Telit autonomous nav module uses internal sensors, GNSS

November 7, 2016  - By

Telit has announced the commercial availability of the SL869-3DR, a GNSS module for global use that leverages information from internal gyros, accelerometers and a barometric pressure sensor to perform dead-reckoning navigation for application areas such as track and trace and in-vehicle systems.

The module delivers accurate position data either directly from its multi-constellation receiver or from a fully autonomous dead-reckoning system, requiring no connections to external devices or components other than an antenna for satellite signal reception and power.

The module allows integrators to design zero-installation, in-vehicle navigation and tracking devices for fleets and other commercial or consumer applications that operate perched on the dashboard, connected only to vehicle power.

Photo: TelitThe SL869-3DR is a flash-memory based module capable of tracking three constellations simultaneously. The module integrates an array of micro electromechanical systems (MEMS) designed to provide it seven degrees of freedom. The innovative design of the internal sensor array in conjunction with the Telit MEMS-only Dead Reckoning (MoDR) software and intellectual property, deliver the host device unparalleled portable, turnkey dead-reckoning performance.

The Telit MoDR solution ensures that reliable position, velocity and time information is constantly available to the host application even when GNSS coverage is compromised, without the need for connection to the vehicle for wheel-ticks for speed or reverse-gear data. Its standard footprint lets navigation and tracking system integrators reuse existing device designs, eliminating complexity from external sensors and other apparatus, getting to market quickly with updated designs or product innovation.

“A significant number of the millions of commercial vehicles and fleets on the roads today are still operating with no or unreliable navigation systems because installation costs to connect the device to vehicle sensors are too high and require very specialized skills,” said Felix Marchal, executive vice president of GNSS and Short Range Wireless. “With the SL869-3DR we overcome that barrier because it enables devices that you simply connect to vehicle power and go. Up until now, ‘power-and-go’ navigation systems have largely relied on open-sky visibility, which is not typically where most commercial fleets operate. They are moving through tunnels, urban canyons and other environments where these systems cannot produce a position solution. Reliable MEMS-only dead reckoning, or MoDR as we call it, relies on very complex mathematical modeling and expert design of the sensor array. Developers must therefore, thoroughly scrutinize performance of the different products in the market. I am delighted that the SL869-3DR has outperformed competing products in its class across a wide range of test cases.”

The SL869-3DR is designed to support GPS, QZSS, GLONASS, Beidou and is Galileo ready. Telit MoDR technology boosts position accuracy in areas with adverse satellite reception conditions like urban canyons, overhead foliage, tunnels and parking garages. It integrates an embedded array of sensors including accelerometers, gyroscopes and a barometer (pressure sensor).

An antenna ON, antenna sense (open / short circuit) feature, allows the host application to inform the user of problems with the connection to the external antenna. An additional LNA delivers better sensitivity in harsh environments, better enabling devices with integrated antennas. The module also features fast calibration and is pin-to-pin compatible with the SL869, SL869-V3 and SL869-ADR.

Below is a video where performance the autonomous SL869-3DR MoDR is compared with the SL869-ADR automotive navigation module connected to vehicle sensors (wheel ticks and reverse signal).