This paper presents a new method for receiver calibration of interferometric radiometers. It is based on the distributed noise injection mechanism and it consists of fully calibrating the baseline error terms of the central antennas (which share the same noise source) while keeping only separable error calibration for the distant ones. This improves the accuracy of the shortest baselines, which are the most significant ones due to the smoothness of the brightness temperature to measure. Simulations show that, compared to previously reported methods, the improvement on the radiometric resolution can be as high as 3.9. The robustness against frequency response mismatch between receivers is improved by a factor 2.9.