Abstract :
Multipath interference limits the speed and accuracy of determining position by differential Global Positioning System (DGPS) techniques. A geodetic surveyor for example, requires multipath interference rejection of about 36+20log10sinε dB, where ε is the elevation angle of the satellite being observed. Signal processing in a GPS receiver cannot satisfy this requirement. A receiving antenna is required that can sufficiently reject signals arriving from below the horizon. Available antennas have inadequate rejection, and brute-force methods of improving them, e.g., by enlarging their ground-planes, are impractical. A compact, ground-planeless, dual-band GPS antenna with improved multipath rejection has been designed and field-tested. This antenna resembles a vertical post rather than a horizontal platter; within its 0.1-m diameter, 0.4-m tall randome is a vertical array of turnstile elements. In field tests, a three-element array antenna rejected multipath better than a 0.5-m diameter ground-plane antenna by an average of 5 dB. A five-element array antenna appears superior to a 0.9-m diameter ground-plane antenna
Keywords :
Global Positioning System; antenna arrays; antenna testing; interference suppression; multifrequency antennas; multipath channels; radio receivers; radomes; receiving antennas; 0.05 m; 0.25 m; 0.4 m; 0.45 m; DGPS; GPS receiver; accuracy; array antenna; diameter; differential GPS; differential Global Positioning System; elevation angle; field tests; geodetic surveyor; ground-plane antenna; ground-planeless dual-band antenna; multipath interference rejection; multipath-rejecting GPS antennas; randome; receiving antenna; satellite; signal processing; turnstile elements array; Antennas and propagation; Directive antennas; Global Positioning System; Linear antenna arrays; Microstrip antenna arrays; Microstrip antennas; Microwave antenna arrays; Multifrequency antennas; Satellite antennas; UHF antennas;