Retrofit Antijam Applique for Handheld GPS Receivers

The land warrior has become increasingly dependent on handheld GPS (Global Positioning System) receivers for providing location information in high interference environments for Situation Awareness, etc. on modern battlefield. A solution is to replace thelegacy antenna with a relatively inexpensive smart antenna appliqu¿ to null out the jam. This smart antenna should be a direct replacement for the current antenna, without any change to the receiver, and with minimal consumption of battery power. A jamindicator and interference signal level measurement can be provided with manual activation of antijam operation only when jam is detected. In Phase-I, Wang Electro-Opto Corporation (WEO) successfully demonstrated the feasibility of such an antennaappliqu¿ for GPS L1 band. We propose a Phase-II program to expand the design to cover both L1 and L2 bands. Two approaches will be taken, one using conventional antennas, and the other using WEO's patented miniaturized slow-wave antenna. Brassboardantenna appliqu¿ with jam sensor and indicator with low power-consumption will be developed.