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While the GPS is well known to be an accurate provider of position information across the globe, its low power level makes it susceptible to spoong. Given its status as the primary (perhaps only) provider of position in many safety critical applications, this susceptibility is of great concern. Several possible methods to detect a spoong event at a single GPS receiver have been proposed in the literature. We note, however, that almost all of this prior work has been on the conceptual level; there has been very little analysis of the resulting detection performance.

Recognizing that redundant equipment may already exist for some users, we have proposed to detect spoong by comparing the position solutions from two or more COTS receivers mounted on the same platform (ION ITM, Jan. 2013). The concept is that the existence of a spoofer would make the statistical relationship of the observed positions dierent than it would be during normal, nonspoofed, operation. The primary advantage of such an approach is that its implementation does not require receiver hardware modication or even access to software GPS methods; a separate processor could easily monitor the positions generated by each of the receivers and decide spoof versus no spoof. Our earlier paper initiated a performance analysis of the approach; this paper continues and extends the investigation.