Over
50 years experience in
* Inertial Navigation Systems (INS)
* Gyro-Compassing (GC)
* Attitude, Heading Reference Systems
(AHRS)
* Electronic Flight Instrument Systems
(EFIS)
* Satellite Car Navigation Solutions
(SATNAV)
* Inertial Measurement Units (IMU)
* Horizontal Directional Drilling (HDD)
* Applied Mathematics, Physics,
Electronics, Software and Complex Solutions
Submarine
and Ship Inertial Navigation
Systems Precision
Horizontal Directional Drilling with Fibre
Optic Gyroscopes Primary
Flight Display Systems Miniature
MEMS 1 cm2 BP416A, BP416B, BP416C Precision
SMD Inertial Measurement Units
Miniature Inertial Measurement Units
Our concept is to take all the complex processing out of a 6-degrees-of-freedom inertial sensor.
The units deliver precisely calibrated, pre-processed inertial data, containing scaled angular and velocity incremental data.
The output data is formatted for direct processing in navigation equations.
Output data is transmitted in multiple-byte frames at one of two hardware selectable baud-rates (38400 baud or 460,800 baud)
Output data is in UART format.
The frequency of transmission frames can be selected by the user at one of the following rates:
8 Hz, 16
Hz, 32 Hz, 64 Hz, 128 Hz, 256 Hz, 512 Hz
Note: 128 Hz, 256 Hz and 512 Hz are only available at 460,800 baud.
The internal sensor transmits 16-bit angular rates in degrees per second at one of the following selectable ranges:
±125, ±250, ±500, ±1000, ±2000, ±4000 degrees per second
The internal sensor transmits 16-bit accelerations in one of the following selectable ranges:
±2g, ±4g, ±8g, ±16g, where g is the standard acceleration of gravity = 9,81 m/s/s.
Range switching is automatically controlled by the internal processor, so the user never has to think about this.
Angular rate ranges and acceleration ranges are treated separately.
Switching up to the next higher range is done when any one of the 3 measured values is > 70% of the current range
Switching down to the next lower range is done when all 3 of the measured values are < 30% of the current range
The internal processor always reads the 3 gyro and 3 accelerometer values at 512 Hz.
If necessary range switching is done immediately so that the next set of measurements are taken using the correct range settings.
The internal processor performs pre-calibrated scaling and bias (zero offset) corrections at 512 Hz.
The data is then converted to angular increments (delta theta dTh) and velocity increments (delta velocity dV) values.
Fine corrections are then applied to theses values to correct for small misalignments about the X, Y and Z axes.
It then performs coning corrections at 512 Hz, to improve the quality of the dTh values due to rotation in 3 dimensions
It follows this by performing sculling corrections so that the dV values are referenced to the corrected rotational angles (dTh)
Internally the processor computes all data with 40-bit scaled accuracy
On transmitting output data at 38,400 baud, the upper 2 bytes of each data value is transmitted.
On transmitting output data at 460,800 baud, the upper 3 bytes of each data value are transmitted.
The upper bytes are then set to zero, but the lower bytes are retained, thus minimising any possible loss of data.
The inertial measurements units available are as follows:
* BP416A This is a low-cost version, calibrated once at +25 °C and has no internal temperature compensation
* BP416B This unit is calibrated at +50 °C and 0 °C and uses linear temperature corrections for scale factors and biases
* BP416C This unit is calibrated at multiple temperatures for best performance.
* BP3010X This is a version of BP416C in a different housing which will fit onto a 24-pin DIP socket
BP416A, BP416B and BP416C are 1 cm square devices designed for surface mounting.
Calibration uses a 26-State Kalman filter and a 2-axis rotating platform, where the inner axis periodically reverses direction.
The procedure accurately estimates 6 scale factors, 6 biases and 9 misalignments of the sensors to the X, Y and Z axes.
All inertial measurement units are designed to operate over the temperature range -40 °C to +85 °C.