发表机构
National Astronomical Observatory（国立天文台）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
针对BepiColombo激光测高仪（BELA），开发了包含非高斯脉冲和地形效应的回波模拟框架，用于校准并评估水星表面粗糙度与反射率测量误差，表明脉冲形状比脉宽更可靠。
AI 中文摘要
表面反射率和粗糙度是理解水星地质演化的关键。BepiColombo激光测高仪（BELA）将随地形一同测量这些属性，但预测其性能需要真实模拟激光回波脉冲形状，而非早期模型中简化的高斯近似。我们为BELA开发了一个全面的回波脉冲模拟框架，该框架包括非高斯发射脉冲、接收链路中的模拟滤波以及足迹尺度地形对脉冲形状的修正。利用高分辨率月球数字地形模型和合成分形地形作为水星类比物，我们开发了校准和修正方法，并估算了未来BELA观测中预期的测量误差。在1000公里高度以下，距离误差平均为1.5米或更小；在900公里以下，能量误差小到足以区分暗色沉积物、风化层和裸露的冰。在现实条件下，脉冲宽度被证明作为粗糙度代理并不可靠；我们转而从数字化脉冲形状中约束粗糙度，这凸显了时间分辨数据对未来行星测高仪的价值。
英文摘要
Surface reflectance and roughness are key to understanding Mercury's geologic evolution. The BepiColombo Laser Altimeter (BELA) will measure these properties alongside topography, but predicting its performance requires realistic modeling of laser return pulse shapes, unlike a simplified Gaussian approximation in earlier models. We develop a comprehensive return-pulse simulation framework for BELA that includes non-Gaussian transmitted pulses, analog filtering in the receiver chain, and pulse-shape modification by footprint-scale topography. Using high-resolution lunar digital terrain models and synthesized fractal topography as Mercury analogs, we develop calibration and correction methods and estimate measurement errors expected in future BELA observations. Range errors average 1.5 m or less below 1000 km altitude, and energy errors are small enough to distinguish dark deposits, regolith, and exposed ice below 900 km. Pulse width proves unreliable as a roughness proxy under realistic conditions; we instead constrain roughness from digitized pulse shapes, underscoring the value of time-resolved data for future planetary altimeters.
CommentsSubmitted to Earth, Planets and Space
