A new lunar digital elevation model from the Lunar Orbiter Laser Altimeter and SELENE Terrain Camera

TLDR

The study presents an improved lunar digital elevation model covering ±60° latitude with 60 m horizontal resolution and 3–4 m vertical accuracy. The DEM is built by merging ∼4.5 × 10^9 LOLA altimetry points with 43,200 co‑registered TC stereo DEMs, correcting LOLA geolocation errors (<10 m horizontal, <1 m vertical) and assessing seams and crossover errors in the resulting SLDEM2015. Co‑registration improves TC DEM vertical residuals to <5 m for 90% of tiles, yielding a near‑global, highly accurate DEM without surface interpolation.

Abstract

We present an improved lunar digital elevation model (DEM) covering latitudes within ±60°, at a horizontal resolution of 512 pixels per degree (∼60 m at the equator) and a typical vertical accuracy ∼3 to 4 m. This DEM is constructed from ∼4.5×109 geodetically-accurate topographic heights from the Lunar Orbiter Laser Altimeter (LOLA) onboard the Lunar Reconnaissance Orbiter, to which we co-registered 43,200 stereo-derived DEMs (each 1°×1°) from the SELENE Terrain Camera (TC) (∼1010 pixels total). After co-registration, approximately 90% of the TC DEMs show root-mean-square vertical residuals with the LOLA data of <5 m compared to ∼ 50% prior to co-registration. We use the co-registered TC data to estimate and correct orbital and pointing geolocation errors from the LOLA altimetric profiles (typically amounting to <10 m horizontally and <1 m vertically). By combining both co-registered datasets, we obtain a near-global DEM with high geodetic accuracy, and without the need for surface interpolation. We evaluate the resulting LOLA + TC merged DEM (designated as “SLDEM2015”) with particular attention to quantifying seams and crossover errors.