Improved noise rejection in automatic carrier landing systems

A technique for reducing the effect of sensor noise in automatic carrier landing systems (ACLS) is developed. For demonstration purposes, the effect of radar noise on the altitude control portion of an ACLS is studied using digital computer simulation. A noise rejection filter, which blends model estimates of the plane’s vertical velocity and acceleration with altitude information obtained by radar, is added to the tracking/control algorithm to decrease the sensitivity to noise. However, this results in an unacceptable increased sensitivity to turbulence. An optimization of the tracking/control gains is then performed to prevent degradation of the system’s response to turbulence while simultaneously achieving high noise rejection and adequate transient response. In the simulation, a 90% improvement in noise rejection capability is achieved using the new tracking/control algorithm, without increased turbulence response.