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Method to Measure Total Noise Temperature of a Wireless Receiver During OperationA method has been developed to measure the total effective noise power in a GPS receiver, including contributions from the system temperature, the antenna temperature, interference, lossy components, etc. A known level of noise is periodically injected before the preamplifier during normal tracking, with a switch set to a very low duty cycle, so that there is insignificant signal loss for the GPS signals being tracked. Alternately, a signal of known power may be injected. The coupling port is fed with a switch that can be controlled from the receiver s digital processing section. The switch can connect the coupling port to a noise or signal source at a known power level. The combined system noise is measured, and nearly continuous noise calibrations are made. The effect from injected noise/signals on the performance of the GPS receiver can be less than 0.01 dB of SNR loss. Minimal additional components are required. The GPS receiver is used to measure the SNRs required to solve for the noise level. Because this measurement is referenced to the preamplifier input, it is insensitive to variations in the receiver gain.
Document ID
Acquisition Source
Jet Propulsion Laboratory
Document Type
Other - NASA Tech Brief
Young, Lawrence E.
(California Inst. of Tech. Pasadena, CA, United States)
Esterhuizen, Stephan
(California Inst. of Tech. Pasadena, CA, United States)
Turbiner, Dmitry
(California Inst. of Tech. Pasadena, CA, United States)
Date Acquired
August 27, 2013
Publication Date
May 1, 2013
Publication Information
Publication: NASA Tech Briefs, May 2013
Subject Category
Report/Patent Number
Distribution Limits
Public Use Permitted.
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