Question

CHAPTER 13 FROM Elementary Surveying An Introduction to Geomatics 15th Edition by Ghilan

1- why clocks are important part in satellite system?

2- how does code matching work ?

3- Gps uses two fundamental methods to determine distance between satellite and receivers,what are they?

4- what are the common accuracy's using code matching ( pseudoranging )?
5- what is the most accurate method of GPS measurement and its accuracy ?

6- what is real time kinematic GPS surveying and how its different than static GPS surveying ?

  

Answer 1

Q.1.     Why clocks are important part in Satellite system?

Ans.     Atomic Clock - It is an instrument, which utilizes the oscillations of an atom at different energy state to count the number of ticks between a second. Atomic clocks are very playing an important role in our day to day life. An atomic clock provides high-level accuracy in Air Traffic controlling so that our skies remain safe and risk-free.

The Global Positioning System network and satellite navigation are the best examples of why the atomic clock is important in a satellite system. The accuracy of this instrument is very sensitive which can be observed in a cars GPS satellite navigation system works.

Q.2.     How Does Code Matching works?

Ans.     Every satellite transfers a unique binary code of 1’s and 0’s – very accurately timed by an atomic clock – which is received by a GPS receiver’s antenna and matched with the same code produced inside the receiver. By matching up this code, the receiver then determines how long the signal will take to travel from the satellite to the receiver. This time required and the velocity is converted to distances using the speed of light (about 300,000 kilometers per second), the same speed with which radio waves travel.

Q.3.     GPS uses two fundamental methods to determine to determine distance between satellite and receivers, what are they?

Ans.     There are two fundamental methods to determine the distance between satellite and receiver; viz.,

1. Static GPS survey
2. Kinematic GPS survey

Q.6.     What is real-time kinematic GPS surveying and how it is different than static GPS surveying?

Ans.     Real-time kinematic GPS surveying is a satellite navigation technique used to improve the accuracy of position data derived from global navigation satellite systems. It uses the measurements of the phase of signal's carrier wave in addition to the information content of the signal and relies on a single reference station or interpolated virtual station to provide real-time corrections, providing up to centimeter-level accuracy. It has different applications in land survey, hydrographic survey, and unmanned aerial vehicle navigation.

            In the static GPS system, a GPS receiver is required to be stationary whereas, in Kinematic GPS system, a GPS receiver collects signal while moving.