A Simulated Aircraft RADAR with Real Radar Scope Tube and ADS-B Data from an RTL-SDR
Over on YouTube we've found an interesting project by RingingResonance where he's created a simulated traditional radar scope using a real analog radar scope tube, and ADS-B data gathered from an RTL-SDR running dump1090 on a Raspberry Pi 3B.
The project uses a real radar scope tube which is controlled by SPI signals sent from the Raspberry Pi into a DAC, which is in turn connected to the analog radar scope. RingingResonance has uploaded the open source code to GitHub. He notes that the code currently pushes the Raspberry Pi 3 to it's limits, so the sweep speed is limited.
A PPI PSR and/or SSR monochrome CRT display required the the display to synchronize the display with the azimuth angle that the RADAR dishes pointed to during a sweep, the begin of the interrogation and delay for the passive/active reply for the display to have a accurate range display between the the Radar station in the center and targets-echos/-replies.
The first PPI display had mechanical rotating turning the sweeps.
To small for ATC, but easier to setup was the display of the PSR/SSR data on an oscillospe. You needed to connect an additional sinus/cosinus sweep generator for the x/y input to a Oscilloscope to provide the signal for the rotating sweeps from the Radar location to the max. range and apply the analoge Radar data to the z-input (intensity modulation) for highlighting Targets/darkening between targets.
Without the analoge signals from the radar you have to convert the target information to a synthetic PPI which requires more calculation power than just displaying the targets.
On youtube you can find another similar project https://www.youtube.com/watch?v=90ij3rzH5wg .