IRIG-106 CHAPTER 7TELEMETRY DOWNLINK

ETTC JUNE 2015

Balázs BagóZodiac Data Systems

IRIG106 CHAPTER 7 PRESENTATION IRIG106 CHAPTER 7 PRESENTATION OVERVIEWOVERVIEW

Topics:

• Idea behind it• Key elements• Some examples• Benefits

Presentation length: 15 Minutes

CURRENT AIRBORNE SYSTEM CURRENT AIRBORNE SYSTEM ARCHITECTURESARCHITECTURES

Recorders (Total Data Capture)

• Capturing high rate raw data of all on-board communications, video (HD/SD), high rate analog and output from FTI Encoders

• Recorded data is in IRIG106 Chapter 10 Format

Encoders

• Capturing selected transducers and data from busses for insertion into Time Division Multiplexed PCM Data Streams

• Trend: Network output from Telemetry Encoders

TELEMETRY DOWNLINK METHODS TELEMETRY DOWNLINK METHODS TODAYTODAY

•Most Telemetry today utilizes IRIG 106, Class I or II, Chapter 4 PCM stream formats•Tedious job to match periodically sampled data and asynchronous data placing into the PCM Stream•It can be challenging and requires extensive testing

• Often requires excess bandwidth to insure data is not missed

• Ground decommutation requires extensive testing for proper measurement placement and sampling into the PCM stream

• Dynamic reconfiguration is difficult

TECHNOLOGY EVOLUTION TECHNOLOGY EVOLUTION OBSERVATIONSOBSERVATIONS

• Extensive build up around IRIG 106 Ch10 file and Chapter 10 UDP live data streaming

• Moving toward Network Telemetry

• Quick look only requires PC with network connection to verify all data types

• Many COTS Software Applications are enabled to handle Ch10 File and UDP live streaming

• Post Mission Processing centered around Ch10 files

IRIG106-15 CHAPTER 7IRIG106-15 CHAPTER 7TELEMETRY DOWNLINKTELEMETRY DOWNLINK

• Will be released as part of IRIG106-15

• Based on PCM technology as carrier

• Using Time Division Multiplexed Packet Telemetry methods based on CCSDS

• Allowing transmission of various packetized data: Chapter 10, Ethernet data, TmNS (iNET) packets, …

• Chapter 7 does not require any programming assignment of data in the Ch4 PCM stream which is typically required for traditional PCM Encoders

CHAPTER 7: MULTIPLEXING DATA INTO CHAPTER 7: MULTIPLEXING DATA INTO ASYNCHRON PACKETSASYNCHRON PACKETS

Chapter 10 Video

Packets

Streaming Ethernet Data (e.g. TmNS)

Fill Packet, Status

Information

TM DOWNLINK FORMATTM DOWNLINK FORMAT

Frame Sync

Header Fill Ch10 Packet Ethernet Packet Frame Sync

First Header Pointer

Minor Frame(IRIG106 Chapter 4 PCM Standard)

• First Header Pointer method used from CCSDS Packet Telemetry concept (both Frame Synch and Header are 32 bits)

• First Header Pointers help synchronization or resynchronization in case of transmission errors

LOW LATENCY DATA HANDLINGLOW LATENCY DATA HANDLING

LL

FS

Pck #N

Transfer packets may overlap transfer frames

• Low Latency Packet mechanism helps keeping packetization overhead low and inserting time critical data anywhere into the stream

• Flag in the frame header allows, that the low latency data can overtake standard packets

• Latency can be kept below 20ms for critical data

FS

Pck #NFS

Pck #NFS

Pck #N

Low Latency Data

PROTECTING STRUCTURE CRITICAL PROTECTING STRUCTURE CRITICAL ELEMENTSELEMENTS

• Transmission errors can lead to multiplied error rate, if they are modifying the data interpretations (e.g. altering structure length or data type information).

• Extended Golay coding is used to protect structure critical information, as:

• Frame Headers, Packet Header data type and packet length information, Length and Data Type information in Chapter 10 and TmNS headers

• Extended Golay (24,12,8) code corrects 3 of 24 transmitted bits with 100 % overhead on structure critical elements

• Simple realization possible with small look-up tables

ADDITIONAL ERROR CORRECTION ADDITIONAL ERROR CORRECTION AND RANDOMIZATIONAND RANDOMIZATION

• Additional error correction or data randomization methods are NOT part of Chapter 7

• Reed-Solomon, LDPC or other error correction methods shall be included in telemetry transmitters and receivers

• Randomized PCM code: IRIG106 Chapter 4 is increasing the error rate by factor 3, so CCSDS additive randomization is to be considered.

PACKET HEADER CODINGPACKET HEADER CODING

23 22 21 20 19 18 17 16 15 14 13 12

Reserved Content Fragment Length (15..12)

11 10 9 8 7 6 5 4 3 2 1 0

Length (11..0)

Content: Packet Content (bits 21..18) 0000: Fill Packet0001: Application Specific Packet0010: Test Counter Packet0011: Chapter 10 Packet0100: Raw Ethernet MAC Frame Packet0101: Ethernet IP Packet0110: iNET TmNS Packet0111 – 1111: reserved

Fragment: Packet Fragmentation. (bits 17..16).

00: Complete Packet 01: First Fragment of a Packet10: Middle Fragment of a Packet11: Last Fragment of a Packet

Length. (bits 15..0)

Splitted to 2x12 bits, transmitted as 2 x 24 bits Golay(24,12,8)

VIDEO APPLICATION EXAMPLEVIDEO APPLICATION EXAMPLE

On-Board Video Camera

On Board Chapter 10 Streaming

Frame Rate Decimation and/or HD to SD conversion

Low Rate PCM Downlink

HD High Bit Rate H.264 Video Ch10 Encoding

HD Video Interface

IRIG106 Chapter 7 Interface

On Board High Rate Recording

SIMULTANEOUS LIVE AND RECORDED DATA SIMULTANEOUS LIVE AND RECORDED DATA TRANSMISSIONTRANSMISSION

On Board Chapter 10 Streaming

Live data, Filtered MIL 1553 Messages

Low Rate PCM Downlink

All Bus Capture

MIL-1553 Interface

IRIG106 Chapter 7 Interface

On Board High Rate Recording

BC RT

Recorded data from the recording media

GROUND REPRODUCTION SIDEGROUND REPRODUCTION SIDE

Chapter 10 UDP

Quick-look and real-time monitoring

PCMData+ Clock

Traditional PCM decom

systems

Receiver and bit synchronizer

Selected Sources

Selected Sources

Reproduction of Native Data

Types

Video, Voice1553, Analog

Ethernet

Ground RecorderChapter 7 Native Signal Reconstruction

Ethernet gateway TmNS

IRIG106 CHAPTER 7 TELEMETRY IRIG106 CHAPTER 7 TELEMETRY DOWNLINK SUMMARYDOWNLINK SUMMARY

• Totally compatible with TM encryptors, decryptors,

transmitters, receivers, bit syncs • IRIG106 Chapter 7 Telemetry Downlink can greatly simplify

TM downlink process• Switching cost is low• Minimal testing required to setup mission• Ideal for HD recording and SD Video downlink• Ethernet gateway applications with priority handling• Low latency is achievable• Ideal for missions with quick reaction dynamic data

requirements

THANK YOU !