Design of an Improved Orbit-Aware Store-and-Forward System for Space-IoT Applications

Severe conditions in hard-to-reach regions, where terrestrial networks are limited, make data backhaul from these areas challenging. In this context, advances in the Space-IoT have created new opportunities for data collection and monitoring using LEO satellites. To address this issue, this paper presents an orbit-aware S&F architecture for data collection from an intelligent ground terminal located in remote areas using a 3U CubeSat orbiting at 500 km altitude in a Sun-synchronous orbit. The designed ground terminal integrates an ESP32 microcontroller and a 433 MHz LoRa module and is enhanced with an embedded satellite pass prediction, Doppler pre-correction, and an adaptive LoRa strategy. The CubeSat utilizes a TOTEM SDR receiver, onboard data buffering, and an S-band downlink with variable coding for throughput enhancement. The orbital model for satellite prediction is validated using Ansys STK software version 12, while UHF and S-band links are evaluated using time-varying link-budget analysis. The adaptive transmission is compared with fixed configurations in terms of usable contact time and data delivered per pass. Results indicate that the proposed system demonstrates the feasibility of a Store-and-Forward mission co-design that combines precise orbit prediction, Doppler compensation, and adaptive transmission for future Space-IoT applications.