INDUSTRIAL ATTACHMENT WITH

GHANA CIVIL AVIATION AUTHORITY. (G.C.A.A)

NAME: HENRY NARH KWAME NARTEY

INTERN NO.:

EMPLOYER: G.C.A.A.

DATE OF SUBMISSION:

STUDENT ID: 07.ECE.67

DATE & PLACE: 7TH MAY 2010, ACCRA.GHANA.

Section 1:

PRIVATE AUTOMATIC BRANCHING EXCHANGE (P.A.B.X).

The PABX serves the purpose if handling the communications for the entire airport as well as connecting the company extension via trunk lines to the public network, also the internal to the external communications. External lines include VSAT (Very Small Aperture Terminal) communications to other Aviation stations at other regions of the country and beyond e.g. Lome, Brazzaville, Ouagadougou, Abidjan etc.

The PABX office handles the administration of the internal extension lines of almost 1000 plus subscribers all of the GCAA and Ghana Airport Company Limited. For individual offices that require a unique line; they are provided the subscriber loop lines. Apart from the central office lines (16 lines) which serves as the gateway for the internal connection to be linked to the man grid being VODAFONE GHANA LIMITED.

The office also handles the measurement of the communication and monitors outgoing calls for the internal grid as well as providing security measures in order to avoid excessive use.

The company presently is using the SIEMENS HIPATH 4300, VERSION 1. Which runs AMOS language, used for administrating lines, runs on the Linux operating system, which is the basic OS for the majority of the administrating computers at the location? The name over signed to the computer is Subscriber or Station Configuration Unit (SCSU). It has an RMX generating system with a UNIX interface.

The system is composed of Four (4) cabinets with 24 modules and 16 modules.

The Automatic call distribution ( ACD ) / Voicemail (VM ) system also at the PABX operation room welcomes callers from outside the extension via trunk else the call is linked with the operator. The operators are equipped with an extension board that makes creation the connection much easier by a press of a button, the line is put through the required receiver.

Whenever there is a call from the public network to the internal extension the particular trunk line is taken over completely. Hence reducing the number of available trunk lines, until the two parties as disconnected.

The PABX administration also keeps track of the phone bills and compares them with their records since the trunk line is equipped with itemized billing system. The two also compared with the individual users with their Personal Identification Numbers, PINs.

Some tools used by the technicians at the PABX room are as follows:

Kroning tool: used to terminate wires into the punch block. Pressure is applied to the back of the device while the pair of lines is placed over a slotted post, a snap is audible once the wire breaks and makes contact with punch block. To disconnect the wire is forcibly pulled out.

Pliers: for cutting the wire bending, peeling the insulation around the wire in order to get the insulator.

UI Connector: To join together two wires securely.

Color coding of the Wiring system:

Primary or Leading colors (TIP colors): White, Red, Black, Yellow, Violet.

Secondary Colors (Ring colors): Blue, Orange, Green, Brown, Slate.

To create a band, one pairing color is paired with each secondary color. E.g. white –W with Blue –B.

Hence 1st Band. WB, WG, WO, WBr, WSl.

Same is done to obtain other alternative bands.

PABX Structure:

Made up of:

a. LPC (Line Power Cover): the modules operate on DC power which is directed from the AC power converted to 208V, 230V and 547V whiles the DC breaks down to 12V.

b. Control Cabinet: Also known as the compact Shelf Peripheral interconnect houses the line trunk unit 1.

c. Switch Unit (SWU): I. Common control unit: starts and controls all call processing functions

when a call is initiated.II. Switching Network: the data highway for carrying information through

the network.III. Service Unit: Controls certain function such as conferencing, ringing,

DTMF and other miscellaneous functions that are later on programmed into the system.

IV. Magnetic Optical Disk / Drive (MOD): Used for linking back up of the data so as to perform a system restore in a case of data loss. A backup is performed every Thursday (By the company regulations).

d. Administrating and Data Port Unit (ADPU): I. Caters for the booting of the machine.

II. Grants access for the configuration, management, administrating and maintenance; under two rules termed as Class of Service (COS) and Class of Parameter (COP) and for maintenance use HBR (Hipath Backup & Restore).

III. Provides interface for connection of the local terminal unit.IV. Data and switch processor for compact shelf PCI extension.

e. Dongle: Hosts’ the code word (Product Key) which limits the functions the device provide, despite the possibility of other functions. It provides connection to a printer for the printout routine operation and regeneration list.

f. LTU & LTUCX :Line Trunk Unit & Line Trunk Unit Control Extended. The LTU holds a max of ten peripheral cards being Subscriber Line Module Analogue (SLMA) and Subscriber Line Module Optic (optical).Basic form consisting of 24 circuits usually can take 8, 16, 24 etc in that order at a time. Trunk module takes charge of external lines in LTUCX next to supervision as the ADP is found in every cabinet.

Section 2:Automatic Massage Switch Room / Flight Information Region.

(AMS/FIR).This section was made up of Two equipments:1. Communication Server (C.S) A & B.

Purpose is to administer protocol and voice configuration.2. File Server (F.S) A & B.

Purpose is for administrating data configuration.

3. A Rack mounted modem with 32 lines of which only 16 is used when the alternative line is active. Hence the system is always kept on A line, B being the standby. But during the period of observation the stand-by line was the only active line.

The general purpose of AMS:

To send information to other airports of different countries across the world when required. All of such countries have their addresses registered in the system, in cases where the address isn’t available the information is directed to the controller who then interprets and assigns a permanent address for future communications.

To send flight plans of flights destination including the routing. Receive and send weather information of departure and destination

countries for the use of pilots. Send or receive NOTAMs (Notifications to Airmen).

FIR station is made up of mostly the VHF systems that are used by the Air traffic controllers to control and provide alerting service to airplanes that are within the Ghana Aviation Airspace. GCAA has a vast airspace that covers majority of West Africa due to the modern infrastructure they are equipped with compared to the other neighboring countries. There is no standard size for FIRs; it is a matter for admin convenience of the country concerned. An information service and alerting service are the basic levels of Air Traffic service, providing information pertinent to the safe and efficient conduct of flights and alerting the relevant authorities should an aircraft be in distress. Available at the FIR station are specific VHF channels for specific purposes of communication between the ground and air as well as the ground to ground communication.

Air traffic control is made up of 80% of voice transmission. It also has a portion being data transmission that is handled by the AMS station. For the voice control the Air Traffic Services - Direct Speech (ATS-DS) is used whiles for data information; Aeronautical Fixed Telecom Network (AFTN), a worldwide system of aeronautical fixed circuit provided as part of the Aeronautical Fixed Service (AFS) for the purpose of exchanging messages and/or digital data between aeronautical stations being the same or compatible communication characteristics. It exchanges vital information for aircraft operations such as distress messages, urgency messages, flight safety messages, meteorological messages, flight regularity messages and aeronautical administration message.

Section 3.

Satellite Communication Station.

Satellite communication is a very essential part of the GCAA due to its Huge geographical coverage, No line-of-site problems, Extreme reliability (99.9% up time), Reliable data broadcast or multicast, Single vendor, Easy to deploy, supports multiple applications: Video, Data, and Voice.

Alternatives to Satellite Communications:

Microwave LMDS

MMDS

Basic Satellite Fundamentals

VSAT – Very Small Aperture Terminal

Bandwidth

Frequency

Bit rate

Space Segment

Uplink

Downlink

Outbound

Inbound

Spectrum Analyzer

dB – Decibel

Gain

Attenuation

EIRP (Effective Isotropic Radiated Power)

C/N (Carrier/Noise)

Eb/N0 - Energy (in bits)/Noise

BER – Bit Error Ratio

Link Budget/Link Margin

Transponder

Footprint

Satellite Frequencies: According to that of GCAA configurations.

C-Band

Extended C-Band

Ku-Band

Ka-Band

Types of Orbits:

There are 4 main types of

Orbits that nearly all

Satellites are located in:

LEO – Low Earth Orbit

MEO* – Medium Earth Orbit

GEO – Geosynchronous Orbit

HEO* – High Elliptical Orbit

Types of Orbits.

Low Earth Orbit :

200to1400km’s

200-1400 Km above the EarthApproximately 90 Minute Period A single satellite in LEO orbit is ‘In View’ for approximately 20 minutes from AOS to LOS

Light, small, easy to launch, inexpensiveMinimal delayIdeal for Telephony

Short life span as compared with GEO SatellitesMust work in a Constellation to be effective

Section 4:

NAVIGATION AIDS. (NAV-AIDS)

1. Non-Direction Beacon (NDB):

There are two beacons for the GCAA at Accra, one located from the approach of the airport and the other at the take off. Named;

Alpha Lima Beacon (AL) @ Cantonments.

Alpha Alpha Beacon (AA) @ Ashaley botwe .

The above mention areas lie in a straight line with the runway.

2. Distance Measuring Equipment (DME):

There are two different types of this equipment for the airport aviation.

Terminal DME (TDME); located within the tarmac used to aid maneuver the aircrafts to and from the tarmac.

Enroute DME (EDME); Used by aircrafts that are making their way across the FIR of the station.

3. Instrument Landing System (ILS):Made up of the Localizer (LLZ) and the Glide path (GP).

4. VHF Omni directional Radio/Range (VOR):There are two types, Doppler VOR having a reference frequency of 30Hz AM and a variable 30Hz FM, and the Conventional VOR with a reference frequency of 30Hz FM and a variable 30Hz AM.

Conventional VOR is the only under operation, with a specification as follows:113.1MHz carrier frequency & 9960Hz subcarrier frequency.30Hz is kept at constant as the reference signal, with a variable of 30Hz.Composition of a CVOR signal:9960Hz AM sub-carrier-30% Variable- 30Hz- 30%I-dent- 10% (a periodic programmed beep that is heard by the receiving plane, identifies the CVOR location)Voice (optional) -20%

CVOR Pattern.