Improvements in Space Wire Test Paul Walker Barry

Improvements in Space. Wire Test Paul Walker, Barry Cook 4 Links Limited www. 4 Links. co. uk Imrovements in Space. Wire Test: International Space. Wire Conference, Nara, Japan, 2008 -11 -6, Paul Walker, Barry Cook, 4 Links 1

Content Why record test results? Why time-tag the recordings? Resolving anomalies Scalable recording Monitoring Time Codes Generating low-jitter Time Codes RMAP Responder Integrating all of these together A real-life example for Bepi. Colombo: Imrovements in Space. Wire Test: International Space. Wire Conference, Nara, Japan, 2008 -11 -6, Paul Walker, Barry Cook, 4 Links 2

Why record test results? In Assembly, Integration and Validation (AIV/AIT ) of satellites and their subsystems, you need to record the tests: to resolve anomalies to archive successful results as a reference With a bus such as MIL 1553, a bus spy is fine With Space. Wire, it is not so easy 4 Links offer a solution Imrovements in Space. Wire Test: International Space. Wire Conference, Nara, Japan, 2008 -11 -6, Paul Walker, Barry Cook, 4 Links 3

Recording Space. Wire Multi-link Space. Wire Recorder records up to four links Records both directions of each link Computer and disc(s) need to be fast and dedicated Imrovements in Space. Wire Test: International Space. Wire Conference, Nara, Japan, 2008 -11 -6, Paul Walker, Barry Cook, 4 Links 4

Why time-tag the records? With 1553, traffic is purely sequential, but is timetagged anyway. Space. Wire has lots of concurent communications, so time tagging the records is even more important With Space. Wire-RT, there is even more need to know when events occur in the network Recordings are analyzed off-line to produce readable logs, for example: Time-tag Direction Data 10. 079 194 952 0 s 1<--2 Data @0000 05 55 1<--2 EOP at 10. 079 195 792 0 s 1<--2 Data @0000 05 55 1<--2 EOP at 10. 079 196 30 552 0 s (SOP + 0. 600 us) 30 392 0 s (SOP + 0. 600 us) Imrovements in Space. Wire Test: International Space. Wire Conference, Nara, Japan, 2008 -11 -6, Paul Walker, Barry Cook, 4 Links 5

Resolving anomalies Pairs of packets should be arriving at 10 ms intervals 10. 480 772 121 4 s 10. 480 772 961 4 s 10. 480 773 800 0 s 10. 680 351 792 0 s 1<--2 1<--2 Data @0000 05 55 EOP at 10. 479 772 Data @0000 05 55 EOP at 10. 479 773 Data @0000 05 55 EOP at 10. 479 774 Data @0000 05 55 EOP at 10. 680 352 32 721 37 561 70 401 73 392 4 s (SOP + 0. 600 us) 4 s (SOP + 0. 601 us) 0 s (SOP + 0. 600 us) Third packet arrives immediately after first pair, too early Fourth packet arrives 20 ms later, too late Imrovements in Space. Wire Test: International Space. Wire Conference, Nara, Japan, 2008 -11 -6, Paul Walker, Barry Cook, 4 Links 6

Scalable recording Recorders need to be synchronized to preserve time relationship Just connect the sync daisy chain and they synchronize Multilink Space. Wire Recorder Imrovements in Space. Wire Test: International Space. Wire Conference, Nara, Japan, 2008 -11 -6, Paul Walker, Barry Cook, 4 Links 7

Adding datation The recorder is sychronized to an absolute reference clock, such as GPS, Loran, or the on-board clock Synchronization is via the IRIG standard IRIG references are available in rack units or boards Imrovements in Space. Wire Test: International Space. Wire Conference, Nara, Japan, 2008 -11 -6, Paul Walker, Barry Cook, 4 Links 8

Dated time-tagged records Day: hh: mm: ss ms us ns Flow 288: 15: 25: 10. 263 728 870 1 s 1<--2 1<--2 (SOP+2. 500 us) 288: 15: 25: 15. 249 072 811 5 s 1<--2 1<--2 (SOP+2. 500 us) Activity Data @0000 01 02 03 04 05 Data @0008 09 0 A 0 B 0 C 0 D Data @0010 11 12 13 14 15 Data @0018 19 1 A 1 B 1 C 1 D Data @0020 21 22 23 24 25 Data @0028 29 2 A 2 B 2 C 2 D Data @0030 31 32 EOP at 288: 15: 25: 10. 263 731 Data @0000 01 02 03 04 05 Data @0008 09 0 A 0 B 0 C 0 D Data @0010 11 12 13 14 15 Data @0018 19 1 A 1 B 1 C 1 D Data @0020 21 22 23 24 25 Data @0028 29 2 A 2 B 2 C 2 D Data @0030 31 32 EOP at 288: 15: 25: 15. 249 075 06 0 E 16 1 E 26 2 E 07 0 F 17 1 F 27 2 F 08 10 18 20 28 30 370 1 s 06 0 E 16 1 E 26 2 E 07 0 F 17 1 F 27 2 F 08 10 18 20 28 30 311 5 s Imrovements in Space. Wire Test: International Space. Wire Conference, Nara, Japan, 2008 -11 -6, Paul Walker, Barry Cook, 4 Links 9

Scalable datation IRIG Time of Year reference Absolute Time Interface Multilink Space. Wire Recorder Imrovements in Space. Wire Test: International Space. Wire Conference, Nara, Japan, 2008 -11 -6, Paul Walker, Barry Cook, 4 Links 10

Integrating Time Codes The Absolute Time Interface has a Space. Wire port Used to generate low jitter Time Codes Default is 1 pps Time Code Optionally four Time Codes, as NASA/JWST, with settable intervals All aligned to IRIG (hence to GPS or on-board clock) Imrovements in Space. Wire Test: International Space. Wire Conference, Nara, Japan, 2008 -11 -6, Paul Walker, Barry Cook, 4 Links 11

Datation on Time Codes Day: hh: mm: ss ms 288: 15: 19: 31. 000 288: 15: 19: 32. 000 288: 15: 19: 33. 000 288: 15: 19: 34. 000 288: 15: 19: 35. 000 288: 15: 19: 36. 000 288: 15: 19: 37. 000 288: 15: 19: 38. 869 us 000 000 933 ns 000 000 928 5 s 5 s 8 s Flow 1 -->2 1 -->2 1<--2 1<--2 (SOP+2. 500 us) 288: 15: 19: 39. 000 000 5 s 1 -->2 288: 15: 19: 40. 000 000 5 s 1 -->2 Activity Time Code 00 Time Code 01 Time Code 02 Time Code 03 Time Code 04 Time Code 05 Time Code 06 Time Code 07 Data @0000 01 02 03 04 05 Data @0008 09 0 A 0 B 0 C 0 D Data @0010 11 12 13 14 15 Data @0018 19 1 A 1 B 1 C 1 D Data @0020 21 22 23 24 25 Data @0028 29 2 A 2 B 2 C 2 D Data @0030 31 32 EOP at 288: 15: 19: 38. 869 936 06 0 E 16 1 E 26 2 E 07 0 F 17 1 F 27 2 F 08 10 18 20 28 30 428 8 s Time Code 08 Time Code 09 Time Codes are aligned to IRIG to within nanoseconds Recordings can include mix of Time Codes and packets Imrovements in Space. Wire Test: International Space. Wire Conference, Nara, Japan, 2008 -11 -6, Paul Walker, Barry Cook, 4 Links 12

12 hour Jitter accumulation 200 ns/div IRIG Reference edge Space. Wire S signal, showing: ESC Data Start of Null Start of Time Code is aligned with IRIG Imrovements in Space. Wire Test: International Space. Wire Conference, Nara, Japan, 2008 -11 -6, Paul Walker, Barry Cook, 4 Links 13

8 hour Jitter accumulation 20 ns/div IRIG Reference edge Leading edge of Time Code Approx 30 ns jitter in eight hours Imrovements in Space. Wire Test: International Space. Wire Conference, Nara, Japan, 2008 -11 -6, Paul Walker, Barry Cook, 4 Links 14

RMAP responder RMAP needs support from test equipment New RMAP resonder provides local memory for RMAP, managed by a computer Provides ideal combination of low-latency response consistent access to the RMAP memory full control of RMAP memory by user Test functions appropriate for any stage of project Existing product can be upgraded by replacing the plug-in memory card Diagnostic. Space. Wire Interface. DSI-RG 408 Memory Card Imrovements in Space. Wire Test: International Space. Wire Conference, Nara, Japan, 2008 -11 -6, Paul Walker, Barry Cook, 4 Links 15

Integrating a test system IRIG Time of Year reference Absolute Time Interface Multilink Space. Wire Recorder Space. Wire Packet Generator Diagnostic Space. Wire Interface RMAP Responder Imrovements in Space. Wire Test: International Space. Wire Conference, Nara, Japan, 2008 -11 -6, Paul Walker, Barry Cook, 4 Links 16

Test set for Bepi. Columbo Absolute Time Interface IRIG Reference RMAP Responer Diagnostic Space. Wire Interface DSI-RG 408 Multilink Space. Wire Recorder Diagnostic Space. Wire Interface DSI-RG 408 Space. Wire Ethernet Reference OBC Sync daisy-chain Imrovements in Space. Wire Test: International Space. Wire Conference, Nara, Japan, 2008 -11 -6, Paul Walker, Barry Cook, 4 Links 17

Conclusions Recording Space. Wire packets is a necessary part of system verification For detecting and resolving anomalies For archiving evidence clean runs Records need to be time tagged Time tags often need to be dated 4 Links provides the solutions, for any size of system, often with boxes you already have Test functions appropriate for any stage of project Diagnostic. Space. Wire Interface. DSI-RG 408 Imrovements in Space. Wire Test: International Space. Wire Conference, Nara, Japan, 2008 -11 -6, Paul Walker, Barry Cook, 4 Links 18