2.0 System Design
Integrated Processor (CIP)
2.2 AN / APG-77 Radar
/ Navigation / Identification (CNI)
/ Intra-Flight Data Link (IFDL)
Management System (SMS)
2.7 Power Supplies
2.9 Avionics Racks
Reference System (IRS)
The F-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-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-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.
Integrated avionics means different things to different
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.
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
- Integrated Electronic Warfare System (INEWS)
- Signal and data processing in a collection of modular
- Linking to the sensors, subsystems,
- High-speed data busses.
Common Integrated Processor (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
There are two CIPs in each F-22, with 66 module slots per CIP.
They have identical backplanes, and all of the F-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
Each module is limited by design to only 75 percent of its
capability, so the F-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-22 can be met easily.
CIP also contains mission software that uses tailorable
mission planning data for sensor emitter management and
mission-specific information delivered to system through
Fairchild data transfer equipment that also contains mass
storage for default data and air vehicle operational flight
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
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-22s. Airframe contains
provisions for IRST and side-mounted phased-array radar.
AN / APG-77 Radar
The radar is key to the F-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-22.
Communications / Navigation / Identification (CNI)
The F-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.
Inter / Intra-Flight Data Link (IFDL)
Included in the CNI system is an Inter/Intra-Flight Data Link
(IFDL) that allows all F-22s in a flight to share target and
system data automatically and without radio calls. One of the
original objectives for the F-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-22 flights to be added to the net for
multi-flight coordinated attack.
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-22's expendable countermeasures (chaff and
The EW aperture locations provide all-aspect coverage, and the
system includes a missile launch detection capability.
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.
Boeing manufactures the power supplies for most of the F-22's
electronic systems. The power supply modules designed for the
F-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.
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-22's environmental control system (ECS).
The LRM concept is the baseline for all of the power supply
modules built for the F-22 to minimize maintenance time.
Built-in diagnostic routines will pinpoint a failed power
supply on an F-22 and allow maintenance personnel to remove
it, replace it and verify proper operation within 15 minutes.
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).
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
In normal flight, IRS data is fused with Global Positioning
System (GPS) data to provide an extremely reliable
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
This is taken care of by the Sanders/General Electric
AN/ALR-94 electronic warfare (RF warning and countermeasures)
Fused situational awareness information is displayed to pilot
via four Sanders/Kaiser colour liquid crystal multifunction
displays (MFD); MFD bezel buttons provide pilot fortnat
The software that provides the avionics system's full
functionality is composed of approximately 1.7 million lines
of code. Ninety percent 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
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-22s and will likely include helmet-mounted
cueing, AIM-9X integration, and JTIDS-send capability.
Data courtesy of Lockheed Martin,
written and made by http://www.f-22raptor.com
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