Novus NR2110-R User manual

USERS MANUAL
NR2110-R/O/G
REVISION
B
DATE
120120
Page #:
1 of 47
www.novuspower.com
NR2110-R/O/G
10MHz Frequency Reference, PPS, GNSS-Locked, Dual Channel,
with Rubidium Holdover
All information provided herein is the property of Novus Power Products LLC. The
information included may be reproduced without the permission of Novus Power
Products LLC for the purpose of operating the equipment.

USERS MANUAL
NR2110-R/O/G
REVISION
B
DATE
120120
Page #:
2 of 47
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Contents
Summary.........................................................................................................................3
Controls and Indicators –Front Panel.............................................................................5
GNSS Status...............................................................................................................7
GNSS Receiver - Standard .............................................................................................9
Sensitivity....................................................................................................................9
TTFF (Time to First Fix).............................................................................................10
PPS Availability.........................................................................................................12
Cable Delays.............................................................................................................13
Pulse Width...............................................................................................................13
Factory Default Settings............................................................................................13
GNSS Receiver-High Performance...............................................................................14
Status LEDs..............................................................................................................16
Power Supply Status (with optional DC supply).........................................................16
Alert Threshold..........................................................................................................19
Latch Channel Value.................................................................................................22
Save Configuration....................................................................................................22
Fault Status..................................................................Error! Bookmark not defined.
UTC Mode....................................................................Error! Bookmark not defined.
GMT Offset...................................................................Error! Bookmark not defined.
Power Switch ............................................................................................................23
Rear Panel....................................................................................................................23
Channel Output - BNC...............................................................................................23
Antenna Input A/B - SMA ..........................................................................................23
Antenna Connection (with GNSS option only)...........................................................24
DC Input....................................................................................................................24
AC Input....................................................................................................................25
RS232 DB9 (Status)..................................................................................................25
RS232 DB9 (NMEA)..................................................................................................26
Ethernet Port.............................................................................................................27
Functional Description...................................................................................................27
Phase Noise..................................................................................................................28
Outputs .....................................................................................................................29
Built-in Test...............................................................................................................29
Power Supplies .........................................................................................................29
Crystal...........................................................................................................................29
Calibration.....................................................................................................................36
Programming Guide (RS232 Status Port)......................................................................36
7.1 RS232 Commands (Status Port) .........................................................................37
Status String ($GPNVS,1) Fault Bytes ......................................................................40
Status String ($GPNVS,2) Channel Values...............................................................41
Status String ($GPNVS,3) Power Supply Values......................................................42
Technical Specification..................................................................................................43
Performance..............................................................................................................43
Environmental and Mechanical..................................................................................44
LIMITED HARDWARE WARRANTY.............................................................................45
Appendix: GNSS Command Reference.........................................................................47

USERS MANUAL
NR2110-R/O/G
REVISION
B
DATE
120120
Page #:
3 of 47
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Summary
The NR2110-R/O/G is a dual channel precision GNSS/GPS locked 10MHz and
PPS. The amplifier is a low phase noise design to preserve the integrity of the
reference signal. All outputs are transient, and fault protected.
This unit is a versatile timing platform that can be configured to meet several
synchronization applications. With atomic holdover capability, the unit provides
critical timing in GPS-denied or unreliable environments.
Features:
-atomic holdover maintains timing accuracy (< 50 usec /24 hours)
-precision 10 MHz frequency reference
-optional frequencies synthesized from GPS locked 10 MHz (10 KHz to 10
MHz)
-1.544, 2.048 or 5 MHz outputs available
-PPS output (LVCMOS) 20 ns rms
-RS232 NMEA
-LCD display provides time, status
-optional dual time base
-optional high performance GNSS receiver
When locked to the GPS, the NR2110-R/O/G operates as a GPS/GNSS locked
frequency reference and PPS source. While locked to the GPS, the OCXO
reference is continually being disciplined in frequency and its internal PPS is
aligned to UTC PPS within <50 ns. If GPS is lost, the unit uses the disciplined
Rubidium or OCXO as the master time reference. The PPS remains aligned to
UTC PPS with a drift rate of <40us/day (Rb) less than 5 ms/day (OCXO)
(assumes 24 hours of GPS locked).
The unit features auto-calibration, which ensures the most recent OCXO
compensation coefficients are stored in non-volatile memory. The compensation
values eliminate drift due to aging and/or temperature and are stored and applied
to the OCXO during loss of GPS lock conditions. These coefficients are updated
after two hours of continuous GPS locked state. This effectively eliminates long-
term OCXO changes.
Excellent aging characteristics are achieved using intrinsically low-jitter overtone
SC cut crystals in a temperature-controlled oven. There are two 10MHz outputs
on the rear panel (BNC) connector. Low phase noise is achieved by the inherent
crystal characteristics and appropriate design techniques for noise mitigation.

USERS MANUAL
NR2110-R/O/G
REVISION
B
DATE
120120
Page #:
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TYPICAL PHASE NOISE PERFORMANCE
Offset Frequency, Typical
Offset (Hz)
Standard (dBc/Hz)
10
-125
100
-145
1K
-155
The NR2110-R/O/G delivers a low phase noise curve, which can be seen in the
sample production test below.
NR2110-O/G PHASE NOISE MEASUREMENT
The unit features extensive reporting via the rear panel RS232 port - equipment
status, output voltage on each channel. By being able to monitor the output
voltage, the user can detect cabling issues that cause an impedance change and
replace cabling before it completely fails. Reporting is also easily accessible via
the front panel display.

USERS MANUAL
NR2110-R/O/G
REVISION
B
DATE
120120
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Nominal power is global AC power, but a DC power option can be ordered that
acts as the back-up power supply. Nominally 24 Vdc, this port is used for power
when AC power fails. Switching between power sources is automatic and there is
no transient power outage at the equipment level. The primary power supply is
followed by low noise linear converter assemblies.
The optional dual time base adds an additional GNSS receiver that monitors the
primary GNSS receiver, detects when the timing source is out-of-tolerance and
sends an email and alert locally. The redundancy can be duplicated all the way to
the antenna or a single antenna can be used with a splitter located inside the
chassis.
Controls and Indicators –Front Panel
The three LEDS provide a comprehensive status of the unit:
ALERT:
This LED should always be GREEN. There are several self-tests executed within
the unit and the summation of these tests is that the unit is functional. A RED
indication is a failure, and the unit should be removed from service.
OVEN:
This LED serves several functions:
GNSS Lock Status: Flashing GREEN indicates that the unit has not achieved
GNSS lock. The flashing state of this LED should not exceed 15 minutes. If it
stays in the flashing state too long or is found to be going in and out of the
flashing state- there may be a problem with the antenna or cabling to the
antenna. Monitoring the GNSS strings on the serial port will advise locking status
in more detail.

USERS MANUAL
NR2110-R/O/G
REVISION
B
DATE
120120
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Rubidium Lock: The Rubidium must achieve a fixed temperature to
achieve a plasma that can be used for timing. This will take on the order of
15 minutes.
Fault: a flashing indicator warns of a faulted 10 MHz output. If this state is
observed, remove the 10 MHz loads and install a 50 Ohm load and confirm the
fault is cleared. The Novus status strings will assist with troubleshooting a fault
problem.
$GPNVS
1
hhmmss
mmddyy
A
nn
0x00
0x00
0x00
*
XX
1
2
3
4
5
6
7
8
9
10
# Description Range
1. Identifier $GPNVS
2. String ID 1
3. Time (UTC) hhmmss
4. Date mmddyy
5. GPS Lock (Valid) “A” = Valid, “V” = Not Valid
6. # of Sats in View Greater of GPS or GNSS count
7. Channel Fault Byte 0x00 to 0x3F (Hex OR’d value)
8. Power Supply Fault Byte 0x00 to 0x3F (Hex OR’d value)
9. Error Message Byte 0x00 to 0x0F (Hex OR’d value)
10.NMEA Checksum *XX (xor’d value of bytes between $ and *)
Example:
$GPNVS,1,233518,092516,A,10,0x00,0x00,0x00*62
Time: 23:35:18; Sep. 25, 2016, GPS locked; 10 Satellites in view; No channel
faults; No power supply faults; No error messages.

USERS MANUAL
NR2110-R/O/G
REVISION
B
DATE
120120
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GNSS
On power-up, the GNSS receiver will begin the process of searching and locking
to available satellites. The systems to be used can be programmed and the
default will depend upon the receiver selected.
Novus offers two levels of GNSS receivers. The basic receiver is a 26 channel
GNSS receiver. The receiver and companion elements generate the GNSS sine
wave, PPS and NMEA serial link. The serial link conforms to NMEA 0183
protocol. The 26 channel high-sensitivity, high-accuracy multi-GNSS receiver.
supports TRAIM, GPS, GLONASS, QZSS, SBAS, Active Anti-Jamming and
Advanced Multipath Mitigation functions.
The more advanced receiver meets the most stringent 5G timing requirements, is
ideal for global deployments due to GPS, BeiDou, Galileo, and GLONASS
reception, and is unaffected by ionospheric errors. The module provides
differential timing mode for highly accurate local timing and built-in security for
highest robustness against malicious attack
Standard PPS 25ns(1σ) (@-130 dBm) 50ns(1σ) (@-150 dBm)
High accuracy PPS 5ns(1σ) (@-130 dBm) 10ns(1σ) (@-150 dBm) with vibration
and thermal isolation.
The PPS stability also effects the Allan Deviation for the reference.

USERS MANUAL
NR2110-R/O/G
REVISION
B
DATE
120120
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High Stability Allan Deviation
Standard Receiver Allan Deviation Performance:

USERS MANUAL
NR2110-R/O/G
REVISION
B
DATE
120120
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The PPS source can be either directly from the radio or from the stabilizer.
This is software selectable.
GNSS Receiver - Standard
The 26 channel GNSS receiver and companion elements generate the GNSS
PPS and NMEA serial link. The serial link conforms to NMEA 0183 protocol.
GPS, GLONASS, QZSS, SBAS, Active Anti-Jamming and Advanced Multipath
Mitigation functions.
Supports concurrent GPS, GLONASS, SBAS and QZSS. Galileo ready.
Sensitivity
GPS
Tracking: -161 dBm
Hot Start: -161 dBm
Warm Start: -147 dBm
Cold Start: -147 dBm
Reacquisition: -161 dBm

USERS MANUAL
NR2110-R/O/G
REVISION
B
DATE
120120
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GLONASS
Tracking: -157 dBm
Hot Start: -157 dBm
Warm Start: -143 dBm
Cold Start: -143 dBm
Reacquisition: -157 dBm
TTFF (Time to First Fix)
Hot Start: <5 sec (@-130 dBm)
Warm Start: 35 sec (@-130 dBm)
Cold Start: 40 sec (@-130 dBm)
・Active Anti-Jamming
・Advanced Multipath Mitigation
The receiver needs at least four satellite vehicles (SVs) visible to obtain an
accurate 3-D position fix. When travelling in a valley, or built-up area, or under
heavy tree cover, you will experience difficulty acquiring and maintaining a
coherent satellite lock. Complete satellite lock may be lost, or only enough
satellites (3) tracked to be able to compute a 2-D position fix, or a poor 3D fix due
to insufficient satellite geometry (i.e. poor DOP). It may not be possible to update
a position fix inside a building or beneath a bridge. The receiver can operate in 2-
D mode if it goes down to seeing only three satellites by assuming its height
remains constant. But this assumption can lead to very large errors, especially
when a change in height does occur. A 2-D position fix is not considered a good
or accurate fix; it is simply “better than nothing”.
The receiver’s antenna must have a clear view of the sky to acquire satellite lock.
Remember, it is the location of the antenna that will be given as the position fix. If
the antenna is mounted on a vehicle, survey pole, or backpack, allowance for this
must be made when using the solution. The GNSS receiver provides power for
the LNA in the antenna. The unit was designed to provide 3.5 Vdc < 40 mA of
current.