Dead reckoning enables exact 3D navigation

September 28, 2015 // By Christoph Hammerschmidt
Urban canyons, this expression describes narrow streets amidst towering skyscrapers or in tunnels, both hampering the reception of navigation signals from satellites. Chipmaker STMicroelectronics (ST) counters the problem with a new firmware for its Teseo-III automotive navigation devices. The company promises that the positioning will be always available and accurate – by means of a navigation technique used in the early years of aviation: Dead reckoning.

The new Teseo Draw firmware version for the chipmaker’s positioning ICs enables navigation systems to provide continuous, accurate location and turn-by-turn instructions even when satellite signals are unavailable, such as in tunnels, covered car parks, or multi-level highways. The firmware also enhances performance in built-up areas, where navigation systems frequently lose accuracy.
The algorithm merges the satellite information with data from vehicle sensors such as the gyroscope, accelerometer, and wheel-speed sensors, to calculate location in three dimensions including elevation. If the satellite signal is fading, the firmware compensates for the loss of accuracy, and if the signal becomes unavailable, navigation continues uninterrupted based on calculated location – the so-called dead reckoning.

The company says that road tests carried out in difficult under-cover and urban environments have demonstrated continuous tracking from entry to exit in complex multi-level car parks, and at street level between tall buildings, where conventional systems have been unable to track the vehicle.

Global navigation satellite systems (GNSS) have revolutionized activities such as commercial logistics, asset management, and personal mobility. Today, over four billion GNSS devices in use worldwide. By enabling high-accuracy 3D dead reckoning, Teseo Draw expands the opportunities for developers to commercialize new applications.
“Teseo Draw strengthens GNSS performance and eliminates barriers to continuity, enabling exciting new services to emerge,” said Fabio Marchiò, Microcontroller and Infotainment Division General Manager, Automotive Product Group, STMicroelectronics. “Users can also experience significant improvements in existing services such as fleet tracking, eCall, or ERA-GLONASS emergency response, usage-based insurance, road tolling, and anti-theft systems.”

The new firmware has multiple modes and is capable of referring to sensors on the vehicle’s CAN bus or discrete sensors such as the odometer, reverse sensor, MEMS accelerometer and gyroscope, or MEMS inertial module connected to the Teseo III IC.

Teseo III chips loaded with the new firmware are sampling now, and are scheduled to enter mass production in Q1 2016.

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