SII M2 Navigation Theory GPS

2. SII M2 – Navigation TheoryGPS

3. YSSR GPS Course - Outline Start: 0900 Classroom session Introduction to GPS Brief history of development System components How does it work? What can it do for us What can it NOT do for us Coffee Break

4. YSSR GPS Course - Outline Positioning/Mapping review Mapping systems/projections MGRS positioning example and exercises Common mapping/GPS terminology Typical GPS receiver specifications and features Screen examples from selected GPS units GPS Mapping Demo (OziExplorer)

5. YSSR GPS Course - Outline GPS Set-up exercise Datum, units, format, etc. Waypoint entering/retrieval exercise General questions and answers Lunch Break: 1200 to 1245 Map Exercise: 1300-1400 Brief Outside Exercise Write GSAR exam 1500 hrs

6. GPS - Introduction What is the Global Positioning System? Space-based, worldwide radio-navigation system Uses a constellation of 24 satellites (plus spares) in geosynchronous orbits, and a network of ground control stations. Free access, highly accurate positioning data is available to GPS receivers anywhere in the world.

7. GPS Constellation

8. GPS – Brief History Developed (and owned) by the US DOD In development since the early 1970’s First satellite launched in 1978, full constellation by 1994 Originally intended to be a military tool 2 levels of service Standard Positioning Service (SPS) Precise Positioning Service (PPS) Public uses SPS. Selective Availability (SA) limited accuracy of SPS SA removed by Clinton in May 2000

9. GPS: 3 Segments

10. GPS – Segment Components Space segment (Satellite Vehicle – SV) 2 tonne weight, 12m solar panel wingspan 4 Atomic clocks 10 year design life Several generations of satellites now in orbit Assembled by several US Defense Contractors, first ones by Lockheed Martin Corp.

11. GPS Space Segment: SV

12. GPS Ground Segment: Control Master control station is at Schreiver AFB in Colorado. Defense contractors maintain a duplicate ground control station, which is activated semi-annually to ensure readiness. Monitor satellite health, positional accuracy, transmit correction and information updates to satellites. 4 unattended monitoring stations also relay data to master control station and SV’s.

13. GPS Ground Segment: Control

14. GPS User Segment: US! Any one of dozens of forms of passive GPS signal receivers configured to receive either SPS or PPS frequencies. Receivers can be as small as a watch, but are more commonly a hand-held, 12-channel receiver with a built-in antenna. SPS is free and available to anyone, 24/7.

15. Handheld GPS Receivers Garmin Venture Cx ~$229 (+ Memory Card) Garmin Rino 530 ~$ 500 Garmin 76csx $459 Survey Grade Units >$5,000

16. How Does GPS Work? 1 Uses “satellite ranging”. Satellites travel in predictable paths (i.e. we can predict where they are in relation to any point on the earth at any time) Radio frequency signals travel at a predictable (and constant) speed – the speed of light. GPS receivers are programmed with the general positions of the satellite constellations, and their identifier data.

17. How Does GPS Work? 2 SV’s constantly transmit a stream of coded signals at low power. Signals include timing data that receivers can compare to predicted timing data programmed in their memory. By determining the time difference in the predicted vs. the actual signals, and multiplying by the speed of light, a distance to a satellite can be determined.

18. How Does GPS Work? 3 When the distances to at least 3 satellites are known, a 2-dimensional position can be determined. Altitude is unknown in a 2-d position. When 4 or more SV’s are resolved, 3-d positions are possible (allows more accurate elevation determination) More SV’s are better for improving position accuracy.

19. How Does GPS Work? 4

20. How Accurate Is It? SPS accuracy advertised to be +/- 15m, 95% of the time. Many schemes to improve GPS accuracy Differential GPS Requires separate receiver WAAS (North America) Not very effective inland NB with tree cover EGNOS (European WAAS)

21. Errors – yes, there are some Sources of Errors Satellite errors (clock, orbit and control) Accidental/Intentional signal jamming Ionospheric/atmospheric interference Multipath signals Poor satellite geometry (DOP) Shading/poor overhead visibility Receiver clock errors Carbon interface errors… MOST COMMON.

22. What Can GPS Do for You? Can provide you with your current position, anywhere and at any time, with a reasonable degree of accuracy. Can display a line of past positions (a track) and store them. Can store a large number of known locations (waypoints) and provide a range and bearing to any one of them. Can give real-time estimates on your progress to or from a known location (range, bearing, ETA, etc.) Can provide an estimated altitude, and can keep accurate time.

23. Something to note……..

24. What Will GPS NOT Do for You? Will NOT give you much useful data without a suitable MAP. GPS will NOT replace map and compass skills Will NOT necessarily give an accurate indication of magnetic north, or current heading. Will NOT assist you home unless you can tell it where home is in a way it can understand. Will NOT be accurate over short distances (less than 15m) Will NOT be any use without sufficient battery power (consider cold temps) or a clear enough view of the sky. Will NOT replace common sense.

25. GPS Requires Extra Vigilance! IN SEARCH AND RESCUE WORK, AND IN MOST OUTDOOR ACTIVITIES, GPS WILL NOT REPLACE MAP AND COMPASS WORK, AND CAN REQUIRE MORE VIGILANCE IN NAVIGATION THAN LESS. GPS is only one more tool, and it must be used carefully, along with all other tools available for navigation.

26. Do we need a 15 min break ?

27. Positioning/Mapping Review 1 When we discuss our ‘position’, we always use some form of reference frame. We do this automatically: “I’m about 10 feet in front of you”; or “He lives next to the Tim Hortons”; or “I’m at Grid reference ” 19 FL 81935 902937 The last statement uses a Grid reference – an artificial grid of lines drawn on a map to provide a standardized reference frame for all users.

28. Positioning/Mapping Review 2 There are many reference frames used around the world, some will be familiar with Latitude and Longitude, but that is only one of dozens. Hiking - UTM (Universal Trans Mercator) grid reference system, since it is over-laid on all topo maps, and is widely accepted for terrestrial operations. Easy and efficient to use in the field. MGRS (Military Grid Reference System) is a version of the UTM grid that is even easier to use. Now adopted by YSSR/TCGSAR YSSR members will be able to set GPS unit to read Latitude & Longitude as required for Aircraft and marine operators. Maps are by necessity flat representations of the curved surface of the earth. They use “Projections” to approximate the curves of the earth’s surface. Mercator projections “peel back” the curved surface of the earth, and represent areas as flat “Zones” on maps.

29. YSSR Mapping Review Transition From: Forest Inventory (Traditionally Lat & Long) To: Forest Inventory- Custom (via UTM /MGRS Grid overlay) Also use Digital Maps: - SNB Orthophoto series (NAD 83, stereographic double projection, 1:10,000 scale) Garmin Topo Canada (user can set preferences) eTopo Series Canada Other digital maps as they become available

30. UTM / MGRS Grid Zones Of The World

31. UTM / MGRS Grid Zones Of The World

32. UTM / MGRS Grid Zones Of The World

33. Positioning/Mapping Review 4 LL UTM zones of Canada

34. Positioning/Mapping Review 5 One UTM zone segment, showing the central meridian and shape of the segment. New Brunswick is half 19 and half 20

35. Positioning/Mapping Review 3

36. Positioning/Mapping Review 6 Horizontal lines measure northing Vertical lines measure Easting. UTM positions are read Easting first, then Northing.

37. Positioning/Mapping Review 7 The Northing numbers mean actual distance North of the equator. Since Canada’s Southernmost point is over 4,620,000 m north of the equator, all Northing figures will be above this number. The Easting numbers measure from an imaginary line 500,000 m to the west of the zone’s central meridian. This means that lines to the left of the central meridian will be lower than 500,000, and those to the right higher.

38. Positioning/Mapping Review 8 Why do we care about all these numbers? Because all GPS units are configured to work with multiple reference frames, anywhere in the world. They give far more information than is required for local navigation. Practically, this means YOU must be able to configure a GPS to work correctly in YOUR zone (with your maps) and be able to extract the important numbers from a position screen.

39. Positioning/Mapping Review 10 Once a grid system is chosen, That system must itself be referenced to the land-masses shown on the maps. This refers to the DATUM of the topographical map you are using. DATUM is the set of survey data used to create the map. It is shown on the map, in a title block. It is critical that your GPS be set to use the same DATUM as your map!

40. Positioning/Mapping Review 11

41. Positioning/Mapping Review 11

42. Positioning/Mapping Review 12 Incorrect datum settings can result in errors in position of hundreds of meters. CHECKING and setting the position format (UTM) and the DATUM (usually NAD 83, or NAD 27) is the first thing to do EVERY time you turn on a GPS.

43. Positioning/Mapping Review 13 Typical position read-out from a GPS. Note the ‘UTM’. Note the UTM Zone designator, 19-T. Note the 14 digit position read-out!

44. Positioning/Mapping Review 14 These are the numbers we are interested in. Our position would be read as “0683676” “5098786”

45. Positioning/Mapping Review 13 Typical position read-out from a GPS. Note the ‘MGRS’. Note the UTM/MGRS Zone designator, 19-T. Note FL Grid ID Note the 10 digit position read-out!

46. Positioning/Mapping Review 14 These are the numbers we are interested in. Our position would be read as “65207” “89453”

47. Positioning/Mapping Review 14

48. GPS Navigation Terms 1 UTM Universal Transverse Mercator (grid), or our common reference frame. Datum The set of survey or mapping data that were used to create a topographical map. SV’s Space Vehicles, or GPS satellites.

49. GPS Navigation Terms 2 Position (POS, POSN) Your current location, given in reference to a chosen grid system. Waypoint/Landmark (WPT, LMK) A location described by a name and a grid reference. Bearing (BRG) The angle, in degrees, from magnetic North between your current position and a waypoint.

50. GPS Navigation Terms 3 Range (RNG) The straight-line distance between your current position and a waypoint. Track (TRK) A group of past positions, strung together in sequence, showing a relative path.

51. GPS Navigation Terms 4 Heading (HDG) Your current direction of travel EPE Estimated Position Error XTE or CTE Cross-Track Error ETA, TTG Estimated Time of Arrival, Time To Go

52. Typical Hand-Held GPS Receivers 12 - Channel parallel receivers now universal Water resistant, if not submersible. Rugged cases with built-in antenna. 12-30 hrs operation on batteries. Capable of external power and data transfer. Most have basic mapping capabilities. Various added features: Digital compass, altimeter, databases, etc.

53. General Usage Tips: ALWAYS check setup and clear track log. Be patient - allow unit to lock on to 4 or more satellites before using data. ALWAYS save your starting point (Command Center, trail head, parked car, etc.). Pick a unique starting point that can be found visually from 40 - 50m away. Clear the track log before starting on a task. Keep batteries fresh and keep GPS warm. Update firmware/software when possible.

54. Hand-Held GPS Units Number and ID of SV’s received Indication of signal quality Estimated position accuracy

55. Hand-Held GPS Units

56. Garmin 76 5 Main pages

57. Hand-Held GPS Units All have system and navigation set-up screens

58. Hand-Held GPS Units All have basic position/navigation screens

59. Hand-Held GPS Units Waypoints are stored with a symbol and a name. Once a waypoint is selected, it may be used to create a “go to” screen.

60. Hand-Held GPS Units Pressing “enter’ will set up a “go to” screen, automatically giving a range and a bearing to the chosen waypoint. Waypoint features may also be edited in this screen.

61. Hand-Held GPS Units Note that the “compass” is not really a compass. It tells you your current heading. This is only accurate when you are moving.

62. Hand-Held GPS Units …Unless you have a built-in Digital Compass, and it is calibrated, and turned on. Note that most must be held level as well.

63. Hand-Held GPS Units Some have a base map showing basic features. Some units allow topographical information to be displayed.

64. GPS Map screens

65. Map screens

66. Map screens – Killarney Lake

67. Killarney Lake - Waypoints

68. GPS Mapping YSSR is now using downloaded tracks from teams returning from taskings. Confirms ACTUAL path and assists in continued Search Management process Updated PODs, elimination of areas, identifies new tracks/trails not on maps, etc. Many recreational software mapping packages available. OziExplorer, Fugawi, Touratech QuoVadis, etc.

69. GPS Mapping Magenta line is recorded track

70. GPS Mapping Close-up of track resolution

71. GPS Mapping Switch to OziExplorer for Demo - GM

72. GPS Hands-On Exercise Turn on GPS units. Check Datum Check position format Check units Clear tracks, and clear unwanted waypoints. Reset trip odometer

73. GPS Hands-On Exercise Settings should look similar to these:

74. Hand-Held GPS Units All have basic position/navigation screens

75. GPS Hands-On Exercise Program the following waypoints into your GPS 82026 92945 (name it waypoint – loc 1) 81851 92945 (name it waypoint -loc2)81725 92914 (name it waypoint - loc3) 81867 92846 (name it waypoint loc4) - Map Datum - WGS 84- Position Format - MGRS

76. Positioning/Mapping Review

77. GPS Hands-On Exercise ALWAYS check setup and clear track log. Be patient- allow unit to lock on to 4 or more satellites before using data. ALWAYS save your starting point (Command Center, trail head, parked car, etc.). Pick a unique starting point that can be found visually from 40 - 50m away. Clear the track log before starting on a task. Keep batteries fresh and keep GPS warm. Update software when possible.

78. Now, out of the classroom