OPTICALLY COUPLED DIGITAL ALTITUDE ENCODER FOR GENERAL AVIATION ALTIMETERS

摘要

An optically coupled pressure altitude encoder which can be incorporated into commer¬cially available inexpensive general aviation altimeters has been successfully developed. The encoding of pressure altitude is accomplished in 100-ft (30.48-m) increments from -1000 to 20 000 ft (-304.8 to 6096 m). The prototype encoders were retrofitted into two different in¬ternal altimeter configurations. A prototype encoder was checked for accuracy of transition points and environmental effects. Each altimeter configuration, with the encoder incorporated, was laboratory tested for performance and was subsequently flight-tested over the specified altitude range.nWith few exceptions, the assembled altimeter-encoder met aeronautical standards for altimeters and encoders. Design changes are suggested to improve performance to meet re¬quired standards consistently.