1.0 Introduction
1.1 Integrated Avionics
2.0 System Design
2.1 Common Integrated Processor (CIP)
2.2 AN / APG-77 Radar
2.3 Communications / Navigation / Identification
(CNI)
2.4 Inter / Intra-Flight Data Link (IFDL)
2.5 Electronic Warfare (EW)
2.6 Stores Management System (SMS)
2.7 Power Supplies
2.8 Liquid Flow-Through Cooling
2.9 Avionics Racks
2.10 Inertial Reference System (IRS)
2.11 Self-defense
3.0 Instrumentation
4.0 Software
1.0 Introduction
The F/A-22's avionics and software system is the most advanced
ever integrated into an aircraft. It is the first aircraft
to use integrated avionics, where the radar, weapons management
system and electronic warfare system work as one, giving
the pilot unprecedented situation awareness.
Most fighters currently in use do have similar sensing
capabilities and subsystems as used for the F/A-22, although
these fighters avionics have a so-called federated systems
architecture. This means that each avionics function has
its own processor and essentially works independently.
This makes the pilot the integrator of data and the manager
of all the supporting subsystems, distracting him/her
from more relevant tasks during air-combat. The F/A-22 avionics
concept however, integrates all of the various systems
like radar, communications, navigation, identification,
electronic warfare, stores management, sensor control
and the displays that are the primary means of communication
with the pilot.
Using the power of the onboard computers, coupled with
the extensive maintenance diagnostics built into the F-22
by the maintainers, that workload has been significantly
reduced. The idea is to relieve pilots of the bulk of
system manipulations associated with flying and allow
them to do what a human does best – be a tactician.
1.1 Integrated Avionics
Integrated avionics means different things to different
people. To the pilot, it means all the information is
coordinated and available from a single source. Coherent
presentation and control is not simply a way of routing
lots of data to a single display, but it includes additional
functionality, such as situation assessment and weapons
fire control.
To the software engineer, it means access to shared data
about the situation, the mission, and the aircraft systems,
having access to coherent information such as track files,
navigation data, mission data, and aircraft system status
information.
To the hardware designer, it means a hardware architecture
built on common components, common modules, standard buses,
and common operating system providing the infrastructure
for the processing data and communication between the
mentioned components. This modular approach allows easy
capacity increase and possible future reconfiguration.
2.0 System Design
The design of this integrated system has been done during
the Engineering and Manufacturing Development (EMD) program.
This included development of
- Integrated Communications Navigation Identification
Avionics (ICNIA)
- Integrated Electronic Warfare System (INEWS)
- Signal and data processing in a collection of modular
processors
- Linking to the sensors, subsystems,
- High-speed data busses.
2.1 Common IntegratedProcessor
(CIP)
The Hughes-built Common Integrated Processor (CIP) is
the 'brain' of the avionics system. The CIP, which is
quite literally the size of a oversized bread box, supports
all signal and data processing for all sensors and mission
avionics.There are two CIPs in each F/A-22, with 66 module
slots per CIP. They have identical backplanes, and all
of the F/A-22's processing requirements can be handled by
only seven different types of processors.
Currently, 19 of 66 slots in CIP 1 and 22 of 66 slots
in CIP 2 are not in use and can be used for future growth.Each
module is limited by design to only 75 percent of its
capability, so the F/A-22 has thirty percent growth capability
with no change to the existing equipment.
There is space, power, and cooling provisions in the aircraft
now for a third CIP, so the requirement for a 200 percent
avionics growth capability in the F/A-22 can be met easily.
CIP also contains mission software that uses tailorable
mission planning data for sensor emitter management and
multisensor fusion; mission-specific information delivered
to system through Fairchild data transfer equipment that
also contains mass storage for default data and air vehicle
operational flight programme;
General purpose processing capacity of CIP is rated at
more than 700 million instructions per second (Mips) with
growth to 2,000 Mips; signal processing capacity greater
than 20 billion operations per second (Bops) with expansion
capability to 50 Bops; CIP contains more than 300 Mbytes
of memory with growth potential to 650 Mbytes. Intra-flight
data link automatically shares tactical information between
two or more F/A-22s. Airframe contains provisions for IRST
and side-mounted phased-array radar.
2.2 AN / APG-77 Radar
The radar is key to the F/A-22's integrated avionics and
sensor capabilities. It will provide pilots with detailed
information about multiple threats before the adversary's
radar ever detects the F/A-22. Click on AN/APG-77
for more details about this radar system.
2.3 Communications / Navigation
/ Identification (CNI)
The F/A-22's Communications/Navigation/Identification (CNI)
'system' is really a collection of communication, navigation,
and identification functions, once again employing the
CIP for signal and data processing resources. Each CNI
function has its associated aperture installed throughout
the aircraft.
2.4 Inter / Intra-Flight
Data Link (IFDL)
Included in the CNI system is an Inter/Intra-Flight Data
Link (IFDL) that allows all F/A-22s in a flight to share
target and system data automatically and without radio
calls. One of the original objectives for the F/A-22 was
to increase the percentage of fighter pilots who make
'kills'.
With the IFDL, each pilot is free to operate more autonomously
because, for example, the leader can tell at a glance
what his wing man's fuel state is, his weapons remaining,
and even the enemy aircraft he has targeted. This link
also allows additional F/A-22 flights to be added to the
net for multi-flight coordinated attack.
2.5 Electronic Warfare (EW)
The Electronic Warfare 'system' is also a collection of
apertures, electronics, and processors (again using the
CIP) that detect and locate signals from other aircraft
and controls the F/A-22's expendable countermeasures (chaff
and flares).
The EW aperture locations provide all-aspect coverage,
and the system includes a missile launch detection capability.
2.6 Stores Management System
(SMS)
The Stores Management System (SMS) controls weapons launch
sequences, including door control (for the internal weapons
carriage) and emergency weapons jettison.
2.7 Power Supplies
Boeing manufactures the power supplies for most of the
F/A-22's electronic systems. The power supply modules designed
for the F/A-22's avionics are cooled with liquid coolant
to carry away heat generated by the supplies' power-conversion
process. The reduced temperature allows the component's
power output to increase from 250 watts to 400 watts.
Each module measure 6.41 inches by 5.99 inches by 0.58
inches and weighs 1.8 pounds.
2.8 Liquid Flow-Through
Cooling
The PAO cooling concept also applies to all types of Line-Replaceable
Modules (LRMs) in the CIP. Liquid flow-through cooling
improves reliability, lending to an mean time between
failures (MTBF) of 25,000 hours. The coolant, polyalphaolefin
or (PAO), which is routed through the module, comes from
the F/A-22's environmental control system (ECS).
The LRM concept is the baseline for all of the power supply
modules built for the F/A-22 to minimize maintenance time.
Built-in diagnostic routines will pinpoint a failed power
supply on an F/A-22 and allow maintenance personnel to remove
it, replace it and verify proper operation within 15 minutes.
2.9 Avionics Racks
The avionics racks, located in the forward fuselage, contain
the processing, not only for the mission avionics, but
also for the Vehicle Management System (VMS) and Integrated
Vehicle System Controller (IVSC).
2.10 Inertial Reference
System (IRS)
Two Litton LN-100F ring laser gyroscopes in the forward
fuselage provide the aircraft a self-contained method
of knowing where it is. These inertial measurement units,
placed nose to nose behind the radar on the aircraft's
centerline, are operated off separate data buses to provide
independent measurement data.
In normal flight, IRS data is fused with Global Positioning
System (GPS) data to provide an extremely reliable navigational
capability.
The IMUs are the only completely reliable source of data
for the aircraft at attitudes above 30 degrees angle of
attack (AOA). One of the IRS units feeds data directly
into the CIP for gun control steering.
2.11 Self-defense
This is taken care of by the Sanders/General Electric
AN/ALR-94 electronic warfare (RF warning and countermeasures)
subsystem.
3.0 Instrumentation
Fused situational awareness information is displayed to
pilot via four Sanders/Kaiser colour liquid crystal multifunction
displays (MFD); MFD bezel buttons provide pilot fortnat
control.
4.0 Software
The software that provides the avionics system's full
functionality is composed of approximately 1.7 million
lines of code. 90% of the software is written in Ada,
the Department of Defense's common computer language.
Exceptions to the Ada requirement are granted only for
special processing or maintenance requirements.
The avionics software is to be integrated in three blocks,
each building on the capability of the previous block.
Block 1 is primarily radar capability, but Block 1 does
contain more than 50 percent of the avionics suite's full
functionality source lines of code (SLOC) and provides
end-to-end capability for the sensor-to-pilot data flow.
Block 2 is the start of sensor fusion. It adds radio frequency
coordination, reconfiguration, and some electronic warfare
functions.
Block 3 encompasses full sensor fusion built on enhanced
electronic warfare and CNI functions. It has an embedded
training capability and provides for electronic counter-counter
measures (ECCM).
Block 3.1 adds full GBU-32 Joint Direct Attack Munition
(JDAM) launch capability and Joint Tactical Information
Distribution System (JTIDS) receive-only capability.
Block 4 software (as proposed) will be post-EMD. It is
scheduled to be integrated on the Initial Operational
Capability (IOC) F/A-22s and will likely include helmet-mounted
cueing, AIM-9X integration, and JTIDS-send capability.
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