Introduction

GPS measures the time phase difference of signals travelled from satellite to receiver instrument and computes the distance using simple relationship "distance = velocity*time" and then determines the coordinates using empheris of the satellites.
This experiment is useful to study of measurements using GPS.

Principle

GPS measures the time phase difference of signals travelled from satellite to receiver instrument and computes the distance using simple relationship "distance = velocity*time" and thendetermines the coordinates using empheris of the satellites.

Equipments Used

1. Receiver.
   
2. Controller (display and commands).
   
3. Battery for power supply.
   
4. Tripod or stand.
   
   

Dos and Don'ts

Dos

1. Always calibrate the GPS receiver to a known benchmark.
   
2. Always take the observations when more than four satellites are tracked as it will give a better intersection.
   
3. Spend more than 5 minutes for observation on each point in order to have better mean value.
   
4. Use DGPS technique if higher accuracy of observation is desired.
   

Don'ts

1. Never take single observation of a point from GPS, as it may give incorrect reading.
   
2. Never keep the GPS instrument surrounded by high rise buildings, forest area etc., as these surrounding features will block the signals from satellites.