A Comparative Study of LEO-PNT Systems and Concepts

作者：B. Eissfeller, T. Pany, D. Dötterböck, Roger Förstner · 发表于：ION Pacific PNT · 年份：2024 · DOI：10.33012/2024.19646 · 被引用次数：25

Currently, about ten dedicated LEO-PNT activities are under way on a worldwide basis. The SOOP (signals-of-opportunity) research within existing mega-constellations and plans for LEO-PNT research satellites are left out of consideration here. Thus, we observe a kind of hype and euphoria for LEO-PNT. However, shortcomings, contradictions and risks in several system designs are observed. In particular, many system designers underrate user segment aspects. In the paper we try to analyze the advantages and disadvantages of the proposed concepts, and to consider the most reasonable and realistic approach for LEO-PNT in a trade-off. We perform systematic assessments of the technical & non-technical characteristics of the LEO-PNT concepts: Orbit and constellation, carrier frequency, bandwidth and signal power issues, atmospheric (rain) and foliage attenuation and C/N 0 as function of carrier-frequency (UHF to Ku-Band). Additionally, satellite platform issues (dedicated satellite versus hosted payload), payload technology and SWAP-budgets, LEO satellite classes are considered. We expect that a LEO payload will also show code-and phase bias delays in the individual satellite signals (not different from MEO). If this is the case and calibration does not solve the bias issue with required