Addressing the severe challenges of multipath fading, Doppler shift, and complex interference faced by Unmanned Aerial Vehicles in high-speed mobile scenarios, this study proposes and implements a set of key physical-layer technologies for a high-performance data link. Core innovations include: a rapid signal acquisition technique based on the joint detection of multi-segment independently modulated Pseudorandom Noise codes, effectively resolving the significant Doppler shift (up to ±54 kHz) and timing synchronization challenges caused by high-speed mobility, achieving an acquisition success rate exceeding 99%; a cyclic sliding correlation channel estimation method combined with a Single-Carrier Frequency-Domain Equalization with Iterative Decision Feedback architecture, significantly enhancing the robustness of carrier tracking and signal demodulation in fast-fading multipath channels; an overlapping window frequency-domain notch filtering technique integrated with adaptive spectrum sensing, enabling effective suppression of narrowband, mid-band, and full-band interference. Theoretical analysis, formula derivation, and simulation verification demonstrate that the proposed scheme achieves an approximate 4 dB performance gain compared to traditional 1-bit differential demodulation across various complex channel environments (e.g., suburban, urban), substantially improving communication reliability for high-speed mobile platforms.