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

2. CALIBRATION OVERVIEW FOUR 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 Spectral budget considerations
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
√( )= 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