Preliminary investigation on digital signal processing techniques for echo signal analysis in geodetic and wildlife monitoring

Abstract In large-scale remote monitoring of animals/mammals, echo signals localization with Internet of Things (IoT) modules has proved significant progress. Accurate information of echo signal extraction is difficult due to the frequent overlapping of signals in field recordings. The Digitization of these echo signals is essential to reconstruct interpretation of accurate signal in various geodetic fields, bird’s/mammal’s vocalization, seismic data collection, and GNSS signal processing. As a preliminary examination, this research examines on digital signal processing operations on four sampling rates namely 16 kHz, 32 kHz, 48 khz, and 96 kHz and their influences on the clarity, noise impact by employing GNU Radio Companion (GRC). It is observed that the lower rates 16 kHz and 32 kHz results in pronounced aliasing effects and the loss of higher-frequency signal components, hindering accurate interpretation. In contrast, the higher sampling rates 48 kHz and 96 kHz preserved signal details and demonstrated stronger resistance to noise. In this study, to measure aliasing and signal reconstruction quality, this study proposed the Fidelity Score (FS), a normalised quality metric that ranges from ‘0 to 10’ i.e. poor fidelity to perfect fidelity, and the Aliasing Severity metric (ASI), which is the ratio of aliased to original signal power. For instance, at 96 kHz, the aliasing severity was 0.5, and the fidelity score reached 9 out of 10, indicating near-perfect reconstruction. Further the work is validated using real-time bird vocalizations, including a 48 kHz recording of the White-throated Laughingthrush and a 15 kHz dominant frequency call of the Common Babbler, confirming its applicability to real-world data. These preliminary findings help in appropriately choosing sampling rates to achieve reliable signal acquisition in geodetic, automatic bird/animal sound separation applications that require high precision and signal clarity.