This paper presents tighter lower bounds on the maximum aperiodic ambiguity function (AF) magnitude of unimodular sequences under certain delay-Doppler low ambiguity zones (LAZ). These bounds are derived by exploiting the upper and lower bounds on the Frobenius norm of the weighted auto- and cross-AF matrices, with the introduction of two weight vectors associated with the delay and Doppler shifts, respectively. As a second major contribution, we demonstrate that our derived lower bounds are asymptotically achievable with selected Chu sequence sets by analyzing their maximum auto- and cross- AF magnitudes within certain LAZ.

翻译：本文针对特定延迟-多普勒低模糊区域（LAZ）下的单模序列，提出了更紧致的非周期模糊函数（AF）最大幅值下界。这些下界通过利用加权自模糊与互模糊矩阵Frobenius范数的上下界推导得出，其中引入了分别与延迟偏移和多普勒偏移相关联的两个权重向量。作为第二项主要贡献，我们通过分析所选Chu序列集在特定LAZ内的最大自模糊与互模糊幅值，证明了所得下界具有渐近可达性。