Common use of Comparable Foreign Systems Clause in Contracts

Comparable Foreign Systems. The only foreign system directly comparable to GPS-PPS is the GLONASS satellite navigation system being fielded by Russia. Availability of GLONASS user equipment is believed to be extremely limited. A more likely alternative for foreign military users who cannot access GPS-PPS is to use a commercially derived differential capability to improve the accuracy of the signal. Differential GPS based upon the civil SPS is highly vulnerable to jamming and spoofing, however, and is not judged useful for military users in active combat.