The design of the tri-axial magnetometer utilises Anisotropic Magneto-resistance (AMR). The sensors are implemented as ceramic packages and co-located with drive electronics in a potted sensor head - ideally at the end of a rigid boom. Closed loop control improves the overall linearity and limits sensitivity drift.

The MR driver ensures the sensor maintains low noise operation by holding the sensor at its optimum position on the sensor transfer function. The sensor delivers the three components of the magnetic field plus a temperature measurement.

The magnetometer requires an electronics card sized for a standard CubeSat platform. The sensor connects to the electronics card via a lightweight harness. Power requirements are one digital (3.3 or 5V) and one analogue (12V-15V) line. A digital serial interface and/or a 28V unregulated isolated power converter can be added if required. A digital serial interface can be included if required. In microsat applications, the additional electronics is integrated with the sensor head resulting in a very compact unit that is simple to accommodate.

The magnetometer has been developed in collaboration with the The Space and Atmospheric Physics group of Imperial
College London which has flown many scientific magnetometers of the last 30 years. Three flights of this unit are planned for 2011.

FUNCTIONAL CHARACTERISTICS

• Orthogonality: better than +/- 1
• Measurement Range: +50,000nT to -50,000nT
• Sensitivity: 10nT
• Update rate: up to 10Hz
• Noise density: < 150pT RMS/Hz @1H
• Frequency Response: 3dB @ >200Hz

PHYSICAL CHARACTERISTICS

• Analogue output Impedance: 100Ohm +/-5%
• Size sensor: 10x10x5mm
• Size electronics: 90x30x11mm
• Mass: 15g sensor; 150g electronics
• Power consumption: 400mW

ENVIRONMENTAL SPECIFICATIONS

• Operating temperature: -50°C to +85°C
• 16g rms random vibration
• >15krad total dose

INTERFACES

• Power Supply: +5V and +15V DC or 28V unregulated option
• 3-axis analogue output : 0-5V, temperature output 0-5V, or serial (RS422 or I2C) option
• Connector (microsat version): 9-Pin D-Type Male

FEATURES

• Very small size
• Very low mass
• Simple and flexible interface options
• Fully calibrated

APPLICATIONS

• Low cost magneto-resistive magnetometer
  designed for use in LEO smallsats and
  cubesats
• Can be used for the calculation of magnetorqer
  control torque levels
• Attitude determination sensor, when used with
  an IGRF reference model
• Angular rate determination sensor by
  comparing successive measurements

Click on the image to download the datasheet.