Vision-Based Terrain Relative Navigation on High-Altitude Balloon and Sub-Orbital Rocket

TL;DR

This paper demonstrates a camera-based terrain relative navigation system for high-altitude balloons and sub-orbital rockets, achieving accurate position estimates despite challenging conditions like rapid rotations and obstructions.

Contribution

It provides an experimental analysis of terrain relative navigation using satellite-mapped landmarks and inertial sensors across different altitudes and vehicle speeds.

Findings

Less than 290 meters average error over 150 km for high-altitude balloon

Less than 55 meters average error during sub-orbital rocket flight

Robust performance despite rapid rotations and camera obstructions

Abstract

We present an experimental analysis on the use of a camera-based approach for high-altitude navigation by associating mapped landmarks from a satellite image database to camera images, and by leveraging inertial sensors between camera frames. We evaluate performance of both a sideways-tilted and downward-facing camera on data collected from a World View Enterprises high-altitude balloon with data beginning at an altitude of 33 km and descending to near ground level (4.5 km) with 1.5 hours of flight time. We demonstrate less than 290 meters of average position error over a trajectory of more than 150 kilometers. In addition to showing performance across a range of altitudes, we also demonstrate the robustness of the Terrain Relative Navigation (TRN) method to rapid rotations of the balloon, in some cases exceeding 20 degrees per second, and to camera obstructions caused by both cloud coverage and cords swaying underneath the balloon. Additionally, we evaluate performance on data collected by two cameras inside the capsule of Blue Origin's New Shepard rocket on payload flight NS-23, traveling at speeds up to 880 km/hr, and demonstrate less than 55 meters of average position error.