Spoofers are not only of the Black Sea type, as reported in
the press, kids are going that direction too. It is time to take spoofers seriously.
Spoofers are completely different from jammers that block GNSS signals. Spoofers create GNSS-like signals that fool receivers to provide false location solutions.
We combat spoofers in two ways: (Patents Pending)
Detect and alarm that spoofer exist. We ignore the spoofer and use valid satellite signals.
Help find the direction that spoofed signals are coming from.
With 864 channels and about 130,000 quick acquisition correlators in our TRIUMPH chip, we have resources to assign more than one channel to each satellite to find ALL signals that are transmitted with that GNSS satellite PRN code.
If we detect more than one reasonable and consistent correlation peak for any PRN code, we warn you that you are being spoofed and identify the spoofed satellites.
When we detect that spoofing is in effect, we use the position solution provided by all other clean signals (L1, L2, L5, etc... GPS, GLONASS, Galileo, Beidou, etc... ) to ignore the spoofer signal and use the real satellite measurement. If all signals are spoofed, then we alarm you to ignore GNSS and use other sensors in your integrated system.
The screenshots below are from a real spoofer in a large city. The bold numbers are for the peak that is used in the position solution.
When you detect that spoofers exist, you can also try to find the direction that the spoofing signals are coming from. For this, hold your receiver (e.g. TRIUMPH-LS) horizontally and rotate it slowly as shown in the picture (one rotation about 30 seconds) and find the direction that the satellite energies become minimum. This is the orientation that the spoofer is behind the null point of the antenna reception pattern.
After one or more full rotations observe the resulting graph that shows approximate orientation of the spoofer as shown in figure below.
Direction by Num
Direction by SNR
This screenshot is from the experiment within the anechoic chamber.