with me ... i will come back with the log data after getting the dongle ..probably two to three days ..
Hi
Thanks to creators of this wonderful tool ..which helped me lot in my work.
I am developing a tool which will compare my Radar data with the ADSB (from dump tool) data for bias calculation.
I am using the "NooElec NESDR Mini 2 SDR & DVB-T USB Stick " and dump1090 .
I have following problems
I tried following methods ...but not able to solve the problem a) changed the buffer size and number of buffers in rtlsdr_read_async function.. b) changed the receive using "rtlsdr_read_sync " c) removed mutex and signals ...instead i used POSIX message queue bet receive and process threads...
still data is repeating some times .
Is it the bug in rtlsdr library which makes repeated messages OR ADSB system itself broadcast messages like this ...?
Kindly help me.
Thanks and Regards K.Chandrasekaran