Spoofing time instead of location using Skydel

Skydel Discussion
1

We want to test the resilience of GNSS timing receivers to spoofing, i.e. we want to introduce time errors of milli-/ microseconds. The idea is the following: One SDR should transmit the ‘genuine’ signal, the other one the signal which will be sent a millisecond later. We then ramp up its signal to make the receiver clock catch up (=run fast).
However, the starting time of the simulation (for replay attacks) can only be entered with a precsion of 1 second, whereas the location can be entered in Skydel with a very high precision.
Is there a possibility to circumvent this?

Help will be very much appreciated!
Clemens

2

Hi @ClemensKIT ,

thank you so much for your question, and please forgive our tardy reply.

You are correct, the precision is indeed of the order of a second with Skydel’s start time parameters.

To enter another precision below 1s, you can use the pseudoranges and clock error settings.

  • For pseudoranges, add a ramp error on all satellites using the menu Settings ->GPS → Errors → Pseudorange offset

  • For clock errors (of the order of ms), you can modify the value of the Delta af0 parameter in Settings → GPS → Errors → Ephemeris errors

Please get back to us if you need more help.

-ad