Timing in Multi Sensor Systems for Measurement


Timing is an immensely important and difficult matter in distributed multi sensor systems.

From the created signal to the storage, the data package with the measured values passes through several software blocks and systems, such as measurement adapters or Ethernet switches. In the process, propagation and transmission delays (e.g. store and forward) and process-related clock jitter occur.

Due to these phenomena, the collected measurement data will not arrive and be processed chronologically with respect to their origin at the data recorder unit, which is responsible for recording and storage.

However, an exact temporal correlation of the data packets forms the basis for a meaningful fusion of sensor values. Without it, the values are not correctly assigned and cannot represent a system in its complete model. A reliable and safe statement beyond one measured value is therefore not possible.
 


Clock synchronization and time stamps as a solution


To compensate for the effects mentioned above, it is important to time stamp each data package with the creation time in order to be able to assign it later. The timestamp has to be applied to the data package as early as possible in order to be able to consider transmission delays at the same time.

Taking the individual time stamps and the underlying time into account, the clocks in the complete system must run on a time basis and be continuously synchronized to form a time domain.

This forms the basis for demanding safety-critical applications and provides the basis for safety certification of this multi sensor system.

XTSS – Time Synchronization Service in the AVETO Toolbox


Specifically, b-plus offers with XTSS a widely configurable, plug and play capable
and above all highly accurate time synchronization solution in the AVETO Toolbox.

Within XTSS there are two main components:

CTSS – Cluster Time Synchronization Service
 

This service provides synchronization over Ethernet based on gPTP (IEEE 802.1AS-2020) and PTP (IEEE1588v2).

PTSS – Plattform Time Synchronization Service
 

This service synchronizes clocks of the interfaces of a measurement platform via hardware mechanisms.

XTSS – The Universal Timing Service for Automotive Measurement Technology


We support with XTSS in our Building Blocks in AVETO a widely configurable,
Plug and Play capable and very accurate timing concept - ideal for any measurement application and best data quality.
 

Overview of clock synchronization support

XTSS FeatureUSB Dongle

for 3rd Party Hardware

BRICKplus

BRICK2

DATALynx ATX4

MDILink

EDSwitch

EDSwitch 10G

MDSwitch

i210 PCIe x1 Set IP Core FPGA  

b-HiL

PTSS – Within the platform hardware synchronized clocks
PTSS

X

Only with DATALynx und BRICK Families

X

X

X

       
CTSS – Clocks synchronized via Ethernet
Ordinary Clock (Master/Slave)

X

X

X

X

 

X

X

(SW based IEEE 1588v2)

X

X

  
Ordinary Clock Slave Only    

X

    

X

X

Boundary Clock

X

X

X

X

 

X

X

(SW based IEEE 1588v2)

X

   
Transparent Clock      

X

(IEEE 1588v2)

    
TAI Time Source 

X

(GPS)

X

(GPS)

X

(GPS)

       

Overview of timestamping of data sources


In addition to clock synchronization, we also support time stamping of data packages on reception.
We offer highly accurate hardware pulse synchronized time stamps for reception.

Product Interfaces with reception timestamp
BRICKplus 5x 1 Gbit Ethernet
BRICK2 6x 10Gbit Ethernet 3x 1Gbit Ethernet 1x PPS Output (NMEA)
BRICK Add-On BMC ETH6000 6x 1Gbit Ethernet
DATALynx Add-on XTSS + PCIe with b-plus QX550 DATALynx Add-on XTSS + PCIe with b-plus QX550

Contact our experts and learn more about our timing concept

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