Inertial sensor system for use in an inertial navigation system of a missile, said inertial sensor system comprising: a first inertial sensor base module that comprises at least two first inertial sensors (15a,..., 15d) of a first inertial sensor type and at least two second inertial sensors (16a,..., 16d) of a second inertial sensor type that is different from the first inertial sensor type; a second inertial sensor base module that comprises at least two first inertial sensors (15a,..., 15d) of the first inertial sensor type and at least two second inertial sensors (16a,..., 16d) of the second inertial sensor type that is different from the first inertial sensor type; and a cross-system control system having a central control processor that is coupled to the first inertial sensor base module and to the second inertial sensor base module, and said central control processor is designed for the purpose of performing a plausibility check on sensor measured values of the first and second inertial sensors of the first inertial sensor base module using the sensor measured values of the first and second inertial sensors of the second inertial sensor base module; wherein the first and second inertial sensor base modules (1, 2) in each case comprise a control processor that is designed for the purpose of processing the sensor measured values of the first and second inertial sensors and making said sensor measured values available to the central control processor as an output via a system interface that the central control processor is connected to; characterised in that a "lock step" functionality is implemented in the central control processor and said lock step functionality is configured so as to trigger an output of an entire sensor output value by means of the central control processor only if the control processors of the individual inertial sensor modules (1, 2) have output, as error-free adjusted, output data per measuring period. a first inertial sensor base module that comprises at least two first inertial sensors (15a,..., 15d) of a first inertial sensor type and at least two second inertial sensors (16a,..., 16d) of a second inertial sensor type that is different from the first inertial sensor type; a second inertial sensor base module that comprises at least two first inertial sensors (15a,..., 15d) of the first inertial sensor type and at least two second inertial sensors (16a,..., 16d) of the second inertial sensor type that is different from the first inertial sensor type; and a cross-system control system having a central control processor that is coupled to the first inertial sensor base module and to the second inertial sensor base module, and said central control processor is designed for the purpose of performing a plausibility check on sensor measured values of the first and second inertial sensors of the first inertial sensor base module using the sensor measured values of the first and second inertial sensors of the second inertial sensor base module; wherein the first and second inertial sensor base modules (1, 2) in each case comprise a control processor that is designed for the purpose of processing the sensor measured values of the first and second inertial sensors and making said sensor measured values available to the central control processor as an output via a system interface that the central control processor is connected to; characterised in that a "lock step" functionality is implemented in the central control processor and said lock step functionality is configured so as to trigger an output of an entire sensor output value by means of the central control processor only if the control processors of the individual inertial sensor modules (1, 2) have output, as error-free adjusted, output data per measuring period.