A GPS-at-GEO system is provided that includes a receive antenna design that enables improved tracking of GPS space vehicle side-lobe signals. The receive antenna design is a conical mode helix antenna configured to produce a conical mode radiation pattern, which has zero gain at Nadir and higher gain in the side-lobe signal regions. The conical mode radiation pattern provides several advantages for GPS-at-GEO navigation applications. For example, this mode provides higher gain in the GPS space vehicle side-lobe signal regions for improved acquisition and tracking performance and lower gain at Nadir, providing reduced noise temperature and higher signal to noise ratio.