Investigating Vertical Profile of Atmospheric Refractivity Using Unmanned Aerial Vehicle

Project Title

Investigating Vertical Profile of Atmospheric Refractivity Using Unmanned Aerial Vehicle

Project Area of Specialization Internet of ThingsProject Summary

Among the different layers of the atmosphere, the troposphere layer is the nearest layer to Earth. A radio signal can propagate through the troposphere layer by adapting one of the propagation mechanisms i.e. reflection, refraction, scattering and diffraction, refraction being the prevalent mechanism. The extent of refraction of the radio signal, propagating through the Troposphere can be analysed by the “Effective Earth Radius Factor”, also called k-factor. As most of the weather changes take place in Troposphere, its refractive index (and in turn its refractivity) changes. This also changes the k-factor. According to the International Telecommunication Union (ITU), the sites for which the precise value of k-factor is not present, standard atmospheric conditions can be assumed and a value of “4/3” can be used for the k-factor. ITU has also published values for refractivity gradients throughout the world, based on two years’ data from 1992 and 1993. However, much confidence cannot be placed on this datasheet, since the weather conditions for a particular site can change with time and altitude. The classical method of obtaining the refractivity data is via radiosondes. In its absence, data from the weather stations has been used historically. However, the weather radar stations might not be collected with the radio sites, as they are mostly located outside the city. There is a lack of research work on the investigation of the behaviour, statistics and variations in k-factor in Pakistan, sans a few studies in and around Karachi and Islamabad. Radio link planners and designers make simplyfying assumptions about how atmosphere will behave with reference to wireless signal propagation through it.

Thus, our project consists of a unmanned aerial vehicle i.e. quadcopter with which different sensors are connected in order to fine the values of meteorological variables i.e. Pressure, Temperature, Humidity. The values of meteorological variables will be collected at different time, height, and seasons. These meteorological variables help in determining the refractivity gradient and k-factor values and help describe the refraction behaviour of the radio signal that is ducting, sub refraction, normal refraction etc. This multi-industry potential project can assist in better prediction, planning, interference analysis of wireless links and radio networks by providing accurate, on-site data.

In addition, we have mounted Air Quality sensors, with a view to include air quality measurements as well. The idea is to gather data at multiple sites, espceially high pollution zones, to build an atmospheric profile of air quality. Also, any potential correlatin with wireless signal level variaton can be investigated, if the latter is available. This can make contribution to the feasibility studies and reports compiled by Environmental agencies and Climate Action Groups.

Project Objectives

The main aim of this project is to acquire and record data of different meteorological variables that affect the refractivity behavior of the atmosphere, as well as air quality sensors (basic to start with) to develop a database of air quality values at different locations and sites. For this, values will be recorded at different sites and heights, in different seasons. This will be compared with relevant previous data, if available. It is expected to assist in radio and telecommunication network planning, as well as in environment awareness, Climate Action and relevant goals.  

Project Implementation Method

First of all, the project block diagram was conceived. Then available sensors and other essential modules were identified and shortlisted ones were purchased. All sensors and modules were individually interfaced with the Microcontroller and their operation verified. Thereafter, all the modules were connected simultaneously and the relevant codes were combined into one operational code.  

A quadcopter is used as Unmanned Aerial Vehicle (UAV) to mount the sensors that records weather variable values i.e. humidity, temperature and pressure. The sensors are connected to the Arduino UNO Microcontroller. GSM Sim 900 module is used to connect to the UAV through mobile phone and access and transfer data. Global positioning System (GPS) module is used to track and locate the UAV and to record the height data. The target is to collect the relevant data at different sites, times, seasons, and heights. Once the data is collected it will be analyzed by using MATLAB software to get seasonal, monthly and CDF (cumulative distribution function) graphs of k-factor for different sites of Pakistan.

The target is to cover the lowest 100m of atmosphere. Currently, readings at mutiple sites have been recorded, upto height of 40m. Further studies are planned, subject to clearance from relevant authorities.

Benefits of the Project

1. Improving the link budget management and link planning.
2. Providing high resolution, localized meteorological data for different sites, heights, seasons.
3. Making available latest status of radio refractive behavior of Troposphere, which will aid in understanding of Radio propagation in such areas.
4. Improving the accuracy of prediction of network planning software/simulators.
5. Identifying potential interference related to refractive anomalies of atmosphere

The benefits of our project are for both the Telecommunication Industry, as well as Environmental and Meteorological Agencies. Improvement in wireless link budget will help the industry to enhance the quality of prediction. Any correlation with air quality and/or weather parameters will assist in identifying the possible causes of link unavailability/non-reliability. Project is also helpful for weather department as it will act as a Private Weather Station to provide weather reports by collecting and providing high-resolution, local meteorological dataset for different sites, heights and seasons, hence informing about latest behavior of Troposphere. The project aims to assist weather department, environment engineers, policy makers and network planners in marking informed decisions.

This project can also act as a bridge between academia and industry, whereby the final deliverable can be utilised by relevant industry stakeholders for data collection, validation, case studies, decision making and so on.

Technical Details of Final Deliverable

The final form of the project will be a Quadcopter based weather station that could be used to collect the values of different meteorological variables ie pressure, temperature, humidity and air quality at different heights seasons and time. The data will help in understanding the behaviour of atmospheric refractivity, refractivity gradient an k-factor that can affect the radio signal propagation in the troposphere layer. It will also assist in Air Quality profiling, with the flexibility of recording data at locations where needed. all the relevant sensors are mounted on the Quadcopter, and values being recorded and sent as SMS to mobile phones.

The final project data sheets will contain the values of meteorological values along with the Effective Earth Radius Factor 'K-factor' for different cities of Pakistan i.e. Peshawar, Mardan, Hassan Abdal etc which will help in understanding the radio signal propagation behaviour for such cities of Pakistan and will also help in link budget management and planning.

The climatic data can be used by Environment Ministry and Climate Action Groups.

Final Deliverable of the Project HW/SW integrated systemType of Industry Health , Telecommunication Technologies Internet of Things (IoT), Others, Clean TechSustainable Development Goals Industry, Innovation and Infrastructure, Responsible Consumption and Production, Climate Action, Life on LandRequired Resources

Item Name	Type	No. of Units	Per Unit Cost (in Rs)	Total (in Rs)
			Total in (Rs)	78467
Digital Temperature And Humidity Sensor DHT22	Equipment	2	660	1320
BMP180 Pressure Sensor	Equipment	2	600	1200
GPS neo 6m Sensor	Equipment	1	3373	3373
MQ135 air quality sensor	Equipment	1	660	660
Arduino UNO Microcontroller	Equipment	2	1000	2000
Connecting Wires	Miscellaneous	100	7	700
GSM SIM900	Miscellaneous	1	5420	5420
9 volts batteries	Miscellaneous	2	100	200
Battery Caps	Miscellaneous	2	22	44
Quadcopter	Equipment	1	60000	60000
Quadcopters Self lock Propellers	Miscellaneous	4	200	800
Lipo Battery Charger	Miscellaneous	1	2000	2000
UHU Glue	Miscellaneous	2	100	200
Scotch Tape	Miscellaneous	2	50	100
Elfee (glu)	Miscellaneous	2	40	80
Hard Board	Miscellaneous	1	150	150
Double Tape	Miscellaneous	1	220	220