Table of Contents
1.0IntroductionandDescription
1.1PurposeofThisDocument
1.1.1RelationshiptoOtherDocuments
1.2SummaryofOperationalCharacteristics
1.3SystemDescription
1.3.1InertialReferenceUnit(IRU)Functions
1.3.2ControlandDisplayUnit(CDU)Functions
1.4Interchangeability
1.4.1"GenerationInterchangeability"Considerations
1.5Reliability
1.6RegulatoryApproval
1.7TestabilityandMaintainability
2.0InterchangeabilityStandards
2.1Introduction
2.2FormFactors,Connectors,andIndexPinCoding
2.2.1InertialReferenceUnit(IRU)
2.2.2ControlandDisplayUnit(CDU)
2.2.3ControlandDisplayUnit(CDU)(CustomerOption)
2.3StandardizedSignaling
2.4StandardInterwiring
2.5PowerCircuitry
2.5.1ACPowerInput(Primary)
2.5.2Back-upDCPower
2.5.3TheCommonGround
2.5.4TheACCommonCold
2.5.5GroundingandBonding
2.6Weights
2.7ThermalInterfaceandDesign
2.7.1IRU
2.7.2CDU
2.8EnvironmentalTestCategories
2.9InertialReferenceUnitMounting
2.9.1SensorUnitOrientation
2.9.2MountingTolerances
2.10AirplaneDynamicEnvironment
2.11InitializationProtocolandHeadingSet
3.0SystemDesignConsiderations
3.1Introduction
3.2General
3.2.1RangeofAttitudeOperation
3.2.2RelationshiptoRemoteComputers
3.2.3AlignmentStatus
3.2.4RangeofGeographicOperation
3.2.4.1World-WideNavigation
3.2.4.2Non-PolarNavigation
3.3BasicModesofSystemOperation
3.3.1OFF
3.3.2Alignment(ALIGN)
3.3.3Navigation(NAV)
3.3.4AttitudeReference(ATT)
3.4Outputs
3.4.1AnalogOutputs
3.4.2DigitalOutputs
3.4.2.1BasicOutputs
3.5IntegrityMonitoringandSelf-Test
3.5.1IntegrityMonitorsandFailureWarningOutputs
3.5.1.1FailureWarningIndication
3.5.1.2WarningOutputs
3.5.1.2.1FailureWarningOutputs
3.5.1.2.2MonitorIntegrity
3.5.2Built-InTestEquipment(BITE)
3.5.3Self-Test
3.6InertialReferenceSystemAccuracy
3.7InitializationProtocol
3.8HeadingSet(AttitudeModeOnly)
3.9IRSUpdatingwithGNSSData
4.0StandardSignalCharacteristics
4.1Introduction
4.2GeneralAccuracyandOperatingRanges
4.2.1Resolution
4.2.2InputandOutputSignalCharacteristics
4.2.2.1DigitalDataStandards
4.2.2.2Standard"AppliedVoltage"
4.2.2.3Standard"Open"Signal"
4.2.2.4Standard"Ground"Signal
4.2.2.5StandardDiscreteInput
4.2.2.6StandardDiscreteOutput
4.3DataSignals
4.3.1DigitalDataInputs
4.3.1.1InitializationDataEntry
4.3.1.2RemoteInitializationDataEntry
4.3.1.3RemoteInitializationDataEntry
(Alternate)
4.3.1.4DigitalAirDataInputs
4.3.1.5GNSSInputsPorts
4.3.1.6DifferentialGNSSandIntegrityMonitor
Inputs
4.3.2DigitalDataOutputs
4.4ControlSignals
4.4.1DigitalControlInputs
4.4.2DigitalControlOutputs
4.4.3DiscreteInputs
4.4.3.1ControlDiscretes
4.4.3.2DADSDiscretes
4.4.3.3Air/GroundDiscrete
4.4.4DiscreteOutputs
4.4.4.1IRSFailureWarning
4.4.4.2"OnBack-upPower"Operation
4.4.4.3LowBack-upPowerVoltageIndication
4.4.4.4Align/NotReadyIndication
4.4.4.5CDU"OFF"Switch
4.4.5GNSSTimeMarkInput
5.0Control/DisplayUnit(CDU)Design
5.1General
5.2FormFactorsandConnector
5.3Cooling
5.4PanelIllumination
5.5AnnunciatorDimming
5.6PowerSupplyforCDUOperation
5.7CDUInterfaceSummary
5.7.1CDUInputs
5.7.2CDUOutputs
5.8LiquidSpillageProtection
5.9DisplayTest
6.0ProvisionsforAutomaticTestEquipment
6.1General
6.2UnitIdentification
6.2.2UseofATE
Attachments
1.IRUDimensionsandTolerances
2.IRUMountingTray
3.IRURearConnector
4.StandardInterwiring
5.IRUConnectorPinUseReference
6.Control/DisplayUnit(CDU)OutlineandMounting
7.CDUConnectorPinLayout/Usage
8.CDUAnnunciatorDisplayDimming
9.IRSBlockDiagram
10.IRS/GNSSTypicalArchitecture
11.NavigationalMnemonics
12.EnvironmentalTestCategories
13.IRSDigitalInputs/Outputs
14.AdditionalIRSDigitalInputs/Outputswhenusedwith
ARINC743AGNSS
15.GNSSTimeMark
Appendices
ANon-StandardApplications Abstract
Gives the basic features for a 4 MCU Inertial Reference System (IRS), which consists of the necessary inertial measuring devices and associated electronics that are specifically designed for installation in commercial transport-type aircraft, that can be used in place of an in-service 10 MCU ARINC 704 Inertial Reference System. The aim of this document is to give general and specific design guidance for the development of an IRS for airline use. Describes the standards that are necessary and the desired operational capability of the system to ensure interchangeability.
