Precision timing GNSS module targets cellular networks

16th October 2014

Alpha Micro

Mick Elliott

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A precision timing GNSS module that achieves high accuracy by disciplining a local oscillator or other clock source with timing signals received from satellite-hosted atomic clocks is available from Alpha Micro Components. The LEA-M8F module from u-blox is a compact, surface-mount unit which generates a precise 30.72 MHz reference clock crucial for synchronising industrial data and communication systems such as small, femto and macro-cell mobile networks.

To ensure satellite availability, the module is able to acquire and track all 50+ GPS, GLONASS and BeiDou satellites. High sensitivity and aided GNSS option enables quick autonomous start-up even inside structures with limited sky-view.

"A reliable, compact and cost-effective precision reference clock is a crucial component used in many systems in the Critical Infrastructure and Key Resource sectors (CIKR)," said Thomas Nigg, Vice President of Product Marketing at u-blox, "Our LEA-M8F GPS/GNSS satellite-disciplined timing module enables the proper operation of many mission-critical infrastructure systems including mobile and fixed-line communication networks, power generation and distribution systems, gas and chemical processing plants, banking, postal and goods distribution processes."

Measuring only 17 x 22 mm, the module includes a low-noise 30.72 MHz VCTCXO (voltage and temperature controlled oscillator), meeting the master reference requirements for LTE Small Cells while providing 100 parts-per-billion autonomous hold-over accuracy. It is also suitable for TD-LTE, LTE-Advanced and other applications requiring extended hold-over times when integrated with small cell platforms.

External sources of synchronisation are supported through time-pulse and frequency inputs and a message interface. This allows measurements from macro-sniff, Sync-E or packet timing to be combined with measurements from GNSS to extend the availability of accurate synchronization and in doing so maximise cellular service availability.

LEA-M8F can track signals from satellites from any two constellations (e.g. GPS and GLONASS, GPS and BeiDou, GLONASS and BeiDou) simultaneously. Compatibility with multiple GNSS systems gives the LEA-M8F access to a large number of satellites, allowing synchronization even in urban or indoor areas with limited sky view. For stationary applications, once a location is known, accurate timing can be maintained based on the signal from just a single satellite.