A Review of the Interference Resistance of SPS GPS Receivers for Aviation

Abstract

Demonstrations of GPS‐based approach and landing systems have caused many potential users of the Microwave Landing System (MLS) to question whether it is appropriate to install such a costly system. An investigation of the resistance to electromagnetic interference of Standard Positioning Service (SPS) C/A‐code GPS receivers in aviation environments demonstrated their susceptibility to inband noise; for example, 1 W of radiated power jammed an airborne receiver at ranges in excess of 30 km. Although resistance to out‐of‐band interference is significantly greater, transmissions from communications systems in frequencies adjacent to the GPS bands present considerable problems for GPS reception. Consequently, the use of C/A‐code receivers for applications requiring high reliability and integrity, such as approach and landing, must be questioned.