Antenna Tracking System for Airborne Vehicles in UHF Communication Range

The purpose of this projecct is to design and development of an Antenna Tracking System for Airborne vehicles in UHF communication range. It will reduce human involvement and help track automatically the exact position of a system under consideration. It could be an unmanned air vehicle to an unmanned ground vehicle or even a satellite.

Fig. 1: Image showing field testing of Antenna Tracking System

System Requirements for the Tracking System:

Antenna Design:

•      Following are the elements of Yagi-Uda:

–      Directors

–      Driven Element

–      Reflector

•       And the following are the parameters of a Yagi-Uda

–      The wavelength of the electromagnetic wave, ?

–      The length of the driven element

–      The length of the directors

–      The length of reflector

–      Spacing between directors

–      Spacing between reflector & driven element

–      Spacing between driven element & director

–      The type of driven element used

Communication:

Fig. 2: Typical image of 433 MHz RF Module

Control System Design

•       Free body diagram

Fig. 3: Free Body Diagram of Control System used in Antenna Tracking System

•       J1, J2 – moments of inertia

•       B1, B2 – coefficients of sliding friction

•       T- Torque applied

•      O1 – intermediate rotation

•      O– Rotational output

Fig. 4: Image showing calculations used in design of control system

Hardware Control

Servo specifications:

•       Voltage: 4.8V –  6V; [5V]

•       Speed: 0.16sec/60 deg (4.8v) – 0.18sec/60deg (6v)

•       Torque: 9kg.cm (4.8v) – 10kg.cm (6v)                                                  

•       Size: 40.2mm x 20.1mm x 42.7mm

•       Weight: 48g

•       Gear Train: metallic

Fig. 5: Typical Image of Servo Motor

Stepper motor (STH – 39D21) specifications:    

•       Step angle: 1.8°                                                            

•       Voltage :8 V                               

•       Current : 0.75 A

•       Resistance : 19 ?

•       Inductance:32 mH

•       Control Wires: 4

Fig. 6: Typical Image of Stepper Motor

Stepper motor driver (L298N) specifications:

•       Supply voltage:upto 46V

•       Total DC current:upto 4 amps

•       Can connect two unipolar motors simultaneously

Fig. 7: Typical Image of Power Regulator

Arduino Specifications:

Fig. 8: Typical Image of Arduino Uno

Methodology

•       The system is in the ready state initially

•       As soon as an airborne system is located in its range of operation, the system starts to receive its GPS coordinates

•       On receiving the GPS coordinates, the azimuth and elevation are decoded

•       The software module updates the hardware module in accordance with the decoded values

•       The antenna, which is controlled by the hardware module, follows the airborne system and collects data from it

•       The process repeats till a reset is pressed to stop

Finding Azimuth and Elevation(ECEF: Earth Centered Earth Flat)

•       The current azimuth is found using azimuth formula

–      The latitudes and longitudes of AURORA are taken as 0₁ and 0₁ respectively

–      The current values for the airborne system are 0₂ and 0 ₂

–      f = 1/298.257223563  and  1 – e² = (1 – f)²

Fig. 9: Image showing Azimuth Formula

•       Elevation is found using the linear latitude and longitudes

–      If 0 is the latitude in degrees,

–      Linear latitude = 111132.954 – 559.822 cos(2 0) + 1.175 cos(4 ?)

–      Linear longitude = (p/180)6378137 cos(tan^-1 (0.99664719 tan(0 )))              

–      If x is the latitude and the average radius of the earth is taken into account

–      Linear average longitude = (p/180)(6367499) cos(0)

Results

Antenna and its gain pattern

Fig. 10: Graph showing Frequency-Gain Relation for different wavelengths

                             Radiation patterns:

                                                                                  Elevation (linear

Fig. 11: Image showing linear gain pattern of Antenna at 90 degree elevation

                                                                                  Elevation (log)

Fig. 12: Image showing log gain pattern of Antenna at 90 degree elevation

                                                                                  Azimuth (linear)  

Fig. 13: Image showing linear gain pattern of Antenna at 0 degree azimuth

                                                                                  Azimuth (log)

Fig. 14: Image showing log gain pattern of Antenna at 0 degree azimuth

Antenna and Range

Antenna and its range

Height of transmitter (quadcopter) = 10 m

Height of receiver =1 m

Responses and Stability of System

Step Response

Fig. 15: Graph showing step response of Antenna

Root Locus

Fig. 16: Graph showing root locus of Antenna

Linear GPS Coordinates and Azimuth at a particular elevation of 56 °

Fig. 17: Table showing Linear GPS Coordinates and Azimuth at a particular elevation of 56 degree

               List of azimuths at 50°- 60° elevation range  at bus parking lot of RVCE

Fig. 18: Table showing List of azimuths at 50°- 60° elevation range at bus parking lot of RVCE

The average azimuth range was found out to be 324.936° This gives the efficiency of  90.26%.

Project Source Code

###



// ------ Code for Elevation 



 #include <math.h>

#define DEG_To_RAD 0.0174532925

double deg_lat_base=12.922490;

double deg_lat_tar=12.922608;

double lat,lat_base,lat_tar;

double lon,lon_base,lon_tar;

double rad_lat;

double tar_h=0.005;

double base_h=0.000038;

double rad_long;

void convert(double deg_lat_pass)

{

rad_lat=DEG_TO_RAD*deg_lat_pass;

lat=111132.954-(559.822*cos(2.00*(rad_lat)))+(1.175*cos((4.00*rad_lat)));

rad_long=atan(0.99664719*tan(rad_lat));

lon=DEG_TO_RAD*6378137.00*cos(rad_long);

}

double distance,h;

void dist()

{

distance=((lat_tar-lat_base)*(lat_tar-lat_base))-((lon_tar-lon_base)*(lon_tar-lon_base));

distance=sqrt(fabs(distance));

Serial.println(distance,10);

}

void calc_h()

{

h=(tar_h-base_h);

h=atan(h/distance);

h=h/DEG_TO_RAD;

Serial.println(h,10);

}

void setup()

{

Serial.print(h,9);

}

void loop()

{

Serial.begin(9600);

convert(deg_lat_base);

lat_base=lat;

lon_base=lon;

Serial.println(lat_base,10);

Serial.println(lon_base,10);

convert(deg_lat_tar);

lat_tar=lat;

lon_tar=lon;

Serial.println(lat_tar,10);

Serial.println(lon_tar,10);

dist();

calc_h();

}




// ------- Code for Servo Motor ----




 #include <Servo.h>

Servo myservo; // create servo object to control a servo

// a maximum of eight servo objects can be created

int pos = 0; // variable to store the servo position

void setup()

{

myservo.attach(9); // attaches the servo on pin 9 to the servo object

}

void loop()

{

for(pos = 0; pos < 180; pos += 1) // goes from 0 degrees to 180 degrees

{ // in steps of 1 degree

myservo.write(pos); // tell servo to go to position in variable 'pos'

delay(15); // waits 15ms for the servo to reach the position

}

for(pos = 180; pos>=1; pos-=1) // goes from 180 degrees to 0 degrees

{

myservo.write(pos); // tell servo to go to position in variable 'pos'

delay(15); // waits 15ms for the servo to reach the position

}

}




// ------- Code for Stepper Motor





 int Pin0 = 9; // INP B1

int Pin1 = 10; //INP B2

int Pin2 = 11; // INP A1

int Pin3 = 12; //INP A2

// exchange A1-2 or B1-2 pins if its not working

int _step = 4; // initialize to -1 when dir = true, 4 when dir = false

boolean dir = false;// gre

void setup()

{

pinMode(Pin0, OUTPUT);

pinMode(Pin1, OUTPUT);

pinMode(Pin2, OUTPUT);

pinMode(Pin3, OUTPUT);

pinMode(6,OUTPUT);

pinMode(7,OUTPUT);

digitalWrite(6,HIGH);

digitalWrite(7,HIGH);

}

void loop()

{

if(dir){

_step++;

}else{

_step--;

}

if(_step>3){

_step=0;

}

if(_step<0){

_step=3;

}

switch(_step){

case 0:

digitalWrite(Pin0, HIGH);

digitalWrite(Pin1, LOW);

digitalWrite(Pin2, HIGH);

digitalWrite(Pin3, LOW);

break;

case 1:

digitalWrite(Pin0, LOW);

digitalWrite(Pin1, HIGH);

digitalWrite(Pin2, HIGH);

digitalWrite(Pin3, LOW);

break;

case 2:

digitalWrite(Pin0, LOW);

digitalWrite(Pin1, HIGH);

digitalWrite(Pin2, LOW);

digitalWrite(Pin3, HIGH);

break;

case 3:

digitalWrite(Pin0, HIGH);

digitalWrite(Pin1, LOW);

digitalWrite(Pin2, LOW);

digitalWrite(Pin3, HIGH);

break;

default:

digitalWrite(Pin0, LOW);

digitalWrite(Pin1, LOW);

digitalWrite(Pin2, LOW);

digitalWrite(Pin3, LOW);

break;

}

delay(10);

}###
 

Circuit Diagrams

Circuit-Diagram-Antenna-Tracking-System-Airborne-Vehicles-Uhf-Communication-Range

Project Video

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Filed Under: Electronic Projects
Tagged With: antena, Arduino, stepper motor
 

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