What does HackerNews think of gps-sdr-sim?

> not trivial or cheap

From your previous comment, it sounds like your experience may have been from a while ago? In 2022, it is fairly trivial and cheap: https://github.com/osqzss/gps-sdr-sim

I can not ;^) personally confirm that this works with a HackRF, which is like $300, but probably also with any other reasonable tx-capable sdr.

> while spoofing GPS is significantly harder

You are very wrong. Spoofing GPS is downloading a file, and then running a commandline program with a hackrf attached. The *only* hard part is getting a HackRF or other TX capable SDR.

Download and compile https://github.com/osqzss/gps-sdr-sim

Download today's ephermis https://cddis.nasa.gov/archive/gnss/data/daily/

run:

gps-sdr-sim -e $EPHERMISFILE -l $LAT,$LON,$ALT

And, if you're nearby an airport, you're violating felonies with FCC AND FAA.

Completely unrelated - an inexpensive Software Define Radio (SDR) and GPS simulator code (https://github.com/osqzss/gps-sdr-sim) can quickly and reliably spoof cell phone GPS to any location you desire.

Yes, it can be pretty trivially falsified. https://github.com/osqzss/gps-sdr-sim

It can be done for probably less then a thousand dollars, even.

It's also pretty trivial to detect the simple falsification schemes, but outside of exotic military and research projects, none of the easily available GPS SoCs bother.

Sure, GPS SDR Sim[1] works just fine. You will want to be in an RF chamber of some kind not only to prevent the terminal from seeing natural GPS signals, but also to prevent you from screwing up the GPS in nearby satnav systems. Also because broadcasting on those bands on public airwaves is illegal as a private citizen.

Of course putting your satellite antenna inside of a RF chamber also prevents it from working, so this may not be a viable long term strategy. Plus the terminal is undoubtedly using the GPS coordinates to calculate the antenna steering profile so you won't be able to lock on if your GPS is wrong. But since all they want to do is enable access to dump the firmware this probably isn't an issue.

[1] https://github.com/osqzss/gps-sdr-sim

You can fix that! Get a BladeRF, HackRF, LimeSDR, and you can transmit your own GPS signals:

https://github.com/osqzss/gps-sdr-sim

(Seriously: Don't do this unless you're taking extreme care not to radiate outside your lab.)

In other words, uhh, don't use these projects:

https://github.com/Mictronics/pluto-gps-sim

https://github.com/osqzss/gps-sdr-sim

Or if you use them, do so in a completely RF shielded environment. You wouldn't want to wreck havok with drones, Lime scooters, Bird Scooters, cell phones, etc. Right? :)

I did with a hackRF and use it in our production line to test the GPS modules of our PCBs.

Project link https://github.com/osqzss/gps-sdr-sim

Here is some slides from Defcon 23 : https://media.defcon.org/DEF%20CON%2023/DEF%20CON%2023%20pre...

They did a record, replay with a USRP B210 and GPS antenna.

And here is a project that generates GPS baseband signal data streams for bladeRF, HackRF, and USRP.

https://github.com/osqzss/gps-sdr-sim