N121-006 TITLE: Magnetic Noise Reduction in a Small Unmanned Aerial Vehicle

TECHNOLOGY AREAS: Air Platform, Sensors

ACQUISITION PROGRAM: PMA 264

RESTRICTION ON PERFORMANCE BY FOREIGN CITIZENS (i.e., those holding non-U.S. Passports): This topic is "ITAR Restricted". The information and materials provided pursuant to or resulting from this topic are restricted under the International Traffic in Arms Regulations (ITAR), 22 CFR Parts 120 - 130, which control the export of defense-related material and services, including the export of sensitive technical data. Foreign Citizens may perform work under an award resulting from this topic only if they hold the "Permanent Resident Card", or are designated as "Protected Individuals" as defined by 8 U.S.C. 1324b(a)(3). If a proposal for this topic contains participation by a foreign citizen who is not in one of the above two categories, the proposal will be rejected.

OBJECTIVE: Develop a magnetic noise reduction system that will reduce platform magnetic noise in a small Tier 1 and/or Tier 2 unmanned aerial vehicle (UAV).

DESCRIPTION: The next Navy antisubmarine warfare (ASW) airborne platform is the P-8A. During the ASW mission, the P-8A is flown at high altitudes. Currently, a magnetic anomaly detection (MAD) system is used on ASW aircraft to contact, confirm, localize, and track submarines. However, magnetometers have a short intrinsic range and therefore will work only at low altitudes. To enable the P-8A to complete its mission successfully, a UAV with a magnetometer on board can be launched from the P-8A that will then fly down to a workable altitude to detect, localize, and track the submerged submarine.

Two types of UAV systems have been considered for this activity: small, modest-endurance, disposable platforms (Tier 1) and medium, long-endurance retrievable platforms (Tier 2). However, both platforms produce magnetic noise that can reduce their ability to detect the magnetic field produced by the submarine. Classic sources of magnetic noise include noise produced by the UAV's permanent, induced, and eddy current magnetic moments. Electronic sources of noise include noise produced by the UAV's avionics, wiring, and power generation/supply. The combination of classic magnetic noise and electronic noise is termed the platform noise. Additionally, there are environmental noises such as geomagnetic (sunspot and solar activity), geologic, and ocean swell that affect the detection range. This topic primarily addresses platform noise issues, but environmental noise cancellation techniques may also be included.

Current magnetometers have a sub-pico Tesla (pT) noise level, and it would be ideal to reach that noise level in the air, but previous work has shown that platform and environmental noise compensation have effective limits. The realistic goal of this project is to reduce the platform noise contribution to <10 pT/rt Hz in the 0.05 to 0.5 Hz band and <1 pT/rt Hz in the .05 to 5 Hz band, and <10 pT/rt Hz in the power line frequency and harmonic band.

The company selected for this project should be expert in airborne magnetometry and noise reduction tailored to a typical small Tier 1 and/or Tier 2 UAV.

PHASE I: Propose effective methods for reducing the platform noise of a Tier 1 or 2 UAV using hardware and/or software tools in order to maintain the noise level specified in the description.

The magnetometer, any other sensors, and the UAV will need to be provided by the contractor. The Navy will not furnish a UAV nor coordinate the use of a UAV for testing in the Phase I or Phase II effort.

Environmental noise cancellation techniques and automatic target detection may be addressed in this phase but are not required.

PHASE II: Develop a prototype magnetic noise reduction system that implements the hardware and software tools proposed in Phase I and validate the system in ground and flight tests. Also verify that the noise reduction techniques do not reduce the target signal. Typical target magnetic moments will be specified in the Phase II testing.

PHASE III: Integrate the magnetic noise reduction system in a Navy-selected UAV and demonstrate its effectiveness.

PRIVATE SECTOR COMMERCIAL POTENTIAL/DUAL-USE APPLICATIONS: Geophysical exploration companies use magnetometery for locating oils and minerals. A small, sensitive magnetometer aboard a UAV would permit more extensive and less costly exploration. Additionally, MAD-equipped UAVs can be launched from surface ships for ASW missions. Also, the Army is investigating the use of magnetometer and E-field-equipped UAVs for power line monitoring and detection.

REFERENCES:
1. Tolles, W. E., & Lawson, J. D. (1950). Magnetic compensation of MAD-equipped aircraft. Report No. 201-1. Mineola, NY: Airborne Instruments Laboratory, Inc.

2. Leliak, P. (1961). Identification and evaluation of magnetic field sources of magnetic airborne detector equipped aircraft. IRE Transactions on Aerospace and Navigational Electronics, 8(3), 95-105.

KEYWORDS: MAD; magnetometer; UAV; ASW

** TOPIC AUTHOR (TPOC) **

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