Novel Stealth Radio Concept. Based on a Direct Sequence System and Using Filtered211 Spreading Codes

摘要

At the Department of Communications Systems, a research project on stealth211u001eproperties of radio signals has been going on for several years. As part of this 211u001eproject, a novel radio concept was invented, a variant on the well known direct 211u001esequence technique, and it was expected to improve the stealth properties. The 211u001eauthors applied for a patent on this system in 1995 in several countries and it 211u001eis now sold to L.M. Ericsson AB. This report summarizes many of the results that 211u001ehave been derived in this project since 1995. The authors present the new 211u001espreading code and its properties together with descriptions of two possible 211u001eapplications. Both these applications are shown to have good stealth properties 211u001ecompared to a normal direct sequence system. This comparison is done by 211u001esimulations in MATLAB and shown in various plots and is evaluated for some usual 211u001ehostile detectors. Also, some other properties of these systems are discussed. 211u001eFurthermore, two other similar systems are presented, one developed in the 211u001eauthor's project as a variant on the patented system and one developed in South 211u001eAfrica with a slightly different approach.