WHAT S NEW IN ARINC 818 SUPPLEMENT 2

Transcription

1 WHAT S NEW IN ARINC 818 SUPPLEMENT 2 Paul Grunwald, Great River Technlgy, Inc., Albuquerque, NM This paper was presented at the Thirty-secnd Digital Avinics Systems Cnference in Syracuse, New Yrk, Octber 6-10, Since then, n Octber 31, 2013, the Executive Cmmittee f the Airlines Electrnic Engineering Cmmittee unanimusly endrsed the ARINC 818 Supplement 2 draft discussed in this paper. On December 18, 2013, ARINC, Inc., published Supplement 2 as Specificatin Abstract Avinics Digital Vide Bus (ADVB) r fficially, ARINC 818 was initially ratified in Octber f 2006 with great industry supprt and backing. Since then, ARINC 818 has been used as the vide transprt prtcl fr cckpit displays n the Being 787, Airbus A350 and A400M, C-130 AMP, and the C-17, F15, F18 upgrade prgrams, and numerus ther cmmercial and military aircraft. In 2013, the ARINC 818 cmmittee will prduce the next versin f the specificatin. This update will add new features and standardize sme custmer and industry ptins that have been develped as pint designs. Great River Technlgy is the Industry Editr fr the next Supplement; this paper will review the current technical items being added fr Supplement 2. ARINC 818 is a great example f hw a welldefined standard, written in a cllabrative, industry partnership, can fster interperability and best practices. Updates t a specificatin t add new features and capability keep the standards and implementatins fresh, insuring that industry needs are being meet. The ARINC standardizatin prcess brings the participants, thught leaders, and custmers all tgether cperatively s that the ARINC 818 ecsystem remains healthy and vibrant. Intrductin designatin f the standard is ANSI INCITS FC-AV uses Layers 0-4 f the Fibre Channel (FC) standards. Like HOTLink, FC-AV can use cpper r fiber fr the Physical Layer (FC-0) and als uses 8B/10B encding as part f the transmissin prtcl (FC-1). FC-2 defines a cntainer system fr the vide. The cntainer system describes hw the vide frame is partitined in Fibre Channel frames fr transmissin and is made f a cntainer header and bjects. Objects cntain ancillary data, audi data, and vide data. The cntainer header describes the frmat f the vide and hw it is ging t be arranged in the fllwing FC frames. The Fibre Channel management layer (FC-3) is generally nt used in FC-AV, but the Mapping Layer (FC-4) is, specifically the Frame Header Cntrl Prtcl (FHCP). The frame header is used as a means t cmmunicate infrmatin that is needed t recnstruct the vide image that is encapsulated in the cntainer. FC-AV is als a bi-directinal prtcl. Fr detailed infrmatin n FC-AV, please see In 2005, Airbus and Being drve the effrt t further capabilities fr the new 787 and A400M prgrams, and a new standardizatin effrt was initiated thrugh the Digital Vide Subcmmittee f ARINC. The primary driver fr the standard was t cnslidate many prprietary standards that existed in the avinics supply chain. Fr example, display manufacturers such as Hneywell, Rckwell Cllins, and Thales each had their wn prtcls fr their prducts. The new standard als incrprated increased bandwidth and features discussed belw. The majr aim f the ARINC 818 specificatin was t prvide a rbust prtcl t handle the high bandwidth f mdern avinics vide systems and include the precise timings fr line synchrnus displays. Fibre Channel remains the physical layer fr the bus and als ffers the advantages f ruting and prtcl capabilities fund in mdern netwrking prtcls. FC als is deterministic with lw latency. ARINC 818 includes errr detectin. Prir t ARINC 818 there was the FC-AV (Fibre Channel, Audi Vide) standard. The fficial

2 High Bandwidth At the time ARINC 818 was ratified, the fiber channel prtcl supprted link rates f , 2.125, 4.25, and 8.5 Gbps. Since then, link rates f , and Gbps have been released with even higher speeds planned as the market needs it. Fr example, a display at WQXGA reslutin (2560 x bit clr) at 30 Hz wuld need a bandwidth f 3,864 Mbps. Lw Latency One f the mst imprtant features f ARINC 818 is the ability t deliver uncmpressed vide with very lw latency, in many implementatins, less than ne frame. Lw latency is imprtant in real-time cckpit displays and especially in Heads-Up Displays (HUD) where differences in the HUD display images and real-wrld backgrund can cause vertig r mtin sickness in the pilt. Latency is generally determined by the implementatin. In sme cases, the image is streamed thrugh FIFOs and can be almst real-time. Other implementatins use tw image buffers and display ne while the ther is filling ( ping png ) giving a latency f a single frame. At 30 Hz, this equals latency f 33 msec, at 60 Hz it is 16 msec, which is lw enugh fr even the mst demanding applicatins [1]. In ARINC 818, there are n limitatins n the frame rate and even shrter latencies are pssible with high frame rates. ARINC 818 was riginally published in Octber f 2006 with Supplement 1 released a year later. Since then, the prtcl has been used in dzens f prgrams and ARINC 818 displays are lgging hundreds f thusands f flight hurs n bth military and cmmercial aircraft. As these prgrams have advanced, new requirements and applicatins fr the ARINC 818 prtcl have arisen. In the interest f maintaining interperability in the ARINC 818 cmmunity, ARINC Prject Initiatin/Mdificatin (APIM ) was sent t the Digital Vide Wrking grup and the prject was apprved at the January 2013 meeting in Cral Gables, Flrida. Thrughut the spring and summer representatives frm Airbus, Being, Ctswrks,, Elbit, Thales, Hneywell, DDC, SRB Cnsulting, Inc, and Great River Technlgy prpsed, discussed, and drafted the items fr the Supplement. On August 20-2 in Annaplis, Maryland, a face t face meeting was held and the draft Supplement was cmpleted. It is anticipated that Supplement 2 will be ratified at the 2013 AEEC Mid-Term sessin in Zagreb, Cratia n Octber 31st Nvember 1 st. The fllwing items were incrprated int the Supplement and will be discussed belw. Faster speeds: Fiber Channel 6x, 12x, 16x, 24x, 32x and thers. Vide cmpressin prvisins Vide encryptin prvisins Vide switching guidelines Supprt fr Field Sequential Clr Channel Bnding Bi-directinal camera interfaces and synchrnizatin Data nly links Supprt fr stere/3-d displays Optical signal perfrmance Guidance fr Cmputatin f Prir Image CRC Speeds In ARINC 818-1, the fllwing speeds are supprted. Table 1. ARINC Speeds Rate (Gbps) Nte FC 1x rate FC 2x rate FC 3x rate 4.25 FC 4x rate 8.5 FC 8x rate Supplement 2 expanded the list t include the fllwing link rates:

3 Bit Rate (Gbps) Table 2. ARINC Speeds Nte FC 1x rate FC 2x rate FC 3x rate 4.25 FC 4x rate FC 6x rate 8.5 FC 8x rate FC 12x rate FC 16x rate FC 24x rate FC 32x rate The 6x, 12X, and 24X speeds were added t accmmdate the use f high speed, bi-directinal cax with pwer as a physical medium. The 5Gbps rate was added t accmmdate s implementatin specific speeds supprted by certain FPGAs. In additin t the abve speeds and Interface Cntrl Dcument (ICD) can specify ther rates fr a specific data nly return path implementatin. Fr example, a camera might have a lw speed cntrl link that des nt need even the FC 1x rate. Cmpressin and Encryptin The initial ADBV specificatin was envisined as carrying nly uncmpressed vide and audi. With tday s high reslutin sensrs and displays, cmpressin is desirable fr recrding. Als, sme data may be sensitive and need t be prtected. With these requirements in mind, the specificatin was amended t allw new bject class types t indicate a paylad is cmpressed, encrypted, r bth. As ADVB was riginally derived frm the Fiber Channel Audi Vide Specificatin, it used the same Object Class types. These class types are specified in the ADVB cntainer header fr the Objects 0-3. These were 50h fr ancillary data in bject 1, 40h fr audi data in Object 1, and 10h fr vide in bjects 2 and 3. Rather than try and cver every type f cmpressin cdec r encryptin algrithm the decisin was t fllw the philsphy f ARINC 818 and let the ICD be cntrlling dcument and define the algrithms used fr the prject. Additinal Class types f 51h, 52h, and 53h can nw be specified fr cmpressed, encrypted, r bth respectively fr ancillary data. Likewise, fr audi, bject types 41h, 42h, and 43h are available. Fr vide, types 11h, 12h, and 13h may be used. Shuld an implementatin use multiple cdecs r algrithms, the Simple Parametric, Digital Vide index field is available as a selectr. What this means is that like ther items in ARINC 818, the specificatin itself is agnstic and the ICD will specify the implementatin details. Switching ARINC 818 was defined as a pint-t-pint interface t insure 100% quality f service. Hwever since avinics systems ften have multiple channels, allwing switching has becme imprtant. Again, t insure interperability, it was imprtant t frmalize sme f the implementatin details and recmmendatins int the specificatin. Only a few hard requirements were inserted. The first requirement is that active switching nly ccurs between cntainers. Frm a practical standpint, what this means is that if yu are transmitting vide, the switch wuld wait until the vertical blanking perid t prevent brken vide frames. Fr data and audi, this becmes a little tricky and the cntainer size must be cnsidered r the switching latency may becme t large while waiting fr the end f a cntainer. Like the ther items discussed, ARINC prvides guidance n the ICD cvering items such as in band r ut f band cntrl, multicast, prt states, diagnstics, and latency. Field Sequential Clr A Vide Frmat Cde was added t supprt field sequential clr. The clr field-sequential

4 mde will typically send each clr cmpnent in a separate cntainer. Fr example, the RGB mde typically wuld send R, then G, then B and repeat. Each cntainer wuld be at 3X the base rate, i.e. 180 Hz fr 60 Hz vide. Channel Bnding A cmmn methd used t vercme link bandwidth limitatins has been t use multiple links t transprt the vide. The vide frame is brken up int smaller segments and transmitted n 2 r mre links. Using multiple links may be dne t reduce the implementatin cst, fr example, using an FPGA capable f prviding 2 links at Gbps may be cheaper than 1 at 6.375Gbps. Fr example, a WQXGA image with 24-bit clr depth at 60 Hz wuld require bandwidth f 737,280,000 Bps. With Channel Bnding, this image culd be split and transmitted n tw ARINC Gbps links. The methd f breaking up the vide is implementatin specific but is typically left/right halves, r dd/even pixels. Again the ICD is the cntrlling dcument and shuld specify items such as allwable skew and latency between channels. T be cmpliant with the specificatin, each link will transmit a cmplete ADVB frame with header and ancillary data. T minimize buffer depth, it is recmmended that the links be synchrnized within 1/5 f the maximum ADVB frame duratin. Data-nly Links Anther prvisin added t the ARINC 818 spec allws data-nly links. Data-nly links prvide a methd fr cmmand and cntrl, status, r tuch screen crdinates. In this situatin, nly Object 0 cntainers are sent. The ADVB cntainer header will cmmunicate the sizes (in bytes) f Object 0 data t the receiver and the receiver will be able t detect that the transfer is data-nly in three pssible ways: (1) The Object sizes in the ADVB cntainer header will be set t 0 fr Objects 1, 2, and 3. (2) The rw and clumn values in ancillary data Wrd 0 will be set t 0. (3) Object 0 Wrd 3 (miscellaneus cntrl wrd) will transmit a Parameter type 1 with bit 8 set. Data nly transfers can be f any size and may be cmprised f multiple ADVB frames. The ttal size (in bytes) will be indicated in the Object 0 size field in the ADVB cntainer header. Any special rules fr packetizatin (e.g., the ADVB frames will be f a fixed size) must be specified in an ICD. Data nly ADVB link rates may be f ne f the standard link rates described abve, r may be at a different rate established by the ICD. Bi-directinal Camera Interfaces Practically speaking, a bi-directinal camera interface is just a special case f a data nly link but it was felt that sme guidance fr these classes f implementatins be incrprated. The vide interface frm the camera shuld use ne f the standard data rates and the cntrl channel will adhere t the abve rules fr a data nly link. Anther ptential use f the data nly camera cntrl interface is t use the packet fr synchrnizatin fr multiple cameras as t make peratins such as merging and blending easier. In this case, a bit is prvided indicating that the cntainer is a sync marker and t synchrnize n the Start f Frame Initiate (SOFi) symbl fr the vide channel. Once again, the prject ICD will specify the camera cntrl parameters and vide timing tlerances. Stere and Other Displays It has always been pssible t make stere displays with ARINC 818, but Supplement 2 added sme cntrl parameters t give mre flexibility t nt nly d stere but t als d partial image, tiling, and regin-f-interest displays. Examples include vertical banding (Figure 1), hrizntal banding (Figure 2), and tiling (Figure 3).

5 Figure 1. Transmissin f a vertical band using parameters types 8 and 9. Figure 2. Transmissin f a hrizntal band using parameters types 6 and 7.

6 Figure 3. Transmitting a rectangular tile using parameter types 6, 7, 8, and 9 With the additinal cntrl, it is pssible t d hrizntal and vertical slices. With a hrizntal slice and vertical slice are used tgether, a regin f interest can be defined. Als pssible are Left and right channel images, and inset areas. Prvisins were als added t insure that the Cyclic Redundancy Check (CRC) is calculated n the desired pixels. Optical Perfrmance The ADVB specificatin has never directly specified a physical medium; rather it has referenced ther specificatins such as ARINC 801 (Fiber Optic Cnnectrs) and ARINC 802 (Fiber Optic Cable). T insure interperability and system perfrmance; an Optical Signal perfrmance sectin has been added t the ICD. The recmmendatin is that fr transmitters, the ICD cntain the fllwing parameters: Type f ptical fiber in which the signal is injected Data rate Multimde r single mde Graded index r step index Cre and cladding diameter Optical wavelength and maximum spectral width Minimum and maximum ptical utput pwer Peak-t-peak ptical mdulatin amplitude and/r extinctin rati

7 Maximum rise and fall times and/r eye diagram Fr receivers t fllwing shuld be added t the ICD: Type f ptical fiber frm which the signal is received Data rate Multimde r single mde Graded index r step index Cre and cladding diameter Optical wavelength and maximum spectral width Minimum and maximum received ptical pwer (CW) Signal detect assert and de-assert levels Standard ICD s can nw be defined fr each link rate. CRC Calculatin One f the mre difficult implementatin issues that arse with ARINC was the crrect calculatin f the prir image CRC. The CRC calculatin is cmplex and easy t make implementatin errrs. A detailed example has been added shwing each step in the Image CRC calculatin. ARINC and Future Systems The ARINC 818 vide interface and prtcl standard was develped fr high-bandwidth, lwlatency, uncmpressed digital vide transmissin. The standard has been advanced by ARINC and the aerspace cmmunity t meet the stringent needs f high-perfrmance digital vide. Even befre its release, the prtcl was adpted by majr aerspace and military prgrams, and has becme the de fact standard fr high-perfrmance military vide systems. Already ARINC 818 is being evaluated fr applicatin in industry medical and machine visin. ARINC 818 vide systems include infrared and ther wavelength sensrs, ptical cameras, radar, flight recrders, map/chart systems, synthetic visin, image fusin systems, heads-up displays, heads-dwn multifunctin displays, and vide cncentratrs. These vide systems are used fr taxi and take-ff assist, carg lading, navigatin, target tracking, cllisin avidance, and ther critical functins. ARINC adds features t the specificatin t accmmdate cmplex, end-t-end vide systems, including sensrs, prcessing/ switching and driving displays. Cnclusin ARINC 818 cntinues t be adpted n mre and mre prgrams due t its rbust errr checking, lw latency, and high bandwidth fr displays, cameras, and sensrs. It is being used literally arund the wrld fr bth civilian and military aircraft new develpment and upgrade prgrams. As demnstrated by the active participatin in the develpment f this Supplement t the specificatin, it ADVB has wide industry supprt frm aircraft manufacturers and suppliers. With the additin f higher speeds, supprt fr cmpressin, and encryptin, netwrking, and sphisticated display schemes, ARINC 818 adptin will cntinue t grw and expand the missin prfiles within and beynd avinics. Reference [1] Randall E. Bailey, J.J. (Trey), Arthur III, Steven P. Williams, and Lynda J. Kramer, Latency in Visinic Systems: Test Methds and Requirements, Hamptn, VA, NASA Langley Research Center. 32nd Digital Avinics Systems Cnference Octber 6-10, 2013