Lecture

Leading Cadet Training

Basic Navigation

4Practical Navigation

Aids to Navigation

Good navigators will not rely solely on accurate compass work & good distance measurementto find their way around. They will use a number of techniques to improve their navigation:

Aids to Navigation

ROAMERS

These are used to find

a 6 figure grid reference

more accurately than guess work.

ROAMERSAlways read the nearest low figure (SW corner)

Check that the roamer you are using is of the correct scale for the map.

Aids to Navigation

RESECTION

To find your physical location on a map, you will need THREE clearly visible landmarks.

Take a compass bearing – deduct the magnetic variation – your position is somewherealong that line.

Repeat for the other landmarks.

Aids to Navigation

RESECTION

Plot the three bearingsonto your map.

Draw a pencil line from each

You are in the middle of the triangle where the 3 lines cross.

Aids to Navigation

Aids to NavigationHANDRAILING

You can use linear features of the landscape that

form straight lines as a ‘path’.

Like following

the edge of a wood

to the road.

AA

BB

Aids to NavigationAIMING OFF

Imagine that you are at point A and you want to cross the river at the bridge. If you aim directly for the footbridge, the chances are that you might miss it, and you wouldn’tknow to turn upstream or downstream.

AABridgeBridge

Aids to NavigationAIMING OFF

AABridgeBridge

Instead of aiming straight for the bridge, you should deliberately aim off slightly to one side.

You would then know which way to turn when you hit the stream.

Aids to NavigationCONTOURING

Going over the top of a hill (from A to B)

may be shorter in distance, but remember ;

for every 200m climb

add 30mins to your

journey time.

It may be much easier

to go around the hill,

following the contours.

B

A

ATTACK POINTS

Instead of taking a direct route from A to B,that might lead you off course.

Aim for an easily identifiable feature that is closeto your target –

It increases the chances of reaching your objective.

Aids to Navigation

B

A

DOG-LEG & BOXING AROUND

Following your route may sometimes be difficult.

There may be unexpected or unlooked for

obstacles in your path.

In cases like this making

a Dog-Leg Detour,

or Boxing Around

can be good ideas.

Aids to Navigation

DOG-LEG

As you approach an obstacle,

turn 45o and walk an exact distance.

Turn back 45o and walk the same exact distance.

Turn another 45o and

check the bearing,

so that you are back

on your original route.

Aids to Navigation

100

m10

0 pa

ces 100 m

100 paces

Then turn another 90o, and walk until

the obstacle is cleared.

Turn another 90o and walkthe same exact distance.

Aids to Navigation

100

m10

0 p

aces 100 m

100 paces

Turn another 90o and

check the bearing,

so that you are back

on your original route.

BOXING AROUND

As you approach the obstacle, turn 90o and walk an

exact distance.

MAPPING SPIRAL

An expanding series of 90o turn walking legs which are multiples of the limit of visibility.

It gives a wide search area, but can be extremely time consuming and inefficient.

It is very useful however, if you are close to a known feature.

Aids to Navigation

GLOBAL POSITIONING SYSTEM (GPS)

GPS is a space-based satellite navigation system thatprovides location and time information in all weathers, anywhere on or near the Earth.

Aids to Navigation

Satellites are in known locations

Four satellites are usedto pinpoint locations

GPS signals are blocked by mountains and

buildings Accurate travel time for signals

Each satellite is identified by

a complex digital code

Location pinpointed by correcting

atmospheric signal delays

Although not actually part of Basic Navigation,Route Cards are an essential item for planning

and confirming your expedition.

and act as a safety net, should anything go wrong.

Route Cards

Check of UnderstandingWhat is the six figure grid reference

shown on the roamer?

375 064

385 056

056 385

064 375

Check of UnderstandingIf you wanted to find your position on a map

using prominent features in vision, what would give the best result?

Three bearings that cross to give a small triangular fix.

Three bearings that cross to give a large triangular fix.

One exact bearing to give a line fix.

Two bearings that cross to give a position fix.

Check of UnderstandingFollowing linear features to guide you to your destination is known as what?

Using Attack Points

Aiming Off

Handrailing

Contouring

Check of UnderstandingWhen making a dog-leg detour

at what angle should you make your turns?

90o

25o

60o

45o

Check of UnderstandingWhat is meant by contouring?

Walking up a hill

Walking around a hill

Walking down a hill

Walking over a hill

Check of UnderstandingWhat is making an expanding series of 90o turn walking legs known as?

Boxing around

Aiming off

Mapping spiral

Attack points

Check of UnderstandingInstead of taking a direct bearing you deliberatelyveer to the left or right to hit an obvious feature,

what is this known as?

Boxing around

Contouring

Dog-leg

Attack points

Leading Cadet Training

Basic Navigation

End of Presentation