Perhaps I didn’t read it thoroughly enough but it seems that lat/long of the “radar” are expected to be entered by user, I think using wifi positioning could be of great assist and could be done from mcu itself without involving web portal, though maybe portal already does it (didn’t get to see it)
Cool project! Funny how similar projects can pop-up at the same time; here is a somewhat similar project for identifying close-by flights, but this is a mobile app: https://github.com/etnt/skyoverhead
Looks pretty cool, though kinda "cheating" by pulling from adsb.fi - though I think you'd need something a lot more powerful than an ESP32 to receive and decode ADS-B ;)
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 more than double the frequency, and those should be able to handle ADS-B in without issue.
> TLS is supported in hardware, so it takes no more processing power than moving the data around without encryption.
Specifically, common PC CPUs support AES acceleration, so you can get the ongoing encryption for an established connection with minimal overhead. There is still some initial overhead for establishing the TLS connection due to the need to do key exchange (with asymmetric cryptography primitives typically based on Diffie-Hellman with finite fields or elliptic curves).
Gotta admit that's what I clicked through hoping for.
I've seen a few projects that use SDR to detect doppler shifts of reflections of broadcast FM radio station off planes as "passive radar". But that doesn't get much in the way of direction info, just approach velocity. I've pondered building something that uses that and correlates it with an ADS-B receiver, to see it it can detect aircraft that are not transmitting ADS-B. But that'd get me on another "list" if I published it I suspect...
I suspect it's possible to build an active radar without exceeding the limits of the ISM bands.
Actually, I know it's possible, that's how the automotive radars (used for adaptive cruise control) work. The real question is if someone can get enough range to pick up aircraft.
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/punnerud/mpedb
“Finally, the firmware now supports authenticated OTA updates, so future builds can be installed through the browser instead of connecting the board over USB.”
I believe the ESP32 runs a small web server that supports WebSerial (?), if you can reach it over WiFi or somesuch, you should be able to upload the new firmware blob that way.
These kind of project are now so easy. A few prompts and you have something like this. I did it with quite a few similar like projects.
You can buy super cheap esps with integrated lcds for less than 20 dollars.
making esp32-based radar emitter would've been cool, tho
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 more than double the frequency, and those should be able to handle ADS-B in without issue.
Specifically, common PC CPUs support AES acceleration, so you can get the ongoing encryption for an established connection with minimal overhead. There is still some initial overhead for establishing the TLS connection due to the need to do key exchange (with asymmetric cryptography primitives typically based on Diffie-Hellman with finite fields or elliptic curves).
(But is is a cool project)
I've seen a few projects that use SDR to detect doppler shifts of reflections of broadcast FM radio station off planes as "passive radar". But that doesn't get much in the way of direction info, just approach velocity. I've pondered building something that uses that and correlates it with an ADS-B receiver, to see it it can detect aircraft that are not transmitting ADS-B. But that'd get me on another "list" if I published it I suspect...
This is not the project I remember, but it's the same idea and technique: https://github.com/Max-Manning/passiveRadar
Actually, I know it's possible, that's how the automotive radars (used for adaptive cruise control) work. The real question is if someone can get enough range to pick up aircraft.
Biggest problem isn’t that it’s not powerful enough, but the USB port bandwidth don’t match most SDR.
Using some clever tricks you can receive parts of the message on a slower USB and be able to decode ADS-B
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/punnerud/mpedb
What does that mean?