Stepped Frequency Microwave Radiometer (SFMR)

The Stepped Frequency Microwave Radiometer (SFMR) developed by ProSensing has been used by the National Oceanic and Atmospheric Administration (NOAA) aboard their hurricane reconnaissance aircraft to measure over-ocean wind speed and rain rate in hurricanes and tropical storms. The SFMR is a compact, airborne radiometer designed to measure surface brightness temperature in 6 frequency bands spanning 4.5 to 7 GHz.

Calibrated values of brightness temperature generated by SFMR are reported in real time to a windspeed retrieval algorithm, developed in cooperation with NOAA's Hurricane Research Division. This algorithm generates a real time measure of surface level wind speed and rain rate in hurricanes and tropical storms.

ProSensing's SFMR system, shown above, was built in 2001 for the US Naval Research Laboratory as part of a multi-sensor imaging system for measuring ocean salinity. Since 2001, our engineers have made a number of system improvements, including a new compact pod mounted design with an internal cold load that improves system precision and accuracy. Two of the pod mounted SFMR's are now flown aboard NOAA AOC's WP-3D Orion aircraft (as shown in the picture below) with two more units scheduled for delivery to NOAA AOC in 2005.

Standard SFMR (model SFMR2000-P) features:

  • Wide band (4.6 - 7.2 GHz) receiver.
  • High efficiency, wide band corrugated horn antenna.
  • System control and data reporting via RS-422.
  • Microprocessor-based thermal control maintains receiver at a constant temperature.
  • Outputs radiometric brightness temperature at six frequencies.

New SFMR (model SFMR2005-W) includes these additional features:

  • Single board computer with a flat panel screen display.
  • Real-time wind retrieval algorithm.
  • One second ocean surface wind speed and rain rate updates.
  • Internal cold calibration developed by ProSensing provides significantly improved measurement accuracy.

SFMR Radiometer Specifications:

Radiometer Type:

Hach
Tuning bandwidth:

4.6 -7.2 GHz
Number of channels:

Up to 8
Receiver Channel Bandwidth:

100 MHz (at RF)
Antenna Type:

Corrugated horn
Antenna Beamwidth (3 dB):

20-28 deg (over the tuning bandwidth)
Polarization:

Linear
Cross-polarization isolation:

25 dB
Front End Loss:

0.25 dB
System Noise Temperature:

490 K (Noise figure = 4.3 dB)
Measurement precision:

0.4 K (0.5s averaging per channel)
Electronics Power Requirements:

28VDC, 2A
Thermal Control Power Requirements:

28VDC, 4A (max)
Power:

168 W
Operating Temperature:

TBD
Survival Temperature:

-51°C to +43°C per MIL-STD-810F
Humidity:

0 to 100%
Size (L x W x H):

29" x 11" x 15"
Weight:

55 lbs.

SFMR Processor Specifications:

Computer:

PC/104
CPU:

ATLAS 133 MHz
System Memory:

62 MB
Compact Flash Memory:

512 MB
Display:

LCD (size 2" by 1.5")
Interface Inputs:

Military style circular multi pin connector (1) (interface with the SFMR radiometer)


BNC (4) (radar blanking)


RS-232 (1) (AUX data)
Interface Outputs:

RS-232 (1)(SFMR data)
LAN (1) (ethernet)
Power Supply:

110 V AC
Electronics Power Requirements:

18W (163 mA @ 110V)
Operating Temperature:

0°C to 60°C (32°F to 104°F)
Humidity:

0% to 90%, non-condensing
Size (L x W x H):

13" x 19" x 3.5"
Weight:

15 lbs

Available Models:

Model SFMR2000-P

  • Includes Radiometer Unit
  • Standard Delivery: 9 Months
  • Includes one year full warranty (parts and labor)

Model SFMR2005-W

  • Includes Radiometer Unit and Processor
  • Standard Delivery: 9 Months
  • Includes one year full warranty (parts and labor)