Spoofing detection using gnss clock offset and moving window curve fit

A method comprising:

• receiving a plurality of global navigation satellite system (GNSS) signals;
• determining GNSS measurements based on the GNSS signals;
• computing a solution for position and clock offset based on the GNSS measurements;
• placing the clock offset of the solution into a moving window time buffer having a time window of a particular size;
• performing a curve fit procedure on the clock offset of the solution in the moving window time buffer to obtain a curve fit;
• computing curve fit residuals by subtracting the curve fit from the clock offset;
• examining magnitudes of the curve fit residuals over the time window to identify a largest curve fit residual of the curve fit residuals in the time window;
• determining whether the largest curve fit residual in the time window exceeds a predetermined detection threshold;
• and
• determining that spoofing is present when the largest curve fit residual in the time window exceeds the predetermined detection threshold.

A non-transitory computer-readable medium comprising a set of instructions that, when executed by at least one processor, cause the at least one processor to:

• receive a plurality of global navigation satellite system (GNSS) signals;
• determine GNSS measurements based on the GNSS signals;
• compute a solution for position and clock offset based on the GNSS measurements;
• place the clock offset of the solution into a moving window time buffer having a time window of a particular size;
• perform a curve fit procedure on the clock offset of the solution in the moving window time buffer to obtain a curve fit;
• compute curve fit residuals by subtracting the curve fit from the clock offset;
• examine magnitudes of the curve fit residuals over the time window to identify a largest curve fit residual of the curve fit residuals in the time window;
• determine whether the largest curve fit residual in the time window exceeds a predetermined detection threshold;
• and
• determine that spoofing is present when the largest curve fit residual in the time window exceeds the predetermined detection threshold.