دانلود رایگان مقاله استفاده از تبدیل Karhunen-Loeve برای تشخیص تداخل و کاهش در GNSS

Abstract

Improving the Global Navigation Satellite System (GNSS) receiver robustness in a radio interfered environment has been always one of the main concerns for the GNSS community. Due to the weakness of the signal impinging the GNSS receiver antenna, GNSS receiver performance can be seriously threatened by the presence of stronger interfering signals. In these scenarios, classical interference countermeasures may fail due to the fact that interference detection and removal process causes also a non-negligible degradation of the received GNSS signal. This paper introduces an innovative interference detection and mitigation technique against the well-known jamming threat. This technique is based on the use of the Karhunen–Loève Transform (KLT) which allows for the representation of the received interfered signals in a transformed domain where interference components can be better identified, isolated and removed, avoiding significant degradation of the useful GNSS signal.

5. Conclusions

This paper demonstrated the capability of the use of a transformed domain technique based on the use of the KLT. By means of the KLT the signal is projected on the subspace spanned by the eigenfunction where interference components can be better identified and extracted from the received signal, avoiding a large degradation on the useful GNSS signal. Although the KLT-based method offers good performance in mitigating the interference, the computational burden of its implementation is quite heavy especially with respect to the traditional interference countermeasures. The complexity of the KLT is mainly caused by the eigenvalues problem that has to be solved. As mentioned in [11], if N is the length of the autocorrelation, N 2 is the number of calculation requested to find the KLT. Although the use of the KLT is unsuitable for real-time processing, it can be considered a powerful tool for post processing operation for those applications where careful analysis of the interference environment on jamming critical area is required; in fact, according to the energy criterion for the eigenvalues–eigenfunctions selection, it is possible to reconstruct a synthetic version of the interfering signal from an inverse KLT starting from the eigenfunctions which contain the jamming information only.