A Digital Processor for Atmosphere Telemetry Data

Upper air primary meteorological data (pressure, humidity and temperature )and other derived data (namely air density, sound speed..etc) are important for aviation , marine , science , agriculture ,military operations and industry. Primary information are measured by sensors within radiosonde carried by balloon or special tailored rockets. Collected data are multiplexed in time division multiplex format (TDM) whose basic slot time is about one second and frame time is 8-10 seconds. Each slot contains a signal whose frequency or code sequence usually represents the respective sensor information: pressure , temperature and humidity. Other information relevant to calibration and synchronization may also be included. The TDM packet is then used to frequency modulate (FM) a carrier at either of two frequencies that are allocated to meteo telemetry data :400 MHz(-10 MHz) or 1680 MHZ. This signal is received by a ground station, where it is processed so as to extract the actual temperature ,pressure and humidity and present their behavior as function of altitude over the ground. Further data processing so as to format the meteo data in a prescribed report format may be requested. Extraction of real meteo data would necessitate frame synchronization of the received signal packets in order to demultiplex the signals and deliver their actual variation with height as well as local time. This task is usually partitioned between a reception segment and a processing segment. Such a processing segment has to perform the following functions : -Frame and clock-slot- synchronization--Data extraction within each slot- -Filtering and or short-term data smoothing. -Measurand-to-physical'dSta conversion. --Global- or long-term data smoothing to yield the required
data profile with altitude and even graphical display. -Derivation of the required end-user meteo reports and data
logger functions. The present work is devoted to the processing function of the system. Most of the above mentioned functions :acquisition, synchronization , filtering,data extraction are considered Examples of graphical displays for real data are presented.