Direction dependent calibration of widefield radio interferometers estimates the systematic errors along multiple directions in the sky. This is necessary because with most systematic errors that are caused by effects such as the ionosphere or the receiver beam shape, there is significant spatial variation. Fortunately, there is some deterministic behavior of these variations in most situations. We enforce this underlying smooth spatial behavior of systematic errors as an additional constraint onto spectrally constrained direction dependent calibration. Using both analysis and simulations, we show that this additional spatial constraint improves the performance of multi-frequency direction dependent calibration.
翻译:广域无线电干涉计的向向依附校准估计了天空多方向的系统错误。 这一点是必要的, 因为大多数系统错误是由电离层或接收器光束形状等效应引起的, 空间差异很大。 幸运的是, 这些变化在多数情况下都有某些决定性行为。 我们执行系统错误的这种潜在的平稳空间行为, 作为对光谱受限制的方向依附校准的额外制约。 我们通过分析和模拟, 表明这种额外的空间限制改善了多频率方向依附校准的性能 。