Inertial sensor system for use in an inertial navigation system of a missile, comprising: a first inertial sensor module having at least two first inertial sensors (C1,..., Ci) of a first inertial sensor type, and said first inertial sensors comprise different measuring properties, and said first inertial sensor module having a first multiplexer that is coupled to the outputs of the first inertial sensors (C1,..., Ci), wherein the first inertial sensor type comprises acceleration sensors; a second inertial sensor module having at least two second inertial sensors (D1,..., Dj) of a second inertial sensor type that is different from the first inertial sensor type, and said second inertial sensors comprise different measuring properties, and said second inertial sensor module having a second multiplexer that is coupled to the outputs of the second inertial sensors (D1,..., Dj), wherein the second inertial sensor type comprises rotational speed sensors; and a control processor that is coupled to the first multiplexer and the second multiplexer and is configured so as - to determine a current flight phase of the missile, - to control the first multiplexer so as to output the sensor measured values of an inertial sensor of the first inertial sensors (C1,...Ci), and said first inertial sensor is selected by means of the control processor, and so as to select an inertial sensor of the second inertial sensors (D1,..., Dj) in dependence upon the current flight phase of the missile, - to control the second multiplexer so as to output the sensor measured values of an inertial sensor of the second inertial sensors (D1,..., Dj), and said second inertial sensor is selected by means of the control processor, and - to relay detected acceleration sensor measured values and rotational speed sensor measured values so as to calculate a current flight position of the missile in a flight guidance system. a first inertial sensor module having at least two first inertial sensors (C1,..., Ci) of a first inertial sensor type, and said first inertial sensors comprise different measuring properties, and said first inertial sensor module having a first multiplexer that is coupled to the outputs of the first inertial sensors (C1,..., Ci), wherein the first inertial sensor type comprises acceleration sensors; a second inertial sensor module having at least two second inertial sensors (D1,..., Dj) of a second inertial sensor type that is different from the first inertial sensor type, and said second inertial sensors comprise different measuring properties, and said second inertial sensor module having a second multiplexer that is coupled to the outputs of the second inertial sensors (D1,..., Dj), wherein the second inertial sensor type comprises rotational speed sensors; and a control processor that is coupled to the first multiplexer and the second multiplexer and is configured so as - to determine a current flight phase of the missile, - to control the first multiplexer so as to output the sensor measured values of an inertial sensor of the first inertial sensors (C1,...Ci), and said first inertial sensor is selected by means of the control processor, and so as to select an inertial sensor of the second inertial sensors (D1,..., Dj) in dependence upon the current flight phase of the missile, - to control the second multiplexer so as to output the sensor measured values of an inertial sensor of the second inertial sensors (D1,..., Dj), and said second inertial sensor is selected by means of the control processor, and - to relay detected acceleration sensor measured values and rotational speed sensor measured values so as to calculate a current flight position of the missile in a flight guidance system. - to determine a current flight phase of the missile, - to control the first multiplexer so as to output the sensor measured values of an inertial sensor of the first inertial sensors (C1,...Ci), and said first inertial sensor is selected by means of the control processor, and so as to select an inertial sensor of the second inertial sensors (D1,..., Dj) in dependence upon the current flight phase of the missile, - to control the second multiplexer so as to output the sensor measured values of an inertial sensor of the second inertial sensors (D1,..., Dj), and said second inertial sensor is selected by means of the control processor, and - to relay detected acceleration sensor measured values and rotational speed sensor measured values so as to calculate a current flight position of the missile in a flight guidance system.