Categorieën: Alle - satellites - navigation - disadvantages - control

door NUR AIN AMIRAH BINTI CHE SAAD 4 jaren geleden

231

Writing an Essay

An accelerometer is a key component in navigation systems, providing critical data on velocity and distance. Typically, two accelerometers are used, mounted at right angles to measure acceleration in different directions, such as north-south or west-east.

Writing an Essay

Essay Title

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Inertial reference system

Disadvantages
Time information cannot be given
INS is an expensive technology
Vibration and thermal variation may cause flaws in information data
An increase in computing complexity
Advantages
Operates at all the altitudes
Greater reliability
Reduced size
Lower cost

Inertial system

Sources of error
How these error can be overcome?

They might decide to deselect the system

If one system’s position differs from the other two by a predetermined amount the crew can be alerted to this

Gyro error
Alignment errors
Initialization errors

Alignment process

Important
Determine a local vertical and direction of true north
In inertial navigation system
Initial heading using

Laser gyro

Accelerometer

Determining the local vertical

How the accelerometer provides reference output

Processed to develop navigation data
Example

Two accelerometer and directed to N-S or W-E

Two accelerometer

Give out data velocity and distance in any lateral direction

Measure acceleration

Mount together with right angles

Calculate velocity and distance information

Only one direction

Operation of GPS system

In event of poor satelite coverage
The system uses other navigation sensor inputs to enter into a dead reckoning mode
Less than 30 seconds

Control segment

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Location

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Ground antennas

Located on

Five monitoring stations

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Located in

Ascension Island

Diego Garcia

Kwajalein

Hawaii

Colorado Springs

One master control station (MCS)

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Located at Schriever in Colorado Springs, USA

Purpose

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Take into consideration the interests of your audience.

Ensures that GPS satellite orbit and clock remain within acceptable range
To predict the behavior of each satellite orbit and clock

Differences

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Almanac data
Considered valid for up to several months
Not very precise
Ephemerus data

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of the essay which you're going to analyze.

Necessary for precise positioning
Clock correction for each SV
Very precise orbital

Satellite

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FOUR satellites need to be in view to access the datas
Two-dimensional & three dimensional
Altitude
Longitude
Latitude