Sensor takes over when GPS gets lost

Submitted by nestorb on Mon, 2006-06-05 22:37.

5 June 2006 -- Melexis has entered the market for accurate GPS position sensing with a new angular rate sensor (gyroscope). The MLX90609-N2 will enhance the accuracy of GPS instruments in situations where satellite reception is lost, for example in tunnels, between tall buildings and mountainous terrain. The Melexis MLX90609-N2 gyroscope, based on a thick SOI (silicon on insulator) high performance MEMS (microelectromechanical systems) technology, enables the realisation of very compact, high accuracy and cost-effective GPS systems with dead reckoning capabilities.

As a direct result of exceptionally low zero rate output drift, high resolution (better than 0.1deg/s) and high dynamic range, accurate positioning can be guaranteed even when satellite reception is lost over long distances.

The MLX90609-N2 offers both an analogue (0-5V) and digital (SPI) output.

The digital (SPI) output simplifies the interface to the microcontroller eliminating the need for an additional ADC.

The EEPROM allows programming of date code, serial number, and calibration parameters.

The factory set full scale ranges available are: +/-75, +/-150 or +/-300deg/s.

Programmable calibration parameters allow the temperature compensation of the bias and gain.

The mechanical structure of the MEMS gyroscope is sensitive to Coriolis forces created by movement.

Designed with a differential mechanical structure, the MLX90609-N2 exhibits low vibration and angular rate cross sensitivity and a high immunity to external linear acceleration.

Each section of the differential structure comprises a double-frame gyroscope.

The use of two frames allows for better decoupling between the driven and sensing modes.

The use of monocrystalline silicon ensures better long-term behaviour and reliability than gyroscopes based on polysilicon micromachining.

Michel Bourdon, MEMS and Sensor Interface ICs Marketing Manager at Melexis, comments: 'Melexis' ten years experience with automotive MEMS products and our good understanding of the expectations from automotive customers assures that this gyroscope will provide high added value to manufacturers of next generation navigation systems'.

The MLX90609-N2 enjoys operating in the automotive -40 to +85C temperature range.

It comes in a cost effective and small footprint SMD CLCC32 package to allow compact system designs.