Automated Meteorological Profiling System (AMPS) Description

The Automated Meteorological Profiling System (AMPS) was developed by Orbital Sciences Corporation under contract to the USAF Space and Missile Systems Center beginning in 1996. The system will be used for upper air measurements of winds and other atmospheric parameters in support of space launch operations at both the Eastern and Western Spacelift Ranges. The basic contract to develop and deliver first articles for test and evaluation has been completed. The system is intended to replace the current Meteorological Sounding System (MSS) and the radar-tracked Jimsphere, both of which are more costly to operate and maintain than AMPS.

The AMPS system consists of two types of flight elements and a ground processing system. AMPS is designed to track multiple radiosondes (up to six) simultaneously while processing and displaying all data in near real-time. A PC-based system serves as the operator interface and controller for a rack-mounted system that houses the six individual signal processing subsystems (SPS). Both the flight elements and the ground element employ GPS technology in order to provide differential GPS tracking accuracy for wind measurements and other functions. One type of flight element is lofted by a standard latex balloon and carries a "low resolution" radiosonde instrument package for measurement of winds and pressure, temperature, and humidity up to an altitude of 30-km (100,000 feet). The "high resolution" radiosonde is carried aloft by a clear Mylar two-meter Jimsphere and measures only winds up to an altitude of 17-km (56,000 feet). Both instruments employ a 10-channel all-in-view GPS receiver. A 403 MHz narrow-band downlink transmitter telemeters all measurements to a ground receiving system that employs two omni-directional antennas, each of which feed all six SPS units.

A Kalman filter is employed to provide smooth, robust differential GPS tracking of each radiosonde type. A second-stage filter, implemented currently as a classical notch filter, is tuned to remove the self-induced motion unique to each lofting device so as to provide accurate measurements of the wind vectors and radiosonde position and altitude. Using differential GPS altitude accuracy and measured atmospheric temperature and humidity, ambient pressure is calculated, thus saving the weight and expense of a pressure transducer.