摘要
针对给定空域亮温成像的辐射计在成像时间受限条件下温度灵敏度难以提高的问题,在分析典型辐射计成像体制温度灵敏度基础上,提出了通过增大阵列稀疏比提高综合孔径辐射计温度灵度的方法。设计了一种具有多倍冗余基线的稀疏阵列配置,阵面单元可构成多个T型稀疏子阵,每个T子阵独立实现综合孔径辐射计亮温图像重构,并通过多幅亮温图像平均提高辐射计温度灵敏度。系统设计中引入阵列稀疏比作为设计自由度,可实现综合孔径辐射计温度灵敏度、空间分辨率和硬件复杂度的最佳平衡。提出了多倍冗余综合孔径辐射计亮温图像重构算法,分析了温度灵敏度性能。给出了满阵为11×20单元均匀矩形阵列的多倍冗余综合孔径辐射计设计实例,计算了不同阵列稀疏比时系统温度改善度,仿真了典型阵列配置的亮温成像效果。结果表明,冗余倍数1~20的系统温度灵敏度比相同孔径的均匀密布阵全功率辐射计提高1.5~8 dB,图像信噪比改善4.5~11 dB,温度灵敏度比稀疏阵综合孔径辐射计理论值损失为1.3~3.7 dB。
It is difficult to improve the temperature sensitivity of radiometer used in imaging in a given space when total imaging time is limited.The method of increasing temperature sensitivity of synthetic aperture interference radiometer(SAIR)through increasing sparse ratio of antenna array is proposed.An array configuration with multiple redundant baseline set is designed.Multiple T-shape sparse arrays can be constructed with the antenna units in the array.Bright temperature image of space can be reconstructed through SAIR of each T-shape sparse array independently.The average of all the images achieves the final image with less noise,thus improving the temperature sensitivity of system.The sparse ratio of array is introduced as a freedom to achieve best balance among temperature sensitivity,space resolution and hardware complexity in radiometer imaging system design.The algorithm of image reconstruction of the suggested multiple redundant SAIR is present and sensitivity performance is analyzed.A system design based on full rectangular array with 11×20 units is given as an example.The relative improvements of temperature sensitivity with various sparse ratios are calculated.The image results of typical array configurations are simulated.It is shown that temperature sensitivity improvements of 1.5 dB to 8 dB or image signal-to-noise ratio improvements of 4.5 dB to 11 dB are achieved with 1 to 20 times redundancy.The loss of temperature sensitivity relative to its theoretical value of SAIR with sparse array is 1.3 dB to 3.7 dB.
作者
黄建
裴乃昌
HUANG Jian;PEI Naichang(Southwest China Institute of Electronic Technology,Chengdu 610036,China)
出处
《电讯技术》
北大核心
2022年第1期17-23,共7页
Telecommunication Engineering
关键词
综合孔径辐射计(SAIR)
温度灵敏度
稀疏阵列
冗余基线
synthetic aperture interference radiometer(SAIR)
temperature sensitivity
sparse array
redundant baseline
