Gyroscope enhances GPS performance

21st June 2006

Melexis

ES Admin

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Melexis has entered the market for accurate GPS position sensing with its angular rate sensor or 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 upon a thick SOI (Silicon on Insulator) high performance MEMS (Micro-Electronic Mechanical Systems) technology, enables the realization of compact, high accuracy and cost-effective GPS systems with dead reckoning capabilities.

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

The MLX90609-N2 offers both an analog (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 °/s, ±150 °/s or ±300 °/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 Si ensures better long-term behavior and reliability than gyroscopes based on poly-Si micromachining.