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Investigations of the sea state bias in TOPEX altimeter measurements of sea surface height show considerable regional variability of the estimated SSB values.
We describe the design of a large dual-beam, dual polarized reflectarray designed for a space-based radar altimeter. This application requires a 2.16 X 0.35 m aperture that can be folded for launch stowage. Low mass and >50% efficiency are also required. A reflectarray antenna offers the best approach but also presents unique technical challenges since a reflectarry has never been used in a space based radar application. In what follows, we describe the design, analysis and measurements of a breadboard test array built to demonstrate the reflectarray concept.
This paper describes a large dual-beam, dual polarized Ka-Band reflectarray antenna prototype which was developed to demonstrate that key requirements of a space borne interferometric radar altimeter are achievable. The antenna consists of a 2.5 x 0.26 m aperture comprised of a rectangular grid of square patch printed circuit elements. The 2.6 m focal length offset-fed reflector is illuminated by a waveguide slot array feed focused in the nearfield. Measured results show good agreement with gain and radiation pattern predictions and demonstrates >50% aperture efficiency.
The Mercury Laser Altimeter (MLA) is one of the payload instruments on the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft, which was launched on August 3, 2004. MLA maps Mercury's shape and topographic landforms and other surface characteristics using a diode-pumped solid-state laser transmitter and a silicon avalanche photodiode receiver that measures the round-trip time of individual laser pulses. The laser transmitter has been operating nominally during planetary flyby measurements and in orbit about Mercury since March 2011. In this paper, we review the MLA laser transmitter telemetry data and evaluate the performance of solid-state lasers under extended operation in a space environment.
TOPEX/POSEIDON has been collecting altimeter data continuously since October 1992.
Lunar surface bias on landing module altimeter signal
Signal processing in satellite radar altimeter model above geoid
Random noise calculations in altitude reading of lunar module altimeter for rough surfaces target
Lunar reflectivity, acquisition altitude, landing radar altimeter beam bandwidth, and Doppler equations verified for use in mathematical model
Terrain bias error analysis in pulse modulated planetary radar altimeters
Radar altimeter as spaceborne navigation aid
Computer study of station location, tracking, and altimeter errors for satellite position
Equipment specifications for GEOS C mission altimeters
Statistical analysis of altitude measuring unit of lightweight continuous wave radar altimeter
Electromagnetic wave scattering by sea surfaces relevant to geodetic satellite altimeter design
Hybrid radio and barometric altimeter using strapdown inertial navigation system
Precise location of GEOS-C satellite in short arc orbits for radar altimeter test
Signal processing techniques applicable to geodetic satellite altimeter program