Introduction:

There are number of educational institutions and industries surrounding this local area, but no significant facilities are available in the surrounding where academicians, researchers, technologists can get together and share their views & experiences about new techniques and applications of various instruments in research under one roof. In order to cater the needs of all the departments for sophisticated instruments at Institute of Environmental Sciences and Engineering (IESE), Advanced Analytical Laboratory (AAL) was established in 1996.
All students, researchers and faculty members from Environmental Sciences and Engineering Departments of the university are free to avail the services of AAL as per the guidelines laid by the Committee of the AAL. These guidelines are regularly reviewed from time to time. While outside users from Industries, Research & Development Organizations and other educational institutions can be allowed to avail this facility with permission as per guidelines.

Objectives:

The researchers, technologists of advanced Analytical Lab. can share their views about recent development in instrumentation with a broad objective to trains/update students & researchers about advances in instrumentation. We at AAL
Carry out the analysis of samples received from researchers working in various educational and research institutions, industries, labs etc.
Provide facilities to researchers to carry out measurements on sophisticated instruments not available in their own institutions.
Organize short term courses/workshops/training on the use and application of various instruments for the benefit of research scholars, teachers and personnel from other laboratories, universities and industries
Train the scholars about latest sophisticated instruments available in research field.

Facilities:

Elemental Analysis   (Na – U)
Particle size determination  (0.1 -600um)
HC/ THMs Analysis (FID, ECD)
Solvent Separation
wastewater collection
Autotitration

High Tech Instruments:

Element Analyzer  (Model : JSK 3202M,  Manufacturer: Jeol Germany)

Element analyzer is used particularly in the investigation of metals, glass, ceramics, building materials, and for research in geochemistry. It can be qualitative (determining what elements are present), and quantitative (determining how much of each are present).

 

Total Organic Carbon  total Nitrogen (TOC/TN) Analyzer  (Model : Multi N/C 3100,  Manufacturer: Analytic Jena)

A total organic carbon analyzer determines the amount of carbon in a water sample.  TOC analyzer measure the CO2 formed when organic carbon is oxidized and/or when inorganic carbon is acidified. Once the CO2 is formed, it is measured by a detector. TOC is typically measured in Parts Per Million (ppm or mg/L).

 

Gas Chromatography (GC)    (Model: GC-2010, Manufacturer: Shimadzu)

A gas chromatograph (GC) is an analytical instrument that measures the content of various components in a sample. The instrument consists of two detectors Electron Capture Detector (ECD) and Flame Ionization Detector (FID) along with hydrogen generator air compressor.

​Flow Injection analysis (FIA)   (Model : Quick. Chem 8500,  Manufacturer: Lachat)

FIA is an automated method of chemical analysis in which a sample is injected into a flowing carrier solution that mixes with reagents before reaching a detector. FIA methods are quite versatile used in Industrial, clinical, environmental, agricultural, metallurgical, geological, food mixture relevant, pharmaceutical, and biotechnological research. FIA methods of analysis could be very useful for water analysis.

Laser Scattering Particle Size Distribution Analyzer    (Model : LA -300, Manufacturer: Horiba)

Particle size distribution analyzers determine both the size of particles and their state of distribution are used for the production control of powders in such fields as ceramics, chemistry, and foodstuffs in the range of 0.1µm to 600 µm.it is very useful in wastewater analysis.

Laser Induced breakdown Spectroscopy (LIBS)   (Model : CFR-200 , Manufacturer:Ocean Optics USA)

Laser-induced breakdown spectroscopy (LIBS) offers the ability to analyze soil samples with little sample preparation, provides detection of all elements in the periodic table, and has a large dynamic range (ppm to wt. %). LIBS can detect elements from H – Pu, which includes non-metals, such as H, N, F, and O, along with high sensitivity for lighter elements (B, Li, C, K, Ca, Mg, Al, Si, etc.)

​​Autotitrator  (Model : D55122, Manufacturer:  SCHOTT)

Titration is one of the most established analytical technique and is still commonly used in laboratories across the wide variety of application fields. This wide range of applications are possible with Automatic Potentiometric Titrator when it is having high accuracy & reproducibility. It should also have flexibility, good scope to select right parameters for right applications.

Rotary Evaporator   (Model : LABORTA 4000 , Manufacturer:   Heidolph)

A rotary evaporator is a specially designed instrument for the evaporation of solvent (single-stage or straight distillation) under vacuum. The evaporator consists of a heating bath with a rotating flask, in which the liquid is distributed as a thin film over the hot wall surfaces and can evaporate easily. The evaporation rate is regulated by the heating bath temperature, the size of flask, the pressure of distillation and the speed of rotation.

Digital Stroboscope  (Model : DT-311A , Manufacturer:  Nidec-Shimpo)

Stroboscope is an instrument used to make a cyclically moving object appear to be slow-moving, or stationary. Stroboscopes play an important role in the study of stresses on machinery in motion, and in many other forms of research

Oil Content Analyzer  (Model : OCMA-310 , Manufacturer: Horiba)

The Horiba OCMA-310 analyzer simplifies measurement of oil in water or soil for a wide variety of applications. Use this precision instrument for surveying water quality and hazardous waste sites, industrial wastewater monitoring, post-cleaning discharge analysis, and measuring adherent oil residuals on textiles and metal parts.

​Automatic Water Sampler  (Model: Wag-WE-50190 , Manufacturer: Rizvi & Company)

Automatic water samplers collect samples from a water source to provide accurate water-quality data for stormwater, wastewater, and other water-quality applications.

Sediment Core Sampler  (Model No: Wag-WE50320 , Manufacturer: UK/EEC/USA)

Core samplers are used when an undisturbed sample of sediment is required. They are suitable especially for clay, silt, or sand bottom and are used more widely in lakes than in streams.

Introduction:

Water & Wastewater Treatment are the essential focus areas in Environmental Engineering. Water has been extensively used in different activities and then wasted. There is very little consideration regarding treatment and reuse of this water. Our lab has been established with the aim to study different technologies for Water & Wastewater treatment and propose for the better option. After enough research on MBRs, we were able to establish an MBR plant here at NUST for domestic Wastewater Treatment. Research students study different techniques like Membrane Bioreactor, Anaerobic Digestion, and Membrane Distillation etc.

Equipment List:

  • Atomic Absorption Spectrophotometer
  • Muffle Furnace
  • Centrifuge
  • COD Reactor
  • Distillation Apparatus
  • Kjeldahl Apparatus
  • Oven

Available Parameters:

  • Biochemical Oxygen Demand (BOD)
  • Nitrates
  • Volatile Suspended Solids (VSS)
  • Dissolved Oxygen (DO)
  • Total Kjeldahl Nitrogen (TKN)​
  • pH
  • TS, TSS & TDS
  • Conductivity
  • Turbidity
  • Alkalinity (Carbonate & Bicarbonate)
  • Hardness
  • Chlorides
  • Heavy Metals (Cd, Cr, Cu, Zn, Fe, Mn & Pb)
  • Chemical Oxygen Demand
  • Mixed Liquor Suspended Solids

Completed/Current Research Activities:

  • Membrane Bioreactor for Domestic Wastewater Treatment
  • Upflow Anaerobic Sludge Blanket Reactor for Textile Wastewater Treatment
  • Performance evaluation of Anaerobic MBR using FO Concentrate
  • Biofouling reduction in Electrocoagulation integrated MBR using Quorum Quenching technique
  • Bio-solar Reactor for Pond water Treatment
  • Membrane Distillation for Desalination of Brackish water
  • Capacitive Deionization for Desalination of Brackish Ground water
  • Arsenic & Hardness Removal by Ion-Exchange Membrane
  • Development of Titania nano particle tape for decontamination of shopping cart handles
  • Development of Titania coatings to enhance corrosion resistance

Introduction

In order to conduct experiments to investigate man-made poisonous chemicals and their effects on the aquatic life, “Environmental Toxicology Lab” was established at Institute of Environmental Sciences and Engineering (IESE) in July, 2015. Chemical as well as bio-monitoring approaches are being used to study the effect of chemicals, natural water, pollutants, and wastes on aquatic and terrestrial lives.

Experimental Tanks

​​​

Toxicity of Chloroform and Idoform

Toxicity of Idoform (CHI3) along with highly abundant trihalomethane, {Chloroform (CHCl3)} was determined in the present study. Young specimens (five fishes per batch) were exposed to control and experimental basin and mortality was observed against applied doses to identified LD50 for (24, 48, 72 and 96 hrs.) of exposure duration. At 96 hrs. the observed LD50 is 90 mg/L and 3 mg/L for chloroform and iodoform respectively. After identification of LD50 acute toxicity was measured by applying single-cell gel electrophoresis (Comet Assay) under Fluorescent Microscope (Optika- B353FL).​

 

 

WATER DISTRIBUTION NETWORK OF NUST

​​In this research project spiking of 3 out of 5 microbial species in consortium to the prototype distribution network is  used to analyze the potential at varying disinfectant dose ( 1%, 10%, 50% V/V ) and contact times (10 sec, 1 min, 10 min). Dose and Ct optimization against individual species and in microbial consortium. Addition of precursors to simulate real distribution network conditions.

 

PRODUCTION OF BIO MASS BY USING CHLORELLA VULGARIS​

​In this research project the idea is to make micro-algal biomass production viable by designing advanced low cost photo bioreactor; requiring no additional land, minimal water use and mitigate atmospheric CO2. Porous Substrate Bioreactor (PSBR) uses a principle to separate the algae from a nutrient solution by means of a porous reactor surface on which the microalgae are trapped in biofilms.​

Major Tests

​​Kirby-Bauer Test

Kirby-Bauer test is used to measure antibiotic sensitivity. In Kirby-Bauer testing, bacteria are placed on a plate of solid growth medium and wafers of antibiotics (white disks, shown) are added to the plate. After allowing the bacteria to grow overnight, areas of clear media surrounding the disks indicate that the antibiotic inhibits bacterial growth. The concentration of antibiotic that diffuses into the media decreases with increasing distance from the source. Therefore, the more sensitive the bacteria are to a given antibiotic, the larger the clear bacteria-free zone that forms around the disk containing that antibiotic.

 

​​Disk Diffusion Test

The disk diffusion test is used to measure antibiotic sensitivity of bacteria. It uses antibiotic discs to test the extent to which bacteria are affected by those antibiotics. In this test, wafers containing antibiotics are placed on an agar plate where bacteria have been placed, and the plate is left to incubate. If an antibiotic stops the bacteria from growing or kills the bacteria, there will be an area around the wafer where the bacteria have not grown enough to be visible. This is called a zone of inhibition.

 

Introduction

The Environmental Chemistry Teaching Laboratory (ECTL) provides teaching and research capacity in the areas of analytical and environmental chemistry. Scientists identify and measure concentrations of toxic chemicals in many different media including air, water, soil, hazardous waste streams, and biological or human tissues. These efforts require the application or adaptation of existing procedures as well as the development of new analytical methods when required. The cycling of chemical species, the effect of man-made inputs, and environmental analytical methodology are stressed. This laboratory is active in several research areas including emerging contaminants, advanced analytical techniques, and conventional and novel physical-chemical treatment processes for water and waste systems.

Available parameters

  • pH
  • Conductivity
  • Temperature
  • Turbidity
  • Total Alkalinity
  • Total Hardness
  • Total Solids (TS)
  • Total Dissolved Solids (TDS)
  • Total Suspended Solids (TSS)
  • Chemical Oxygen Demand (COD)
  • Biochemical Oxygen Demand (BOD)
  • Nitrate-Nitrogen (NO3-N)
  • Sulfate (SO4-2)
  • Phosphates
  • Silicates
  • Chlorides
  • Color

Research projects

  • Biogas production through dry anaerobic digestion of organic solid waste.
  • Development of Titania Nanoparticle coated tape for decontamination of shopping cart handles.
  • Improving NUST’s lake water quality for potable use.
  • Phosphorus removal in Wastewater: A Comparison between Biological v/s Physico-Chemical Processes.
  • Up flow Anaerobic Sludge Blanket Reactor in continuous and intermittent operation treating Textile Wastewater
  • Development of photodegradable polyethylene films for food packaging to increase shelf life of food.
  • Phenolic spent caustic degradation in flat bed photoreactor using TiO2 nanoparticle immobilized on polystyrene beads.
  • Determination of phototoxicity in rice in response to nanoparticle and their impact on animal model
  • Anaerobic digestion of high strength wastewater of distillery and by-products of sugar cane industry to enhance energy balance
  • High Solids Anaerobic Digestion of Sewage Sludge
  • Anaerobic Digestion of Pre-treated Sludge in Pilot Scale Reactor
  • Anaerobic Digestion of High Strength Wastewater from the Distillery and By-products from Sugarcane Industry to Enhance Energy Balance
UV-Vis Spectrophotometer

A spectrophotometer is commonly used for the measurement of transmittance or reflectance of solutions. Tests like determination of Nitrate-Nitrogen (NO3-N), Sulfate (SO4-2), Phosphates, Silicates, Chlorides and Color are conducted on this instrument.

Conductivity meter

A conductivity meter measures the conductivity in a given solution and is used for conductivity determination which a major test for determining water purity.

Water bath

A water bath is a device used to incubate samples in water maintained at a constant temperature. Temperature may be controlled digitally or by a dial and once set, the water bath cycles on and off to ensure constancy of the temperature. It is mostly used in determination of Total Solids, Total Suspended Solids and Total Dissolved Solids.

Incubator

An incubator is a device used to grow and maintain microbiological cultures or cell cultures. The incubator maintains optimal temperature, humidity and other conditions such as the carbon dioxide (CO2) and oxygen content of the atmosphere inside. It is used in determining the Biological Oxygen Demand (BOD) of samples.

Turbidimeter

Turbidity is one of the most commonly used parameters for determining the quality of water. The turbidity value is an important factor in various fields of application such as drinking water, disinfection processes, industrial processes and water treatment plants. It is used in determination of turbidity by nephelometric method.

Oven

An oven is used in sterilization, experiment management, drying, processing, and testing. Mostly used in TDS, TSS and TS determination.

pH meter

It is used to measure hydrogen-ion activity (acidity or alkalinity) in a solution. Mostly used for pH determination in a wide range of experiments.

Vacuum Filtration Assembly with pump

Vacuum filtration Assembly is used for separating a solid product from a solvent or liquid reaction mixture. The mixture of solid and liquid is poured through a filter paper in a Buchner funnel. It is widely used in determination of Total Dissolved Solids and MLSS.

BOD Trak Apparatus

BOD analysis (Biochemical Oxygen Demand) is a chemical procedure for determining the amount of dissolved oxygen consumed by aerobic biological microorganisms in water. BOD analysis is carried out on a given water sample at certain temperature over a specific period. The BOD Trak apparatus features easy set-up, quick sample preparations, no titration dilutions.  This unit gives results directly in mg/l. Mostly used in BOD determination.

Six Paddle Stands Jar Testing Apparatus

The Jar test is a common laboratory procedure used to determine the optimum operating conditions for water or wastewater treatment. Mostly used in determining optimum coagulant dose and chemical requirements for water softening.

Electronic Analytical Balance

It is used in a wide range of experiments for chemicals measuring and solution preparation.

Hot Plate Stirrer

Hot plate stirrers are widely used instruments for numerous applications. Moreover, homogenous mixing can be achieved by this instrument.

Introduction:

In order to conduct Microbial analysis of all environmental samples at Institute of Environmental Sciences and Engineering (IESE), Environmental Microbiology Teaching Lab was established in 2005.
Research activities in the Environmental microbiology teaching lab are divided between teaching basic microbiology experiments to the undergrad and providing full state-of-art equipment and lab infra-structure for conducting MS and PhD level research. The sophisticated instrumentation in lab needs proper care and precautionary measures. Keeping this in view all the research students are advised to follow the set of instructions.

Major Tests

  • Bacteriological examination of water by MF Technique
  • Microbiological Monitoring of Air and water Quality
  • Effect of Temperature on Growth of Microorganisms
  • Study of the Algal population of waste stabilization ponds
  • Enumeration of Soil Microorganisms
  • Identification of bacterial species
  • Genotoxicity of Chlorine by-products
  • Biodegradation studies
  • PCR and gene sequencing
  • Testing of erythrocyte nuclear abnormalities
  • Enumeration of helminthes eggs and parasitic worms
  • Translocation pf microorganisms in plants
  • Enumeration of entophytes
  • Quorum sensing

Microbial Water Quality Analysis

The testing is precise, accurate and reliable due to the latest apparatus available in the lab in addition to the expertise of the staff. The entire equipment used in testing is regularly calibrated in order to maintain its accuracy.

  • Standard Plate Count Test
  • Standard Coliform
  • Fecal Coliform

Major Equipment:

Gradient Thermal Cycler

It is used to amplify segments of DNA via the polymerase chain reaction (PCR). Thermal cyclers may also be used in laboratories to facilitate other temperature-sensitive reactions, including restriction enzyme digestion or rapid diagnostics

​Gel Electrophoresis Horizontal

It is a method for separation and analysis of macromolecules (DNA, RNA and proteins) and their fragments, based on their size and charge.

 

​Gel Doc system

It is used in molecular biology laboratories for the imaging and documentation of nucleic acid and protein suspended within polyacrylamide or agarose gels.

 

​​Digital Autoclave

It is to sterilize equipment, glassware and media by subjecting them to high pressure saturated steam at 121 °C (249°F) for around 15–20 minutes depending on the size of the load and the contents.


​Incubator (Adaptive multifunctional Digital PID Capacity) :

It is a heated, insulated box used to grow and maintain microbiological or cell cultures. The incubator maintains optimal temperature, humidity and gaseous content of the atmosphere inside.


​Portable UV/Vis Spectrophotometer

Purpose of this is to measure Optical density of a sample. It can measure intensity as a function of the light source wavelength

Laminar Flow Hood

Provide sterilize environment for microbial inoculations and culture handling.


​Refrigerated Micro centrifuge:

A microcentrifuge, is used to spin small (2 ml or less) liquid samples at high speeds. Centrifugation of small samples is important for many biological applications, such as pelleting nucleic acids for downstream application such as PCR and sequencing, or isolating proteins from solution for use in western blot or 2D electrophoresis. Refrigerated centrifuges protect sensitive samples from heat degeneration, protect the sample’s integrity.


​Ice Flaking Machine:

Ice flaking machine is conceptualized and designed to meet the continuous requirement of ice to store biological samples along with transportation to other facilities. It is made up of corrosion free metal components with advance insulation ensuring maximum thermal efficiency and durability.


​Leica Microscope

An instrument used to observe objects that are too small for the naked eye. Light microscopes from Leica Microsystems are of high quality and meet the highest demands whatever the application – from routine laboratory work to the research of multi-dimensional dynamic processes in living cells.


​Water Bath

It is a device for regulating the temperature of anything subjected to heat, by surrounding the vessel containing it with another vessel containing water which can be kept at a desired temperature.


​DO meter:

Measures dissolved oxygen in wastewater, surface water and aquaculture applications. Calibrates easily in a saturated air environment and displays in % or ppm (mg/L) values.

​Colony counter

Petri plates are inserted inside the colony counter where they are properly lit and magnified. Operators can tick detected colonies with a specifically devised marker, meanwhile a digital display will increase the total counts.

​Orbital Shaker

It is used to blend or agitate samples within flasks or tubes. These shakers also provide convenience of programmable speed as well as running time with option of customizing its platform as per ones requirement and application.

Introduction

Environmental Biotechnology Research Group started in Jan 2011 at IESE, NUST. The group is working in the field of environmental biotechnology particularly on various aspects of plant responses to environmental stresses including physiology, nutrition, mechanisms, soil environment, heavy metals toxicity, nanoparticles application, microbial and bacterial degradation of toxic compounds, bioremediation & phytoremediation, ethanol production from cellulose, etc. We are optimizing experimental protocols, exploring new opportunities for innovation and ultimately contributing in the development of society

Major research activities

  • Investigating the effects of nanoparticles on different plant species
  • Isolation of resistant and plant growth promoting bacteria and fungi
  • Functional and molecular characterization of microorganisms
  • Treatment of heavy metal contaminated soil through biological and chemical means
  • Plant waste management

Instrument List

 

​ ​​Thermolyne Shaker

Thermolyne Shaker is instrument that help to form a homogenous mixture from more than one ingredient or mix liquids. Mixing and shaking are very important in performing different type of experiments. Which is used to endorese the molecular reactions of chemical substances.

​ ​Orbital shaking Incubator

This type of incubator often use for cell culturing in controlled environmental condition. In addition to stable temperature condition, its use an orbital agitation at variable speed makes them more suitable for the growth of cell cultures.

​ ​Incubator

Incubator is used to provide an optimum temperature for microbial culture. Incubators are widely involved in number of biological applications such as cell and tissue culture.

 

​ Ph Meter

pH meter is used to measure the acidity and alkalinity of liquids. Its widely use in many industries with applications such as waste water, drinking water, food & beverages, chemical and pharmaceutical testing.


​Hot air oven

Oven is mostly used for drying and sterilizing glassware such as Petri dishes, Test tubes and Pipettes etc.

​Flask Shaker

Valuable time can be saved by using flask shaker instead of mixing bottles and flask by hand. It is specially use for applications where prolonged mixing and shaking is needed


​Astell Auto Clave

Autoclave is used more commonly for sterilization of media, plasticware and glassware etc. Sterilization is the complete distruction of all microorganism inclduing the most resistant bacterai and spores. Moslty autoclave are use sterilize equipmenta and labware by subjecting them to high steam at 121°C for around 15-20 minutes depending on the size of loaded material.


​Portable Autoclave

Portable autoclave is used to sterilize surgical equipment, laboratory instruments, pharmaceutical items, and other materials. It can sterilize solids, liquids and instruments of various shapes and sizes.


​Water Bath

It is used to incubate samples in water by providing required temperature. Temperature may be controlled digitally and water bath cycles on and off to ensure constant temperature


​Horizontal Laminar Flow Cabinet

Its provide an excellent working area devoid of contaminants. Almost all of the research laboratories require sterile working environment in order to carry out out reserch work. Laminar flow cabinet is the solution and provide excellent clear air environment for number of laboratory requirements.

​ ​Microscope Triocular with Fluorescence attachment and attached Digital camera

Fluorescence microscope is used in different applications including localization of specific proteins, cells, intracellular structure and studying proteins interaction and observing live cells. The use fluorescence has made it possible to identify cells and sub cellular components of cells with a high degree of specificity. Using the facility researcher can capture video and images of sample with the help of attached digital camera.

 

​Chlorophyll meter

Chlorophyll meter is used to determine chlorophyll contents in plant leaves. For quick and easy measurement of the chlorophyll content of plant leaves without damaging the leaf.


​Comet Assay Tank

A technique use to study toxicology and carcinogenicity by detection and quantification of DNA damage in cells. The COMET assay units are specifically designed to minimize exposure to light and reduce background DNA damage.


​Computerized Microwave digestion system

The computerized microwave digestion system is used to increases reaction rates while decreasing digestion times for sample preparation for heavy metal analysis.

Introduction:

Air, noise and solid waste analysis lab is fully equipped with latest technology for air quality monitoring along with solid waste analysis and management. It is highly capable to facilitate undergraduate, Masters and PhD level students in their research work.

Available Parameters:

  • Noise analysis
  • Particle pollution PM10 , PM2.5
  • Total suspended particles in air
  • NO2 analysis
  • SO2 analysis
  • O3 measurement
  • Aerosols, VOCs and formaldehyde measurement
  • Leachate analysis

Research Projects:

  • NO2 monitoring along national highway of northern using MAX DOAS instrument
  • Investigating the temporal changes in precipitation and consequent flooding in Pakistan.
  • Spatiotemporal analysis of Methane concentration over Pakistan during the time period of 2008-2015.
  • Investigating the diurnal and weekly cycle of NO2 by using MAX DOAS observations.
  • Comparative analysis of CHOCHO during MAD-CAT campaign in Mainz, Germany and IESE-NUST, Pakistan
  • Persistent winter fog over indo-gangetic plains – a multi country study.
  • Biogas production from cow dung through the co-digestion of leachate and cotton gin.

Major instruments:​

Max-DOAS

The DOAS Technique Is A Widely-Used Remote Sensing Method To Retrieve Trace Gases With Narrow Band Absorption Structures In The UV And Visible Part Of The El​​Ectromagnetic Spectrum​

Automatic Weather Station

The weather station is used everywhere, where a comprehensive picture of the local weather conditions is gathered over a longer period of time

Noise Meter

A sound level meter is a measuring instrument used to assess noise or sound levels by measuring sound pressure. Often referred to as a sound pressure level (SPL) meter, decibel (dB) meter, noise meter or noise dosimeter, asound level meter uses a microphone to capture sound

PM Sampler

​High and low volume air samplers are instruments used to collect samples of air particles. The difference between high and low volume air samplers is the amount of air sampled

GPS

The GPS (Global Positioning System) is a “constellation” of approximately 30 well-spaced satellites that orbit the Earth and make it possible for people with ground receivers to pinpoint their geographic location​