The NASA Robotic Lunar Lander Development Project is a joint effort between NASA's Marshall Space Flight Center and the Johns Hopkins University Applied Physics Laboratory (JHU/APL) to create a new generation of autonomous robotic landers to achieve scientific and exploration goals on both the lunar surface and other airless celestial bodies, including near-Earth asteroids. In mission concepts, the Entry, Descent, and Landing phase relies on optical navigation algorithms to provide precise spacecraft state corrections using real-time imagery. JHU/APL recently completed helicopter-based navigation field trials in southern California to collect representative descent imagery of terrain types that have some similarity to foreign bodies. This imagery will further demonstrate optical navigation algorithm readiness in addition to prior validation with artificially-rendered lunar surface imagery. This paper provides background and discusses the detailed design of the field trial avionics system used to collect flight data.