Function of Component

IMU: An inertial measurement unit (IMU) measures and reports the satellite’s specific force, angular rate, and orientation. It does this using accelerometers, gyroscopes, and magnetometers. The IMU is considered one of the “sensors & inputs” in the ADCS architecture. For more information, refer to IMUs

Accelerometer: An accelerometer measures the specific force on or acceleration of the system. Accelerometers are a part of the IMU and so are considered one of the “sensors & inputs”.

Gyroscope: A gyroscope measures the angular rate of the system. Gyroscopes are a part of the IMU and so are considered one of the “sensors & inputs”. For more information, refer to Gyroscopes

Magnetometer: A magnetometer measures the magnetic field surrounding the system. Magnetometers are a part of the IMU and so are considered one of the “sensors & inputs”. For more information, refer to Reaction Wheels

Key Parameters

• Inertial Measurement Unit (IMU) Performance
  • IMU performance in this context refers to the ability to measure and report the spacecraft’s specific force, angular rate, and orientation.
  • The ability to perform IMU responsibilities relies on using sensors such as:
    • Accelerometers
    • Gyroscopes
    • Sometimes magnetometers.
• IMU Output Data Rate
  • IMU output data rate in this context refers to the frequency at which the device reports usable information.
    • Implied in this is the frequency of sensor sampling.
  • For ADCS applications, the more information available, the more accurate a picture can be made regarding the satellite’s orientation. So, a higher frequency is generally more desirable
  • The IMU output data rate will depend on the sensor sampling rate of the aforementioned sensors.
• Gyroscope Performance
  • Gyroscope performance in this context refers to the ability to measure (and notably not maintain) the spacecraft’s orientation and angular velocity.
  • Good gyroscope performance may include a range on the order of 1000s of degrees per second (deg/s).
• Magnetometer Performance
  • Magnetometer performance in this context refers to the ability to measure magnetic fields and/or magnetic dipole moments.
  • Good magnetometer performance may include a range on the order of 1-10 Gauss.
• Pitch/Roll Accuracy
  • Pitch/Roll accuracy in this context refers to the accuracy at which the device can measure the spacecraft’s pitch and roll orientation.
  • For the 2023 competition cycle, the primary payload required a pointing accuracy of 1-1.5 degrees while the secondary payload required a pointing accuracy of 0.1-0.2 degrees.
• Size
  • Size in this context refers to the overall volume of the device as well as each individual major axis dimension.
  • Ideally, the device should be as compact as possible, on the order of 20-40 mm for its length and width and <10 mm for its height.
• Weight
  • Weight in this context refers to the overall weight of the device.
  • Since the entire spacecraft for the 2023 cycle needs to be within 4kg, the device should not take up a significant portion of that weight.
• Input Voltage
  • Input voltage in this context refers to the amount of supplied voltage that the device requires.
  • For the 2023 cycle spacecraft, the input voltage should be between 1 and 5 V, depending on its current draw.
• Input Power
  • Input power in this context refers to the amount of supplied power that the device requires.
  • For the 2023 cycle spacecraft, the input power must be less than 5W.
• Interface
  • Interface in this context refers to the communication between the device and the rest of the spacecraft.
  • The interface between the device and the rest of the spacecraft should be as non-complex as possible.

Selection Criteria

• IMU Performance
  • Must have:
    • Accelerometer
    • Gyroscope
    • Magnetometer
• IMU Output Data Rate
  • Over 100 Hz
• Gyroscope Performance
  • Over 1000 deg/s