Always try to use the global decode method as it is able to check itself against even and odd frames, yet only on the dondition the samples are within 10 seconds. Otherwise, try the local method that is seeded with the last emission. This only works if the transmission happened 10 seconds ago. If all else fails, try the local method seeded by the user's position.
For airborne packets, the nbits is 17. For surface packets, the nbits is 19. There was also so optimizations of reducing the number conditionals.
Looking at the SBS output, flight ID is just aircraft ID + 100. Aircraft ID is just a unique count to make parsing the output file easier. I'm not sure how useful this is but it makes us a step closer towards mimicking the SBS. I also pull out the ID for squitters 0, 4, and 5.
So .. from the terminal, "-A RX2", would set the device to use the RX2 antenna.The UHD manual will define your options. If the user puts in a bad selection, it will complain and list the options.
A learning experience I guess. If the pulse isn't REALLY square, and instead is bandlimited in any way, integrate & dump doesn't work as well as center sampling. At any rate, the completely rewritten decoder should be both faster and more sensitive than before.
* Rewrote preamble detector. Uses integrate-and-dump along with correlator to perform optimal receive. * No longer using framer. Determining packet length via header. Missing some anti-FRUIT stuff. * Pulled out the slicer logic into its own function. Lots of todos and fixmes.
… cheesy "bit_energy" thing