Design and Simulation of Telemetry Link and Power System for ABT-18 Unmanned Aerial Vehicle

ABSTRACT

The Airbeetle-18 unmanned Aircraft is an Aircraft design for the purpose of surveillance following the fact that the parent Airbeetle-18 has almost reached the end of its life time. Hence, there is need to convert it to an unmanned aircraft in other to extend its service life time.

A comprehensive literature review was carried out on Telemetry and power system design and the previous work done as it pertains to aircraft in Airbeetle-18 category.

Furthermore, system requirement analysis was carried out in accordance with various specification standards which include CS 23, CS Vla, RTCA DO 178C, RTCA DO 258B to ensure that the Airbeetle-18 is designed to approved aviation regulatory bodies’ specifications.

Preliminary system safety analysis such as functional hazard analysis and fault tree analysis were carried out. This is expedient so as to know the probability of the system failing (MBBT) and how severe such failure could be on the aircraft as this determines whether a redundant system is necessary or not.

Software defined radio was implemented on Airbeetle-18 having considered several other types of radio putting into consideration there pros and cons. SDR is a multimode radio which provides unrestricted flexibility and is easily upgradeable.

The communication system consist of VHF radio and HF radio, while the latter is meant for beyond line of sight (Long range) voice and data communication , the former is meant for line of sight communication.

Power budget and communication link budget calculation was done, the power budget analysis highlight the power required by each component and each phase of flight with reference to the power sources whereas the communication link budget calculation was meant to ensure that a particular transmitting antenna power is sufficient to provide a communication link with the receiver and at the same time give a high signal to noise ratio and low bit error ratio taking into cognizance transmission losses due to environmental conditions and the range of communication.

The telemetry and power system were implemented by COTS components which meets standard at a low cost and minimal weight. The performance analysis and simulation of the communication system was done using the matlab Simulink. System safety assessment was done to establish that the final design met the set safety target of  set during Functional Hazard Analysis

 

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TABLE OF Contents

TITLEPAGE……………………………………………………………………………iError! Bookmark not defined.

DECLARATION………………………………………………………………………iiii

APPROVAL…………………………………………………………………………...iv

DEDICATION……………………………………………...………………………….v

ACKNOWLEDGEMENTS……………………………………..…………………….vi

ABSTRACT………………………………………………………………………......vii

TABLE OF CONTENTS…………………………………………………………….……………..ix

LIST OF FIGURES…………………………………………………………………………….xii

LIST OF TABLES………………………………………………………………….…………..xiv

LIST OF ABBREVIATIONS………………………………………………………………......xvi

LIST OF EQUATIONS………………………………………………………………………...xvii

1 THE AIRBEETLE-18 UNMANNED AERIAL VEHICLE.. 1

1.1 INTRODUCTION.. 1

1.2 BACKGROUND.. 2

1.3 OVERVIEW OF THE GROUP DESIGN PROJECT. 3

1.3.1 Problem Statement and Research Hypothesis. 3

1.3.2 Goals of the project3

1.3.3 GDP ORGANISATIONAL FLOW... 4

1.3.4 Phases of the GDP.. 4

1.3.5 Sub-Division of the GDP.. 5

1.3.6 SECONDARY TASK.. 7

1.4 TELEMETRY AND POWER SYSTEM GANTT CHART. 8

1.5 ABT-18 UAV Development Methodology. 10

1.5.1 Water Fall model10

1.5.2 V-MODEL. 11

2 REVIEW OF PRIOR WORKS.. 12

2.1 AIRCRAFT TELEMETRY SYSTEM.. 12

2.2 UAV data link. 14

2.3 FACTORS AFFECTING UAV COMMUNICATION.. 14

2.4 PROPAGATION OF ELECTROMAGNETIC WAVES.. 15

2.5 TRANSCEIVER.. 17

2.6 AIRCRAFT COMMUNICATIONS ADDRESSING AND REPORTING SYSTEM (ACARS)18

2.7 FRONT END/ANALOGUE PROCESSING COMPONENTS.. 19

2.8 DUPLEXER.. 19

2.9 ANTENNA DESIGN.. 19

2.9.1 Array antennas. 20

2.9.2 Reflector antennas. 20

2.9.3 SELECTION OF AN ANTENNA.. 22

2.10 CLASSIFICATION OF COMMUNICATION SYSTEM BASED ON TRANSMISSION FREQUENCY   26

2.10.1 MODULATION AND DEMODULATION TECHNIQUES.. 28

2.10.2 Digital Modulation.. 32

2.11 MULTIPLEXING TECHNIQUE.. 37

2.11.1 Frequency Division Multiplexing. 38

2.11.2 Time Division Multiplexing (TDM)39

2.11.3 MULTIPLE ACCESS.. 39

2.12 Spread spectrum techniques. 40

2.13 VERY HIGH FREQUENCY COMMUNICATION.. 41

2.13.1 VHF COMMUNICATION MODE OF OPERATION.. 41

2.13.2 VHF WAVE PROPAGATION.. 42

2.13.3 VHF DATALINK.. 42

2.14 Satellite Communication.. 42

2.15 HIGH FREQUENCY COMMUNICATION.. 43

2.15.1 HF data link. 44

2.16 MEANS OF ESTABLISHING TELEMETRY LINK.. 46

2.16.1 By Laser46

2.16.2 By Fibre-optics. 46

2.16.3 TELEMETRY BY RADIO.. 47

2.17 POWER SYSTEM.. 49

2.17.1 POWER PROPULSION.. 49

3 REQUIREMENT CAPTURE AND VERIFICATION.. 50

3.1 Preliminary System Safety Assessment (Pssa)50

3.1.1 Functional Hazard Analysis of ABT-18 UAV Communication System.. 50

3.2 FAULT TREE ANALYSIS.. 61

4 SYSTEM DESIGN.. 65

4.1 Selection of Communication Radio. 65

4.2 Analogue RF front End Design.. 66

4.3 POWER SYSTEM.. 69

4.3.1 POWER SYSTEM PROTECTION.. 75

5 SYSTEM BEHAVIOUR ANALYSIS AND SIMULATION.. 77

5.1 LINK BUDGET ANALYSIS.. 77

5.1.1 Effective Isotropically Radiated Power (EIRP)78

5.1.2 Path Losses/Free space path loss (FSPL)79

5.1.3 VHF Link Budget Analysis. 79

5.1.4 HF Link Budget Analysis. 82

5.2 BIT ERROR RATIO WITH MATLAB.. 84

6 HARDWARE SELECTION.. 88

6.1 Very High Frequency Radio (VHF) Radio. 88

6.1.1 VHF ANTENNA.. 88

6.2 HF ANTENNA.. 89

6.3 IMPLEMENTATION AND INTEGRATION OF ABT-18 TELEMETRY SYSTEMS   93

7 SECONDARY TASK.. 94

7.1 MASS AND CG TEAM REPORT. 94

7.2 CHALENGES AND THREATS DURING THE DESIGN.. 99

8 FUTURE WORK.. 100

APPENDICES…………………………………………………………………………………………………………………116