UM7-LT Orientation Sensor (AHRS / IMU)

The UM7 is a 3rd-generation Attitude and Heading Reference System (AHRS / IMU) that takes advantage of state-of-the-art MEMS technology to improve performance and reduce costs. Like its predecessors, the UM7 combines triaxial accelerometer, rate gyro, and magnetometer data using a sophisticated Extended Kalman Filter to produce attitude and heading estimates.

The UM7 also adds many new features, including higher gyro bias stability and lower noise, a new communication architecture for improved flexibility, optional NMEA packet transmission, UTC time-synchronization with external GPS, and support for third-order temperature compensation on all sensors.

Even with its added features, the UM7 is offered at a significantly reduced priced compared to other sensors in its class.

The UM7 comes with one 5-pin cable assembly for the main IO header.

High performance

• Excellent gyro bias stability over temperature
• Adjustable low-pass filter and EKF settings provide customizable performance for various applications.
• States and sensor data synchronized to GPS position and velocity using optional external GPS module.
• Supports alignment calibration and third-order bias and scale factor temperature compensation for accels, gyros, and magnetometer (optionally performed in-factory or by the end-user).
• Magnetometer soft and hard-iron calibration

Lower Cost

• State-of-the-art MEMS devices designed for mass-market consumer applications drastically lowers cost
• OEM version reduces overall cost, size, and weight

Ease of use

• Transmits data using human-readable NMEA strings, binary packets for higher efficiency, or a combination of both
• Flexible communication architecture allows UM7 to transmit any combination of data at individually adjustable rates
• Connects to the CHR Serial Interface software to allow for real-time plotting of sensor data, logging, device configuration, and magnetometer calibration

Attitude and Heading Specifications

• EKF estimation rate: 500 Hz
• +/- 1 degree typical static pitch/roll accuracy
• +/- 3 degree typical dynamic pitch/roll accuracy
• +/- 3 degree typical static yaw accuracy
• +/- 5 degree typical dynamic yaw accuracy
• 0.5 degree angle repeatability
• 0.01 degree angular resolution

Other Specifications

• Input voltage: 5.0V
• Communication: 3.3V TTL UART, SPI bus
• Supported baud rates: 9600, 14400, 19200, 38400, 57600, 115200, 128000, 153600, 230400, 256000, 460800, 921600
• Power consumption: 50mA at 5.0V
• Operating temperature: -40 to +85 C
• Dimensions: 1.06″ x 1.02″ x 0.26″ (27mm x 26mm x 6.5mm)
• Weight: 0.4 oz. (11 grams)
• Data outputs rates: 1 Hz to 255 Hz (binary packets), 1 Hz to 100 Hz (NMEA packets)
• Output data: Attitude and heading (Euler Angles), Attitude quaternion, GPS altitude, position, velocity (w/ external GPS), magnetometer, accelerometer, gyro data

Documents

• UM7 Datasheet
• AN1005 – Understanding Euler Angles
• AN1006 – Understanding Quaternions
• AN1007 – Estimating Position and Velocity Using Accelerometers
• AN1008 – Sensors used for Orientation Estimation

Software Downloads

• CHR Serial Interface v3.0.7 Windows Installer
  Use the Serial Interface software to configure the UM7, log data, and plot data in real-time.
• Latest firmware revision (U71B, comes pre-installed on new sensors)

Example Code

• Example Matlab communication code