29-06-2012, 04:54 PM
Fast Self Switching type Frequency Agile RADAR processing unit implemented on Xilinx FPGA
Today RADARs are used both in military and civilian applications. In military applications RADARs play vital role in detecting the enemy aircrafts at larger distances. Jamming is a technique which is usually adopted to make a RADAR non functional. Hence a robust RADAR must be able to work even when there is jamming attach from enemy side. Many kinds of technology can be applied to modern pulse radar to meet diversified jamming in a word, they all enhance useful echo signals and avoid or weaken interference signals in order to ensure the radar works properly to the maximum extent. Among so many anti-jamming technologies, frequency selection is widely used and also very effective.
The common frequency selection method includes manual frequency modulation, frequency agility, frequency diversity, spread spectrum technology, etc. Frequency agility can be divided into random frequency agility and self-adaptive frequency changing, which are effective methods to resist jamming. Self-adaptive frequency agility can adapt the changing of the jamming environment to a certain extent. It analyzes jamming spectrum real time so that to control the
radar transmission frequency, it make the radar signal spectrum center locate at the weak part of the jam spectrum all the time, so as to improve the signal-interference ratio.
In this project an architecture to achieve self switching type agile RADAR is realized with FPGA using Hardware Description Language (VHDL) , the validity is proved by suitable test signals. The self-adaptive frequency agility module can analyze the type of jamming to select transmitting frequency to avoid the frequencies which have interference, under frequency diversity and fixed frequency, respectively. The high level blocks include jamming analysis, monitor control and receiver. We use Xilinx real time pipelined FFT core for spectrum estimation block.
The practical application of this for searching radar will be discussed to prove that this has good real-time and anti-jamming capacity.
Modelsim will be used for functional simulation and results verification. Xilinx ISE will be used for synthesis, place & route and bit file generation. Xilinx FPGA board will be used for results verification. The Chipscope software is used to display the real time FPGA signals on computer screen for validating the implemented architecture.