1 / 13

Satellite Construction

Satellite Construction. Attitude Control and Determination System. Jan Hales, Martin Pedersen & Klaus Krogsgaard. ACDS Concept. Magnetometer and magnetotorquers Sun sensor for unambiguous determination B-dot control Optional: full three-axis control. Sun Sensor.

aida
Download Presentation

Satellite Construction

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Satellite Construction Attitude Control and Determination System Jan Hales, Martin Pedersen & Klaus Krogsgaard

  2. ACDS Concept • Magnetometer and magnetotorquers • Sun sensor for unambiguous determination • B-dot control • Optional: full three-axis control

  3. Sun Sensor • Linear analog slit sensor (MOEMS) • FOV: 70° (Required: 54.75°) • Theoretical resolution: 0.07° (Required: 1°) • Chip size: 8100µm  6900µm • Expected mass: 2.5-3g • Expected size (PCB): 25mm  35mm

  4. Sun Sensor – Reflection

  5. Reference area used to cancel out various dependencies Sun Sensor – Linear, how? • Independent of: • Degradation • Temperature • Dark currents • Cosine dependence • Sun power fluctuations • Albedo intensity contributions • Division implemented using Vref of an ADC

  6. It2 It1 It It Sun Sensor – Linear

  7. It/Iref Iref It It/Iref Sun Sensor – Linear

  8. Sun Sensor – Circuit

  9. Conservative mask design • Digital sensor chip with 70° FOV and 0.6° resolution Sun Sensor Chip • Process sequence compatible with MIC’s cleanroom

  10. Magnetometer • Specification: • Range: |B|[18200nT;49800nT] • Accuracy: < 1º  sin(1º)·18200nT=300nT • Resolution: > 8.4-bit effective • Design goals: • Range: ± 64000nT • Accuracy: < 50nT • Sample time: < 2ms per axis

  11. Magnetoresistive sensor • Sensor • Honeywell HMC1021: Wheatstone bridge with intergrated offset and reset coils • Compensation • Constant field, linearity error reduced to noise • Temperature drift: sensor, amplifier, A/D converter, and voltager reference

  12. Magnetotorquers • H-brige configuration as driver circuit. • Torque 0.6 – 1.5Nm Switch frequency: f = 32kHz

  13. Environment Modeling • Environment models: • Orbit (SGP) • Geomagnetic (IGRF2000) • Sun positioning • Gravity Gradient

More Related