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Ruggedized
Flight Qualified
Available with vibration-isolated OCXO or CSAC Oscillator options
Gigabit Ethernet
GNSS, SAASM, or M-Code supported
Designed for GPS denied environments

Manufactured By: Brandywine Communications

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The Brandywine Communications Compact Airborne Timing Unit is a robust time reference LRU designed for airborne environments.

The CATU processes time of day from an internal GPS receiver (either Commercial or Military), while generating precise dual 10MHz frequency references and dual UTC-aligned ICD-GPS-060B-compliant one-pulse-second signals (1PPS). In addition, the CATU LRU features IEEE 802.3ab (1GbE) Stratum 1 NTP Server functionality.

This versatile timing unit employs its GPS for basic disciplining of its internal Oven Controlled Crystal Oscillator (OCXO), and an – optional – Chip Scale Atomic Clock (CSAC), providing holdover capabilities in a GPS denied environment in excess of 20 hours. Complimented by a low phase noise, vibration compensated 10MHz reference output locked to the 1PPS ICD-GPS-060B compliant output, the Brandywine Communications Compact Airborne Timing Unit provides unparalleled availability of reliable TOD in highly demanding fixed, and rotary-wing applications.

A commercial version with GNSS Receiver is also available.

GPS Antenna Input

Signal Type	GPS CA GPS P(Y) (optional) GPS M-Code
Input Signal Level (at receiver RF connector)	P(Y) on L1: -153 dBW to -121 dBW P(Y) on L2: -153 dBW to -124 dBW C/A on L1: -150 dBW to -119 dBW
Minimum Operating Bandwidth	L1 1575.42 MHz ± 10.23 MHz L2 1227.60 MHz ± 10.23 MHz
Input Impedance	50 Ω (nominal)
Input VSWR	2.5:1 maximum at center frequency of L1 and L2.

Power

Number of Inputs	1
Voltage	28VDC per MIL-STD-704F
Rated Current Draw	1A
Interface Type	IS-GPS-154

Phase Noise

G-sensitivity

5x10^-11/G

Vibration Frequency Range

10Hz-2000Hz

Allan Deviation

1 second 1x10^-11

10 seconds 1x10^-11

100 seconds 5x10¹¹

1PPS Output

Number of Outputs	2
Signal Type	Per ICD-GPS-060B
Signal Rate	1 pulse per second
Rising Edge	On Time
Rise Time	<50ns
Signal Type	Sinusoid
Fall Time	<100ns
Pulse Width	20 µs ±5% default
Output Amplitude	10V ±10%
Coherency	1PPS = 10MHz/10⁶

10 MHz Output

Signal Type	Sinusoid
Output Frequency	10 MHz
Output Amplitude	13dBm/1V_rms
Harmonic Distortion	-30dBc
Frequency Accuracy (Locked)	1x10^-12 avg. over 24 hours
Holdover	1µSecond 24 hours

Ethernet Interface

Signal Type	Gigabit Ethernet (IEEE 802.3ab)
Protocols Supported	NTPv4, SNMPv3, SSH

Physical

Dimensions	7.29” x 4.52” x 2.36” (185.166mm x 114.808mm x 59.944mm)
Weight	3 lbs. (1.36 kg) nominal
Connectors	J1 Antenna, SMA J2, J3 1PPS SMA J4, J5 10 MHz SMA J6 D-Sub17 for KLIF, DS/101-232 J7 1Gb Ethernet
Battery	MMCx
Antenna Supply	5V @ 35mA

Environmental

Operating Temperature	-40°C to +55°C
Altitude	41000 ft.
Humidity	95% non-condensing
Environmental Certifications	Tested to the following specifications: MIL-STD-810F, MIL-STD-461: CS101, CS114, CS115, CS116

Brandywine CATU Datasheet.pdf

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Brandywine - Compact Airborne Timing Unit (CATU)