مقالة علمية منشورة في مجلة scientificbulletin upb الرومانية المتخصصة تتضمن التطوير الأولي لاشارة كوستاس بنسختها الأولى المُعدَّلة.

In this paper we propose to incorporate scattering coefficients of a target

into weighted Costas waveform model and using adaptive technique to find these

optimal weights, and hence to improve the radar’s Narrowband Ambiguity Function

(NAF). We confirm that the proposed formula of NAF is considered as a better

representation of the target echo and results in much better Auto-Correlation

Function (ACF) in the sense of decreasing the sidelobe level without needing to

increase the number of the frequencies in the Costas waveform. We will also show

that the obtained adaptive waveform doesn’t affect the original resolution and yields

less sensitivity to delay-Doppler coupling problem. We suppose that the received

signal depends on scattering coefficients obtained from Swerling models. The

developed optimization problem, to adaptively design the weighted Costas

waveform, adequately describe the features of the target such that the volume under

the corresponding NAF surface best approximates the volume under a desired

ambiguity function (AF) surface. What is more, we demonstrate that the optimal

solution will redistributes the signal energy at scatters of the target such that the

weaker scatter should be assigned with more energy than the stronger one. Finally,

we will prove the effectiveness of our adaptive waveform design through simulation

results.