What is GBS
These three characters GPS is an abbreviation of the words: Global Positioning System, which means: the Global Positioning SystemIt is a navigational system consisting of network satellites up to 24 satellites installed in orbits specific from outer space by the U.S. Department of Defense the main objective of this network of satellites military target purely, but in 1980 the government allowed the U.S. to be system available for civilian use. The GPS system works under all types of weather conditions, and everywhere in the world, 24 hours a day, and you must sign up in order to get this service as it is free.
These satellites orbiting around the earth at a speed of 7,000 miles per hour, and relies on solar energy, as it is equipped with batteries rechargeable in order to ensure continued operation in the absence of solar energy, and there on each satellite missile small in order to walk the moon in the correct way
Parts of the system (Global Positioning System GPS):
1 - space segment: consists of
24 satellite
6 orbits every round Includes 4 satellites
Each satellite is all a complete cycle (12) hour
Moon rise from the earth (20200) miles
Moon during the rotation speed (4) kilometers per second
Cover over (24) hours in all parts of the world
2 - command and control part: This part consists of the following:
Monitoring stations
A main control station
Ground antennas
The most important and follow-up monitoring stations:
Colorado Springs station
Hawaii station
Station Asncioa
Station Daagoffarca
Kwajalein station
3 - part users: part consists users of a device called a device (GPS) and the task of this device receiving the signal from the satellite group, and the most popular types of devices used widely:
Device Alcilan (MAGELLAN) American-made
Garmin device (GARMIN) German-made
Facts about those satellites:
1 - The first satellite was launched in 1978.2 - The completion of the release of all satellites and the 24 satellites in 1994.3 - the life span for each satellite is ten years. Note that alternatives to these satellites launched in their orbits.4 - satellite weighs approximately one ton, and approximately 6 meters in diameter, including solar power strips along the sides of the moon.5 - Moon only consumes 50 watts or less of power in the case of transmission.6 - these satellites broadcast two signals low:L1 = 1575.42MHz
L2 = 1227.6MHz
Important note:Each satellite of these satellites will be broadcast in the same frequencies above but Bchwirat different (different ranging codes) from those used in other satellites, then this system of satellites broadcast navigation data using two frequencies and using a technique called:
Code Division Multiple Access (CDMA)
The navigation data (Navigation Data) give all the (GPS receiver) information to locate the moon to send the signal moment, while encrypted term (Ranging Code) enables the device user to determine the time of signal transmission (propagation) and thus determine the range between the moon and the user. This technique requires that device has an hour correspond to the hour of the moon.
How does it work?The GPS satellites orbiting the Earth in orbits very specific and accurate twice per day (24 hours) and during Edoranha broadcast signals carry information on the ground. Receiver you have received this information and do some computational processes to determine the exact location of the user. There is also a ground stations receiving information from satellite and on the basis These stations provide important information to the Moon in order to work better on the face, such as the timing and orbit and location .. Etc. This means that the dual connection between ground stations and satellites.
As regards to the receiver (GPS) to have it must know two things essential and important:1 - Where do these satellites? (Website)2 - How far these satellites for the device? (Distance)To answer the first question, the device captures information from satellite locations include those satellites approximate, and this information be sent down and the device stored in the memory in order to know over each satellite, and where I should be, and this kind of information occurs continuously by ground stations that we talked previously, it provides Moon located the correct path and the moon turn sends this information to the receiver you have. permission through the receipt of information determines the sites satellites all the time either answer the second question, which specializes distance the device after locating satellites in space with precision - as I said above - still needs to know how far it these satellites (distance) and can do so by finding out how long it took the signal to reach, and this is determined by the time of starting signal from the moon and the time of receipt and the time difference between them is the time it took the reference in the space for access to the device, of course satellite provider are very accurate, as well as your device albeit less accurate .. To simplify it, I say: if the moon of the device say that this reference was launched in time ... The device looks at his watch when he received this signal now
Select the time it took the signal to reach the base says: time x speed = distance. Remember when we were young, if we wanted to know whether the clouds far or near that we calculate the time between see lightning and hear thunder had a great time between them, the clouds away, though the difference a few clouds soon? This same idea: the device you have hit time at the speed of radio waves of 186,000 miles per second and the result is the distance between the satellite and the device.Now we have identified the most important things in the process, namely: the moon and the distance between us and him, and so the device can be determined location is as follows:
Suppose we just 11,000 miles from the first satellite in this case would be our website at any point of the millions of points on the circumference of a circle radius of 11,000 miles a satellite in the middle, so the satellites and one is not enough to locate the device ..Suppose we just 12,000 miles from the moon a second, this second moon would send signals intersect with the first moon signals consisting circle, and the site will be at any point of the perimeter of this circle, once again it is impossible to determine site Bakmaren only ..
Therefore we need to add a satellite Third Suppose that after 13.000 miles we will have two points: (a) and (b) due to the intersection of the three circles for satellites three, but two points are far from each dimension vastly and knowing that we have become points only the select whichever device requires you to enter your height in your site in order to know the device any two points is. And all if we adding a fourth moon device can be determined three dimensions (3D) is (Longitude + Latitude rise. (Receipt of data:
Data is received in accordance with the system known:National Marine Electronics Association: NEMA0183, v3.0))
And through this system receive messages graphs (NEMA Messages data) the following:GGA, VTA, GLL, ZDA, GSA, GSV, and RMC.
Each message contains data or may resemble differ from Almlomat in another message. And Almlomat task and required in all receivers and be complete within the message (RMC) are:UTC (Universal Time Coordinated)
Post-state
LAT.
LAT. (N, S)
LONG.
LONG. (W, E)
SPD (Knote)
HDG (degree)
DATE
Mag.Variation (degree)
The direction of the target (Heading: HDG):
Given direction in GPS navigator location relative to true north (Arctic) and unit (degree), as well as the direction of the target also given relative to true north. Sources of error in the GPS signal:GPS devices in recent years has become very precise highly so that the average error rate dropped to 15 meters away!! , Thanks to the development of programs and pieces of home inside the device, that the matter is not free from some of the barriers that affect the accuracy of GPS devices, and perhaps the most important sources of error in this area include:1 - errors caused by slow signal from the satellite, because the signal velocity below when they traverse the atmosphere on its way to the device, and are usually equipped with receivers calculates the rate of delay in order to correct this error.2 - errors caused by reflection or echo signal as a result of a collision with by obstacles such as buildings long or rocks and mountains .. Etc.
3 - errors caused due to the device's internal clock; because this time is not accurate atomic clock in the satellite, and for that there may be errors due to timing.4 - errors that occur due to the accuracy of the information sent by the satellite for its location in space.5 - Number of satellites that the device can see it; greater the number of satellites increased precision and vice versa; Buildings and electric and magnetic fields cause you do not see the device for satellites and thus causing cut signal and cause errors in the selection or even the possibility inability device to determine the location permanently.
Quality of the received signal (Signal Quality):
and paint these values in the form of bars (Bars) and remember the value of all proportion at the top of the tape so the tape format will change depending on the value ratio, but for the numbers at the bottom of each bar in the chart, it will be the ID of the satellite or may represent (Pseudo Random Number: PRN) Note Figure (10 \ left).
The values (SNR) vary from one device to another, so when you buy a device (GPS) must make sure this value, as an example:Garmin II, II plus, and III: min SNR = 30dB
Max SNR = 55dB
Define these values of activation message (GPGSV NMEA message) will be extracted angle horizon and height for each satellite was received statements by the (GPS), which will give the value of the (Number: PRN (Pseudo Random with angle horizon know the symbol (A) and the height value ID code (E)
World Geodetic System 1984 (World Geodetic System: WGS84):
Most devices Global Positioning System (GPS) give geographic coordinates based on the system (WGS84). Free this system in 1984 based on the geodetic data and gravitational Hemisphere, and the center of this system is the center mass of the Earth, and is supposed to form the earth is oval (Ellipsoidal) and assumes that the earth revolves at a constant speed on the axis connecting the poles so when you use the (GPS) should attention to this because each country (or group of States) own geodetic system and each system there is a set of measurements that explains it.
The readings given device (GPS) is the geographical coordinates, as the longitude and latitude of any point are geographic coordinates and reflects the values of both degrees, minutes and seconds.
It is built on the basis of (60) Muscat Markitr
Browser rate and separately, and all six degrees of longitude be introduced and the extension of the line (80) degrees south latitude (84) degrees north.
Coordinates given quadratic Balchmal (Northing) and Tashreeq (Easting), and unity in most squared squared meter.
And know straight lines stretching up and down the map (b Tashreeq lines) and the increase in value from west to east, while you know straight lines stretching from one side of the map to the other side (b lines Alchmal) and increase in value from the south to the north.
In many cases, prefer to use squared coordinates on the geographical coordinates in the maps and military:
1 - Easy to extract coordinates squared.
2 - The unit of measurement is squared meters coordinates and so we get the real distance readings.
3 - squared coordinates straight lines and horizontal so it can be painted easily and accurately on a map, while the lines of geographical coordinates are curved and pass the ball on the ground and can not be accurately drawn on a flat sheet.
And usually prove the geographic coordinates and squared on topographic maps, whether military or civilian, regardless of scale map
And there is a known mathematical rates for the purpose of conversion between the two systems and the requirements of work, and containing devices (GPS) current on the possibility of giving the coordinates squared values or geographical as well as the type Geodetic System used in the country
These three characters GPS is an abbreviation of the words: Global Positioning System, which means: the Global Positioning SystemIt is a navigational system consisting of network satellites up to 24 satellites installed in orbits specific from outer space by the U.S. Department of Defense the main objective of this network of satellites military target purely, but in 1980 the government allowed the U.S. to be system available for civilian use. The GPS system works under all types of weather conditions, and everywhere in the world, 24 hours a day, and you must sign up in order to get this service as it is free.
These satellites orbiting around the earth at a speed of 7,000 miles per hour, and relies on solar energy, as it is equipped with batteries rechargeable in order to ensure continued operation in the absence of solar energy, and there on each satellite missile small in order to walk the moon in the correct way
Parts of the system (Global Positioning System GPS):
1 - space segment: consists of
24 satellite
6 orbits every round Includes 4 satellites
Each satellite is all a complete cycle (12) hour
Moon rise from the earth (20200) miles
Moon during the rotation speed (4) kilometers per second
Cover over (24) hours in all parts of the world
2 - command and control part: This part consists of the following:
Monitoring stations
A main control station
Ground antennas
The most important and follow-up monitoring stations:
Colorado Springs station
Hawaii station
Station Asncioa
Station Daagoffarca
Kwajalein station
3 - part users: part consists users of a device called a device (GPS) and the task of this device receiving the signal from the satellite group, and the most popular types of devices used widely:
Device Alcilan (MAGELLAN) American-made
Garmin device (GARMIN) German-made
Facts about those satellites:
1 - The first satellite was launched in 1978.2 - The completion of the release of all satellites and the 24 satellites in 1994.3 - the life span for each satellite is ten years. Note that alternatives to these satellites launched in their orbits.4 - satellite weighs approximately one ton, and approximately 6 meters in diameter, including solar power strips along the sides of the moon.5 - Moon only consumes 50 watts or less of power in the case of transmission.6 - these satellites broadcast two signals low:L1 = 1575.42MHz
L2 = 1227.6MHz
Important note:Each satellite of these satellites will be broadcast in the same frequencies above but Bchwirat different (different ranging codes) from those used in other satellites, then this system of satellites broadcast navigation data using two frequencies and using a technique called:
Code Division Multiple Access (CDMA)
The navigation data (Navigation Data) give all the (GPS receiver) information to locate the moon to send the signal moment, while encrypted term (Ranging Code) enables the device user to determine the time of signal transmission (propagation) and thus determine the range between the moon and the user. This technique requires that device has an hour correspond to the hour of the moon.
How does it work?The GPS satellites orbiting the Earth in orbits very specific and accurate twice per day (24 hours) and during Edoranha broadcast signals carry information on the ground. Receiver you have received this information and do some computational processes to determine the exact location of the user. There is also a ground stations receiving information from satellite and on the basis These stations provide important information to the Moon in order to work better on the face, such as the timing and orbit and location .. Etc. This means that the dual connection between ground stations and satellites.
As regards to the receiver (GPS) to have it must know two things essential and important:1 - Where do these satellites? (Website)2 - How far these satellites for the device? (Distance)To answer the first question, the device captures information from satellite locations include those satellites approximate, and this information be sent down and the device stored in the memory in order to know over each satellite, and where I should be, and this kind of information occurs continuously by ground stations that we talked previously, it provides Moon located the correct path and the moon turn sends this information to the receiver you have. permission through the receipt of information determines the sites satellites all the time either answer the second question, which specializes distance the device after locating satellites in space with precision - as I said above - still needs to know how far it these satellites (distance) and can do so by finding out how long it took the signal to reach, and this is determined by the time of starting signal from the moon and the time of receipt and the time difference between them is the time it took the reference in the space for access to the device, of course satellite provider are very accurate, as well as your device albeit less accurate .. To simplify it, I say: if the moon of the device say that this reference was launched in time ... The device looks at his watch when he received this signal now
Select the time it took the signal to reach the base says: time x speed = distance. Remember when we were young, if we wanted to know whether the clouds far or near that we calculate the time between see lightning and hear thunder had a great time between them, the clouds away, though the difference a few clouds soon? This same idea: the device you have hit time at the speed of radio waves of 186,000 miles per second and the result is the distance between the satellite and the device.Now we have identified the most important things in the process, namely: the moon and the distance between us and him, and so the device can be determined location is as follows:
Suppose we just 11,000 miles from the first satellite in this case would be our website at any point of the millions of points on the circumference of a circle radius of 11,000 miles a satellite in the middle, so the satellites and one is not enough to locate the device ..Suppose we just 12,000 miles from the moon a second, this second moon would send signals intersect with the first moon signals consisting circle, and the site will be at any point of the perimeter of this circle, once again it is impossible to determine site Bakmaren only ..
Therefore we need to add a satellite Third Suppose that after 13.000 miles we will have two points: (a) and (b) due to the intersection of the three circles for satellites three, but two points are far from each dimension vastly and knowing that we have become points only the select whichever device requires you to enter your height in your site in order to know the device any two points is. And all if we adding a fourth moon device can be determined three dimensions (3D) is (Longitude + Latitude rise. (Receipt of data:
Data is received in accordance with the system known:National Marine Electronics Association: NEMA0183, v3.0))
And through this system receive messages graphs (NEMA Messages data) the following:GGA, VTA, GLL, ZDA, GSA, GSV, and RMC.
Each message contains data or may resemble differ from Almlomat in another message. And Almlomat task and required in all receivers and be complete within the message (RMC) are:UTC (Universal Time Coordinated)
Post-state
LAT.
LAT. (N, S)
LONG.
LONG. (W, E)
SPD (Knote)
HDG (degree)
DATE
Mag.Variation (degree)
The direction of the target (Heading: HDG):
Given direction in GPS navigator location relative to true north (Arctic) and unit (degree), as well as the direction of the target also given relative to true north. Sources of error in the GPS signal:GPS devices in recent years has become very precise highly so that the average error rate dropped to 15 meters away!! , Thanks to the development of programs and pieces of home inside the device, that the matter is not free from some of the barriers that affect the accuracy of GPS devices, and perhaps the most important sources of error in this area include:1 - errors caused by slow signal from the satellite, because the signal velocity below when they traverse the atmosphere on its way to the device, and are usually equipped with receivers calculates the rate of delay in order to correct this error.2 - errors caused by reflection or echo signal as a result of a collision with by obstacles such as buildings long or rocks and mountains .. Etc.
3 - errors caused due to the device's internal clock; because this time is not accurate atomic clock in the satellite, and for that there may be errors due to timing.4 - errors that occur due to the accuracy of the information sent by the satellite for its location in space.5 - Number of satellites that the device can see it; greater the number of satellites increased precision and vice versa; Buildings and electric and magnetic fields cause you do not see the device for satellites and thus causing cut signal and cause errors in the selection or even the possibility inability device to determine the location permanently.
Quality of the received signal (Signal Quality):
and paint these values in the form of bars (Bars) and remember the value of all proportion at the top of the tape so the tape format will change depending on the value ratio, but for the numbers at the bottom of each bar in the chart, it will be the ID of the satellite or may represent (Pseudo Random Number: PRN) Note Figure (10 \ left).
The values (SNR) vary from one device to another, so when you buy a device (GPS) must make sure this value, as an example:Garmin II, II plus, and III: min SNR = 30dB
Max SNR = 55dB
Define these values of activation message (GPGSV NMEA message) will be extracted angle horizon and height for each satellite was received statements by the (GPS), which will give the value of the (Number: PRN (Pseudo Random with angle horizon know the symbol (A) and the height value ID code (E)
World Geodetic System 1984 (World Geodetic System: WGS84):
Most devices Global Positioning System (GPS) give geographic coordinates based on the system (WGS84). Free this system in 1984 based on the geodetic data and gravitational Hemisphere, and the center of this system is the center mass of the Earth, and is supposed to form the earth is oval (Ellipsoidal) and assumes that the earth revolves at a constant speed on the axis connecting the poles so when you use the (GPS) should attention to this because each country (or group of States) own geodetic system and each system there is a set of measurements that explains it.
The readings given device (GPS) is the geographical coordinates, as the longitude and latitude of any point are geographic coordinates and reflects the values of both degrees, minutes and seconds.
It is built on the basis of (60) Muscat Markitr
Browser rate and separately, and all six degrees of longitude be introduced and the extension of the line (80) degrees south latitude (84) degrees north.
Coordinates given quadratic Balchmal (Northing) and Tashreeq (Easting), and unity in most squared squared meter.
And know straight lines stretching up and down the map (b Tashreeq lines) and the increase in value from west to east, while you know straight lines stretching from one side of the map to the other side (b lines Alchmal) and increase in value from the south to the north.
In many cases, prefer to use squared coordinates on the geographical coordinates in the maps and military:
1 - Easy to extract coordinates squared.
2 - The unit of measurement is squared meters coordinates and so we get the real distance readings.
3 - squared coordinates straight lines and horizontal so it can be painted easily and accurately on a map, while the lines of geographical coordinates are curved and pass the ball on the ground and can not be accurately drawn on a flat sheet.
And usually prove the geographic coordinates and squared on topographic maps, whether military or civilian, regardless of scale map
And there is a known mathematical rates for the purpose of conversion between the two systems and the requirements of work, and containing devices (GPS) current on the possibility of giving the coordinates squared values or geographical as well as the type Geodetic System used in the country
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