錢樺Hwa Chien
高頻(HF)海洋雷達透過主動發射與接收海面散射訊號，利用快速傅立葉轉換形成都普勒頻譜。Bragg 峰位移對應徑向流速，頻寬則反映波浪與紊流結構。為確保頻率穩定與訊號完整，系統設計採用超外差或零中頻架構，涵蓋本地振蕩合成、混頻、濾波、I/Q 解調與數位化等模組。本報告將重點介紹 HF 雷達的電路設計與訊號處理流程，並解析從頻譜生成到物理量反演的細節。最後，將與 GNSS-R Delay-Doppler Map (DDM) 架構進行技術比較，突顯兩者在訊號鏈路與觀測應用上的互補性。
High-Frequency (HF) coastal radar actively transmits and receives sea surface backscatter to derive Doppler spectra, where Bragg peak shifts indicate radial currents and spectral broadening reflects waves and turbulence. The system employs superheterodyne or zero-IF architectures, incorporating oscillator synthesis, mixing, filtering, and I/Q demodulation. This talk introduces the circuit design and processing workflow of HF radar, from spectrum generation to geophysical retrieval, and concludes with a brief comparison to the GNSS-R Delay-Doppler Map (DDM) approach.
