Aiming at the rotor axis of PIGA with a zero bias, the transverse acceleration will be coupled to the direction of the input axis to form a cross-coupling error. For the decoupled nonlinear PIGA output expression, the influence of a time-varying input acceleration and the transverse acceleration which is applied to the output are considered, the computing method of PIGA’s output analytic expression relying on the base acceleration of three orthogonal direction and angles of outer axis and rotor shaft as input information is given. On this basis, the model parameters are calibrated by recursive iteration method, in addition to which, the output value compensation method of gyro accelerometer is given. By comparing the error results before and after parameter compensation, the input acceleration error is reduced from ${0.05}\mathrm{\;g}$ to ${0.002}\mathrm{\;g}$, which verifies the effectiveness of the cross coupling error compensation in the output model in the way of improving the measurement accuracy.