Advanced Sensors for Airborne Magnetic Measurements
NAVAL AIR WARFARE CENTER AIRCRAFT DIV PATUXENT RIVER MD
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Numerous ground tests and platform tests were conducted to evaluate platform integration issues and the performance of the POLATOMIC 2000 magnetometer, a laser-pumped helium-4 total magnetic field sensor. These results are compared with those from lamp-pumped helium-4 magnetometers, the ANASQ-208 and the ANASQ-81 The sensitivity of the digital ANASQ-208 magnetometer is 3 pTsquare roots of Hz from dc to 216 Hz and, the analog ANASQ-81 has a slightly higher noise floor. The POLATOMIC 2000 noise floor is less than 0.3 pTsquare roots of Hz. For airborne measurements, the sensor noise is not usually the limiting noise. In the magnetic anomaly detection MAD band 0.04 Hz to 0.4 Hz, for example, substantial reduction of platform and environmental noise is necessary. Important sources of noise are geology, geomagnetic, platform, gradient, and wave. In order to reduce the effect of these noise sources, ancillary sensors are used in conjunction with noise models. These sensors are fluxgate magnetometers, accelerometers, and a low-noise C-code GPS. The performance of the POLATOMIC 2000 is described, as is the platform integration. Results of ground tests and flight tests are summarized, and the noise models and the effectiveness of the ancillary sensors for ambient and platform noise reduction are discusses.
- Test Facilities, Equipment and Methods
- Electricity and Magnetism