Automatic Robust Antenna Pointing Algorithm for Continuous Lunar Landing Communications

Landing mission on any planetary surface is important to study the planetary body closely. During the descent and landing phase of lunar missions, maintaining continuous, high-rate telemetry and imaging downlink is crucial for real-time monitoring and post-landing assessment. In this phase, the spacecraft undergoes rapid attitude changes and variable descent velocities, making the communication geometry highly dynamic. The onboard high-gain antenna must continuously track the Earth-based Deep Space Network (DSN) station, while the DSN antenna must maintain precise pointing within sub 0.01° accuracy to avoid link degradation. The conventional DSN system works on program tracking mode and can have issues if there is any drift in the pointing. Hence, a hybrid feedforward–feedback pointing architecture becomes helpful to ensure uninterrupted connectivity. The work proposes a Kalman filter based pointing algorithm to maintain the line of sight between the onboard and ground station antenna to maximise the signal strength received at the ground station.