Annular radio-frequency (rf) antenna system for guided projectiles

A method of determining a position of a first object in relation to a second object, the method comprising:

• disposing an annular antenna system on the first object, wherein the annular antenna system comprises a first ring assembly that comprises (i) a first annular conductor, (ii) a second annular conductor, (iii) a first shorting wall that electrically couples the first annular conductor to the second annular conductor, and (iv) at least one radio-frequency (RF) port disposed on the first annular conductor, the at least one RF port is configured to receive an RF signal and apply the RF signal across the first annular conductor and the second annular conductor;
• applying at least one RF signal pulse to the RF port;
• and
• determining the position of the first object in relation to the second object based on a detected return signal.

An annular antenna system, comprising:

• a first ring assembly having a first shorting wall;
• a second ring assembly having a second shorting wall, the second ring assembly being substantially parallel to the first ring assembly;
• and
• four radio-frequency (RF) ports distributed on a top surface of the first ring assembly at ninety-degree intervals, wherein each of the RF ports has a housing electrically connected to the first ring assembly, each RF port configured to receive an RF signal and apply the RF signal to the first ring assembly.