Optimized Design and Implementation of Digital Lock-In for Planetary Exploration Sensors

Exploring life conditions on the near-Earth planets and satellites before carrying out human missions is an important task for space agencies. For that purpose, scientific space missions usually include instruments to measure climatological variables. Within this space instrumentation and measurement context, dust sensors (DSs) aim to measure dust particles in suspension and provide valuable information for persons and equipment life conditions, while they must deal with low signal-to-noise ratios (SNRs). For example, the Exomars mission is focused to characterize the weather on Mars surface and include up to four DSs based on different technologies: infrared (IR), laser, interferometry, impact sensors, and electric field activity sensors. Due to the tight budget in terms of area, weight, power consumption, and data budget in aerospace instruments, as well as ionizing radiation and extreme temperatures, current solutions present low scalability and configurability. In this article, a novel system proposal that extracts valuable information from noisy signals obtained from IR sensors aimed to measure airborne dust is presented. The solution provides competitive capabilities in terms of power consumption, data budget, SNR, and reconfigurability. It has been implemented in a rad-hard Microsemi field programmable gate array (FPGA) (RT54SX32S). Therefore, robustness and scalability are guaranteed. The results reported a maximum power consumption of up to 141 mA (@12 Vdc), a sensitivity of 19.5 mV (input signal), and a data budget of 32 B/s. This research possesses great potential to further instruments not only in planetary exploration but also at Earth applications.