Trimble Thunderbolt

Introduction

The Thunderbolt™ GPS Disciplined Clock is Trimble's latest offering for GPS synchronisation devices targeting the wireless infrastructure. This fourth-generation GPS clock combines an 8-channel GPS receiver, control circuitry and a high-quality ovenized oscillator on a single board, providing increased integrity and reliability at a lower size and cost. Thunderbolt's level of integration makes it a perfect solution for precise timing applications in the wireless industry. Among its uses are synchronising the E911 positioning infrastructure and maximising bandwidth for wireless local loop.

Thunderbolt's architecture is comparable to systems currently used to maintain the tough CDMA holdover specification. This makes Thunderbolt a natural for a CDMA clock, the digital standard for cellular phones. Trimble's approach is unique. The Thunderbolt GPS Clock outputs a 10 MHz reference signal and a 1 PPS signal with an over-determined solution synchronised to GPS or UTC time. The 10 MHz reference accommodates customers requiring sub-microsecond timing. A single microprocessor performs both the GPS navigation and oscillator disciplining functions. The GPS receiver is driven directly by the 10 MHz output signal of the oscillator. This is calibrated against the incoming GPS signal, with the resulting clock and frequency measurements fed into the oscillator frequency control algorithm.

The Thunderbolt GPS Clock leverages Trimble's GPS experience by using a self-survey mode that reduces the effect of Selective Availability. The T-RAIM (Time-Receiver Autonomous Integrity Monitor) algorithm is used to monitor satellites to ensure signal integrity. Matching the Thunderbolt GPS Clock with Trimble's Bullet ™ III antenna creates a system that provides reliable performance in hostile environments. The system can be easily calibrated for different cable lengths. The high level of integration and volume production techniques make the Thunderbolt GPS Disciplined Clock an extremely cost-competitive timing solution for volume synchronisation applications. Trimble's Thunderbolt GPS Disciplined Clock in enclosure, in board form, and 24V power supply.