Tracking the position of a device can be a task that consumes a lot of energy, especially when it comes to maintaining accuracy. While GPS is a highly accurate solution, it tends to fail when the device is too close to buildings or tunnels, and has a fairly high power requirement. Other options, such as the Inertial Measurement Unit (IMU), require less energy but tend to lose accuracy over time when used alone.
Regarding its "third wave" of intelligent MEM sensor technologies, Bosch has recently announced the BHI160BP, a low power consumption position tracking sensor, small and low form factor.
The BHI160BP has an integrated three-axis accelerometer, a three-axis gyroscope and a programmable microcontroller that can be paired with an absolute positioning device, such as GPS, for position tracking.
Bosch courtesy image.
Low power position tracking
What makes this sensor unique is that GPS has a duty duty cycle: between the GPS position report, the other inertia sensors interpolate the current position using a dead pedestrian control algorithm (PDR). This combination reduces the power requirements of an "always active" position tracking system, while maintaining an almost absolute positioning. Bosch says this allows 80% less energy consumption than a GPS sensor always on. The sensor is also reliable in environments where GPS tracking can fail, both indoors and outdoors.
Bosch expects the sensor to be used in small devices such as portable devices and other small devices where battery power can be limited, and in applications that require robust position tracking. In addition, the sensor is also capable of withstanding mechanical stress.
The BHI160BP microcontroller also comes with other algorithms and software available to allow features such as 3D orientation and wake-up to easily use available. A Sensor-API and PDR-GNSS fusion library are also available for easy integration.
- Dimensions: 3.0 × 3.0×0.95 mm.3
- Power consumption: Six typical profiles ranging from 11 A (suspension mode) to 1.3 mA (6 degrees of PDR freedom)
- Typical PDR energy savings: 80%
- Position accuracy: 10%
- Error in step counting: 5%
- Host main interface: I2C, 3.4MHz
Bosch courtesy image.
Classification of dead pedestrians (PDR)
The estimate of dead counts is a method to determine the position using information on the current speed, the known distance traveled and the last known position. It has been applied and used in area navigation, marine navigation and even among animals. In the boats, compasses and time were used to calculate the position when navigating through cloudy or dark waters.
The challenge of taking into account the use of portable devices or smart phones is that there is a complex range of movements and orientations associated with their use. Whether a smart watch on the wrist of a swinging arm or a smart phone thrown randomly in a pocket, these present a bit more complex challenges when calculating the magnitude and orientation of the movement.
That's where the Peatn Dead Reckoning comes in. A variety of sensors provide information on orientation, acceleration and inertia; The algorithms can then detect movement patterns such as walking or balancing the arm and separating that information to perform calculations of dead count.
The third wave of MEMS sensors
If this is the third wave of Bosch MEMS sensors, what were the other two?
Bosch perceives the evolution of its MEMS sensors as waves:
- First wave: Automotive sensors in the 1990s (airbags for safety, engine handling, etc.)
- Second wave: Consumer electronics at the end of the 2010s (in particular, cell phones, but also includes drones, etc.)
- Third wave IoT, as of the decade of 2010 (including smart homes, industry, etc.)
This new sensor is part of the third wave because it is an example of what they call localized intelligence.
A magical application: bringing the marauders map to life
For those who are not familiar with the fantasy world of Harry Potter, the Marauder Map is a map that can show the exact location of people within Hogwarts Castle. While the Map of the Marauders works with magic in the novels, in real life, precise monitoring of the position of individuals within the stone walls of a castle will pose challenges due to poor GPS reception.
Bosch explores the possibility of bringing the Map of Marauder to life using the BHI160BP sensor: if people inside the castle wear smart watches or have smart phones with the available sensor, which then transmits their location to the receivers, live tracking can be performed to show the location and speed of individuals inside Hogwarts Castle without requiring a GPS constant.
If something inspires you, the idea of creating magical objects using current technology can be motivating.