Centimeter-level GPS sensor fusion for precise positioning

21st June 2021

u-blox

Alex Lynn

0 0

u-blox has released a firmware update for its ZED-F9R positioning module, bringing robust centimeter-level positioning to slow moving use cases such as robotic lawnmowers, e-scooters, and shared bicycles. Based on the ZED-F9R high-precision sensor-fusion module, the u-blox ZED-F9R-02B was designed for use in autonomous and industrial applications that require simple and efficient implementation and where rapid access to highly accurate positioning data is key, even in challenging signal environments such as dense cities.

The ZED-F9R uses the u-blox F9 multi-band global navigation satellite system (GNSS) receiver platform to concurrently track up to four GNSS constellations. Applying real-time kinematic (RTK) techniques, the module can derive positioning data with centimeter-level accuracy. The high-precision GNSS measurements are fused with data from the module’s inertial measurement unit (IMU), GNSS correction data, odometry information, and a vehicle dynamics model to provide high-quality positioning accuracy in situations where GNSS alone would fail. The receiver includes dynamic models for robotic lawnmowers, e-scooters, and automobiles.

The ZED-F9R-02B integrates the u-blox GNSS correction data service, broadcast in the highly scalable state-space representation (SSR) format, making it easier to deliver fast time-to-market precise positioning solutions.

Enabling new business models

Robotic lawnmowers achieve further improvements in terms of their positioning accuracy thanks to the module’s ability to calibrate its dead reckoning system even at low speeds. The module’s highly accurate position output lets end users precisely delimit the mowing area using software rather than with boundary wires and deploy robotic lawnmowers on complex lawn shapes while excluding trees and shrubs. Aligning each pass of the mower with the next more accurately than previously possible, delivering a professional-looking striped lawn.

Combining these features allows product designers to use the module to create mowing equipment that enables ‘robotic mowing as a service’ capable of operating in complex environments without the upfront cost and commitment of installing boundary wires.

“Our new ZED-F9R-02B high precision module is a turnkey dead reckoning solution that will enable designers to bring products that need dead reckoning technology to market more quickly than if they had to implement it from scratch,” said Alex Ngi, Product Manager, Industrial Navigation and Robotics, Product Center Positioning at u-blox. “It will also allow companies working in niche markets to employ dead reckoning technologies without needing to build and maintain expertise in the subject.”

The ZED-F9R-02B offers support for a range of correction services, including the SPARTN format, which will make it straightforward to distribute GNSS correction data over large geographical areas.