A Feasibility Study for Signal-in-Space Design for LEO-PNT Solutions With Miniaturized Satellites

The global navigation satellite systems (GNSSs) are increasingly suffering from interferences, such as coming jammers and spoofers, their performance is still modest in challenging urban indoor scenarios. Therefore, there efforts worldwide to develop complementary positioning, navigation, timing (PNT) solutions. One method under current research the so-called LEO-PNT, namely, PNT solutions based on low-Earth orbit (LEO) satellites, particular small-sized or miniaturized satellites. Such satellites have low-to-moderate costs of building, launching, maintenance. Several challenges be overcome when designing a new LEO-PNT solution, concerning all three segments: 1) signal-in-space (SIS) space segment; 2) ground 3) user/receiver segment. This article presents survey SIS design inherent constraints wireless-channel propagation impairments well some recommendations for features. We address different constellation types, achievable coverage limits, geometric dilution precision (GDOP) bounds, carrier-to-noise ratios (CNRs) realistic wireless channel model, MATLAB Quadriga simulator. also discuss several optimization criteria regarding design, by taking into account tradeoff between low cost/low number one hand, sufficient good CNR purposes other hand.