VIAVI LN Rubidium GNS Disciplined Oscillator (LN Rb GNSDO) Low Noise Frequency Standard

Low-noise Rubidium GNSS-disciplined frequency standard with a 72-channel multi-GNSS receiver and sub 1 us holdover.

Long-Term Oscillator Aging: <0.1 ppb (ultimate and premium options), <0.3 ppb (standard) per month without GNSS; Zero aging with GNSS
Frequency Stability Over Temperature (0°C to +70°C): <0.07 ppb (ultimate), <0.1 ppb (premium), <0.7 ppb (standard)
1 PPS Stability: ±10 ns to UTC RMS (1-Sigma)
Holdover Stability: <±0.6 µs over 24 Hour Period @+25°C

Datasheet

Overview

The VIAVI LN Rubidium GNS Disciplined Oscillator (LN Rb GNSDO) is a low-noise Rubidium GNSS-disciplined frequency standard. It builds on, and is backwards compatible with, the VIAVI LN CSAC GPSDO product line. Compared with comparable units, the manufacturer states better phase noise and ADEV performance, lower thermal sensitivity, better holdover performance, and longer lifetime and MTBF.

According to the manufacturer, the Ultimate performance variant typically shows -115 dBc/Hz noise at 1 Hz offset, a noise floor below -168 dBc/Hz, ADEV of 5E-013 from 0.1 s to 20+ seconds, and less than 8E-014 ADEV averaged over 24 hours. Units can also be ordered with a Chip Scale Atomic Cesium Clock (CSAC). That option draws less than 1.4 W and typically reaches atomic lock in under 2 minutes.

GNSS receiver

The unit has a latest-generation GNSS receiver with GPS/Glonass/BeiDou/QZSS and SBAS support. It can optionally be disciplined by an external SAASM GPS receiver. There are several ordering variants, which differ in phase noise/ADEV performance level and in atomic clock performance level and technology (Rubidium or Cesium miniature atomic clocks).

Enclosure, interfaces and power

The unit is housed in a ruggedized, gold-plated aluminum enclosure, and a conformally coated version can be ordered. It supports both SCPI and NMEA communications interfaces. Its avionics-compatible power supply operates from 8 V to 36 V, with 5.6 W steady-state power consumption.

Key Features

Ultra low phase noise/ADEV
GPS/Glonass tracking at -167 dBm
Sub 1 us holdover
Rubidium miniature atomic oscillator
Ruggedized, enclosed unit
Less than 5.6 W power consumption
Small form factor, less than 1 inch high (3.4 x 4.4 x 1.0 inches)
72 channel multi-GNSS receiver allowing simultaneous tracking of any two GNSS systems
Ruggedized gold-plated aluminum enclosure variants available
Conformally coated enclosure version available
Backwards compatible to the VIAVI LN CSAC GPSDO product line
SCPI and NMEA communications interfaces
Avionics-compatible 8 V to 36 V power supply
Optional Chip Scale Atomic Cesium Clock (CSAC) for less than 1.4 W power consumption
Optional disciplining by an external SAASM GPS receiver

Specifications

Frequency Stability

Long-Term Oscillator Aging	<0.1 ppb (ultimate and premium options), <0.3 ppb (standard) per month without GNSS; Zero aging with GNSS
Frequency Stability Over Temperature (0°C to +70°C)	<0.07 ppb (ultimate), <0.1 ppb (premium), <0.7 ppb (standard)
1 PPS Stability	±10 ns to UTC RMS (1-Sigma) GPS Locked in Position Hold mode after 72 hours
Holdover Stability Ultimate, Premium	<±0.6 µs over 24 Hour Period @+25°C Ult and Prem, after 48 hours with GPS lock; static conditions, still air, minimum 48-hour warmup
Warm Up Time/Stabilization Time Without GPS	+25°C to <2E-010 accuracy typical: Rubidium: <8 min, Filter: <15 min
g-sensitivity	Rubidium: <0.2 ppb/g/axis, Filter OCXO: <1 ppb/g/axis
Rubidium Retrace Error	<0.05 ppb at +25°C 24hrs on, 48hrs off, 12hrs on
Magnetic Sensitivity	Less than 0.07 ppb per Gauss

ADEV (Ultimate OCXO Option)

0.1 s Ultimate	<4E-13 96+ hours GPS-locked, +25°C, no airflow, no vibration, no tilt
1 s Ultimate	<5E-13 96+ hours GPS-locked, +25°C, no airflow, no vibration, no tilt
10 s Ultimate	<8E-13 96+ hours GPS-locked, +25°C, no airflow, no vibration, no tilt
100 s Ultimate	<2.5E-12 96+ hours GPS-locked, +25°C, no airflow, no vibration, no tilt
1K s Ultimate	2E-12 96+ hours GPS-locked, +25°C, no airflow, no vibration, no tilt
10K s Ultimate	<5E-13 96+ hours GPS-locked, +25°C, no airflow, no vibration, no tilt
100K s Ultimate	<8E-14 96+ hours GPS-locked, +25°C, no airflow, no vibration, no tilt

Phase Noise Ordering Options

1 Hz offset Ultimate PN	<-114 dBc/Hz Static conditions, still air, minimum 48-hour warmup; low noise outputs measured. Web page states -115 dBc/Hz typical at 1 Hz for the Ultimate variant
1 Hz offset Premium PN	-108 dBc/Hz Static conditions, still air, minimum 48-hour warmup; low noise outputs measured
1 Hz offset Standard PN	-70 dBc/Hz
10 Hz offset Ultimate PN	<-145 dBc/Hz Static conditions, still air, minimum 48-hour warmup; low noise outputs measured
10 Hz offset Premium PN	-141 dBc/Hz Static conditions, still air, minimum 48-hour warmup; low noise outputs measured
10 Hz offset Standard PN	-98 dBc/Hz
100 Hz offset Ultimate PN	<-155 dBc/Hz Static conditions, still air, minimum 48-hour warmup; low noise outputs measured
100 Hz offset Premium PN	-152 dBc/Hz Static conditions, still air, minimum 48-hour warmup; low noise outputs measured
100 Hz offset Standard PN	-125 dBc/Hz
1 kHz offset Ultimate PN	<-162 dBc/Hz Static conditions, still air, minimum 48-hour warmup; low noise outputs measured
1 kHz offset Premium PN	-160 dBc/Hz Static conditions, still air, minimum 48-hour warmup; low noise outputs measured
1 kHz offset Standard PN	-145 dBc/Hz
10 kHz offset Ultimate PN	<-165 dBc/Hz Static conditions, still air, minimum 48-hour warmup; low noise outputs measured
10 kHz offset Premium PN	-163 dBc/Hz Static conditions, still air, minimum 48-hour warmup; low noise outputs measured
10 kHz offset Standard PN	-153 dBc/Hz
100 kHz offset Ultimate PN	<-167 dBc/Hz Static conditions, still air, minimum 48-hour warmup; low noise outputs measured. Web page states a noise floor lower than -168 dBc/Hz for the Ultimate variant
100 kHz offset Premium PN	-165 dBc/Hz Static conditions, still air, minimum 48-hour warmup; low noise outputs measured
100 kHz offset Standard PN	-154 dBc/Hz

Outputs and Interfaces

1 PPS Outputs (Rubidium or OCXO steered)	Two 5 V CMOS outputs, one internal RS-422
10 MHz Outputs	One buffered 10 MHz Sine Wave +13 dBm (±2 dBm), two un-buffered low-noise direct OCXO sine wave outputs (+5 dBm to +10 dBm), one internal +13 dBm
Options Accessible Internally to Enclosure Only	RS-422 (10 MHz out, 1 PPS out, 1 PPS in, serial output), LCD port, 10 MHz +13 dBm Sine Wave, 5 MHz CMOS, USB
RS-232/USB Control	SCPI-99 Control at 9.6 K, 19.2 K, 38.4 K, 57.6 K, 115.2 K
RS-232/RS-422/USB NMEA Output Sentences	NMEA 0183 rev. 2.3, Sentences: GGA, RMC, ZDA, GSV, PASHR, and others
TTL Alarm Output	GNSS Unlock and Hardware Failure indicator
USB, LCD Support (accessible inside enclosure only)	RS-232 or USB controlled, supports 16x2 LCD Displays

GNSS Receiver

GNSS Frequency, Antenna	L1 GPS and/or Glonass, Active Antenna 5 V
GNSS Receiver	72 Channels, GPS, Glonass, BeiDou, QZSS, SBAS: WAAS/EGNOS/MSAS/GAGAN
GNSS Sensitivity, Acquisition	-148 dBm
GNSS Sensitivity, Tracking	-167 dBm GPS and Glonass
GPS Receiver Motion Adaptive Filter Settings	Optimized depending on vehicle velocity (Auto-sensing, Auto-switching option)

Power

Supply Voltage (Vdd)	+8 V to +36 V max, +12 V nominal
Power Consumption	<5.6 W at +25°C steady-state, <17.5 W warmup

Environmental

Operating Temperature	-20°C to +70°C baseplate temperature
Storage Temperature	-55°C to +100°C
MTBF	>200,000 Hours at +40°C baseplate

Physical

Dimensions	3.4 x 4.4 x 1.0 inches Less than 1 inch high

Specifications are taken from the manufacturer's documentation. See the datasheet for complete and current values.

Applications

Defense
5G communications
SATCOM
Transportation
Data center
Energy
Financial
Critical infrastructure

Options & Accessories

Option	Description
22174881	LN Rb GPSDO SA.53 Standard PN no/Encl - RoHS
22174877	LN Rb GPSDO SA.53 Premium PN/ADEV w/Encl - RoHS
22174878	LN Rb GPSDO SA.55 Ultimate PN/ADEV w/Encl - RoHS
22174879	LN Rb GPSDO SA.53 Premium PN/ADEV w/Encl 422 pin rerouting - RoHS
22174880	LN Rb GPSDO SA.55 Ultimate PN no/Encl MMCX - RoHS
22174882	LN Rb GPSDO SA.55 Ultimate PN/ADEV no/Encl MMCX/J1 Vrt/J4USB - RoHS