Navsight Solution
– Hardware Manual
NAVSIGHTHM.1.3
2.2.3. Horizon IMU
Horizon IMU is the highest performance available in Navsight Series. Leveraging on a closed loop Fiber Optic
Gyroscopes technology, this IMU is the unit of choice for most difficult conditions such as high altitude
survey / single antenna airborne applications, high depth survey, harsh automotive environments. The ultra
low gyro bias enable optimal performance even in low dynamic conditions.
2.2.3.1. Accelerometers
A3
Remarks
Full scale (
g)
± 10
Velocity Random Walk (µ
g/√hz)
100
Allan variance – @ 25°C
In run bias instability (µ
g)
100
Allan variance – @ 25°C
Orthogonality (°)
0.02
Over temperature range
2.2.3.2. Gyroscopes
G3
Remarks
Full scale (°/s)
± 495
In run bias instability (°/hr)
0.05
Allan variance – @ 25°C
Angular Random Walk (°/√hr)
0.012
Allan variance – @ 25°C
Orthogonality (°)
0.02
Over temperature range
2.2.3.3. Surface form factor
The Horizon IMU enclosure is composed of two anodized aluminum
parts (6061), one for the cover and one for the base plate. The device
uses high quality alloys and connectors to offer a full IP-68
enclosure and a good resistance to harsh environments.
The Horizon IMU connector is a high quality push pull connector that
offers IP-68 protection even unconnected.
Warning: The Horizon IMU surface model is not
designed for prolonged operation in salt water
environments. Check section Maintenance for more
details about operation in sea water environments.
Mechanical alignment
For best measurement accuracy, a good mechanical alignment is required. During manufacturing, the
Horizon IMU frame has been carefully aligned to 0.02° with the base plate for roll, pitch and yaw angles.
To ease the yaw alignment (X axis), the base plate features two alignment holes Ø 4 mm H8 that
guarantees with two taper pins Ø 4 mm h7 a yaw alignment better than ±0.04°.
Origin of measurements
The Horizon IMU offers the possibility to output data at different measurement points.
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Figure 2.7: Horizon IMU
