Through a unique combination of technology, the Keysight 58503A GPS time and frequency reference receiver provides a highly reliable source of precision time and frequency. The 58503A is based on Keysight's quartz technology. This provides unsurpassed reliability and confidence, as well as excellent short term stability. The core of the design is an oscillator with >500,000 hours of field proven mean time between failures. This delivers superior performance and reliability while eliminating the need for periodic oscillator replacement as required in GPS rubidium sources.