Index

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 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.

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.

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-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 growth.

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 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-22s. Airframe contains provisions for IRST and side-mounted phased-array 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.

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.

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.

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 flares).
The EW aperture locations provide all-aspect coverage, and the system includes a missile launch detection capability. 

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.

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).

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.

This is taken care of by the Sanders/General Electric AN/ALR-94 electronic warfare (RF warning and countermeasures) subsystem.

3.0 Instrumentation

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 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-22s and will likely include helmet-mounted cueing, AIM-9X integration, and JTIDS-send capability.

Above written and made by http://www.f-22raptor.com

Click Here For More!