1. IRIG-106 CHAPTER 7 TELEMETRY DOWNLINK ETTC JUNE 2015 Balázs Bagó Zodiac Data Systems

2. IRIG106 CHAPTER 7 PRESENTATION OVERVIEW Topics: Idea behind it Key elements Some examples Benefits Presentation length: 15 Minutes

3. CURRENT AIRBORNE SYSTEM ARCHITECTURES 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

4. TELEMETRY DOWNLINK METHODS TODAY 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

5. TECHNOLOGY EVOLUTION OBSERVATIONS 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

6. IRIG106-15 CHAPTER 7 TELEMETRY 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

7. CHAPTER 7: MULTIPLEXING DATA INTO ASYNCHRON PACKETS Chapter 10 Video Packets Streaming Ethernet Data (e.g. TmNS) Fill Packet, Status Information

8. TM 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

9. LOW LATENCY DATA HANDLING L FSFS 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 FSFS Pck #N FSFS FSFS Low Latency Data

10. PROTECTING STRUCTURE CRITICAL ELEMENTS 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

11. ADDITIONAL ERROR CORRECTION AND 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.

12. PACKET HEADER CODING 232221201918171615141312 ReservedContentFragmentLength (15..12) 11109876543210 Length (11..0) Content: Packet Content (bits 21..18) 0000: Fill Packet 0001: Application Specific Packet 0010: Test Counter Packet 0011: Chapter 10 Packet 0100: Raw Ethernet MAC Frame Packet 0101: Ethernet IP Packet 0110: iNET TmNS Packet 0111 – 1111:reserved Fragment: Packet Fragmentation. (bits 17..16). 00:Complete Packet 01:First Fragment of a Packet 10:Middle Fragment of a Packet 11:Last Fragment of a Packet Length. (bits 15..0) Splitted to 2x12 bits, transmitted as 2 x 24 bits Golay(24,12,8)

13. VIDEO 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

14. SIMULTANEOUS LIVE AND RECORDED DATA TRANSMISSION 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 BCRT Recorded data from the recording media

15. GROUND REPRODUCTION SIDE Chapter 10 UDP Quick-look and real-time monitoring PCM Data+ Clock Traditional PCM decom systems Receiver and bit synchronizer Selected Sources Reproduction of Native Data Types Video, Voice 1553, Analog Ethernet Ground Recorder Chapter 7 Native Signal Reconstruction Ethernet gateway TmNS

16. IRIG106 CHAPTER 7 TELEMETRY DOWNLINK 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

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