ALTAIR (Radar)

ARPA Long-Range Tracking And Instrumentation Radar (ALTAIR)^[1]
	Cassegrain antenna of ALTAIR
Country of origin	US
Designer	MIT Lincoln Laboratory
Introduced	1969
Frequency	162 and 422 mc
PRF	300 pps
Beamwidth	1.1° (UHF); 2.8° (VHF)
Pulsewidth	80 µsec
Range	42,000 km
Diameter	45.7 m (150 ft)
Precision	20 m (66 ft)
Power	5 MW

ALTAIR (ARPA Long-Range Tracking And Instrumentation Radar) is a radar tracking station on Roi-Namur island in the north part of the Kwajalein atoll in the Marshall Islands. It is a high-sensitivity, wide-bandwidth, coherent, instrumentation and tracking radar that is capable of collecting precise measurements on small targets at long-ranges. ALTAIR supports several operating modes, including tracking and signature collection at VHF and UHF. It is part of a network of contributing radar sensors that perform deep-space tracking.^[2]

The antenna uses a steerable 150-ft dish (46-m-diameter) and employs a focal point VHF feed and multimode Cassegrain UHF feed in conjunction with a frequency selective sub-reflector (5.5 m diameter).^[3]

The radar became operational in 1969.^[4] The original task was to detect and track intercontinental ballistic missiles. It is currently used to measure satellite orbits and meteor echoes in low-Earth orbit,^[5] and to observe ionospheric irregularities and background densities.^[6]

References

^ J. A. Nelson and K. R. Roth, History of Lincoln Laboratory at the Reagan Test Site, Lincoln Laboratory Journal Number 2 2012 (online PDF)
^ Card Index of Radar Sets in Radartutorial
^ S. Close, S. M. Hunt, F. M. McKeen and M. J. Minardi: “Characterization of Leonid meteor head echo data collected using the VHF-UHF Advanced Research Projects Agency Long-Range Tracking and Instrumentation Radar (ALTAIR)”, MIT Lincoln Laboratory, Lexington, Massachusetts, USA, in RADIO SCIENCE, VOL. 37, NO. 1, 1009, 10.1029/2000RS002602, 2002 (online PDF)
^ Sidney G. Reed, Richard H. Van Atta und Seymour J. Deitchman DARPA technical accomplishments : an historical review of selected DARPA projects, Institute for Defense Analyses, Alexandria, Va. und [1990-1991]
^ Sigrid Close et al.: “Simultaneous dual-frequency observations of meteor head echoes using ALTAIR”, In: Proceedings of the Third European Conference on Space Debris, 19–21 March 2001, Darmstadt, Germany. Ed.: Huguette Sawaya-Lacoste. ESA SP-473, Vol. 1, Noordwijk, Netherlands: ESA Publications Division, ISBN 92-9092-733-X, 2001, p. 237 - 242 (online PDF)
^ D.M.Towle: "VHF and UHF radar observations of equatorial F region ionospheric irregularities and background densities", Lincoln Laboratory, Massachusetts Institute of Technology, Lexington, Massachusetts 02173, in Radio Science 1980, p. 71 ([1])