Abstract: Apparatus and methods for characterizing atmospheric refractivity and its evolution in time and space utilizing passive radiation emission measurement devices are disclosed. Based on an instrument such as a passive microwave radiometer, ancillary meteorological measurements and other information and observations, the apparatus and methods provide useful signatures for characterizing atmospheric refractivity. The system can observe to any vector in the sky, giving directional as well as zenithal measurements of the refractivity profile, its spatial and temporal gradients, and the spatial and temporal trending of the profile and its gradients.

Abstract: A Global Positioning System includes a ground monitoring network having a plurality of dual frequency receivers that obtain ionospheric delay measurements to provide double difference ionospheric delay residuals. These double difference delay residuals are converted to zero differences based upon a new mathematical technique. The zero differences are fit to measurement epoch specific and transmitter specific mathematical surfaces (i.e. planes). These planes represent precise ionospheric delay corrections in the area of the ground monitoring network for a specific transmitter at the measurement epoch. The planes are then provided as correction information for use by inexpensive single frequency receivers to obtain highly accurate corrections for single frequency receivers by interpolating the correction planes to the location of the single frequency receiver.

Abstract: An atmospheric water vapor sensing system uses Global Positioning Satellites (GPS) to determine the refractivity and Slant-path Water Vapor Delay (SWD) between an Earth-based GPS receiver and a plurality of satellite-based GPS transmitters. The system provides improved precision in position calculation measurements by eliminating the refractivity effects of water vapor. No other system inputs are required apart from conventional GPS satellite signals and conventional satellite orbit data to implement the method. SWD arises from the refractivity in the integrated atmospheric water vapor in a column of atmosphere at an acute angular line-of-sight path between the Earth-based GPS receiver and any one of the plurality of satellite-based GPS transmitters. The system is especially useful in monitoring the Earth's crustal deformation.

Abstract: An atmospheric water vapor sensing system using Global Positioning Satellites (GPS) to determine the refractivity and Slant-path Water Vapor (SWV) between an Earth-based GPS receiver and a plurality of satellite-based GPS transmitters. Either the refractivity measure or the SWV measure can be input directly into weather forecasting models. SWV is the integrated atmospheric water vapor in a column of atmosphere at an acute angular line-of-sight path between the Earth-based GPS receiver and any one of the plurality of satellite-based GPS transmitters. SWV sensing facilitates atmospheric soundings over land and water to provide global scale high resolution atmospheric tomography for use in operational meteorology and meteorological forecasting.

Abstract: Apparatus and methods for profiling atmospheric temperature, water vapor and/or cloud liquid content utilizing passive microwave remote sensing are disclosed. The apparatus includes an antenna for receiving atmospheric microwave emissions having frequencies of interest, a highly stable, tunable frequency synthesizer, and downconverting system receiving selected frequency outputs from the synthesizer and the received emissions and, responsive thereto, providing output signals indicative of the frequencies of interest and representing the profile.

Abstract: The space station of the present invention makes use of a modified space shuttle orbiter vehicle to provide a pre-assembled pre-tested, modular space station. The modified orbiter vehicle has all the equipment need for manned launch, re-entry and landing removed. The modified orbiter vehicle carries a pressurized laboratory module, a solar power system, and docking apparatus. The modified orbiter vehicle provides instrumentation, attitude control, communications, and life support systems. Another configuration includes an external fuel tank permanently attached to the modified orbiter vehicle. In either configuration, all equipment is fully integrated, installed and checked out on the ground before the launch in a single unmanned launch.

Abstract: Access door pallets for an external tank of a Shuttle Transportation System are provided. Access door pallets replace one or more access doors on the external tank. In addition to carrying out the original function of the replaced access door, they provide a means for attaching a payload to the external tank. The payload can be mounted on either side of the door. For example, thrusters, maneuvering devices, guidance and attitude control systems can be mounted on the exterior; measuring instruments, chemical release devices, transmitters, extensible solar collectors, and pressurized chambers can be mounted on the interior.

Abstract: A passive, multi-channel microwave radiometer includes an antenna-lens assembly for receiving, and a first waveguide designed to provide a common path for propagating, 23.8 GHz and 31.4 GHZ atmospheric signals. The 23.8 GHz signal is above the frequency of relative maximum water vapor absorption and the 31.4 GHz signal is near a relative minimum in the water vapor absorption spectrum. Circuitry is responsive to the atmospheric signals for generating output signals representing the respective water vapor and liquid content in and the temperature of the atmosphere. For realtime calibration a blackbody assembly is mounted in the near field of the antenna-lens assembly. The blackbody assembly emits known blackbody microwave signals at 23.8 GHz, 31.4 GHz and in the V band. The radiometer is calibrated during its normal operation by causing a mirror to select the blackbody signals for propagation along the common path.