This paper presents a new, high-performance SOI-MEMS gyroscope with decoupled oscillation modes. The gyroscope structure allows to achieve matched-resonance-frequencies, large drive-mode oscillation amplitude, high sense-mode quality factor, and low mechanical crosstalk, demonstrating a measured noise-equivalent rate of 90 (deg/hr)/Hz(1/2) even at atmospheric pressure. The angular rate sensitivity of the gyroscope is 100 mu V/(deg/sec) at atmospheric pressure. This value improves to 2.4mV/(deg/sec) at vacuum, for which the measured noise-equivalent rate of the gyroscope reaches to 35 (deg/hr)/Hz(1/2). The R-2-nonlinearity of the gyroscope is measured to be better than 0.02%. The gyroscope has a low quadrature signal of 70deg/sec and a short-term bias stability of 1.5deg/sec.