Timing Test Solutions
6
Timing Test Solutions Testing Primary Reference Time Clocks (PRTC) and Assisted Partial Timing Support (APTS) Clocks in 5G and other Packet Networks Your trusted PNT partner
Transcript of Timing Test Solutions
Timing Test Solutions
Testing Primary Reference Time Clocks (PRTC) and Assisted Partial Timing Support (APTS) Clocks in 5G and other Packet Networks
Your trusted PNT partner
Timing Test Solutions
SOLUTION
2
Time, phase, and frequency synchronisation are key enablers for 5G and Next-Generation Networks. In order to meet these requirements, developers, integrators, and operators need to optimise and verify the performance of their timing equipment.
ITU-T RecommendationsThe ITU recommendations for precision timing in telecoms networks include standard G.8272 and G.8272.1, for PRTC and enhanced PRTC (ePRTC), as well as G.8273.4 for Assisted Partial Timing Support (APTS). They set out the maximum time error that the clock output can exhibit without affecting service quality on the network, as well as requirements on wander, jitter, and holdover and transient performance in the event of GNSS signal issues.
FundamentalsEstablish the baseline accuracy of the PRTC in normal operating conditions and ensure the PRTC continues to provide correct reference time when predictable but infrequent GNSS system events happen. These include leap years, leap seconds and the GPS week number rollover.
For APTS clocks, outputs must be measured in steady-state conditions, as well as during switchover events from GNSS to Precision Timing Protocol (PTP) reference signals.
ResilienceThe low signal strength of GNSS reception-signals on the earth and the widely disclosed GNSS signal format bring vulnerabilities of signal jamming, atmospherics (scintillation and space weather) and location or time spoofing.
PRTCs and APTS clocks must be able to prove resilience to these threats in order to facilitate robust network timing.
PerformanceCheck the PRTC’s timing solution when it is positioned under typical daily impairments such as multipath and obscuration, and verify the receiver autonomous integrity monitoring (RAIM) functionality when segment errors such as satellite clock or ephemeris errors happen.
Check the APTS clock timing (PTP and 1pps) when the GNSS receiver is under typical daily impairments such as multipath and obscuration, and verify the RAIM functionality when segment errors such as satellite clock or ephemeris errors happen.
Vendor Selection Network equipment manufacturers must ensure they take an informed decision when choosing a GNSS timing receiver. With an ever-growing number of multi-constellation and multi-frequency receivers on the market, the choice is not easy. Getting analytical test results by thoroughly evaluating receivers is key to help that decision.
Timing Test Solutions
SOLUTION
3
How can Spirent help?
The only way to thoroughly validate and evaluate the performance and resilience of your timing infrastructure is via comprehensive testing. To have confidence, developers, integrators and users need to know equipment meets the tight synchronisation requirements specified in ITU-T recommendations. The interaction of GNSS and packet timing means high performance GNSS simulation and PTP measurement equipment is a must.
PRTC/ePRTC
PTP
Stable Reference Frequency
(e.g. Cs Atomic Oscillator)
GNSS Simulator withTiming Test Pack
PRTC/T-GM ePRTC
Timing Monitor(Calnex Paragon-neo)
1pps reference
Time of Day (optional)
GNSS RF1pps
APTS
PTP
Stable Reference Frequency
(e.g. Cs Atomic Oscillator)
APTS Clock
GNSS RF1pps
PTP
Time of Day (optional)
1pps referencePTP emulation and Time
Error measurement (Calnex Paragon-neo)
GNSS Simulator withTiming Test Pack
In both examples, Spirent’s GSS7000 provides high fidelity GNSS RF to the distribution clock, and a 1 PPS reference signal to the Calnex Paragon-neo timing test solution. Realistic errors are added to the GNSS RF via predefined and custom models applied by the simulation control, or
via additional tools such as Spirent’s Sim3D multipath and obscuration modelling tool. For APTS, the Paragon-neo also provides a high-precision PTP input with capability to introduce a range of error scenarios.
Timing Test Solutions
SOLUTION
4
Timing Scenario SetThe right test equipment needs the right tests to effectively evaluate and improve timing synchronisation. A predefined set of scenarios built by experts takes much of the time, worry, and cost out of testing.
Spirent’s Timing Scenario Set provides a library of test cases to exercise the performance and resilience of your PRTC or APTS device. As part of a timing test campaign, RF Interference testing – using Spirent’s GSS7765 or onboard interference capability, as well as Sim3D multipath software – is required. This capability is enhanced by the addition of other threat scenarios.
Precision Timing Measurement: Calnex Paragon-neoHigh accuracy measurement is a basic prerequisite of timing and synchronisation test solutions. Real-time sub-nanosecond measurement of PTP and 1 PPS/ToD outputs from the packet clock, compared to the direct 1 PPS reference from the simulator, provides powerful, reliable verification of device performance.
Paragon-neo is the one-box solution for testing PTP and timing precision to the stringent requirements of 5G.
Precision instruments
• Baseline• Leap Year• Leap Second• GPS Week Rollover• Tracking Sensitivity• Multipath• RAIM• Obscuration
GNSS Simulation: Spirent GSS7000The Spirent GSS7000 is a versatile and powerful multi-frequency, multi-GNSS constellation simulator for all test use cases. Class-leading timing accuracy and fidelity combine with ultimate flexibility to deliver reliable results faster. The GSS7000 is fully customisable according to your needs, with capabilities including:
• Simulation of up to 256 satellites simultaneously
• Precise signal output - 1PPS to RF alignment < ±2ns
• 10 MHz and 1 PPS outputs and inputs
• Multipath simulation
• 2 RF outputs
• Embedded in-band interference generation
• Integrated spoofing test cases
Timing Test Solutions
SOLUTION
5
Advanced Multipath Modelling: Spirent Sim3DMultipath and obscuration can severely compromise the performance of a timing receiver. Evaluating and optimising the performance of the system, repeatably, in a broad range of environments is critical.
Sim3D enables developers to use realistic 3D models of real-world environments to assess the impact of challenging signal propagation conditions.
Controlled by Spirent’s SimGEN platform, and with a flexible range of capabilities, Sim3D is critical for the evaluation of any timing equipment to be used in urban locations.
• Supports all civilian signals• Up to 31 multipaths per line-of-sight (LOS) signal• Realistic or geo-typical environments• Static and dynamic scenarios
Installation & Onboarding
Scenario Provisioning
Test-as-a Service
Training
Lab-as-a Service
Tailored Services
Environment Assessment
Spirent ServicesSpirent Services accelerates and de-risks the testing of GNSS-based timing solutions. With Spirent’s industry leading PNT and test expertise readily available through a portfolio of services, you can assure the performance of your equipment to the greatest degree of certainty, and at the lowest cost and time investment. Services include:
• Standards conformance testing against key standards such as ETSI, ITU or MiFID II
• Test scenario creation for specific events• Receiver performance audit• Equipment benchmarking• Environment assessment
Model of San Francisco San Francisco with ray tracing
PTP 2-way time error - open sky conditions PTP 2-way time error - multipath conditions
Threshold
2-Way Time Error
-1200 10,000 20,000 30,000 40,000 50,000
Elapsed Time (s)
60,000 70,000 80,000
-100
-80
-60
-40
-20
0
20
40
60
80
100
120
Tim
e Er
ror (
ns)
Threshold
2-Way Time Error
-1,2000 10,000 20,000 30,000 40,000 50,000
Elapsed Time (s)
60,000 70,000 80,000
-1,000
-800
-600
-400
-200
0
200
400
600
800
1,000
1,200
1,400
1,600
Tim
e Er
ror (
ns)
© 2020 Spirent Communications, Inc. All of the company names and/or brand names and/or product names and/or logos referred to in this document, in particular the name “Spirent” and its logo device, are either registered trademarks or trademarks pending registration in accordance with relevant national laws. All rights reserved. Specifications subject to change without notice. MCD00393 | Issue 2-00 | 10/20
About Spirent CommunicationsSpirent Communications (LSE: SPT) is a global leader with deep expertise and decades of experience in testing, assurance, analytics and security, serving developers, service providers, and enterprise networks. We help bring clarity to increasingly complex technological and business challenges. Spirent’s customers have made a promise to their customers to deliver superior performance. Spirent assures that those promises are fulfilled. For more information visit: www.spirent.com
Americas 1-800-SPIRENT +1-800-774-7368 [email protected]
Europe and the Middle East +44 (0) 1293 767979 [email protected]
US Government & Defense [email protected] spirentfederal.com
Asia and the Pacific +86-10-8518-2539 [email protected]
GNSS6450
PlatinumUntil 2021
ISO/IEC 17025:2005 The GSS9000 is calibrated to the ISO 17025 standard at the time of delivery.
PlatinumUntil 2021
Americas Europe Asia
Why Spirent?Over five decades Spirent has brought unrivalled power, control and precision to positioning, navigation and timing technology. Spirent is trusted by the leading developers across all segments to consult and deliver on innovative solutions, using the highest quality dedicated hardware and the most flexible and intuitive software on the market.
Spirent delivers
• Ground-breaking features proven to perform• Flexible and customisable systems for future-proofed test capabilities• World-leading innovation, redefining industry expectations• First-to-market with new signals and ICDs• Signals built from first principles — giving the reliable and precise truth
data you need• Unrivalled investment in customer-focused R&D• A global customer support network with established experts
About SpirentPositioning TechnologySpirent enables innovation and development in the GNSS (global navigation satellite system) and additional PNT (positioning, navigation and timing) technologies that are increasingly influencing our lives.
Our clients promise superior performance to their customers. By providing comprehensive and tailored test solutions, Spirent assures that our clients fulfil that promise.
