Spirent Sim3D

Realistic Multipath and Obscuration Simulation—

Simulating the Impact of the Local Environment on GNSS Signals

www.spirent.com

Spirent Sim3D

Verify Positioning Performance in a

True-to-Life Synthetic Environment

Obscuration, as well as the reection and diffraction of signals known as

multipath, can be one of the main sources of error in a GNSS receiver.

Multipath errors can vary from a few metres to hundreds of metres according

to satellite geometry and the receiver environment. The characterisation

and study of multipath is complex but important, as its effects need to be

compensated for in most positioning, navigation, or timing solutions.

Sim3D is an innovative real-time system that enables the reproduction

of an authentic multipath environment. The system combines a state-of-

the-art GNSS simulator and an advanced GNSS propagation model. The

propagation model relies on a 3D scene of the environment, which is used to

generate the multipath and obscuration signature that strictly depends on

the location of the receiver’s antenna whether static or dynamic.

Sim3D enables testing in fully customisable environments, ranging from deep

urban to dense forest to highway. With a wide range of models available, and

the ability to build and introduce your own, including true-to-life buildings,

cars, pedestrians, and treesthe level of detail is completely in your control.

Working in conjunction with Spirent’s GSS7000 or GSS9000 simulators,

and our industry leading positioning software platform, Sim3D enables

testing using a broad range of signals.

Users working in the development, integration, or verication of the full

range of GNSS-enabled products are able to verify product performance

under controlled, repeatable, and true-to-life conditions.

Features:

• Supports all constellations,

frequencies, and codes

currently simulated by

Spirent

• The signal code, carrier, and

power are manipulated

based on interaction with the

environment

• Supports static and dynamic

scenarios

• Up to 31 multipath signals

per line of sight (LOS)

simulated

• Up to 6 reflections per

multipath computed

• Ability to generate your own

3D models

• Import externally generated

odels and objects

• Multiple 3D models are

included

• Dynamic trajectory

generation

• Support for a scene size of

up to 5km

—or greater for

highway scenes

• Unprecedented level of

control

— Obscuration mode

on/off

— Multipath on/off

— Number of reections

per multipath signal

• User-dened ltering

algorithms to simulate only

multipath in chosen delay/

power ranges

• Visualise the multipath

direction of arrival

• Building and object

materials are modelled and

taken in to account during

the computation

• Support for hardware-in-

the-loop setups

• Generate GNSS reception

heat maps for mission

planning

• Import user antenna

patterns—with RHCP/LHCP

polarisation

PosApp Sends in Real-Time at each Epoch:

• Satellite and signal information

• Vehicle/antenna location

• Vehicle/antenna attitude

The Sim3D GNSS Propagation Model

Computes in Real-Time:

• Signal Power (LOS/NLOS)

• Code offset (NLOS)

• Carrier offset (NLOS)

• Azimuth and Elevation (NLOS)

PosApp controls multipath channels and output RF to

the DUT according to the provided data.

Benets:

Realistic Multipath and Obscuration Simulation

Multipath and obscuration is simulated based on a synthetic 3D model. Real-life

locations can be regenerated and used in simulation to recreate the multipath signature

of that location. In addition, trafc, crowd, and other objects are used in the simulation

to provide a level of realism not available in any other product in the market.

Ability to Simulate Real Life Applications

Dene your antenna carrier as a vehicle or pedestrian, then position your antenna

relative to the carrier centre of gravity. The multipath and obscuration are computed

considering the antenna carrier body position and motion. This provides valuable

insight for optimising the location of the antenna for optimum performance.

Better Level of Control and Analysis

Sim3D provides a level of control not available in any other multipath/obscuration

simulation approaches. Choose which constellations to simulate, the number of satellite

to simulate, the minimum satellite elevation, and much more.

Fully Veried with Real-Life Data

The performance of Sim3D simulation relative to eld data has been exhaustively

assessed, with good indicative results shown.

Full Level of Customisation

Sim3D enables you to create your own 3D models with the level of accuracy desired.

Many generic 3D model formats are supported using provided convertors, meaning

existing or purchased models can be easily imported.

Generate Heat Maps

Improve mission planning and productivity by identifying areas of compromised GNSS

reception in modeled environments.

RF to DUT

DUT

Ethernet

Spirent Sim3D

About Spirent

Communications

Spirent 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

fullled.

For more information, visit:

www.spirent.com

For more information, call your Spirent sales representative or

visit us on the web at www.spirent.com/ContactSpirent.

www.spirent.com

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

Specications subject to change without notice.

Americas 1-800-SPIRENT

+1-800-774-7368 | sales@spirent.com

US Government & Defense

info@spirentfederal.com | spirentfederal.com

Europe and the Middle East

+44 (0) 1293 767979 | emeainfo@spirent.com

Asia and the Pacic

+86-10-8518-2539 | salesasia@spirent.com

MCD00396 Issue 1-03 04/19

True-to-Life Validation

To establish the true value of Sim3D over the existing multipath testing

methodologies, Spirent carried out extensive validation testing. The failure

of older technologies is the inability to recreate a truly realistic environment,

so overcoming this was the benchmark we set.

We collected eld data from San Jose and San Francisco, California, and

then recreated the environments in Sim3D. Signals simulated in the virtual

environment were then compared to the recorded eld data, demonstrating

strong indicative results, and even close correlation in many cases.

GPS-24GPS-02

Static Scenario Dynamic Scenario

Static Scenario—Positioning Error Static Scenario—Satellite Availability

Field Test

Simulation

Field Test

Simulation

C/NoPR ResidualsDoppler Residuals