Ground calibration of antenna arrays for aeronautical vehicles

Abstract

Ozetçe -Anten dizileri hava araçları gibi platformlarda kullanıldıgında antenörüntüsü veözellikleri büyükölçüde degişir. Anten çevresindeki eksiklikleri düzeltmek için anten dizilerinin kalibrasyonuönemli ve kaçınılmaz bir görevdir. Bu makalede UH-60 model helikoptere yerleştirilmiş ve yön bulmak için kullanılan bir anten dizisinin kalibrasyonu için bir yöntemönerilmiştir.Önerilen yöntemin yerden yansımaları etkin bir şekilde giderdigi ve dogru kalibrasyon verisi oluşturdugu gösterilmiştir. Bu yöntem hem çok etkin hem de anten dizisinin kalibrasyonu için az maliyetli bir yaklaşımdır.Abstract-When antenna arrays are placed on platforms, antenna patterns and antenna characteristics change significantly. Calibration of antenna arrays becomes an inevitable and important task to correct the imperfections due to the antenna surroundings. In this paper, a method is proposed to calibrate the direction finding antenna array on a UH-60 helicopter on ground. It is shown that the proposed approach can be used effectively to eliminate the ground reflections and obtain accurate calibration data. This technique is both effective and a cost cutting approach for array calibration.

Far‐field DOA estimation and near‐field localization for multipath signals

“…In this part, far‐field source DOA is estimated by using a calibration operation in order to model the array imperfections. In DF applications where multipath distortion is dominant, calibration is required to generate a priori information without which DF problem is very hard to solve if it is not impossible [ Elbir and Tuncer , ]. In this study, multipath signals are modeled in the far‐field array model by using a calibration matrix.…”

“…Hence, it is always possible to use MUSIC algorithm to find Θ as long as Γ ( Θ )is known even if the near‐field and far‐field sources are coherent. Here Γ ( Θ ) is found by the calibration operation [ Elbir and Tuncer , ]. While a full matrix for better performance and modeling accuracy may be preferred, the coefficients of this matrix cannot be found from the calibration since there are more unknowns than the known terms in our case.…”

“…In Cherntanomwong et al [], mutual coupling and gain‐phase mismatch of the antenna array are corrected with a fixed full calibration matrix under ideal white noise assumption. In our case, we treat the problem for multipath case [ Elbir and Tuncer , ] where the calibration is used to compensate for directional dependency as well. In addition, an optimum diagonal calibration matrix is used by employing known transmit signals.…”