Hybrid DCT-modal analysis-based compression of vibration signals for telemetry in sounding rockets

Abstract Sounding rockets provide unique opportunities for microgravity and near-space research. Still, telemetry bandwidth limitations pose a significant challenge to handling the large volume of dynamic vibration data generated during flight. This study proposes a novel hybrid discrete cosine transform (DCT)-modal analysis-based compression method tailored explicitly for the telemetry subsystem of sounding rockets, addressing the scientific question of whether incorporating mechanical properties, specifically modal analysis, can enhance compression efficiency while preserving signal integrity. Modal analysis, a reliable method for designing mechanical structures in aerospace applications, forms the foundation of this approach. The proposed method combines the DCT with modal analysis, exploiting the intrinsic structural dynamics of the sounding rocket to achieve superior data compression. This hybrid approach was rigorously tested using shaker-table experiments simulating flight conditions, which are particularly challenging due to the highly dynamic nature of rocket vibration signals. Results demonstrate a significant improvement in compression ratios compared to traditional DCT methods applied to independent channels. Specifically, the hybrid method achieved compression ratios up to 100% higher (e.g. 8.54:1 vs 4.2:1) while maintaining comparable peak signal-to-noise ratios above 53 dB, indicating minimal loss of signal fidelity. Furthermore, analysis in the frequency domain confirmed the preservation of critical vibrational modes with minimal distortion, demonstrating the method’s ability to filter out irrelevant data while retaining essential structural dynamic information. This represents an original measurement methodology in aerospace telemetry by adopting a physics-informed compression technique that embeds structural dynamic responses from the frequency spectrum. This research establishes a foundation for next-generation data acquisition systems in spaceborne telemetry, with potential applications extending to other bandwidth-constrained fields. The findings confirm that combining modal analysis with DCT offers a powerful solution for data reduction in telemetry, paving the way for broader applications in space and other domains where bandwidth is a critical constraint.