Stanislaw Rzewuski

Multistatic passive radar based on WIFI - Results of the experiment

In this paper results of an experiment using a multistatic passive radar system based on packet wireless network illuminators are presented. The network consists of several transmitters/receivers that operate on the same channel and exchange data with each other. The passive radar listens to the communication and performs decoding of captured frames, and determines the WiFi network node which was the source of the transmitted frame. The received data stream is divided, based upon the decoded source address, into data streams sent by each network node, after which the separated data streams are processed using classical Passive Coherent Localization methods in order to detect target presence and to localize detected targets. The paper presents details of the experiments performed and their results.

Doppler only localization in GSM-based passive radar

The localization in a classical multistatic passive radar is based on finding bistatic ellipsoid crossing with at least three pairs of transmitter-receiver. The localization accuracy is dependent on the geometry and bandwidth of the illumination signal. For narrow band signals like GSM cellular phone transmission the bistatic range resolution is very poor, in a range of several kilometers. The paper presents an alternative solution - exploitation of Doppler information and localization based on Doppler-only measurements. Because there were 4 unknowns (in 2-D localization: two spatial and to velocity components) or 6 unknowns (in 3D localization) it is necessary to have at least 4 or 6 bistatic measurements to localized the target. The paper presents the theory of Doppler-only target localization in GSM passive radar, related simulation results and accuracy considerations.

Supersonic target detection in passive radar

The detection of supersonic targets in passive radar is a challenge due to the high speed and acceleration of the targets. In the classical approach, where the crossambiguity function is used, the integration time is limited by the range and Doppler migration. In this paper the application of the extension of the crossambiguity function to the 3-dimensional range-Doppler-acceleration is presented. The target of interest was a supersonic target - a sounding rocket launched by the Student Astronautical Group of the Warsaw University of Technology. As an illumination signal the DVBT-signal was selected.

Wind farm interferences in Passive Coherent Location

Rapid growth in the number of wind farms may influence the performance of many radar systems. The radar echoes originating from wind turbines blades and tower may mask existing objects or generate false plots. In the presented paper the authors analyze the influence of a wind turbine on Passive Coherent Location radars and discuss the effectiveness of simple methods used to overcome problems associated with it. The results of a simulation along with the recorded echoes of the wind turbine gathered by DVB-T based passive radar demonstrator are also shown in the paper.

Airborne targets detection using weather radar

This paper describes airborne targets detection possibilities using weather radar signals. During last two decades air traffics increased significantly. The airborne target like airplane or helicopter is a fast moving object on the radar horizon which gives strong Doppler echoes in received signal. In this paper we would like to show the results of simple processing echo from weather radar on Legionowo and show detected targets, which in our opinion are airborne. Airborne target can be a problem for the radar since it is a source of additional interference especially in wind farm regions. From the other side the weather radar systems after detecting airborne target like small airplane or large bird may share that information with Air Traffic Control systems extending Air Traffic Control knowledge about the airspace situation. Even if the weather radar from its capabilities gives poor resolution of detecting airborne targets it is better to have any poor quality information about the target than no information at all. Airborne target detection possibility using weather radar will be discussed in this paper.