1. An Introduction to GPS / GNSS
Prepared by:
In Partnership with:
This presentation takes ~ 45 mins to get through.
It is used as an introduction to set the stage for an extensive GIS workshop.
NSF DUE ;

2. Outline Terms: GNSS & GPS? Why do we use GNSS? What is GNSS?
How does GNSS Work?
What do you need to know about GNSS?
What can you do with GNSS?
How is GNSS used in the real world?
Self explanatory

3. GNSS and GPS GPS = Global positioning system
GPS refers to the constellation of navigation satellites associated with the American System (which is a global system).
For a long time, GPS was the ‘only game in town’, so everything (satellites, receivers, etc.) was referred to as “GPS”
Times are changing… other options (besides GPS) are quickly developing
Think of term “GPS” as a early model of a car (Ford). When there were no other competitors, everyone referred to their vehicle as a “Ford”. When other car companies brought different models to market, then people started using more generic terms (cars). This is the same situation with GPS and GNSS. GPS refers to a global navigational system developed by the United States. GNSS refers to all satellite-based navigation systems.

4. GNSS = Global Navigation Satellite System
GNSS is an umbrella term that includes any satellite navigation system. Options include:
GPS (U.S. | operational since 1994)
GLONASS (Russian | ‘re-operational’ since 2010)
Galileo (European Union | anticipated operation:2019)
Compass (China | Operational in Asia/Pacific since 2012 / anticipated global operation: 2020)
Most GNSS receivers sold today (Garmin, Magellan, etc.) lock into both GPS and GLONASS. Most smartphone devices (iPhone, Samsung, Ericcson, HTC, etc.) use both GPS and GLONASS for navigation.
Basically, any “GPS” receiver sold today (as well as major smartphone devices and tablets with location-based services) is actually a “GNSS receiver” since it leverages GPS satellites and GLONASS satellites.

5. Why GNSS?
Many features have addresses and landmarks that are associated with a destination.
Some features are associated with street addresses. These features can sometimes be “located” without the assistance of a GNSS.
Fred Jones
332 Elm St.
Frog Holler, VA
42534

6. Why GNSS? However, there are many features that do not have addresses…
There are many MAJOR cities that do not even have STREET NAMES!
And then there is the open ocean and sky…
Many features can not be accurately or efficiently located using a street address. Traditionally, we have relied on expensive (and time consuming) surveying methods. These methods required expertise, and were expensive and time consuming. GNSS does not replace surveying efforts, but these tools enable individuals to be able conduct a reconnissance level inventory of assets, and perform other tasks with some training.
Many cities around the world do not have formal street names or addresses. Addis Ababa, Ethiopia metro area supports a population of approximately 4.5 million people. There are no street addresses in Addis Ababa. Many other cities around the world are in the same situation!

7. Location, Location, Location
Why GNSS?
Location, Location, Location
and
INFORMATION!!!
Location is the key to information. 90% of all information has a spatial, or locational component.

8. Pre-GPS Navigation is critical
Historical Navigational tools have limits:
The Sextant – doesn’t work if it is cloudy
Lowrance – radionavigation: only worked near land…
The military had its own reasons for determining location…
Identify targets
Friendly fire issues
“smart bombs”
Before we had GPS, there were various other tools to help us determine our location. Each one of these tools had an inherent flaw.
The U.S. military was very interested in generating the capability for accurate coordinate information.

9. What is GNSS…
And how does it work?
Self explanatory...

10. What is GPS? GPS (and GNSS) is not a single UNIT!
GPS = Global Positioning SYSTEM
GPS was developed by the Department of Defense at a cost of >$12 billion
Funding for the GPS was contingent on making the system available to the public.
Self explanatory... Just read the slide The main concept to get across here, is that the GPS receiver is just one component in a larger system.

11. GPS (and GNSS) is a SYSTEM
There are three major components in this system:
Satellites
Ground Control Stations
GNSS Receivers (or units)
The three components of a GNSS system...

12. Satellites
There are satellites up there at any given time orbiting the earth at ~11,000 naut. miles.
The DOD knows the EXACT location of each of the satellites at any given moment.
These satellites have VERY accurate clocks on board.
The satellites continuously send radio signals towards earth.
These radio signals are picked up by GPS receivers.
Component #1: The satellites
Just read the slide...

13. Satellites: “A Beehive of Activity”
GNSS satellites are not geostationary. They are constantly buzzing around the earth like bees buzzing around a hornet’s nest. This is just an illustration of what the earth might look like from space with all of the satellites and space debris. Note that the satellites and debris in the image are a bit out of proportion (larger) so that we can see them better... The situation is not quite this bad!
Satellites: “A Beehive of Activity”

14. GPS Control Stations There are five control
stations that monitor the satellites.
Control stations enable information on Earth to be transmitted to the satellites (updates and fine turning).
Control stations continuously track satellites, and update the positions of each satellite.
Without control stations, the accuracy of the system would degrade in a matter of days.
Component #2: Control stations
It is not a coincidence that many of the control stations are on remote islands. The security of the GPS constellation relies on these control stations.

15. GPS Receivers GPS units are referred to as “receivers”.
They receive information (radio signals) from satellites.
The GPS receiver knows how
long it takes the signal to travel
from the satellite to the
receiver.
Component #3: GPS receivers
These are similar to radios, they receive information... They do not “send” information. The GPS receivers that we purchase at Target do not transmit data... So the government can not “track you” if you have a GPS receiver. You can be tracked using a cell phone, but not a GPS receiver.

16. GPS Receivers
The GPS receiver knows how long it takes the signal to travel from the satellite to the receiver.
The Receiver is therefore able to calculate its distance from the satellite.
Distance = time x velocity
Distance = time x 186,355 mi./sec.
The receiver can calculate the time that signal traveled from the satellite to the receiver.
The receiver is therefore able to determine its exact distance from the satellite.
The key to the GPS system is accurate clocks. The GPS satellites have very accurate atomic clocks on board. The GPS receiver has a clock in it as well. Through a couple of tricks, the GPS receiver calculates the amount of time that it takes the signal to leave the satellite, and arrive at the GPS receiver. The receiver then multiplies this time x the speed of light to determine how far away the receiver is from that particular satellite. Accurate clocks are everything...

17. How GPS (and GNSS) Works
One satellite…
This is what happens when the GPS receives a transmission from one GPS satellite... (continued next slide)

18. How GPS Works If the GPS receiver only obtains signals
from 1 Satellite, then it “knows” that it
is located somewhere on this sphere…
Self explanatory... A GPS receiver must receive a signal from more than one satellite in order to acquire an positional “fix”

19. How GPS Works
This is what happens when a GPS receiver acquires information from two satellites

20. How GPS Works If the GPS receiver only obtains signals from 2
Self explanatory.... A GPS receiver must acquire information from more than 2 satellites in order to acquire an accurate positional fix...
If the GPS receiver only obtains signals from 2
satellites, then it “knows” that it is located
somewhere where these 2 spheres intersect

21. How GPS Works
This is what happens when a GPS receiver acquires information from 3 satellites...

22. How GPS Works
If the GPS receiver obtains signals from 3 satellites, then it “knows” that it is located somewhere where these 3 spheres intersect (2 points)
Read the text, self explanatory...
Keep in mind that one of these 2 “coordinate points” may be located somewhere out in space (or on the moon!). So due to the process of elimination, the GPS receiver can provide coordinate information based on 3 satellites
However, a 4th satellite is required to generate elevation data

23. How GPS Works
Here we go.. 4 satellites

24. How GPS Works
A fourth satellite is required to determine the exact location and elevation.
A fourth satellite is required to determine the exact location and elevation.

25. What do you need to know about GNSS?
Self expanatory

26. Different “Grades” of GNSS receivers
Recreational Grade GNSS
Accurate to within 5 meters (could be better, but don’t rely on it)
Suitable for hunting, recreational, and some business uses
Lowest cost (smallest, and easiest to use): ~$100-$800
Mapping Grade GNSS
Accurate to within 1 meter (3 feet)
Requires differential processing (from a base station)
Suitable for many natural resource applications, city planning
$800-$7,000
Survey Grade GNSS
Accurate to within 1 cm
Suitable for building bridges…
$15,000 -$30,000
Basically, you get what you pay for... However, every application does not require sub centimeter accuracy. The trick to identifying which GPS is best for you, is to identify “what you are going to do with it”, and identify what levels of accuracy you can live with.

27. What you need to know about GNSS?
Signal Accuracy Issues
Selective Availability
Tricks of the Trade
Current Applications of GNSS
Future applications of GNSS
Self explanatory

28. GPS: Signal Accuracy There are 2 types of GPS Signals:
P-code: (“Precise” code)
This is only available to the military and some selected public officials.
Very precise, not degraded.
C-code: (“Civilian” Code).
Less precise
Signal can be degraded (by scrambling the signal) especially in times of conflict.
This is what the GARMIN receivers (and all public GPS receivers) work with…
There are two types of GPS signals. P-code is only available to the military. C-code is available to everyone else. GPS receivers that are purchased by the public rely on C-code

29. Correcting for errors: Selective Availability
It is possible to correct for inherent signal errors.
This process is called Differential Correction
Here’s how it works…
There are ways to correct for SA and for other signal errors = Differential Correction!

30. Differential Correction
There are already established base stations established around the U.S.
Surveyors have determined the precise location of these base stations.
Each base station has a GNSS receiver, which collects incoming (error prone) signals.
The true (surveyed) location coordinates are then compared to the GNSS coordinates.
The correction values are then:
Posted to the web for later correction (post-processing);
sent to other GNSS receivers in the field (correction ‘on the fly’).
Read the text

31. Differential Correction
Base station w/ GNSS
receiver at known location:
Differential Correction
Signal
This is an illustration that shows how Differential Correction works. Farmers out west use differential correction so that they can manage their fields in a more efficient manner (precision agriculture). As a side note, almost every French fry that you consume is a product of precision agriculture! The airline industry uses differential correction both on the ground and in the air to support airline safety. Local, state, and federal government agencies use differential correction to improve mapping and inventory efforts. And researchers use differential correction as well.
Base stations are most often not ‘towers’. They are often located on the roof of buildings. They may appear like radio antennae.
GNSS receiver in the field
collecting points, routes, etc.
Exact known (surveyed) coordinates differ from GNSS coordinates at this location = exact amount of error!

32. WAAS
The Wide Area Augmentation System (WAAS) is a differential GNSS system that is being constructed to support GNSS accuracy in aircraft.
WAAS also provides additional accuracy “on the ground”
The GNSS receivers that we are using are WAAS compatible
WAAS was developed through the FAA.
One item to note about WAAS. In the event that WAAS is “turned on” in your GNSS receiver, but no WAAS satellites are visible, then the accuracy of your GNSS receiver will actually DECREASE. WAAS should only be used if a WAAS satellite is visible.

33. WAAS Most (but not all) GNSS receivers are WAAS compatible.
WAAS satellites are different satellites from the GNSS satellites. This is how the WAAS system works:
You GNSS receiver receives a signals from at least 4 GNSS satellites, and calculates your position
At the same time, a WAAS ground station (hopefully nearby) receives signals from GNSS satellites, and calculates the position of the ground station for that particular second in time (remember, that satellites are constantly on the move, and there are other factors that will influence the accuracy of GNSS signals at any given point in time...)
The WAAS ground station compares the GNSS derived position, with it’s exact (surveyed) location. It then calculates a correction. This correction is transmitted to the WAAS satellite.
The WAAS satellite then sends the correction information down to your GNSS receiver. Your GNSS receiver corrects the coordinate locations derived from the GNSS satellite constellation (based on the WAAS correction information). This is all transparent to the user, and happens “on the fly”.
The final product should be a more accurate GNSS locational calculation!
Note that a WAAS satellite must be “visible” (not physically visible, but your GNSS receiver must be in communication with the WAAS satellite) in order for all of this to work...!
Most (but not all) GNSS receivers are WAAS compatible.
95% of GNSS receivers on the market today are WAAS compatible
The GARMIN Venture HC is WAAS compatible

34. Other Tricks of the Trade: Averaging
Averaging: A GNSS receiver can collect points continuously for seconds. The receiver can then average all these locations together
This only works when you are standing still!!
Note that not all GNSS receivers have an averaging capability
Averaging positions can increase accuracy. The line of thinking here is that the average error of many points collected at the same place, is likely smaller than the individual error of a single point.
GNSS Collected Points
GNSS Averaged Position
“True” location

35. Other Tricks of the Trade: Satellite Distribution
It is better for your receiver to get a fix on “distributed” satellites, then poorly distributed satellites.
“Positional Dilution of Precision”
Good
Satellite
Distribution
The good news is that GNSS receivers will identify the constellation of available GNSS satellites that will provide the highest degree of accuracy.
Poor
Satellite
Distribution

36. GNSS planning software...
Trimble offers a free software package that provides users with the ability to pick a location, a date, and time, and the software will determine the availability of satellites for that given period and location.

37. GNSS Satellite Visibility: Blacksburg July 12, 2012
This is an example of the satellite visibility charts look like using Trimble’s GNSS Planning software. In this example, the best time to conduct GNSS-supported field work would be between 4:30 – 6:00, as there would be more (12) satellites available. You might want to avoid working between 10:00 am and 11:30 am (and then around 8:30 pm) as there are fewer satellites available during these time periods.

38. Other Tricks of the Trade: MultiPath Errors
Try and stay away from buildings and other structures when using a GNSS receiver
Satellites may not be visible…
This can introduce error…
Since “time” is the critical component that makes a GNSS work. If any object increases (even by an nanosecond...) the amount of time that it takes a GNSS signal to travel from the satellite to the receiver, then error will be increased. The bottom line, try to stay away from buildings
and other structures, large tree trunks, rock faces, etc. if at all possible.
Also structures tend to “hide” satellites from view. If a satellite is passing behind a structure, then it may not be visible to the GNSS receiver.
Another note of caution... Keep your fingers off of the GNSS antennae. If you finger is on the antennae, then you are limiting your exposure to GNSS satellites (which may result in increased error).

39. Other Tricks of the Trade: Tracking Satellites
GNSS has worldwide coverage… HOWEVER… You can lose satellite coverage (or received degraded signals) in areas with dense foliage, in “urban canyons”, etc. You may also lose satellite coverage (or receive degraded signals) in deep valleys or gorges.
Pretty self explanatory

40. Accuracy How accurate is a $150 GNSS?
That’s the million dollar question…
Everyone wonders “how accurate” their GNSS receiver is. There’s really no single answer to that. It depends on a variety of considerations, including:
The make and model
The satellite constellation at that particular point in time
Buildings, tree canopy coverage, and other factors
WAAS availability
And just plain old luck!

41. How accurate is a $150 GNSS? (It depends…)
This is a good reference when working with accuracy issues
Acknowledgements: Dr. Phillip Rasmussen, Utah Geospatial Extension Specialist

42. Brand “A” Day 1
Brand “A” Day 2
Brand “A” Day 3
Brand “A” Day 4
Brand “A” Day 5
Brand “B” Day 1
Brand “B” Day 2
Brand “B” Day 3
Brand “B” Day 4
Brand “B” Day 5
At Virginia Tech, Dr. Prisley and a graduate student benchmarked a couple of recreational-grade GNSS receivers (priced about $150). “Brand A” was a more expensive receiver that supported positional averaging. “Brand B” was a very basic “entry level” recreational grade GNSS receiver (very similar to the GNSS receiver that we will be using today....). The student visited an array of benchmarks for 5 days, at 10:30 am each day. He held a GNSS receiver (brand A and brand B) in each of his hands and collected Waypoints for 5 consequtive days (and at the same time of day). The tan dots represent the benchmarks where the data were collected. “Brand A” data is shown in hues of green, and data collected with “Brand B” is shown in hues of blue.

43. Surprisingly, “Brand B” outperformed “Brand A” (in terms of accuracy), even though Brand A data was supported by averaging, and Brand B was not. It is suspected that Brand B perhaps had a better antennae, GNSS Chip, or algorithm.

44. GNSS Data Collection Waypoints Tracks Routes Find/GOTO And more..!
Now we are going to explain different data collection options with a GNSS...

45. What can you do with a GNSS?
Collect and store points (positions)
These are called WayPoints.
Field corners, insect infestation areas, crop damage, individual trees, trail heads, creek crossings, point source pollution, camping sites, and don’t forget “your car”!
Download the points onto your computer and integrate them with other mapping programs

46. Waypoints Corner2 Point3 Latitude: 37° 16’ 18” Longitude: W80° 28’ 45”
Elevation: feet
Waypoints can be considered to be “virtual flags”. Each waypoint has a name associated with it (by default, names are usually 001, 002, etc), a lat./ long. coordinate system, a time/date stamp, elevation, and other information. Customized interfaces (pull down menus, radio buttons, etc) can be developed on tablets, pocket PC’s, smartphone devices, etc. to support efficient data collection.
001

47. What can you do with a GNSS?
Collect and store the path that you have walked / driven
These paths are called TRACKS.
Calculate the distance of a track (i.e. perimeter around a field)
Calculate AREA measurements within a TRACK (after walking around a field or parking lot...)
Save and Download TRACKS onto your computer.

48. Tracks (just start walking…)
What
This is what a Track looks like. It would, for example, be difficult to calculate the area of this field if you did not have a GIS or other mapping application. With a GNSS, you can calculate the area “on the fly” by walking around it.
Question #1: Why would a farmer want to know the area of a field?
Question #2: Why would someone want to know the area of a parking lot?
If you had this information, how could it support decision making?
The little red box denotes an area that we’ll zoom into in the next slide.

49. Tracks (just start walking…)
Each track point has important information associated with it...
“Virtual bread crumbs”
Track points can be collected:
Based on a time period (every 10 seconds)
Based on distance (every 20 feet)
Or a combination of time and distance (every 10 secs. or 20 feet, whichever comes first).
Latitude: 37° 16’ 18”
Longitude: W80° 28’ 45”
Elevation: feet
Time: 13:22.15
Date: 05/08/2009
A track is actually comprised of individual “track points” (not a line). You can think of a track point as virtual bread crumbs that are “dropped” as you walk, run, or drive. You do need to be sure that the “track log” is turned on in your GNSS receiver. If not, then your GNSS will not collect any track points.
Each track point contains an array of information associated with it, including:
Lat./Long.
Elevation
Time
Date

50. Tracks You can “track your way back...”*
You can use the track data to estimate area / perimeter*
You can use the time stamp in the trackfile to “georeference (or geotag)” photographs!*
Tracks are very powerful. We’ll get into some of the uses and applications of GNSS derived track data later!
* We’ll do this later!

51. What can you do with a GNSS?
Collect and store ROUTES
Routes are similar to TRACKS, but are created by associating a series of Waypoints
Tracks are straight lines...
Routes can be handy for measuring “square fields” and “straight lines”
You can measure the length and area (acreage) of a Route.
People often get routes and tracks confused. Routes are similar to tracks, but they are created by connecting a series of EXISTING waypoints. Thus, if you have not collected any waypoints, you can not define a route!
Routes are straight lines, tracks can be very curvy and defined.
You can determine length and area from a route.
Question #1: Can you think of a situation when collecting area / perimeter information from a route might be more efficient than from a track?

52. Routes #2 #3 #4 #1 #5 Establish Waypoints at strategic locations
This is what a route might look like. After the waypoints have been collected, you can then generate differerent scenarios based on the waypoints. Once the waypoints have been collected, these scenarios can be generated back in the office. #4 #1 #5
Establish Waypoints at strategic locations
The GNSS Receiver “Connects the dots”
Area and perimeter measurements are generated

53. Routes vs. Tracks
Yellow lines = Route Red lines = Track Red dots = Track points
This is how a route looks in comparison to a track. Notice that routes are much straighter than tracks....

54. What can you do with a GNSS?
Navigation!
The GOTO (or “Find”) function
Using the ‘GOTO’ function, the GNSS will guide you to a predefined Waypoint (you choose which one…) using an electronic compass and “pointer”
The GOTO/FIND function is like using “Autopilot”
You can program the GNSS to “beep” when you are within a certain distance of a selected Waypoint
The “GOTO” function will guide you to a predefined waypoint. This is how car navigation systems work. Keep in mind, though, that car navigation systems lead you to a user-defined destination based on a road network that is loaded into the car navigation system. The lower-end recreational grade GNSS systems do not have road a comprehesive road network databased installed, so they can not be used for car navigation...

55. What can you do with a GNSS?
Tide Tables
Many of the marine GNSS’s have built in tide tables. They provide tidal information and ranges for any date and any place…
The GARMIN Venture HC does not have tide table information…
Extra bell & whistle = extra $!
Different GNSS receivers have different bells and whistles / functions and capabilities.

56. What can you do with a GNSS?
Speed
GNSS’s calculate your ground speed as you walk, run, drive, or fly
All GNSS receivers will provide you with your speed.

57. What can you do with a GNSS?
Elevation
In addition to providing you with your latitude and longitude, GNSS provides you with elevation information. Elevation is not as accurate as X,Y information.
Some GNSS’s have built in barometric altimeters (to increase accuracy of z values). This option costs a bit extra!
As long as your GNSS receiver receives signals from at least 4 satellites, it can provide elevation information. Note that the elevation information is typically not as accurate as the lat./long. Coordinate information.

58. What can you do with a GNSS?
Measure Area / perimeter
Farmers can use a GNSS to measure the area of a pasture or a field of corn…
Natural Resource Agents can measure the area of a proposed conservation easement…
Educators (and students!) can measure the area of impervious surfaces (or green space) around their campus’s and communities...
We’ve already discussed this!

59. Current Application Areas of GNSS
Public Safety
Environmental resource management
Aviation
Military
Local planning
Surveying
Recreation
Business
The use of GNSS is permeating every sector of society. Just look at smartphone applications. A majority of these applications are based on location-based services.
Where’s the nearest ATM or coffee shop relative to my current location?
How far away is the nearest Vietnamese restaurant?
What constellation is that in the southern sky?
Where are the speed traps on this section of the Interstate?
Keep in mind that smartphones are the data base development tools of the future. Everyone with a smartphone will also be a potential data collector!
Also, keep in mind that we not only need people to USE these applications, but there is a tremendous demand for people to DEVELOP applications! This requires an understanding of GNSS, GIS and other discipline-specific needs...

60. The Future of GNSS (is bright)
Acknowledgements: Keith Clarke
The future of GNSS is bright indeed. Smartphone technology and car navigation systems have brought GNSS into the mainstream. There are a number of advances in GNSS that will further support the demand for GNSS services!

61. The Future is bright…
The DoD is in the process of upgrading the existing GNSS satellite constellation
-better coverage availability (i.e. in forested areas)
-anticipated greater accuracy (even for the recreational grade GNSS receivers)
Pretty self explanatory...

62. WAAS Satellites
Historically, some areas in Virginia have had trouble acquiring the WAAS satellite
A new WAAS satellite was launched in Fall 2006
Better coverage for Virginia = higher accuracy levels
More GNSS satellites and more WAAS satellites = better coverage and accuracy!

63. The Russian GNSS System
Is called GLONASS
Has fallen into “disrepair”.
Some new Russian GLONASS satellites are have been launched
Impacts: Potentially increased accuracy for US receivers that receive both US and Russian GNSS satellite signals (the private sector follows demand…)
Just need to keep our eye on the Russian economy (no $, no satellites!)
Not as accurate as the American GNSS system.
The Russians have been trying to upgrade their system since 1995, when the collapse of the Russian economy resulted in a disfunctional GLONASS system. Currently (June 2010) they have 21 of 24 satellites in orbit. 100% of Russia is covered, but they do not have world wide coverage yet.
On May 18, 2007, Russian president Vladimir Putin signed a decree officially providing open access to the civilian navigation signals of the GLONASS system, to Russian and foreign consumers, free of charge and without limitations. The Russian president also directed the Federal Space Agency to coordinating work to maintain, develop and enable the system for civilian and commercial needs.
Mr. Putin acquired a GLONASS-enabled collar for his black Labrador, as an afterthought of using GLONASS to monitor cattle and animals in the wild (from Wikipedia.com)

64. The European GNSS System
Galileo will be Europe’s own global navigation satellite system
More accurate than the U.S.’s current GNSS system (~4 feet)
Better coverage area than the U.S.’s current GNSS system
Compatible and interoperable with the American global positioning system (so we’ve been told...)
Was initially slated to be completed by This has been pushed back to 2014 (as of June 2010).
Intended to be more precise than GNSS or GLONASS
Lots of tensions between EU and USA during the development of the GLONASS
USA afraid that it will not be able to disengage the Galileo system in the event of an international emergency. These tensions have only escalated now that China is a contributing member to Galileo.
Europeans, Chinese, India, etc.

65. GNSS Receivers Continue to get better and better better antennae,
more efficient power consumption,
smaller
increasingly more “bells + whistles” (maps, hard drives, cameras, etc.)
Inexpensive, but the new bells + whistles keeps prices fairly stable...

66. The applications are endless…
…and keep in mind that there are ~322,000,000 wireless subscribers in the U.S. (that’s a market penetration of 101%), as of July 2012.
-Source:
GNSS supported applications are literally supporting applications that range from entertainment to food product, to emergency services, to transportation. It is impacting us in ways that we do not even know about...

67. GNSS recreational (and educational) uses Geocaching….
Geocaching is an entertaining adventure game for GNSS users.
The idea is to “hunt” for objects (prizes) that have been placed in the landscape (virtual orienteering).
Pick a prize, and leave a prize…
Self explanatory. For additional info, see

68. but Geocachcing is so passé…
But have you ever tried Geodashing?
In this game, a list of coordinates, selected at random from around the globe, is presented to all users and teams. “First one there, wins..”
Requirements:
somebody with a lot of free time on their hands,
a GNSS,
Lots of extra batteries,
a new pair of sneakers,
a passport, frequent flier miles
and your dad’s VISA Card (or a trust fund will do)….
Self explanatory.

69. Some GNSS Applications are “innovative”
Use GNSS to locate ‘the loo’!
There’s a GNSS supported application for just about everything....

70. GNSS-based buddy stalkers (oops, I mean buddy tracking)…
“add on” service
Create a buddy list and locate your pals on your Smartphone.
Is your girlfriend really at the library…?
GNSS can be used to track your friends, through buddy tracking

71. Other GNSS Data Loggers and Tracking Devices…
We all know that UPS / FedEx and the major freight haulers use GNSS…
Other folks are tracking people too!
GNSS data loggers collect GNSS coordinates, and store them on a small flashdrive...

72. Car Navigation Systems are getting into buddy tracking as well
Garmin and TomTom have well established systems in place…

73. Car Insurance companies have been eyeing this technology for years…
Pretty self explanatory.
You get reduced rates until you:
Speed
Drive on country roads
Drive at night
Drive a lot
Drive in dangerous areas
Drive too slowly
Etc.
The insurance company monitors your driving habits

74. GNSS-based tracking, routing, and fleet management
You’ve seen those trucks going down the highway with the little “round things” on the top...

75. We are not only tracking trucks...
Active tracking: real-time
monitoring...
Passive tracking:
provides a history..
Active GNSS personal monitoring tracking device allows you to monitor a vehicle at all times. You can see where it is in real time. You can also look at history; where the vehicle was, how long it was there, how fast it was going. Active GNSS tracking can notify you if the vehicle is involved in an accident or if it leaves a specific geographic area.
Passive tracking – passive tracking system records the history of a vehicle. That history can later be downloaded and reviewed. You cannot locate a vehicle in real time with a passive system. It does tell you where a vehicle was and for how long and the speeds at which it was traveling.

76. Example of passive tracking
Rocky Knob Economic Development and Tourism Study

77. Tourist Surveys: Linking GNSS with “traditional surveys”
Rocky Knob, Virginia study used passive tracking to better understand where tourists were spending their time. GNSS surveys were combined with paper surveys
Tourist Surveys: Linking GNSS with “traditional surveys”

78. This is the passive tracking device, a GlobalSat GNSS
This is the passive tracking device, a GlobalSat GNSS. It costs approximately $70. These devices were distributed to tourists (with their consent, of course). The tourists placed the devices on the dashboard of their cars. At the end of their trip, the tourists mailed the GNSS tracking devices back.

79. Results
490 visitors contacted over 4 data collection periods (July, August, September, and October). 
323 agreed to participate (Response rate of 65.9%)
Of these 323 visitors, 312 visitors have returned a survey/GNSS unit (Secondary response rate of 96.6%)
Tremendous response rate using the GNSS surveys~!

80. . How many hours did you spend planning your trip to Floyd
Table 1 6
. How many hours did you spend planning
your trip to Floyd
and Patrick Counties?
Frequency
Percent 30
10.9 %
0.1 – 1
193
70.4
1.1 2 28
10.2
2.1 3 9
3.3
3.1 4 5
1.8
More than 4
Mean = 1.0
Median = 0.5
SD = 1.5
Note that 80 % of the tourists stated that they used 1 hour or less to plan their trip  the emergence of GPS smartphone devices and location-based services powered by GPS.

81. Tourist surveys
Pat. + Floyd Co. GPS Map
Summary of tourist GPS data

82. Take into account existing traffic and tourist visitor patterns
Site Location:
Take into account existing traffic and tourist visitor patterns
There’s a high correlation between the VDOT traffic count map and the GPS tourist surveys…
Tourist survey

83. Car navigation is not “dummy proof”!

84. GPS Fights Crime!
Self explanatory...

85. Self explanatory...

86. The Degree Confluence Project
The "world's largest distributed expedition project“.
Goal: to visit each of the latitude and longitude integer degree intersections in the world, and to take pictures at each location.

87. GNSS related careers Agriculture Conservation managers
Wildlife technicians
Surveying companies
Local governments
State agencies
Federal agencies
The military
Law enforcement
Real estate
Software programmers
Basically, any profession that
requires data collection “in the field” can benefit from using GNSS.
The applications are limited only to your imagination...
And evidence of this can be found on the GNSS based applications developed for SmartPhone devices)

88. There’s a Variety of Software Products Available to Support GNSS
GPS Utility (free)
DNR GPS (free)
USA PhotoMaps (free)
RoboGeo (demo version and $75 version)
Terrain Navigator (~$89)
Data cards (topos, etc.) and aerial photography subscriptions for your GPS receiver
And just think about all of the 1000’s of Smartphone applications (Urbanspoon, etc.)

89. Things to keep in mind...
GNSS can serve as an accurate data collection tool for GIS applications;
GPS applications are becoming increasingly prevalent in our society, and support a variety of applications;
With GNSS receivers, you (more or less) get what you pay for (w/ prices ranging from $20, $59);
This technology is CURRENTLY used to support govt. services / private businesses;
Smartphone apps. are going to make all of this “take off”
Knowing how to use a GNSS does not make you a surveyor!!!

90. Any Questions?