GNSS intro

1. by Asim Khan (MS GNSS )

2.  Introduction Newton Laws
 Main Types Kepler laws and elements
 History conservation of energy and angular
 Types Momentum
 Size Ellipse and its parameters
Mass Trajectory equation
 Orbit Types GNSS Position ,Trilateration
Altitude GNSS Segments
Inclination GNSS Applications
Eccentricity Satellite Orbit Applications
 Mathematical Description Law of Graviataion
 Structure
Bus
Sub System
Payload

3.  Satellite is an artificial or body placed in orbit round the earth or another planet in order to collect information or for communication.

4.  Natural Satellite
A natural satellite is
any celestial body in
space that orbits
around a larger body.
Moons are called
natural satellites
because they orbit
planets
 Artificial Satellite
Satellites that are made
by people and
launched into orbit
using rockets are
called artificial
satellites. There are
thousands of artificial
satellites orbiting the
Earth

5. Galileo Galilei was first to
discover jupitor
satellites(Moon)on January 7,
1610
First Artificial satellite
Sputnik 1 on 3 November
1957
 First Aniamal liaka (Dog )
orbit around Earth
First Manned Satellite Salyut
1 in 1971
 Navstar 1, was launched
February 22, 1978 in GPS
system of Satellites
 1999 Mobile phone manufacturer
Benefon launched the first
commercially-available GPS
phone, a safety phone called the
Benefon Esc!

6.  Size and Mass
 CubeSats are built to standard dimensions (Units or “U”) of 10 cm x 10
cm x 10 cm. They can be 1U, 2U, 3U, or 6U in size, and typically weigh
less than 1.33 kg (3 lbs) per U
Group name[1] Mass (kg) Size
Large satellite >1000 >1000 m³
Medium satellite 500 to 1000 500 m³
Mini satellite 100 to 500 100 m³
Micro satellite 10 to 100 50 m³
Nano satellite 1 to 10 10 cm³ to 100 cm³
Pico satellite 0.1 to 1 <10 cm³
Femto satellite <0.1 <5 cm³
2

7. Group name[1] Function Type
Large satellite  International space station(Laboratory )
 Skylab
Medium satellite Astronomicl Satellites and Communication
Mini satellite SSOT, Smart-1, Spirale(early warning system or
observing )
Micro satellite Astrid-1(Atmosphere Study )
Nano satellite : ExoCube (CP-10), ArduSat(Space Weather )
Pico satellite F-1 Sattelite (Educational )
Femto satellite Zero Gavity (Experiments)

8. Name Function
Astronomical satellites Observation of distant planets, galaxies, and
other outer space objects
Biosatellites To carry living organisms, generally for
scientific experimentation
Communication satellites Telecommunications
Earth observation satellites Environmental monitoring, meteorology, map
making etc
Navigational satellites Navigation Purposes (tracking )
Weather satellites To monitor Earth's weather and climate
Space stations Laboratory
Reconnaissance satellites Military or Intelligence applications
Recovery satellites Recovery of reconnaissance, biological,
space-production and other payloads from
orbit to Earth
Crewed spacecraft (spaceships) To put humans into (and beyond) an orbit, and

9. Name Altitude
Low Earth orbit
(LEO)
180 km - 2,000 km
(1,200 mi)
Medium Earth
orbit (MEO)
2,000 km (1,200
mi) - 35,786 km
(22,236 mi)
Geosynchronous
orbit (GEO)
35,786 kilometres
(22,236 mi)
High Earth orbit
(HEO)
35,786 km (22,236
mi)
Name Inclination
Inclined orbit 1°to 89°
Poalr orbit 90 °
Polar sun
synchronous orbit
90°

10. Name Eccentricity Perigee Apogee
Circular orbit e = 0 equal equal
Hohmann transfer
orbit
e = 0 equal equal
Elliptic orbit: e = 0.1 to 0.99 low earth orbit at Geosynchronous
Geosynchronous
transfer orbit
e = 0.1 to 0.99 low earh orbit at Geosynchronous
Geostationary
transfer orbit
e = 0.1 to 0.99 low earth orbit at Geosynchronous
Molniya orbit inclination = 63.4º low earth orbit at Geosynchronous
Tundra orbit inclination = 63.4º low earth orbit at Geosynchronous

11. low Earth Orbit
Senser work properly(i.e Scientific
and weather Sat)
low Power operating
Cheaper launch
less time dealy signal (i.e
Communication Sat)
Medium Earth Orbit
Minimum no of sats for Global
coverage
Better round trip time(RTT) than GEO
Navigation Sats operating orbit
Geo stationary Earth Orbit
Global Coverage with three sats
Greater Life Time
Communication ,Weather and
Remote sensing for constant
coverage
High Elliptical Orbit
Full disk image
Covers more Area
More coverage on Poles

12. law of Inertia
Every body continues in its state of rest or of uniform motion in a straight line
unless it is compelled to change that state by forces impressed upon it .
F=0Σ
Second Law
The rate of change of momentum is proportional to the force impressed and is in
the same direction as that force .
F=kma where k=1
F=ma
Third Law
 To every action there is always opposed an equal reaction.

14. Any two bodies attract one another
with a force proportional to the
product of their masses and
inversely proportional to the square
of the distance between them

18.  the specific angular momentum h
of a satellite remains constant
along its orbit.

19.  e = eccentricity
 p = semi latus rectum

20. 

21. 

22.  closest radius to centered
body is perigee and
longest radius from
centered body is Apogee
 Velocity at perigee
 V2p = (GM )(2/rp-1/a)⊕
 Velocity at Apogee
 V2a = (GM )(2/ra-1/a)⊕
 Time Period

23.  Epoch Time
 the time at which the Keplerian
Elements were defined
 Orbital Inclination
 the angle btween the elliptic plane
and plane orbit
 Right Ascension of Ascending
Node
 the longitude of ascending node is
the angle between the ascending
node and the unit vector
 Eccentricity
 how much the conic section
deviates from being circular orbit
 Argument of Perigee ;the angle
between ascending node and
periapsis of the orbit .
 Mean Motion ;the mean motion
will tell you how fast the satellite is
going v=GM/r
 Mean Anomaly;angle increasing
uniformly with time by 360 degree
per orbital period from 0 at
perigee
 Drag;low earth orbit gases
prouduce drag to Satellite motion .
 Semi major axis ;it is half of the
longest diameter of an elliptical
orbit .
 Ascending node ;it is the node
where orbiting secondery passes
away from the observer .
 Descending node ;the nodes
where it moves towards the
observer

24.  Longitude of perigee ;the sum of
longitude of scending node and
argument of perigee
 true anomaly at epoch;angle between
periapsis and position of satellite at
particular time to epoch in satellite
orbit.
 Argument of latitude at Epoch ;
Angle between ascending node and
radius vector to satellite at time t in Sat
plane

25.  In this positioning system a
constellation of satellites providing
signals from Space that transmit
Positioning and timing Data to GNSS
receivers ,the receivers then
determine their Position velocity and
time.
 P= (x,y,z,t) v
 Trilateration Principle:
Estimation of Position based on
measurement of distances from three
transmitters is known as Trilateration.
Segments :
Space Segment (Constellation of
Sates)
Control Segment(Control Stations)
User Segment (Receivers)

26. Satellite Clock Error
 Ephemeris Error
Relativistic Effects
Atmospheric Effects
Receiver Noise and Resolution
Multipath and Shadowing Effects
Hardware Bias Errors
Pseudorange Error Budgets

28.  Orbiting satellites acceleration
a = v² / r
Earth Gravity pull on satellite
g= 9.8 m/sec
 Raduis of Earth = 6.4× 10 6 m
 g= v² / r
 v = √gR
 v = √9.8×6.4 × 10 6 m
 v =7.9 km/sec
Critical orbital velocity for a satellite is
7.9 km/se
 Time Period for satellite
 T= 2R / v
T=5060 sec
π

29.  Orbital radius for Geo stationary satellite
r = (GMT²/4 π²)1/3
r =3600 km above from surface of Earth
 Orbital Parameters Of satellite
 a = semimajor axis =ra + rp/2
 b = semiminor axis
 e = ecentricity = ra - rp / ra + rp
 ra = apogee radius = a(1+ e )
 rp + perigee radius = a ( 1- e)
 p =semilatus rectum = a (1- e²)
 = true anomalyθ
 r = p /1+ecosθ

30.  Bus
The bus is the platform that supports
the payload and maintains
the satellite’s position in orbit.
Payload
 Command and Data Handling (C&DH)
System
Communications system and antennas
Electrical Power System (EPS)
Propulsion
Thermal control
Attitude Control System (ACS)
Guidance, navigation, and control (GNC)
System
Structures and trusses
Life support (for crewed missions)

31. Name Function
Structure Provides “real estate” for mounting all bus and
payload units and the interface with the launch
vehicle
Electrical Power Provides electrical power to the payload and
bus units
Attitude Determination and Control Provides the control for achieving and
maintaining orbit and pointing
Propulsion Provides the propulsive power for achieving
and maintaining orbit
Telemetry &
Command
Controls the spacecraft and monitors its health
Thermal Control
Subsystem
Maintains a benign operating environment
Mechanisms Provides the means for deploying appendages
which must be stored for launch, and the
means to adjust appendages

33.  Aviation(GLS)
 Road Transport(car motion)
 Rail(emergency route)
 Maritime(ship motion)
 Agriculture(Mapping crops)
 Surveying and Mapping(Real
estate survey)
 Location based
services(individual position)
 Professional and
Scientific(Servant Account Safety
and wild life Position)
 Stock Exchange(Transaction time
synchronization)
 Education and international
cooperation

35.  Insidegnss.com
 Basics on Geomatics and
satellite orbit by Nicole viola
 Understanding GPS by Kaplan
 Esa.com
 Researchgate.net
 Slideshare.com
 Nasa.com
 Wikipedia
