1 / 7

MAMBO PRE-LAUNCH CALIBRATION CONSIDERATIONS

This document outlines the key calibration considerations discussed during the MAMBO pre-launch meeting held in Paris from February 4-6, 2002. It covers four main areas of calibration: radiometric, spectral, telescope parameters, and boresight and mirror positions. Each section highlights specific requirements, performance metrics, and budget considerations, detailing the need for precise measurements in brightness, frequency stability, beam efficiency, and alignment. The insights provided are essential for ensuring the system's accuracy and reliability in capturing data.

timothy-salas
Télécharger la présentation

MAMBO PRE-LAUNCH CALIBRATION CONSIDERATIONS

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. MAMBO PRE-LAUNCH CALIBRATION CONSIDERATIONS S. Gulkis Paris Meeting February 4-6, 2002

  2. CALIBRATION OVERVIEWFOUR LEVEL WORK BREAKDOWN • RADIOMETRIC CALIBRATION • SPECTRAL CALIBRATION • TELESCOPE PARAMETERS • BORESIGHT AND MIRROR POSITIONS

  3. RADIOMETRIC CALIBRATION • Requirement • brightness temperature between space and atmosphere known to within 1% (3) or noise level • RMS sensitivity less than 1 K in 1 sec • Calibration budget considerations • Optical system • Emissivity and temperature knowledge of calibration target • System linearity • Gain stability (Alan variance) • Sideband ratio • (calibration target and mirror alignment covered later) • Performance measurements • System temperature • Bandwidth

  4. SPECTRAL CALIBRATION • Requirement • Frequency knowledge to 1 m/sec - f/f < 1.0/3e8 = 3.3 e (-9) • Frequency stability to 3.16 m/sec - f/f < 3.16/3e8 = 1 e (-8) • Spectral response of filters /relative gain of spectral channels to 1% • Knowledge of sideband ratio to TBD % • Spectral budget considerations • USO and frequency synthesizers • Frequency response of spectrum analysers and filters • Including stability • Sideband responses /rejection • Temperature suceptabilities

  5. Wind Noise due to Frequency Jitter Requirement Frequency jitter shall produce an error less than .5 m/sec at 10 m/sec Implication for frequency stability f/f < 3.16/3e8 = 1 e (-8) Derivation |xm -xt| < 0.5 xm = measured wind speed = √(xt2 +x2) xt = true wind speed = 10 m/sec; x = freq. jitter (x/xt)2 = 2 (0.5)/xt x(rms) = 3.16 m/sec at xt = 10 m/sec Corresponds to 100 kHz at 10 Mhz √(102 +3.162)= 10.5

  6. Telescope Parameters • Requirements • HPBW TBD • Main beam efficiency >> 0.9 TBD • Sidelobe levels >> -30 db TBD

  7. BORESIGHT AND MIRROR POSITIONS • Requirements • Boresight direction shall known to within 0.2 HPBW and aligned with known WRT SC axis to within xxx • Boresight stability shall be within 0.05 HPBW • Considerations • Scan mechanism position, repeatability and jitter • S/C Stability

More Related