The U-blox LEA-6 GPS receiver module now includes GLONASS coverage. The package measures 17 by 22.4 by 2.4 mm and weighs 2.1 g. It operates from a 2.7- to 3.6-V supply (117 mW at 3 V) from –40ºC to 85ºC.

The enhanced U-blox LEA-6H GPS receiver module supports both the U.S. Global Positioning System (GPS) satellite navigation system and Russia’s GLONASS system (see the figure). By combining both GPS and GLONASS capabilities, the LEA-6H will facilitate more accurate and reliable navigation positioning.

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The U.S. GPS system has been in operation since 1978 and available worldwide since 1994. It uses a 24-satellite constellation in six orbital planes. Satellite spares are in place, and the system is continuously upgraded. The satellites transmit CDMA-encoded signals on 1.57542 GHz and 1.2276 GHz. Receivers pick up and decode signals from three or four satellites to calculate an exact position on earth within less than 10 meters.

Russia’s GLONASS system has been in development for years and is almost fully operational, with 22 of the proposed 24 satellites in place. These satellites transmit on 1.602 GHz and 1.246 GHz using FMDA coding. A similar European navigation service, Galileo, is also under development, with two of the proposed 22 satellites in place.

The LEA-6 series module is a 50-channel receiver for GPS L1 CDMA-encoded signals and GLONASS L1 FDMA-encoded signals. It is available in crystal and temperature-controlled crystal oscillator (TCXO) versions with an onboard real-time clock (RTC) crystal for faster warm and hot starts. The update rate is 5 Hz for the ROM version and 2 Hz for the Flash version.

Cold starts take about 26 to 27 seconds, while warm starts are typically one second. Receiver sensitivity (with an active antenna) is –162 dBm in tracking mode, –148 dBm at cold starts, and –157 dBm for hot starts. Support is provided for both active and passive antennas. External or internal antenna power is available.

Serial interfaces provided include a standard UART, USB 2.0, and I2C. Supported protocols include NMEA, UBX binary, and RTCM. A timepulse (0.25 Hz to 1 kHz) is also accessible. And, U-blox has evaluation kits for testing and development.

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