Groundpounders

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• Groundpounders
• GPS COURSE
• for
• CASARA
• Langley Muir
• MAY 2008

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Outline Session 1

• Introduction to GPS
• Theory
• Practical work with Garmin 76CSx

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Outline - Session 2

• Practical Navigation Exercises
• ESS teams
• Car and ground based Rally.

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Overview

• We assume that you have completed the map and
  compass course and are PROFICIENT.
• Lots of theory and you will not retain it all.
• Practice, Practice, Practice

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GEOGRAPHIC POSITIONING SYTEMS
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Overview

• Satellite based.
• Geodetic accuracy, ie to cm.
• Presently under the control of the US Military.
• Susceptible to jamming, errors, and a multitude
  of electronic problems.

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Satellite Orbits
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Global Coverage
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Satellite Triangulation
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GPS Errors

• The individual values are not constants, but are
  subject to semi-random variation and all are
  approximate values.
•  
• Shifts in the satellite orbits 2.5 meter
• Clock errors of the satellites' clocks 2 meter
• Multipath effect 1 meter
• Calculation and rounding errors 1 meter
• Ionospheric effects 5 meter
• Tropospheric effects 0.5 meter
• Altogether this sums up to an error of
   15 meters. Corrections by systems like WAAS and
  EGNOS mainly reduce ionospheric effects, but also
  improve orbits and clock errors, so that the
  overall error is reduced to approximately
   3 - 5 meters.

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Atmospheric Effects

• Ionospheric effects are magnetic, due to
  ionization.
• Tropospheric effects are mainly due to water
  vapour.
• Wet foliage is a major source of error.

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WAAS

• The Wide Area Augmentation System (WAAS) was
  developed by the Federal Aviation Administration
  to augment the Global Positioning System (GPS)
• WAAS uses a network of ground-based reference
  stations, located in North America and Hawaii, to
  measure small variations in the GPS satellites'
  signals in the western hemisphere. improving its
  accuracy, integrity, and availability.
• Measurements from the reference stations are
  routed to master stations, which generate and
  send the correction messages to geostationary
  WAAS satellites. Those satellites broadcast the
  correction messages back to Earth, where
  WAAS-enabled GPS receiver uses the corrections
  while computing its position to improve accuracy.
• The International Civil Aviation Organization
  (ICAO) calls this type of system a Satellite
  Based Augmentation System (SBAS). Europe and Asia
  are developing their own SBASs, the Indian Gagan,
  the European Geostationary Navigation Overlay
  Service (EGNOS) and the Japanese Multi-functional
  Satellite Augmentation System (MSAS),
  respectively. Commercial systems include StarFire
  and OmniSTAR.

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Doubling of Errors

• Error in original waypoint -- /- 15m
• Current error on GPS -- /- 10m
• Total error possible /- 25m.

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Bottom Line Accuracy

• GPS plus WASS accuracy is
• Guaranteed to 7.6 m, 95, (x,y,z)
• Typical, 1m (x,y) and 1.5m (z).
• Map and Chart Accuracy is
• 1250k charts are accurate to 250m, 90
• 150k charts are accurate to 50m, 90

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GARMIN 76CSx.

• This is the unit in the gun cases
• Many of us own the same unit
• SG1 uses the Garmin 60CSx??
• Generally the same functions.
• Always carry the manual!!
• Practice, Practice, Practice

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Basic Cautions.

• Always
• Put fresh batteries in the unit before startup.
• Remove batteries when storing unit.
• Ensure that you have extra batteries in your
  pocket, ready to replace the dead ones.
• Keep it warm and dry never get it wet or cold.
• Keep it firmly attached to your body.
• Dont put it down anywhere.
• MAKE SURE YOU HAVE A PLAN B.

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Plan B

• Keep track of the status of the battery charge.
• Keep lots of spare batteries available Have a
  notebook and pencils
• write everything down!
• Always have a watch, waterproof map, compass, and
  pace beads.
• Keep track of where you are on the MAP.
• NEVER BET YOUR LIFE ON ANY ELECTRONIC GEAR

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Essential Setup

• Make sure everyone is on the correct
• Datum (normally NAD27 or WGS84)
• Co-ordinate system (Lat-long, UTM, MGRS)
• Time (Zulu or local)
• Units (nm, statute miles, kilometers)
• Bearings (True or Compass)
• Make sure you are recording the TRACK.

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Garmin 76CSx
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Garmin Keypad
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Garmin 76CSx - Main pages

• Welcome - who owns the thing
• Satellite - how many satellites, how good
• Trip Computer statistics of trip
• Map where we are on the map
• Compass what direction is what, off course
• Altimeter how high are we, barometric pressure
• Main Menu set up everything

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Satellite page

• Receiver status and signal strength
• Location and accuracy
• Satellite location - pictoral
• Heading bug

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Satellite Menu Page

• GPS on or off
• Track up or Track North
• Mulitcolour for satellite bars
• New location if you have moved more than 600 km
  or cannot locate satellites
• Elevation (does not stay on)

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Map Page

• Can put in all sorts of map bases.
• Position mode keeps your position in the centre
  of the map field
• Can pan the pointer using the rocker
• Can put data on this page, but uses up screen
  area.
• ZOOM is most useful feature.

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Map Menu Page

• Stop navigation removes route
• Recalculate recalculates route data
• Data Fields sets up data fields on map
• Guidance text will prompt if following route
• Setup map customize map features
• Measure distances using pointer on map
• Declutter map and restore defaults.

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Compass Page

• Compass needs to be calibrated.
• Generally not of much use at walking speeds.
• Very sensitive to level

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Altimeter Page

• Shows current altitude, rate of ascent/descent,
  and profile.
• Not much use in this area for hiking.
• Needs to be calibrated
• Relies on Barometric pressure, not calculated
  altitude!!

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Main Menu Page

• Does much of the setup.
• Can get there by using enter twice.
• Need to use
• Tracks
• Routes
• Setup

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Tracks

• Clear out old track
• Make sure that Track Log is ON.
• Save the track at all rest points.
• Download the track ASAP and save in case it
  becomes part of legal proceedings.
• CASARA to Bill Dunn
• SG1 To Marc Desrosiers.

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Trackback

• Go to the Tracks page
• Highlight the track you want to follow
• Use rocker to move pointer to the place you want
  to get back to and press enter
• Decide if you want to follow roads or not.
• To stop, press menu and select stop navigation

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Routes

• Make up routes by selecting a series of
  waypoints.
• If there is a saved route you can follow it.

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Setup

• Need to check this once per trip.
• System WAAS enabled, battery types.
• Display day/night, backlight timeout and level.
• Routing follow roads or not.
• Time UCT, Local, ??
• Units Position format, datum, distance
• Heading units, true/magnetic
• Calibration compass, altimeter.

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Waypoints

• A waypoint is a position or landmark which you
  can use for navigation.
• Can be created in your GPS by 3 methods.
• Mark current location.
• Use the map
• Enter the co-ordinates.

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Find Stored Waypoints.

• Press find, the select waypoints

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Mark Current location

• Hold the Enter/Mark key until the waypoint page
  appears.
• To accept it highlight OK and enter
• To edit
• Highlight the appropriate field and press
  enter to open the onscreen keypad.
• Save the info - highlight OK and enter

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Waypoint Using the Map

• Use the rocker to get the pointer to the desired
  location.
• Press enter to get to Waypoint page for item.
• Edit entry as required, and SAVE, see it centred
  on the map, or GO TO.

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Waypoint Using Co-ordinates

• Press enter to get to the location page.
• Edit the position, name, and anything else.
• SAVE.

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To Use Waypoints

• Press find
• Highlight Waypoints
• Scroll down use keyboard to waypoint
• Press enter
• Delete, Map, or Go To

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Projecting a Waypoint

• Select the appropriate waypoint to be projected
  from.
• Press menu, then project waypoint
• Enter the distance and bearing of the new
  waypoint. Select enter

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To Create a Route

• Go to Main Menu
• Select Routes, New, Select Next Point.
• Add waypoints in order , select use
• At the end, select navigate or map.
• Routes are automatically saved.

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Navigating a Route

• Always starts from where you are.
• Make sure you have decided to follow the road or
  not.
• If you have turned on Guidance text, the GPS will
  prompt you as you get to turns or waypoints.

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Setup Checklist 1

• Install new batteries, get spares.
• Turn on GPS
• Ensure good reception and battery status.
• Load maps for tasking
• Load waypoints for tasking
• Load Routes for tasking

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Setup Checklist 2

• 7. Main Menu Page
• Tracks - cleared and ON
• Route select and NAVIGATE
• Setup
• Display night or day or auto
• Map - set orientation, zoom, detail, road lock

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Setup Checklist 3

• Time -- UCT, Local, ??
• Units -- position format (DDmm.mm, MGRS)
• -- datum (NAD27 or WGS84)
• -- distance/speed units, (nm,
  km)
• -- heading ( True or Magnetic)
• Calibrate compass and altimeter.

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Summary

• Never trust your life to an electronic gadget
• Always have a map and compass and know how to use
  it.
• Be very clear on datums, grids, and time.
• Practice, Practice, Practice.

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Navigation Rally

• Location CYRO
• Time 1300 L