ADS-B is not radar, despite ATC calling these sorts of things “secondary radar”.
Secondary radar historically was radar. ADS-B can be seen as kind of a replacement or complement, I guess that's why it falls under the same terminology.
An ESP32 based plane radar for my desk
61–65 of 65 posts
Re: An ESP32 based plane radar for my desk
#62radar *display* making esp32-based radar emitter would've been cool, tho
Agree, and the display is called a PPI (https://en.wikipedia.org/wiki/Plan_position_indicator).
Before computers, they were easy to connect to a scanning (rotating) radar since the "memory" was the phosphor in the display.
Re: An ESP32 based plane radar for my desk
#63As I live on a widely used flight path, I also made one a while ago using a cheap ESP32 ($12) XiaoZhi AI display .
I made it multi-purpose by showing air traffic when a flight enters the selected airspace and when there's no new traffic, it defaults to showing my Claude usage and reset duration. It works with ESPHome and also has Home Assistant Voice Assistant as I wanted to experiment with fully local HA Assist.
Re: An ESP32 based plane radar for my desk
#64Earlier quoted context omitted.
The built-in ADC doesn't have a high enough sample rate to decode ADS-B in, so an external one is needed, and USB ADCs are readily available with built-in demodulators, for use as DVB-TV receivers.
No you don’t need an external one, it’s actually possible to sample parts of high bandwidth using a lower bandwidth because of the small buffer in most SDR. The problem is that you can’t freeze the buffer so have to gather multiple “sweeps” get parts of ADSB stitched together. Maybe I post the Rust code after some cleanup. Now I am busy build a new database from scratch to compete with them all https://github.com/pun…
…a new database from scratch to compete with them all…
Re: An ESP32 based plane radar for my desk
#65Earlier quoted context omitted.
TLS is supported in hardware, so it takes no more processing power than moving the data around without encryption. In the US, ADS-B in uses 1.3 MHz of bandwidth, which would require 2.6 Msps. The ESP32-C3 running at 160 Mhz would have ~70 instructions per sample to process the data. That's probably doable, but the ESP32-C3 is one of the less capable variations of the line, and there are dual-core versions running at…
GPS is over 1 GHz, but I don't think you need to have a microcontroller running that fast to decode it?
It's the width of the band that matters, not the carrier frequency. For example a band running from 1.21 GHz to 1.22 GHz has a 10 MHz wide band. A heterodyne tuner would use analog circuitry to output it as a 0 to 10 MHz baseband signal that can the be sampled by the ADC.
GPS bands are from 11 to just over 15 MHz, depending on the band, but decoding is extremely complex, so it's usually done with dedicated hardware, so a microcontroller only needs to read the handful of bytes that hardware outputs per update, and most receivers default to only a single update per second, and max out at tens per second.