Engineering topics
Tanner, A.
Publications and source records attributed to Tanner, A..
Atmospheric Calibration for Cassini Radio Science
The signals from the Cassini spacecraft that will be affected by delay fluctuations in the Earth's atmosphere. These fluctuations are dominated by water vapor in the troposphere, and in the case of Gravitaional Wave Experiment (GWE), they are likely to be a limiting error source. A passive remote sensing system, centered around a water vapor radiometer (WVR), has been developed to provide calibrations of water vapor fluctuations during radio science experiments.
Atmospheric Calibration for Cassini Radio Science
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ARMAR Observations during TOGA/COARE
The NASA/JPL Airborne Rain Mapping Radar (ARMAR) was deployed for rainfall observations during TOGA/COARE on the NASA DC-8 aircraft. A total of approx. 30 hours of rain profiling measurements were collected over the Western Pacific Ocean during January and February 1993.
ARMAR: An airborne rain-mapping radar
A new airborne rain-mapping radar (ARMAR) has been developed by NASA and the Jet Propulsion Laboratory for operation on the NASA Ames DC-8 aircraft. The radar operates at 13.8 GHz, the frequency to be used by the radar on the Tropical Rainfall Measuring Mission (TRMM). ARMAR simulates the TRMM radar geometry by looking downward and scanning its antenna in the cross-track direction. This basic compatibility between ARMAR and TRMM allows ARMAR to provide information useful for the TRMM radar design, for rain retrieval algorithm development, and for postlaunch calibration. ARMAR has additional capabilities, including multiple polarization, Doppler velocity measurement, and a radiometer channel for brightness temperature measurement. The system has been tested in both ground-based and airborne configurations. This paper describes the design of the system and shows results of field tests.
Measurement of Rainfall Path Integrated Attenuation at Nadir: A Comparison of Radar and Radiometer Methods at 13.8GHz
An approach for reducing the ambiguity in the retrieved rainfall profile from spaceborne rain radar is to use the path integrated attenuation as a constraint.
ARMAR Observations During TOGA/COARE
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Pulse Compression with Very Low Sidelobes in an Airborne Rain Mapping Rada
The pulse compression system for an airborne rain mapping rada is described. This system uses time domain weighting of the transmit pulse and is able to achive a pulse compression sidelobe level of -55 dB. This is significantly lower than any values previously reported in the open literature.
Airborne and spaceborne radars for rain mapping
The use of spaceborne rain radars for global and tropical precipitation mapping can provide significant information for atmospheric and climatic studies. Several key design issues for such a spaceborne rain radar are presented. Attention is also given to the design and development of an airborne rain mapping radar that will be used to support the Tropical Rainfall Measuring Mission. The system characteristics and expected measurement performance are summarized.
Laboratory demonstration of an effective range sidelobe suppression technique for spaceborne rain radars
A 13.8 GHz linear frequency-modulated pulse compression radar electronics system for spaceborne and airborne radar rain mapping applications has been built and tested. Preliminary test results indicate that the far range sidelobes can be suppressed to the desired -60 B level in the laboratory environment.
The Electronically Steered Thinned Array Radiometer (ESTAR)
The concept of a thinned array radiometer is described as an alternate to large filled apertures to achieve high resolution imaging from space. The serious limitations of conventional mechanical scanning systems and the practical problems associated with a multiple receiver pushbroom system that utilizes a large antenna are discussed. The thinned array is developed in terms of aperture synthesis techniques used in radio astronomy. Examples of thinned array configurations are presented, and future directions are discussed.