u-blox Automotive Dead Reckoning technology Print Print E-mail�page E-mail page RSS

GPS positioning works well when at least four satellites are within a GPS receiver’s line-of-sight. However, in urban environments where the accuracy of GPS navigation is crucial, the view to the sky is often obstructed, or high-rise buildings reflect GPS signals causing severe multipath effects, degrading the quality of GPS. In tunnels or underground parking garages, GPS positioning may not work at all.

u-blox’ proprietary Automotive Dead Reckoning (ADR) solution solves this problem: based on the last known position; vehicle sensors feed information to the u-blox receiver indicating how far and in what direction the vehicle has travelled. Sensor data and GPS position are both processed, achieving 100% coverage, highly accurate and continuous positioning even in GPS hostile environment (e.g. urban canyons) or in case of GPS absence (e.g. tunnels and parking garages).

u-blox’ ADR supports different sensor inputs. The classical setup, called “Gyroscope plus Wheel Tick” (GWT), consists of a gyroscope providing the heading information and wheel tick providing the speed information.

Alternatively, sensor information from left and right wheels (front or rear) or all wheels are used differentially to deduce heading, called “Differential Wheel Tick” (DWT). This results in slightly lower performance compared to GWT, but has the big advantage of saving the cost of a gyroscope.

Software sensor interface
The industry proven u-blox ADR solution is highly flexible. The application processor can support a vast array of sensors, and must only convert the sensor data into UBX messages and pass them to the GPS receiver via a standard serial interface (USB, SPI, UART, DDC). This makes the u-blox ADR solution very portable between various vehicle platforms and reduces development effort and time-to-market. u-blox ADR is completely self-calibrating, and requires only pre-configuration to the specific vehicle platform.

u-blox’ ADR with software sensor interface is available as a single chip UBX-G6010-SA-DR or as a chipset UBX-G6000/G0010, or as NEO-6V module. The chips are qualified according to AEC-Q100 and manufactured according TS-16949 to meet demanding automotive quality requirements. These components are ideal for factory installed navigation and eCall systems since they use sensor data (wheel tick and gyroscope data) taken directly from the CAN bus.



Hardware sensor interface
The standard quality grade LEA-6R module is a dedicated ADR solution (GWT only) for after market installations with no access to the vehicle bus and no application processor for sensor data processing. Sensors are connected directly to the module: gyroscopes via SPI and ADC and the speedpulse information from the tachometer.

Evaluation tools
u-blox‘ ADR technology can be evaluated with the EVK-6V (for NEO-6V and ADR chips) and EVK-6R (for the LEA-6R module) Evaluation Kits which can be ordered via our Online shop at: www.u-blox.com/en/online-shop.html or via a u-blox sales-representative.

Additional reading:
For complete details about u-blox' Automotive Dead Reckoning chips and LEA-6R Dead Reckoning GPS module, please contact the u-blox sales representative nearest you.
 

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