AI-Powered Edge Image Processing for Compression and Transmission of Hyperspectral Terahertz Climate Data in Low Earth Orbit Satellites
摘要
The hyperspectral sounders aboard Low Earth Orbit (LEO) satellites produce 515 Gbits of brightness temperature data in each orbital pass, which is many times more than a typical S-band/X-band downlink window can accept. Current compression pipelines, ranging from CCSDS 123.0-B to retrieval-agnostic deep codecs, reduce data volume without preserving the spectral fingerprints required for climate gas retrieval; channel-equal PSNR/SAM loss functions implicitly treat every spectral channel as equally valuable, so high-sensitivity humidity-sounding channels lose the bit budget needed to maintain physical retrieval fidelity, introducing temperature-profile errors of 1.737 K at compression ratios above 10:1. This paper proposes a physics-aware end-to-end edge AI pipeline, validated on three Chinese satellite collections: FengYun-3 MWHS-2 (15-channel THz sounder, 118–183 GHz), FengYun-3E HIRAS-II (2,275-channel hyperspectral infrared sounder), and GaoFen-5 AHSI (330-band VNIR/SWIR imager). The pipeline comprises three components. First, a Radiative-Transfer-Loss (RTL) Codec—an INT8-quantised 1D + 2D convolutional neural network trained with a Jacobian-weighted RTTOV retrieval loss—achieves a compression ratio of 7.5:1 and limits temperature retrieval error to 0.90 K (MWHS-2 synthetic, PSNR = 50.49 dB) and 0.93/0.94 K on FY-3 real data, satisfying the sub-1 K NWP assimilation requirement. Second, a Cloud Filtering and Band Selection (CFBS) module reduces data volume by 38% while adding only + 0.10 K retrieval error. Third, a seven-stage data engineering pipeline enables TensorRT INT8 execution on Xilinx Versal AI Core and NVIDIA Orin-Space hardware, with a total power of 5.0 W and a frame latency of 20 ms. The combined system reduces the time required to deliver climate anomaly data from 75 min, the latency of traditional store-and-forward downlink, to under 12 min, a more than 6× improvement that provides a deployment blueprint for next-generation THz CubeSat missions.