Design and assessment of composite civil moderate code structure for efficient global positioning system L2 civil signal acquisition

Abstract

In global positioning system modernisation, a new civil signal namely L2C signal has been broadcast since 2005. Compared with the widely used C/A code signal, although the new signal provides lots of advantages such as better acquisition and tracking performances, the used civil moderate (CM) code and civil long code have much longer periods than C/A code and they make L2C signal acquisition challengeable. Although previous acquisition methods are effective, their computational complexities are still high. To this end, in the study, a composite CM (CCM) code structure is developed by reconstructing the previous return-to-zero CM (RZCM) code through the previous folding technique. Then the CCM code is comprehensively assessed. Compared with the RZCM code, the developed CCM code has following advantages. It can be implemented by small scale FFT block, which is desirable for resource-limited L2C receivers; it is more robust against navigation data and carrier Doppler, and performs more reliable detection performance; for normally received L2C signal, which is usually not <42 dBHz, it spends less time on acquisition. Theoretical and simulation results demonstrate the advantages.

Determination of the Validity of Exclusion Clauses in Institutional Care Service Contracts

“…The reason for this is that, in judicial practice, a significant number of contracts are concluded by one of the parties providing the text of the contract and the other party signing it without objection. If the "repeated use" element is removed, it will easily lead to an over-reliance on the "failure to consult the other party" element in the determination of form terms, which will result in an undue extension of the scope of the determination of form terms (LI H & LU M., 2015). Of course, this does not mean that only repeated use can be considered a form term, as in practice there are some form contracts that are used only once.…”

Low Computational Signal Acquisition for GNSS Receivers Using a Resampling Strategy and Variable Circular Correlation Time

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