Abstract: A two-axis platform comprises an azimuth gimbal rotatable about an azimuth axis. In the azimuth gimbal an inner gimbal is mounted about an axis. A two-axis gyro having input axes and a spin axis is located in the inner gimbal. The spin axis is always maintained horizontal by a torquer which is controlled by a level sensor. By the horizontal component of the rotary speed of the earth, which acts on the input axis of the gyro, the spin axis is rotated into North through the torquer. The azimuth angle of the spin axis is measured in a first position for elimination of the influence of gyro drifts including axial mass unbalance. Then, azimuth gimbal and inner gimbal are simultaneously rotated by 180.degree. about their axes. Subsequently, the azimuth angle is measured again, to which the spin axis is adjusted. The middle between these positions provides a North indication compensated for gyro drifts.

Abstract: A plurality of two-axis rate gyros are arranged in relation to an aircraft-fixed coordinate system such that they redundantly supply angular rate information. A plurality of accelerometers supply correspondingly redundant acceleration information. First signal processing means comprise means for failure detection and elimination, such that angular rate and acceleration information subjected to error are eliminated. The angular rate and acceleration information thus cleared from errors supply stabilization signals for the autopilot. Second signal processing means obtain the angular rate and acceleration information cleared from errors and integrated if required, and therefrom supply heading and attitude reference signals.

Abstract: Deposits and corrosion are to be avoided in a heatable diaphragm pump for smoke gases which are to be analyzed. A heatable pump head comprises a diaphragm chamber which is closed by a diaphragm. The diaphragm is driven by a motor through a connecting rod. The connecting rod is heated by controlled heating means and a temperature sensor. Transmission of measuring signals from the temperature sensor to a controller and the power supply to the heating means is permitted through U-shaped leaf springs.