Study and Improvement in Performance of SNR with Ring Choke Antenna using GPS

Study and Improvement in Performance of SNR with Ring Choke Antenna using GPS

Monika Bhati1, Ranjana Trivedi2

1M.Tech. Scholar, 2Asso.Prof.,ECE

JIET,Jodhpur,India

Bablu Kumar Singp, Hansa Mehra4 3,4Asst. Prof., ECE JIET,Jodhpur,India

AbstractThe global positioning system (GPS) has a capability to support a wide variety of application however multipath is dominant signal which cause fading and error in the received signal. This paper shows the multipath effects of signal strength in terms of Signal to Noise Ration (SNR) using GPS receiver. The observation for SNR is done in different climatic conditions and in different month of the year and a GPS multipath signal propagation model is presented. This paper we estimated multipath error and result were taken and analyzed with the different data collected from different locations of Jodhpur Region of Rajasthan India. By estimating and modeling of multipath with different antenna as a receiver of GPS can reduce the effect of multipath fading.

Keywords GPS, Carrier Phase Multipath, SNR, Ring Choke.

1. INTRODUCTION

   All Global Positioning System is used to simplify accurate navigation Problem, GPS is a radio based navigation system that gives three dimensional coverage of the earth 24 hours a day the system is reliable and accurate. The GPS is an earth orbiting-satellite based navigation system. It is well known from the study that multipath error is one of the major sources of error affecting the positional accuracy of GPS,although, its effect can be reduced by choosing sites without multipath reflectors or choosing proper antennas to minimize the reflected signal. It is very difficult to totally reduce these effects from GPS[9] observations but we can apply some technique to reduce multipath effect. This paper shows that a ring choke [2] antenna can play a vital role in reducing the fading effect. The Global Positioning system is a space-based radio positioning and navigation system that provides 24 hour, all weather, and world-wide coverage with position, velocity and timing information. It is composed of a space segment, a control segment and a user segment. The space segment is a constellation of 25 satellites divided in different blocks; identification is composed of numbers, Pseudo Random Noise (PRN) code and orbital position number. The control segment consists of a system of tracking stations located around the world and a master control station. Then, the user segment is composed of equipment that receives and tracks the satellite signals.

2. ANALYSIS OF SNR WITH GPS RECEIVER

   To observe the effect of Fading in terms of SNR[5] we have collected data from GPS trainer kit ST 2276 receiver having its own receiver antenna as patch Antenna the reading

   were taken in antenna lab of JIET College and nearby locations from January to July month of year 2014.

   We observed that in the month of May The signal strength of satellites in terms of SNR are more because they are in line of sight as compared with the results taken in taken within antenna lab. This can be clearly detected and analyzed with the SNR results.

   Fig. 1 Set up for SNR calculation

   The reading of SNR with the help of Ring choke antenna is also calculated and shows significant improvement in the SNR as it is helpful in mitigating multipath [10] fading effect. A setup for GPS with ring Choke antenna shown at the time of taking reading shown in Fig. 1

3. RESULT

   The Improvement in performance of SNR with ring choke antenna with GPS receiver has been shown in table 2, In table 1the reading shows the average value of SNR taken in months from January to September without Ring Choke and when we used ring choke antenna for reception in GPS there is significant improvement can be easily investigated as shown in Table 2.

   Table 1: Cumulative SNR from January to September without ring base

   Month	January	April	May	June	July	September
   SNR	42	19	39	38	46	42

4. CONCLUSION

This paper shows that SNR improvement can be done using Ring choke Antenna implementing it with GPS receiver system, and this can be validated using results shown in fig. 3 which we have investigated throughout the month of January to December 2014. Since this paper shows only received signal SNR. In future it can be implemented in GPS system by miniaturizing Ring Choke antenna for compatible GPS System.

Fig 2: SNR without ring choke antenna

Table 2: SNR from October to November with and without ring base

ACKNOWLEDGMENT

I would like to acknowledge Prof. K.K. ARORA and Prof. O. P. Vyas Dean Engineering, JIET, Jodhpur, for his valuable guidance, advice and constant aspiration.

.

Fig. 3 SNR with and without ring Choke Antenna

REFERENCES

1. Smriti Sharma, Rajesh Kumar, Pawan Bhadana Terrestrial GPS Positioning System IJRET ISSN: 2319-1163 volume: 02 Issue: 04, Apr-2013.

2. Wang EnCheng, Wang Zhuopeng, and Chang Zhang., A Wideband Antenna for Global Navigation Satellite System with Reduced Multipath IEEE antennas and wireless propagation letters, VOL. 12, 2013

3. IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS,

   VOL. 12, 2013

4. Prof. Dr. Claudia, Investigation of multipath effect on GPS reference station in Parana and the first baseline station at Brazil 18 April 2007.

5. Signal-to-Noise Ratio Effects on the Quality of GPS Observations Sophie HETET, 30 august 2000.

6. Christopher Champion Varmer, DGPS carrier phase Networks and partial derivatives algorithms February 2000.

7. J.K. Ray, M.E. Cannon, Characterization of GPS Carrier Phase Multipath, Presented at ION NTM-99, San Diego, January 25-27. Bharat Lohani and Raman Kumar, A Model for GPS- GDOP Prediction in Urban Environment using LIDAR

   data, Department of Civil Engineering, IIT Kanpur, Kanpur 208016 (India).

8. GPS Trainer ST2276 , Operating Manual Version 1.1, An ISO 9001 : 2000,Scien-Tech. company.

9. Wireless communication by Dr.R.P. Yadav and Dr. Lokesh Tharani ISBN: 81-905711-1-1.