Session 7 at SOAR by Avembsys

The sixth session was held on 19^th Jan 2011. In this session we had discussion about different types of software models, airports and airspace, about the runways and lighting systems.

Different types of software model

Basically three types of software model are there namely water flow model, spiral model and v model.

Water flow model

The water flow model is a sequential design process in which progress is seen as flowing steadily downwards (like a waterfall) through the different phases of software development life cycle. It has lot of disadvantages so only used for small and critical models. At any point of time this model cannot go back to previous stage and errors incurred in the first stage are carried to further stages there by decreasing the stability of the system. Any Request For Change (RFC‘s) by the clients cannot be incorporated in this model.

Spiral model

In this model, first a prototype model is built and shown to the clients for his approval and then every circle in the spiral model undergoes all the phases. The radius of the circle indicates the development of the project. Such a model is used for product development rather than software development. Spiral model is used whenever the goals of the project are unstable.

V model

 The V-Model demonstrates the relationships between each phase of the development life cycle and its associated phase of testing. The main characteristics of this model are at no point of time the requirement is not tested. Used cases in this model form the test cases later. Such a model is used in designing aircrafts, fighters and bombs.

Runways

A runway is defined as rectangular area on a land aerodrome prepared for the landing and take-off of aircraft. Runways are named by a number between 01 and 36, which is generally one tenth of the magnetic azimuth of the runway's heading: a runway numbered 09 points east (90°), runway 18 is south (180°), runway 27 points west (270°) and runway 36 points to the north (360° rather than 0°). If there is more than one runway pointing in the same direction (parallel runways), each runway is identified by appending Left (L), Center (C) and Right (R) to the number. There are runway markings and signs on most large runways. Larger runways have a distance remaining sign (black box with white numbers). This sign uses a single number to indicate the thousands of feet remaining, so 7 will indicate 7,000 ft (2,134 m) remaining. The runway threshold is marked by a line of green lights. The active runway is the runway at an airport that is in use for takeoffs and landings. Since takeoffs and landings are usually done as close to into the wind as possible, wind direction generally determines the active runway.

And about the small project given to us is going on well and only little part of it is pending on it. Since our classes are started we can work only on after lunch. So we need a time extension at least till six in the evening. My interest is more towards the project. So the contents in the blog is going to be less for future sessions

Session 6 at SOAR by Avembsys

The sixth session at SOAR was held on 18^th of Jan. Overview of Software Development Life Cycle (SDLC) was covered in this session. SDLC should result in a high quality system that meets or exceeds customer expectations, reaches completion within time and works effectively and efficiently in the current technology.

Different phases in SDLC

There are different phases that an engineer as to undergo in SDLC. They are mainly divided into four phases as follows:

·         Analysis (10%)

·         Design (20%)

·         Development (20%)

·         Testing (50%)

Each phase has an outcome which serves as the basis for the next phase. The time and how much we work in each phase are given in percentage as in the brackets above considering the entire project to be 100%. The above percentages are the rough estimates. This may differ with the type projects.

Description of each phase

Analysis

In the analysis phase we need to find the exact problem of the client. After finding the problem a feasibility analysis is carried out and lastly requirements for the projects are listed out. The client’s requirement will not be understood perfectly by the engineers. So to fill this gap we have someone called business analyst who gathers the client’s requirement and delivers to engineers in a better way. There are two types of feasibility test namely technical feasibility and financial feasibility or commercial feasibility. The output of this stage is a document called Software Requirement Specification Document (SRSD).

Before going into the next phase there are two important criteria to be satisfied. Firstly SRSD has to be approved by client and secondly software development model has to be decided.

Design

There are two levels of design high level design (top level design) and low level design. High level design consists of algorithms, flowcharts and block diagrams. The output of this stage is high level design document. Low level design consists of data structures, logic and function. A data structure is a particular way of storing and organizing data in a system so that it can be used efficiently. Function related to the selected property of a system. The output of the low level design is a low level design document (it is the detailed document of the project). The design should be flexible to meet the changes required by the clients.

Development

It is translation of low level design document into any language that system can understand. For example–C, C++, JAVA. Modular and subsystem programming code will be accomplished during this stage.

Testing

The code is tested at various levels in software testing. Then checks for errors, bugs and interoperability.

This session was really helpful for us to know how the software industries work. It requires minimum of 10 years for an engineer to work under all the phases of SDLC.

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Session 5 at SOAR by Avembsys

The fifth session was held on 11^th Jan 2011. This session was on introduction to avionics, avionics systems,   navigation, regulation and advisory agencies, examples of avionics systems such as EGPWS and TCAS.

Introduction to avionics

Avionics is a combination of aviation and electronics. It comprises electronic systems for use on aircraft, artificial satellites and spacecraft, comprising communications, navigation and the display and management of multiple systems. All electronics and electromechanical systems and subsystems installed in an aircraft or attached to it. Avionics as used in military aircraft almost always forms the biggest part of any development budget. The cockpit of an aircraft is a major location for avionic equipment, including control, monitoring, communication, navigation, weather, and anti-collision systems. Avionic systems are made up of central integrating technology with mission effectiveness critics. These systems are involved in crucial communication between several ATC’ s and pilot. These systems must be integrated in the conceptual design phase.

Avionics systems in multipurpose aircraft consists of

Military IFF –IFF stands for Identify Friend or Foe. IFF is an identification system designed for command and control. It is a system that enables military, and national (civilian-located ATC) interrogation systems to distinguish friendly aircraft and an enemy aircraft. Each aircraft comprises of universal code. IFF consists of radars which catch those codes and identify the flights.

Microwave Landing System (MLS) is the advanced version of ILS (Instrument Landing System). A MLS is an all-weather, precision landing system originally intended to replace or supplement instrument landing systems (ILS). MLS has a number of operational advantages, including a wide selection of channels to avoid interference with other nearby airports, excellent performance in all weather.

Glide slope (1 and 2) -A glide slope (GS) or glide path (GP) antenna array is sited to one side of the runway path.

Distance measuring equipment (DME) is a transponder-based radio navigation technology that measures distance by timing the propagation delay of VHF or UHF radio signals.

The VHF Omni directional Range navigation system, VOR, was probably the most significant aviation invention other than the jet engine.

Radio altimeter or simply RA measures altitude above the terrain presently beneath an aircraft or spacecraft. This type of altimeter provides the distance between the plane and the ground directly below it.

Automatic Direction Finder (ADF) is an instrument which uses radio signals to find the direction. It is widely used today. It has the major advantage over VOR navigation in the reception is not limited to line of sight distance.

Multi purpose aircraft system also contains a live TV, TCAS (Traffic Collision Avoidance System), ATC transponders, military VHF, UHF SATCOM, C-band SATCOM.

Navigation

Absolute navigation system provides vehicle position referred to a general coordinate system.

Dead reckoning (DR) is the process of estimating one's current position based upon a previously determined position. A disadvantage of dead reckoning is that since new positions are calculated solely from previous positions, the errors of the process are cumulative.

Flight control -A flight control system consists of flight control surfaces, the respective cockpit controls, connecting linkages, and the necessary operating mechanisms to control an aircraft's direction in flight. The direction and speed of the aircraft is also controlled by flight control using flaps, slats, spoilers and rudders.

Engine control - Aircraft engine controls provide a means for the pilot to control and monitor the operation of the aircraft's power plant. Full Authority Digital Engine Control (FADEC) is a system consisting of a digital computer, called an electronic engine controller (EEC) and its related accessories that control all aspects of aircraft engine performance and thrust management.

Flight management –it is the brain and heart of the aircraft. It reduces the work of flight crew by automating a wide variety of in-flight tasks. Steering signals to be send to various flight controls are sent electronically by FMS. FMS can guide the aircraft's autopilot along the flight plan.

Collision avoidance - A traffic collision avoidance system (TCAS) is an aircraft collision avoidance system designed to reduce the incidence of mid-air collisions between aircraft. It monitors the airspace around an aircraft for other aircraft equipped with a corresponding active transponder, independent of air traffic control, and warns pilots of the presence of other transponder-equipped aircraft which may present a threat of mid-air collision (MAC).

Weather conditioning radars - A weather surveillance radar (WSR), is a type of radar used to locate meteorology, calculate its motion, estimate its type (rain, snow, hail, etc.), and forecast its future position and intensity.

Four types of data are received by flight sensors namely fresh and valid, fresh and invalid, stale and valid and stale and invalid. System should take into considering only the fresh and valid data. If the sensor is sending other three types of information, it should be rejected by the system and also it shows that sensor is malfunctioning. Every 50ms data gets refreshed or updated.

REGULATIONS AND ADVISORY AGENCIES

ICAO (International Civil Aviation Organization) –provides understanding and security through cooperative aviation regulation.

RTCA (Radio Technical Commission for Aeronautics) - RTCA is a private corporation that develops consensus-based recommendations regarding communications, navigation, surveillance, and air traffic management system issues.

FAA (Federal Aviation Administration) - is responsible for the safety of the civil aircraft. 

FCC(Federal Communications Commission) - is an independent US government agency.

ARINC (Aeronautical Radio Inc) - is the premier provider of communications, integration, and engineering solutions. Example –ARINC 429 is the technical standard for the predominant avionics data bus.

DO-178B - is software considerations in airborne systems and equipment certification. It is also known as bible of aeronautical software.

EUROCAE(European Organization for Civil Aviation Equipment) – is a regulatory agency for certifying aviation equipment in Europe.

DGCA(Directorate General of Civil Aviation) - The DGCA is responsible for implementing, controlling, and supervising standards, safety operations, crew training.

Examples of avionic systems

EGPWS (Enhanced Ground Proximity Warming System) - A EGPWS is a system designed to alert pilots if their aircraft is in immediate danger of flying into the ground or an obstacle. It has seven modes of operation. It indicates pilot about excessive descent rate, excessive closure to terrain, altitude loss after take off, unsafe terrain clearance, advisory call out etc.

TCAS (Traffic Collision Avoidance System) - A is an aircraft collision avoidance system designed to reduce the incidence of mid-air collisions between aircraft. It monitors the airspace around an aircraft for other aircraft equipped with corresponding active transponders. It consists of traffic advisories (TA’s) to assist the pilot in the visual search for the intruder.

Session 4 at SOAR by Avembsys

The fourth session was held on 7^th of Jan. Discussion in this session was mainly on evolution, classification of aircraft, communication between the pilot and ATC(Air Traffic Control) and Instrument landing system (introduction).

Evolution

 

For many centuries, humans have tried to fly just like the birds. Wings made of feathers or light weight wood has been attached to arms to test their ability to fly. The results were often disastrous as the muscles of the human arms are not like birds and can not move with the strength of a bird. Leonardo Da Vinci made the first studies of flights in 1500.He created ornithopter to show how man could fly. An ornithopter   is an aircraft that flies by flapping its wings. The modern day helicopter is based on this concept. Sir George Cayley is one of the most important people in the history of aeronautics. Many consider him the first true scientific aerial investigator and the first person to understand the underlying principles and forces of flight. In 1804 Cayley designed and built a model monoplane glider which flew successfully. The work on gliders was continued by Otto Lilienthal till 1896 prior to the Wright brothers. The Flyer was the first powered aircraft designed and built by the Wright brothers. They flew it four times on December 17, 1903.Flyers are the first sustained and controlled heavier-than-air powered flight. Gliders led directly to the design of the Flyer.

Classification of aircraft

Based on space they operate -The earth’s atmosphere is divided into different layers such as troposphere, stratosphere, mesosphere and ionosphere. The aircraft fly only in the first two layers. Aircraft fly at a distance of 12 km (35000 ft) from the surface of the earth. A spacecraft or spaceship is a craft or machine designed for spaceflight. Spacecraft is used for a variety of purposes, including communications, earth observation, meteorology, navigation, planetary exploration and space tourism. The main characteristic of spacecrafts is it does not require atmospheric support for lift whereas aircraft requires it.

 Based on propulsion – Propelled -they driven by powerful engines. Example –airplanes.

           Un-propelled -they are driven by wind. They are used in weather monitoring, fun and

           entertainment. Example -airships.             

 Based on crew -Manned –airplanes,

                             Unmanned –UAV (Unmanned Aerial Vehicle), RPV (Remotely Piloted Vehicle).

Based on wings -Fixed-wing aircraft are airplanes in which lift is generated by flapping wings and rotary-wing aircraft in which wings rotate about a fixed point. Rotary wings have less speed and used as air ambulances.

Based on the types of the wings -Monoplane, biplane, tri-plane

Based on landing mode -Sea, land, amphibian (both land and water)

Based on engines -propeller, turbofan and turboprop

Based on number of engines –single, twin, multiple

Based on the function

Fighter –light weight (15 kg), high maneuverability, high speed, short runway, advanced avionics, contains weapon aiming weapons. Example – F16

Bomber –heavy weight, low maneuverability, moderate speed, long runway, deep penetration, advanced avionics, predominant bombers with guns

Transport –huge weight, very long runway, carries passengers, sluggish maneuverability

Special types

Reconnaissance, SR71 black bird, AWACS (Airborne Warning and Control System), Micro plane, Aerial refueling,

Aircraft carriers (ships with airport and infrastructure), Voyager, Secret aircraft, Nuclear powered aircraft,

Sky cars (A combination of airplane and car motor), Solo flying machine  

About the video

The video was shown to us to under the communication and miscommunication between the pilot and ATC.AVIANCA C52 was the flight which was crashed due to miscommunication between pilots and various ATC ’s killing 72 people. Even after two hours extra fuel, the engines were flamed out before the flight could land. AVIANCA C52 did not get a chance to land in John F Kennedy airport because 39 other flights were waiting for landing. This video tells us that how important is communication between pilots, several ATC ’s. AVIANCA C52 was asked to take several holding patterns which reduced the fuel resulting in flaming out the engine. Pilot has to say “I declare emergency” or “mayday” three times to inform the ATC that the condition of the flight is very dangerous. 

FMS (Flight Management System) and ILS (Instrument Landing System)

A Flight Management System is a fundamental part of a modern aircraft's avionics. It has ACARS (Aircraft Communication Addressing and Reporting System) which is a complex system consisting of several software modules. An instrument landing system (ILS) is a ground-based instrument approach system that provides precision guidance to an aircraft approaching and landing on a runway using radio frequency waves. An ILS consists of two independent sub-systems, one providing lateral guidance (localizer), the other vertical guidance (glide slope or glide path) to aircraft approaching a runway. Series of ILS antennas are placed on the runway to track landing of flight. Session 4 makes us think about all the problems in landing the flight. That’s all for this session and very eagerly waiting for further session because they are going to more challenging and interesting.

Session 3 at SOAR by Avembsys

The third session was held on 5^th Jan 2011.The session began with the discussion about the EMP pulses. These are the high density electromagnetic waves used in electronic war fares to destroy the electronic systems of the opponents. Due to the strong EMP pulses, the devices such as capacitors, transistors cannot withstand these high electromagnetic pulses, thus resulting in the explosion of the electronic systems. Then the discussion was about classification of aircraft. As of present, there are two main categories of aircrafts - heavier-than-air or aerodynes and lighter-than-air or aerostats. Then the discussion was moved on to the fundamental concepts of physics such as mass, weight, force, momentum, moment, density, viscosity and different types of pressure.

The mass is the fundamental measure of the amount of matter in the object. Weight is due to the gravity. Force is given by the product of mass and acceleration, similarly momentum and moment are given by the products of mass and velocity and force and distance respectively. Density is defined as it’s mass per unit volume. Density can be changed either using pressure or temperature. Increasing the pressure always increases the density of a material. Increasing the temperature generally decreases the density. Viscosity is a measure of resistance to flow of fluids. It increases with speed, with the increase in the temperature viscosity of liquid decreases where as that of gas increases.

Pressure

Pressure is defined as the force acting per unit area. Absolute pressure is nothing but the pressure in complete vacuum. Static pressure is the pressure at particular point. If the flow of the fluid is slowed down to zero, at that point the pressure is called as total pressure. Pitot static tube is used to obtain airspeed in turn the aircraft speed using static pressure and total pressure. Pitot tube is an instrument used to measure the speed by measuring the change in the pressure of air. Failure of the Pitot tube leads to flight crash for example flight number A447 crashed due to the failure of the pitot tube killing 228 people.

Pressure at any point is given by=gauge pressure/absolute pressure

Aircraft terminologies

Altitude is nothing but the height at which the aircraft is flying. There are three types of the altitude. They are altitude due to pressure, true or sea level altitude and absolute altitude. The following parameters vary with the altitude

                Pressure (Po) =101,325 N/m²

                Density (ρo) =1.225 kg/m³

                Temperature (To) =288.15 k

                Speed of sound (ao) =340.294 m/s

Aircraft Attitude

It is the angle of the aircraft reference line to the horizon. Mach number is defined as the ratio of speed of light to the speed of sound. Hypersonic aircraft have a speed of five times of speed of sound. Aircraft has six degrees of freedom. There are four forces acting on the namely thrust, lift, drag, weight.

Aircraft engine and wings 

The aircraft engine sucks air in at the front with a fan. A compressor raises the pressure of the air. The compressor is made up of fans with many blades and attached to a shaft. The blades compress the air. The compressed air is then blasted out with smaller opening at the back of the engine. As a result aircraft moves in the forward direction. Jet engines move the airplane forward with a great force that is produced by a tremendous thrust and causes the plane to fly very fast. Jet is a small and fast stream of fluid. Wings of aircraft provide the necessary lift for take off of the aircraft from the runway. Parameters with reference to the wings are given below

                              Lift coefficient (cl) =2L/ΡV²S

                                            L-Lift

                                            V-velocity of air

                                            Ρ-density of air 

                                            S-wing span

Major Parts of an aircraft

Cockpit-command and control

Fuselage-carries fuel and passengers

Flaps-is the extended portion of the aircraft wings. It is usually used for take off, landing and increase lift and drag. They are fully extended prior to landing to allow the aircraft to safely approach the runway at the lowest possible speed. The lift is directly proportional to the velocity of the aircraft.

Ailerons - The ailerons primarily control roll. Using ailerons causes adverse yaw that is the nose of the aircraft yaws in a direction opposite to the aileron application.

Spoilers –are used during landing of the aircraft.

Rudders - The rudder is used to control the airplane on the yaw axis (left and right.) It is most commonly used to turn the aircraft.

Slats - are used at takeoff and landing to produce additional force.

Horizontal and vertical stabilizers - The vertical stabilizer keeps the nose of the plane from swinging from side to side. The horizontal stabilizer prevents an up-and-down motion of the nose of the plane.

The post lunch session was even more interesting for me because it started with the discussion of a simple hardware module. Our task was to design a simple transceiver system with light/motion sensors. After the classes I and two of my friends went to S P Road and got some details about the components. Hopefully v will be able to submit the report on Friday. That’s it for this session, looking forward for the next session and implementation small transceiver module.

Session 2 at SOAR by Avembsys

                  The second session of interaction was really an interesting one! In the beginning of the session, there was discussion about our blogs and the mistakes which should be corrected in our blogs.Then CANDIDATES HANDBOOK was issued which helped us to know about the SOAR(Students Orientation for Aerospace & Embedded Systems Requirement) program,the topics to be covered in the training and the code of  conduct of the program.According to me,the book is very advantageous because we come to know the topic to be discussed in the next session in prior,so that we are well prepared for the topic

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                   Today's session was all about introduction to Embedded System,Real Time Operating System(RTOS),application of embedded systems in Defense and Aerospace and the different embedded systems.Firstly missiles,which are used to destroy the moving targets such as a flights.The missiles are of two types namely heat chaser missiles and laser guided missiles.Then we learned about the different networks which are used to control the missiles.Then we came to know about the different control systems used in the aircraft for the safety landing of the aircraft. As the session progressed,we got to know about the exact problems faced by the aircraft's and the pilots while landing the flights such as cross winds.Many videos which were shown to us clearly explained the above mentioned problems.It explained about the corrective measures taken by the pilot during landing such as crab movement.The other videos showed were featuring the different types of air crashes that have taken place so far which added enhancements to our thoughts.

                   The complete session gave me an idea about the various problems faced by the aircraft and made me understand how accurate the embedded systems should be designed as very small error in designing the systems leads to serious disasters.Am sure that the future sessions are going to be more interesting and challenging.Am  going to prepare myself both mentally and physically to face the future sessions and hopefully bring some good innovations in the field of Avionics.   

Session 1 at SOAR by Avembsys

The first session of Avembsys  was held on 27 Oct 2010 in my college campus.I was very eager to know how the class is going to be like others. In the beginning of the session sir spoke on how the  industries work, how are the employees classified.Any company classifies the employees using SMART technique.Every letter in the word SMART signifies one type of employees. 

As the session progressed we got to know about the different plane accidents,reasons for the accidents and about different projects undertaken by the company to avoid the air craft accidents.Then there was a discussion about  the ideas that we have in our mind.But I am yet to know about the topics on which we have to concentrate and the exact problem faced by the aircraft resulting in accidents. If I can get the answer for those questions,it will be helpful for me to think on those problems and get some new ideas.Hope the future sessions will be more interesting and making us think.