Passive radar system for switching among multiple antenna arrays

Abstract

The invention discloses a passive radar system for the switching among multiple antenna arrays. The system comprises a plurality of array antennas, and the combined airspace coverage orientation of the array antennas is 360 degrees. A multi-channel radio frequency switching device selects one array antenna in a fixed time period according to the time sequence, and sends signals received by the array antenna to a multi-channel superheterodyne receiver. In this way, multiple channels of radio-frequency signals are converted to fixed intermediate-frequency signals. After that, the intermediate-frequency signals are sent to a multi-channel AD acquisition and preprocessing sub-machine, so that the AD acquisition and the digital down-conversion of the intermediate-frequency analog signals are completed. After that, the clutter suppression, the target detection, the positioning and the tracking are conducted by a high-speed parallel digital signal processing machine. By adopting the system, aplurality of antenna arrays are switched to take turn and run according to a certain time sequence, so that the orientation360-degree airspace coverage of the passive radar system is realized. Compared with a traditional circular array antenna, the antenna side lobe is low, and the clutter suppression capability is high. Meanwhile, the low-altitude target detection capability is high, and the cost of the system can be effectively controlled.

Description

technical field [0001] The invention relates to the technical field of civil aviation, in particular to the composition structure of a passive radar system for monitoring air targets by utilizing external radiation source irradiation. Background technique [0002] The passive radar system that uses civil radio and television stations as the irradiation source to receive the echo signal reflected by the air target and realizes the positioning and tracking of the target has the advantages of low cost, strong low-altitude detection capability, no electromagnetic pollution and good electromagnetic compatibility. It is widely used in civil aviation. The application prospect of the field is very broad. [0003] Existing passive radar systems usually use digital array antennas and digital beamforming technology, and a single array antenna can cover a wide range of airspace instantaneously. Radar systems usually used for target surveillance in civil aviation need to achieve 360° co...

AI Technical Summary

Problems solved by technology

Radar systems usually used for target surveillance in civil aviation need to achieve 360° coverage in the azimuth direction. In order to achieve 360° azimuth airspace coverage, passive radar systems often use circular array antennas, but circular array antennas The sidelobe of the azimuth pattern is usually high, so it will affect the system's clutter suppression ability and low-altitude and slow-moving target detection ability

If it is necessary to obtain lower sidelobes, it is necessary to increase the number of element antennas in the array antenna. Due to the adoption of the digital array antenna system, the increase in the number of antennas will lead to a linear increase in system costs

Images