• L-/S-Band Calibration Error Analysis

      Taylor, Ralph E.; NASA (International Foundation for Telemetering, 1971-09)
      A statistical error analysis is performed to determine the degree of uncertainty encountered when calibrating steerable receiving antennas with the solar calibration method. The analysis considers the propagation of precision error indexes. It is shown that a worst-case one-sigma (1σ) uncertainty of ±0.8 dB in system noise temperature occurs for a solar calibration at L-band. Somewhat better precision can be achieved by monitoring the antenna gain-to-noise temperature (G/T) ratio at a station; a worst-case uncertainty of ±0.5 dB (1σ) can be realized. An error analysis is made of a method to determine absolute antenna gain based upon solar flux density. The uncertainty in this type measurement is ±0.7 dB (1σ) at L- and S-band frequencies.
    • VHF/UHF Stellar Calibration Error Analysis

      Taylor, Ralph E.; Stocklin, Frank J. (International Foundation for Telemetering, 1971-09)
      A statistical error analysis is performed to determine the degree of uncertainty encountered when calibrating steerable VHF /UHF receiving antennas with the stellar calibration method. The analysis considers the propagation of precision error indexes. It is shown that an antenna gain calibration by the stellar method has a one-sigma (1σ) uncertainty of ±0.65 dB at 1440 MHz (L-band), and ±0.8 dB (1σ) at 136 MHz (VHF). Somewhat increased precision can be achieved by monitoring the antenna gain-to-noise temperature (G/T) ratio at a station; a worst-case uncertainty of ±0.4 dB (1σ) can be realized at both L-band and VHF. Finally, field test measurements of antenna gain, obtained at 136 MHz in the NASA space tracking and data acquisition network (STADAN), demonstrate an uncertainty of ±1.0 dB, or less, which effectively confirms the analytical result.