We report a ∼50PPM precision in-run calibration platform for MEMS gyroscopes. In this work we demonstrate an integrated system capable of extracting instantaneous scale factor, drifts and cross axis sensitivities of the commercial ADXRS646 Z-axis gyroscope, with complete in-run rejection of acceleration sensitivities. The demonstrated method is applicable to any MEMS Coriolis force gyroscopes. The 50ppm calibration result is limited by the inherent limit of the gyroscope, with the calibration system being potentially able to extract even higher levels of accuracy.