STMicroelectronics Unveils MEMS Digital Compass Module

High-performance motion and magnetic-sensing device enhances mobile navigation and enables advanced location-based services

STMicroelectronics has integrated a 3-axis digital accelerometer with a 3-axis digital magnetic sensor in a single module to create a digital compass module. This uses magneto-resistive technology from Honeywell and aims to accelerate the adoption of enhanced electronic compassing in portable consumer applications, including direction finding, map/display orientation, location-based services and pedestrian dead reckoning.
The combination of high-performance motion and magnetic sensing enhances the mobile-user experience in a number of ways. ST’s new module adds forward direction orientation that enables application developers to improve the use of limited phone/PDA display size for maps by putting the current user position at the bottom of the map with the rest of the display in the forward (‘up ahead’) direction.
ST’s digital compass provides accurate heading information, to indicate the direction in which a person or vehicle is moving, when GPS is not available. It also supports dead-reckoning applications, including pedestrian navigation in places with no or low GPS signal, such as inside buildings and structures or in mountainous and forested terrain.
Compass modules in handsets open new possibilities for advanced location-based services. With compassing and GPS capabilities, consumers will be able to identify and retrieve information on nearby points of interest, such as restaurants or shops, by simply pointing their mobile devices in the direction of the object concerned.

”As the one-stop MEMS supplier of choice, STMicroelectronics is paving the way to smart sensor modules,” said Benedetto Vigna, Group Vice President and General Manager of the MEMS, Sensors and High Performance Analog Division, STMicroelectronics. “We have accelerometers, gyroscopes, microphones and now, thanks to our cooperation with Honeywell, also magnetic sensors. We are ushering in an era of integrated sensing capabilities.”

The new module uses high-precision sensing coupled with smart embedded features, including wake-up/power-down function and 6D recognition, which signals if the device is up or down along all three axes (x,y,z). The device has a linear acceleration full-scale of ±2/±4/±8g and a magnetic field full-scale from ±1.3 up to ±8 gauss(2), both fully selectable by the user.

The magnetic sensing element that measures the strength and direction of the Earth’s magnetic field and determines the heading relative to magnetic north is based on Honeywell’s Anisotropic Magneto-Resistive (AMR) technology. This technology combines best-in-class accuracy in compass calculations with low power consumption, which is crucial in battery-hungry portable devices.

The AMR technology provides the same sensitivity on the z axis as it does on the x and y axes, eliminating the need for flux concentrators used in Hall-effect type sensors that can shift the sensor offset after it has been magnetized. This market-unique three-axis sensing approach reduces measurement errors in ultra-low magnetic field strength environments, such as in metal buildings, automobiles, or in higher latitudes like Canada or Northern Europe.

Moreover, Honeywell’s magnetic sensor design includes a built-in offset cancellation circuit to minimize the need for calibration, and patented set/reset straps that de-gauss, or de-magnetize, the sensor for each measurement to improve accuracy.



According to iSuppli, the market for MEMS digital compasses for use in mobile phone applications alone will grow from 8 million units in 2008 to 540 million units in 2013 – a CAGR of 129%. During the same time period, revenues for these components will grow at a CAGR of 110%, from $8 million to $325 million.


ST’s LSM303DLH digital compass module fits in an eco-friendly package of 5x5x1 mm and it is software- and register-compatible with ST’s three-axis digital accelerometer family (LIS331DLH/M/F). Samples are available and the device is ready for mass production. Unit pricing is $2.50 for volumes in the range of 50,000 pieces.

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New way to track GPS phones without contract

RF Solutions in Lewes, UK, has developed a system to allow users to track the location of the GPS/GSM handset supplied from a home or office PC without a contract with pay-as-you-go mobile and Google Internet maps
The Shadow Tracker system is installed on a base PC and polls the handset by text message. It receives the returned SMS from the handset containing GPS co-ordinates, and plots these on the desktop using free-to-access Internet-based maps. Users can also take advantage of features such as breadcrumb/time-lapse tracking and an adjustable geo-fence. The geo-fence automatically generates a warning if the handset is carried beyond user-determined limits.
The handset can store up to four preset telephone numbers, and can be used to make voice calls as well as providing GPS location data via SMS when polled. It also has a touch-activated SOS feature, which sends an emergency signal and GPS position to each of the preset numbers in sequence.
Two SIM cards are provided, for the tracker and the base station, and the system can be expanded to monitor multiple tracker units. The RF Solutions Shadow Tracker system is suitable for vehicle or personal tracking, and allows small businesses or domestic users to implement cost-effective safety and security systems. These may include alarms for lone workers, fleet tracking, valuables tracking, personal tracking, or emergency alarm systems.
RF Solutions supplies a wide range of Radio Telemetry modules with a range from a few metres to 20km. The standard range of products have been designed to provide the user with an "off the shelf" "plug-in" Radio system. Systems range from pocket keyfob to an industrial IP65 rated enclosure, with receivers ranging from a miniaturised hybrid components to compete enclosed systems with mains power supply. The GSM telemetry system can be situated in anywhere in Europe, and operated by an SMS message from a mobile phone.

...as CSR merges with SiRF

Bluetooth leader Cambridge Silicon Radio (CSR) is merging with GPS leader SiRF, in a move that will increase CSR's recent move into GPS (see below for low cost GPS chip), capitalising on its penetration of mobile handsets via Bluetooth.
But the move puts it squarely in competition with Broadcom, which acquired Global Locate three years ago and is moving strongly into combining GPS with mobile chipsets.
SiRF as a long established player in GPS has a significant GPS and assisted GPS (A-GPS) patent portfolio that complements CSR's extensive patent portfolio in eGPS. The rationale is that the combined strengths of SiRF and CSR will drive forward the innovation of new chips incorporating GPS and position the enlarged CSR group to be able to take a substantial share of the fast growing GPS market in mobile devices. CSR estimates the GPS attach rate to be around 20% of mobile handsets in 2008 and this is expected to double by 2012.
SiRF shareholders will own 27% of the enlarged CSR group and the boards of both CSR and SiRF unanimously endorse the transaction, with the merger expected to complete late in the second quarter of 2009. SiRF's Diosdado P. Banatao and Kanwar Chadha will be invited to join the CSR Board as Non-Executive Director and Executive Director respectively.
“Financially, strategically and commercially, this is a compelling transaction," said CSR CEO Joep van Beurden. "We expect it to be significantly earnings accretive, to enhance the enlarged group’s financial strength and cash position and to create new and wider revenue opportunities that neither party on its own could pursue as effectively. Strategically, this deal considerably strengthens our leadership position in the Connectivity Centre, a strategy which we believe encapsulates the way our marketplace is developing. Commercially, there is a powerful, complementary fit between the technologies, skill sets and customer relationships of both companies and the way we both see our customers’ needs evolving. Together we create a group substantially better placed both to meet the challenges of today and to emerge even stronger from the current challenging market conditions. This transaction is an exciting opportunity for shareholders, employees and customers.”