We target the estimation of antenna patterns of distributed array antenna (DAA) systems for satellite communications. Measuring DAA patterns is very difficult because of the large antenna separations involved, more than several tens of wavelengths. Our goal is to elucidate the accuracy of the DAA pattern estimation method whose inputs are actual antenna pattern data and array factors by evaluating their similarity to actually measured DAA radiation patterns. Experiments on two Ku band parabolic antennas show that their patterns can be accurately estimated even if we change the conditions such as frequency, antenna arrangement and polarization. Evaluations reveal that the method has high estimation accuracy since its errors are better than 1dB. We conclude the method is useful for the accurate estimation of DAA patterns.