The 8836 series tactical GPS time and frequency system integrates a ground-based GPS receiver module (GB-GRAM), a rubidium oscillator, time and frequency signal generation, and control/status circuitry in a compact, ruggedized enclosure. Standard outputs include 1PPS, low noise 10 MHz Network Time Protocol (NTP) and two IRIG B outputs over multi-mode fiber. The 8836 can be synchronized from the internal GPS receiver or from an external GPS 1PPS. When tracking GPS with a TFOM of 3 or better, the discipline algorithm steers the internal oscillator providing 1 PPS time accuracy of < 30 nS to UTC and long term frequency stability of < 1E-12 averaged over 24 hours. In the absence of GPS the unit transitions into hold-over mode providing an accumulated time drift of < ± 2 μS in 24 hours. An Ethernet interface provides NTP, SNMP v1, v2 and v3, SSH, syslog and telnet. Three GPS Standard Serial Interface Protocol (GSSIP) ports are provided from the GB-GRAM. Two ports are configured to automatically output ICD-GPS-153 messages and the third port is configured to output NMEA-0183 messages.