Auxiliary beam terrain-scattered interference suppression: reflection system and radar performance

• Published in: IET radar, sonar & navigation Vol. 7; no. 8; pp. 836 - 847
• Main Authors: Björklund, Svante, Nelander, Anders, Pettersson, Mats I
• Format: Journal Article
• Language: English
• Published: Stevenage The Institution of Engineering and Technology 01.10.2013; The Institution of Engineering & Technology
• Subjects: airborne radar; auxiliary beam signals; auxiliary beam terrain‐scattered interference suppression; auxiliary beam TSI suppression; Estimates; Interference; interference (signal); military airborne radar; military radar; Navigation; Radar; radar beam channel; Radar beams; radar performance; radar signal processing; Reflection; reflection system estimation; signal‐to‐interference plus noise ratio; SINR; Sonar; military airborne radar; radar signal processing; auxiliary beam terrain-scattered interference suppression; radar performance; interference (signal); auxiliary beam TSI suppression; signal-to-interference plus noise ratio; radar beam channel; reflection system estimation; military radar; SINR; airborne radar; auxiliary beam signals
• ISSN: 1751-8784; 1751-8792; 1751-8792
• DOI: 10.1049/iet-rsn.2011.0407

Terrain-scattered interference (TSI), that is, jammer signals reflected on the earth's surface, is a significant problem to military airborne radar. In auxiliary beam TSI suppression, the TSI in the main radar beam is estimated by a single or several auxiliary beams and is subtracted from the main beam channel. The signal to subtract is the auxiliary beam signals fed through an estimate of the ‘reflection system’, which describes scattering on the surface. The authors first present results on the structure of this TSI suppression, on the estimation of the reflection system and on the quality of the estimate. Then the authors derive theoretical expressions for the signal-to-interference plus noise ratio (SINR) and the remaining TSI power for a single auxiliary beam. Since the SINR is directly connected to the radar performance, it can be seen what factors affect the performance and how. It was noted that when the estimated reflection system is missing one or more delays of the true system, the TSI filter cannot suppress the TSI signal completely. This phenomenon, which is called ‘TSI leakage’, has a very large impact on the performance. The SINR cannot be kept constant. Instead, an ‘SINR improvement’ can be defined.