Introduction – MOSA, IMA, HAMOSA, and IT Virtualization Architecture

Avionic Systems have traditionally been driven by hard real-time requirements, military standard 

network interfaces, rugged processors, and high robustness languages (ex Ada) to satisfy safety and 

security requirements  Size, power, weight, and cost are critical parameters for avionics systems as 

they directly affect mission endurance and mission effectiveness.  The need to leverage COTS 

processing, networking, and software has lead to wide spread use of Modular Open Systems 

Architectures (MOSA) for avionics embedded systems. For a subset of those systems, requiring 

certification, Integrated Modular Avionics (IMA) architectures have been developed leveraging ARINC

653 with time and space partitioning   More recently, the need to support multiple level security 

exchanges between platforms has driven the need for High Assurance MOSA  (HAMOSA) based on 

MILS/MLS technology. Extending the computing environment for connection to the Global 

Information Grid (GIG) places new requirements for interoperability to support Windows and Linux 

applications.

Communication Systems

®VHF

®HF

®ACARS / AIRCOM

®Secal decoders

®SATCOM

arinc 429

Unlike military standards, the ARINC 429 Specification is not a public document.
Aeronautical Radio, Inc. (ARINC) holds the copyright. Therefore, this
blog  presents a commentary and review of the ARINC 429 Specification
but does not reproduce any sections of it.

ARINC itself is not a standard nor is it a piece of equipment. ARINC is an acronym
for Aeronautical Radio, Inc. The ARINC organization is the technical,
publishing and administrative support arm for the Airlines Electronic Engineering
Committee (AEEC) groups. The AEEC was formed in 1949 and is considered
the leading international organization in the standardization of air transport
avionics equipment and telecommunication systems. AEEC standards define
avionics form, fit, function, and interfaces. The AEEC is comprised of 27 airline
and related organizations. Representatives have engineering, operational, and
maintenance experience within their organization.

ARINC specifications are divided into four numbering systems and two basic
types. The numbering systems include the 400, 500, 600, and 700 series. The
groups are divided into general design requirements and terminal design standards
(characteristics). General Design requirements include the 400 and 600
series of documents. Specific terminal design and testing criteria (characteristics)
are set forth in the 500 and 700 series. The 500 series define older mostly
analog avionics equipment, much of which is still used in modern aircraft with
updated technologies. The 400 series documents are considered the general
design and supporting documents for the 500 series avionics equipment characteristics.
Similarly, the 600 series documents are considered the general design
and support documents for the 700 series of avionics equipment characteristics.
However, there may be some exceptions; suffice it to say that 700 series terminals
are generally digital systems. The 500 and 700 series documents are equipment
specific and, among other things, define how the unit shall operate,
including the input and output pathways for digital and analog information.

ARINC standards define design and implementation of everything from testing
requirements to navigational (NAV) systems to in-flight entertainment. Some
of the newer specifications cover digital systems, testing, development, and
simulation criteria. Aside from the specifications themselves, there are a number
of subgroups, other avionics organizations, and private manufacturers, all
of whom publish information regarding the implementation of avionics systems,
e.g. the General Aviation Manufacturer’s Association (GAMA), who
defines subgroup functionality.

Some of the most prevalent ARINC standards are ARINC 419, ARINC 575,
ARINC 429, ARINC 615, and ARINC 629. Of course, numerous others exist,
and many of the 500 series are considered obsolete. Generally, three specifications
define the characteristics of avionics buses: ARINC 419, ARINC 429, and
ARINC 629. A few of the avionics terminal specifications define their own
unique bus architecture, such as ARINC 709, which includes a high speed
RADAR imaging bus. ARINC 419 is the oldest and is considered obsolete.
However, it is important from a maintenance viewpoint. The vast majority of
avionics terminals employ ARINC 429 for their avionics bus. Currently, only
the Boeing 777 employs ARINC 629.

ADA in safety critical applications

Ada Safety Critical.
This book gives an overview of how Ada is used in safety critical applications.

iontegrated modular avionics

INTEGRATED MODULAR AVIONICS IMA

SATELLITES

Receivers are auxiliary systems mounted on several types of satellites. This substantially reduces the program's cost.

The weather satellites that carry the SARSAT receivers are in "ball of yarn" orbits, inclined at 99 degrees. The longest period that all satellites can be out of line-of-sight of a beacon is about two hours.

The first satellite constellation was launched in the early 1970s by the Soviet Union, Canada, France and the USA.

Some geosynchronous satellites have beacon receivers. Since end of 2003 there are four such geostationary satellites (GEOSAR) that cover more than 80% of the surface of the earth. As with all geosynchronous satellites, they are located above the equator. The GEOSAR satellites do not cover the polar caps.

Since they see the Earth as a whole, they see the beacon immediately, but have no motion, and thus no doppler frequency shift to locate it. However, if the beacon transmits GPS data, the geosynchronous satellites give nearly instantaneous response.

28. HISTORY

The original impetus to the program in the U.S. was the loss of Congressmen Hale Boggs and Nick Begich in the Alaskan wilderness on October 16, 1972. A massive search effort failed to locate them. The result was a U.S. law mandating that all aircraft carry an emergency locator transmitter. Technical and organizational improvements followed.

Cospas-Sarsat is an international organization that has been a model of international cooperation, even during the Cold War. SARSAT means Search And Rescue SATellite. COSPAS is a Russian acronym with the same meaning. A consortium of Russia, the U.S., Canada and France formed the organization in 1982. Since then 29 others have joined.

Cospas-Sarsat defines standards for beacons, auxiliary equipment to be mounted on conforming weather and communication satellites, ground stations, and communications methods. The satellites communicate the beacon data to their ground stations, which forward it to main control centers of each nation that can initiate a rescue effort.

The U.S. Coast Guard once promoted an emergency beacon on maritime VHF emergency channels. It now promotes the superior Cospas-Sarsat system, and no longer services 

STATUTORY EMERGENCY EQUIPMENT

Most general aviation aircraft in the U.S. are required to carry an ELT, depending upon the type or location of operation, while most commercial airliners are not. 14 CFR 91.207. However, in commercial aircraft, a cockpit voice recorder or flight data recorder must contain an underwater detection beacon.

Most commercial off-shore working vessels with passengers are required to carry a self-deploying EPIRB, while most in-shore and fresh-water craft are not.

Most beacons are brightly-colored, waterproof, fit in a cube about 30 cm on a side, and weigh 2-5 kg. They can be purchased from marine suppliers, aircraft refitters, and (in Australia and the United States) hiking supply stores. The units have a useful life of 10 years, operate across a range of conditions (-40°C to 40°C), and transmit for 24 to 48 hours. As of 2003 the cost varies from US$139 to US$3000, with varying performances. Although modern systems are significantly superior to older ones, even the oldest systems provide an immense improvement in safety, compared to not having a beacon