Un compte Premium offert sur le site FCL.055 ! Rendez-vous sur www.fcl055-exam.fr puis créez un compte avec le même email que celui...   [Lire la suite]


Question > security : The reason why the measured distance between a navstar/gps satellite navigation ?

Question 187-1 : Calculated range includes receiver clock error measured distance is based on the pseudo random noise code movement of satellite and receiver during the distance calculation is not taken into account calculated range is based on an idealised keplerian orbit

.satellites use an atomic clock actually 4 for high precision and continuously transmit their positions plus a code number in a set code at exactly the same time the set code appears to be random but isn't which is why it is known as pseudo random noise code it is the means by which a receiver recognises signals from a particular satellite.since the transmission time is known the distance the signal has travelled can be calculated from its arrival time the receiver matches each satellite's code with an identical copy in its database by comparing any shift with its internal clock it can calculate a pseudo range which is similar to comparing a broadcast copy of a song against one already playing on a cd player if they both started at the same time the received one would be slightly behind from the time delay if several 'songs' are received at the same time from multiple sources the gps receiver can correct for errors in its own clock and determine actual travel times.the principle used is that if three perfect measurements can locate a point in space four imperfect ones can eliminate clock offsets or cancel out some timing errors .an error is therefore deliberately introduced and algebra is used to compute where all possible points could intersect the result given is your position because it is calculated the word pseudo is used and the measured distance between a satellite and a receiver is called a pseudo range because the calculated range includes receiver clock error exemple 287 calculated range includes receiver clock error.calculated range includes receiver clock error.

What type of satellite navigation system navstar/gps receiver is most suitable ?

Question 187-2 : Multichannel sequential multiplex any hand held type

.most gps receivers in use today are multi channel type meaning that they can track one satellite per channel a typical receiver will have 12 channels allowing it to track up to 12 satellites simultaneously .the receiver uses the latest almanac data to determine which satellites are visible at its location exemple 291 multichannel.multichannel.

The receiver aerial for a navstar/gps system should be mounted ?

Question 187-3 : On the upper side of the fuselage in the vicinity of the centre of gravity inside the tail fin to minimise the influence of reflections from the wing and fuselage in the vicinity of the receiver to avoid long transmission lines under the fuselage in order to receive correction data transmitted by d gps stations

exemple 295 on the upper side of the fuselage in the vicinity of the centre of gravity.on the upper side of the fuselage in the vicinity of the centre of gravity.

In the navstar/gps satellite navigation system re use of selective availability ?

Question 187-4 : Dithering the satellite clock shutting off selected satellites using a less accurate atomic clock in a satellite for signal processing offsetting satellite atomic clocks by a predetermined constant amount

.the c/a code coarse acquisition clear access or civil access is modulated on the l1 carrier only the p code precise or protected is modulated on both carriers .there are two limitations for civilian users namely selected availability and anti spoofing briefly referred to as sa and as respectively both deteriorate the achievable accuracy for civilian users significantly .selective availability sa the denial of full accuracy is accomplished by 'manipulating' navigation message orbit data epsilon and/or the satellite clock frequency dither so far only the satellite clock frequency has been manipulated with this dithering process the gps satellite clocks are artificially degraded by adding a signal with an unknown frequency and amplitude to the know clock behavior this is done to degrade the performance of gps for the 'normal' users both the frequency and amplitude of the added signal change rapidly over time the amplitude of this 'clock dithering' is of the order of 0 3 microseconds which corresponds to roughly 100 meters and the frequency is of the order of only a few minutes .this sa clock dithering limits the accuracy of real time position estimates to 25 meters rms exemple 299 dithering the satellite clock.dithering the satellite clock.

In the event of the re use of selective availability how does this affect if at ?

Question 187-5 : It degrades position accuracy by manipulating satellite signals it increases because only signals from satellites in the most suitable geometric constellation are selected by the receiver it has no influence because by selecting of the most suitable signals the computing process in the receiver is quicker it degrades accuracy by reducing the number of available satellites

.gps selective availability sa is a currently disabled since may 2000 function of the navstar / gps system which permits the us department of defence to downgrade the l1 signal available to unauthorised civilian users by adding intentional time varying errors to gps signals .these errors of up to 100 meters 328 ft to the l1 signals were intended to deny the use of civilian gps receivers for precision weapon guidance although typical sa errors were 10 meters 32 ft horizontally and 30 meters 98 ft vertically exemple 303 it degrades position accuracy by manipulating satellite signals.it degrades position accuracy by manipulating satellite signals.

In the navstar/gps satellite navigation system receiver clock error ?

Question 187-6 : Is corrected by using signals from four satellites is the biggest part of the total error it cannot be corrected can be minimised by synchronisation of the receiver clock with the satellite clocks is negligible small because of the great accuracy the atomic clocks installed in the satellites

One of the most significant error sources is the gps receiver's clock because of the very large value of the speed of light c the estimated distances from the gps receiver to the satellites the pseudoranges are very sensitive to errors in the gps receiver clock for example an error of one microsecond 0 000 001 second corresponds to an error of 300 metres 980 ft this suggests that an extremely accurate and expensive clock is required for the gps receiver to work since manufacturers prefer to build inexpensive gps receivers for mass markets the solution for this dilemma is based on the way sphere surfaces intersect in the gps problem.it is likely that the surfaces of the three spheres intersect since the circle of intersection of the first two spheres is normally quite large and thus the third sphere surface is likely to intersect this large circle it is very unlikely that the surface of the sphere corresponding to the fourth satellite will intersect either of the two points of intersection of the first three since any clock error could cause it to miss intersecting a point however the distance from the valid estimate of gps receiver position to the surface of the sphere corresponding to the fourth satellite can be used to compute a clock correction exemple 307 is corrected by using signals from four satellites.is corrected by using signals from four satellites.

The influence of the ionosphere on the accuracy of the satellite navigation ?

Question 187-7 : Minimised by the receiver using a model of the atmosphere and comparing signals transmitted by the satellites minimised by computing the average of all signals only significant if the satellites are located at a small elevation angle above the horizon negligible

exemple 311 minimised by the receiver using a model of the atmosphere and comparing signals transmitted by the satellites.minimised by the receiver using a model of the atmosphere and comparing signals transmitted by the satellites.

What are the effects if any of shadowing by parts of the aircraft e g wing on ?

Question 187-8 : It may prevent the reception of signals it causes multipath propagation the signals will be distorted however the error can be corrected for using an algorithm and information from unaffected signals it has no influence because high frequency signals are unaffected

.gps satellites transmit a low powered radio signal that travels by line of sight this means it will pass through clouds glass or plastic but will not go through most solid objects such as a wing it will no longer be able to provide the user with a current location until it can resume a link to at least three satellites and then update its position exemple 315 it may prevent the reception of signals.it may prevent the reception of signals.

Which of the following geometric satellite constellations provides the most ?

Question 187-9 : 3 satellites with a low elevation above the horizon and an azimuth of 120° from each other together with a fourth directly overhead 3 satellites with an azimuth of 120° from each other and an elevation of 45° above the horizon 4 satellites with an azimuth of 90° from each other and a low elevation above the horizon 4 satellites with an azimuth of 90° from each other and an elevation of 45° above the horizon

. 2605 exemple 319 3 satellites with a low elevation above the horizon and an azimuth of 120° from each other together with a fourth directly overhead.3 satellites with a low elevation above the horizon and an azimuth of 120° from each other together with a fourth directly overhead.

In relation to the navstar/gps satellite navigation system what is involved in ?

Question 187-10 : Fixed ground stations compute position errors and transmit correction data to a suitable receiver on the aircraft the difference between signals transmitted on the l1 and l2 frequencies are processed by the receiver to determine an error correction receivers from various manufacturers are operated in parallel to reduce the characteristic receiver noise error signals from satellites are received by 2 different antennas which are located a fixed distance apart this enables a suitable receiver on the aircraft to recognise and correct for multipath errors

exemple 323 fixed ground stations compute position errors and transmit correction data to a suitable receiver on the aircraft.fixed ground stations compute position errors and transmit correction data to a suitable receiver on the aircraft.

Which of the following statements about the accuracy that can be obtained with ?

Question 187-11 : The nearer a receiver is situated to a d gps ground station the more accurate the position fix only d gps allows position fixes accurate enough for 'non precision approaches' the increase in accuracy of position fixes is independent of the receiver position in relation to a d gps ground station a d gps receiver can detect and correct for sa providing a more accurate position fix

exemple 327 the nearer a receiver is situated to a d-gps ground station, the more accurate the position fix.the nearer a receiver is situated to a d-gps ground station, the more accurate the position fix.

How does a receiver of the navstar/gps satellite navigation system determine ?

Question 187-12 : It calculates it by using almanac data transmitted by the satellites the data is stored in the receiver together with the pseudo random noise prn code the data is based on the direction to the satellite determined at the location of the antenna the data is determined by the satellite and transmitted together with the navigation message

exemple 331 it calculates it by using almanac data transmitted by the satellites.it calculates it by using almanac data transmitted by the satellites.

In relation to the navstar/gps satellite navigation system 'search the sky' is a ?

Question 187-13 : Procedure that starts after switching on a receiver if there is no stored satellite data available continuous process by the ground segment to monitor the gps satellites procedure performed by the receiver to recognise new satellites becoming operational continuous procedure performed by the receiver that searches the sky for satellites rising above the horizon

exemple 335 procedure that starts after switching on a receiver if there is no stored satellite data available.procedure that starts after switching on a receiver if there is no stored satellite data available.

Which of the following if any is a prerequisite if a receiver of a navstar/gps ?

Question 187-14 : The prescribed ifr equipment must be installed and operational the prescribed ifr equipment must be in working correctly and the navigation information continuously displayed the raim function of the gps receiver must be able to monitor all prescribed navigation systems multi sensor systems are not certificated for flights under ifr conditions

exemple 339 the prescribed ifr-equipment must be installed and operational.the prescribed ifr-equipment must be installed and operational.

Which of the following is the datum for altitude information when conducting ?

Question 187-15 : Barometric altitude the average of gps altitude and barometric altitude gps altitude gps altitude if 4 or more satellites are received otherwise barometric altitude

.icao doc 8168 part ii section 3 chapter 1 .all fmcs and some stand alone basic gnss receivers provide altitude information .however the pilot must still comply with the published minimum altitudes using the barometric altimeter where the fmc provides vertical information flight director guidance cues or coupled autopilot operation the pilot should follow the appropriate information or cues along with any necessary cross checks with the barometric altimetry exemple 343 barometric altitude.barometric altitude.

Which of the following statements about the 'visibility' of navstar/gps ?

Question 187-16 : It varies depending on the time and observer's location it is the same throughout the globe it is greatest at the equator it is greatest at the poles

exemple 347 it varies, depending on the time and observer's location.it varies, depending on the time and observer's location.

How many operational satellites are required for full operational capability ?

Question 187-17 : 24 18 12 30

exemple 351 24.24.

Which of the following satellite navigation systems has full operational ?

Question 187-18 : Navstar/gps nnss transit cospas sarsat glonass

.there are two main global navigation satellite systems gnss currently in existence with a third which is planned to be fully operational by 2012 they are. usa navstar gps navigation system with timing and ranging global positioning system . russian glonass global navigation satelitte system . european galileo.currently only navstar/gps satellite navigation system is approved for specified flights under ifr conditions in europe exemple 355 navstar/gps.navstar/gps.

Gps system satellites transmit their signals on two carrier waves 1575 mhz and ?

Question 187-19 : Only the 1575 mhz carrier wave and one code only the 1575 mhz carrier wave and two codes only the 1227 mhz carrier wave and one code the two carrier waves and one public code

.each satellite broadcasts ranging signals on two uhf frequencies . l1 1575 42 mhz .l2 1227 6 mhz..there are currently two modes of operation sps standard positioning service for civilian users and pps precise positioning service for authorised users. sps is a positioning and timing service provided only on frequency l1.sps was originally designed to provide civil users with a less accurate positioning capability than pps .pps uses both frequencies l1 and l2 exemple 359 only the 1575 mhz carrier wave and one code.only the 1575 mhz carrier wave and one code.

Which statement about dilution of precision dop is correct ?

Question 187-20 : The value of dop depends upon the geometry and number of satellites in view the value of dop depends upon the accuracy with which the range between satellite and receiver can be measured the value of dop depends upon the availability of abas the value of dop depends upon the availability of raim software in the gps receiver

.the position dilution of precision pdop is the geometric effect resulting from satellites being too close together satellites that appear farther apart in the sky provide a more accurate position solution than ones close together in the latter case the position accuracy is degraded in a similar fashion to when position lines from ground based navaids navigational aids are less than 45° since the ephemeris of each satellite is known by the gps global positioning system receiver it is possible to calculate which combination of gps satellites provides the best geometry at a given time this is translated into a figure called the position dilution of precision pdop since the satellites move across the sky relative to the user the pdop is always changing a low pdop is better a pdop of 4 to 6 is considered good position solutions calculated when the pdop is from 6 to 10 should be used cautiously because they may have significant error a pdop that is above 10 indicates unacceptable error.the icao international civil aviation organization states that a pdop of less than 6 is required for en route navigation with a pdop of 3 or less required for nonprecision approaches i e not ils types exemple 363 the value of dop depends upon the geometry and number of satellites in view.the value of dop depends upon the geometry and number of satellites in view.

The different segments of the satellite navigation system navstar/gps are the ?

Question 187-21 : Control space and user main control station the monitoring station and the ground antennas antenna the receiver and the central control unit cdu atomic clock power supply and transponder

. main tasks of the control segment are . managing sps performance. navigation data upload. monitoring satellites..the space segment consists of a notional constellation of 24 operational satellites.the user segment is the gps receiver side exemple 367 control, space and user.control, space and user.

One of the tasks of the control segment of the satellite navigation system ?

Question 187-22 : Monitor the status of the satellites manufacture and launch the satellites manipulate the signals of selected satellites to reduce the precision of the position fix grant and monitor user authorisations

. main tasks of the control segment are . managing sps performance. navigation data upload. monitoring satellites..the space segment consists of a notional constellation of 24 operational satellites.the user segment is the gps receiver side exemple 371 monitor the status of the satellites.monitor the status of the satellites.

The main task of the user segment receiver of the satellite navigation system ?

Question 187-23 : Selecting appropriate satellites automatically to track the signals and to measure the time taken by signals from the satellites to reach the receiver transmitting signals which from the time taken are used to determine the distance to the satellite monitoring the status of the satellites determine their positions and to measure the time monitoring the orbital planes of the satellites

. user segment .gps supplies three dimensional position fixes and speed data plus a precise time reference the gps receiver used in aviation is a multi channel type and is able to determine the distance to a satellite by determining the difference between the time of transmission by satellite and the time of reception exemple 375 selecting appropriate satellites automatically, to track the signals and to measure the time taken by signals from the satellites to reach the receiver.selecting appropriate satellites automatically, to track the signals and to measure the time taken by signals from the satellites to reach the receiver.

One of the tasks of the space segment of the satellite navigation system ?

Question 187-24 : Transmit signals which can be used by suitable receivers to determine time position and velocity transmit signals to suitable receivers and to monitor the orbital planes autonomously compute the user position from the received user messages and to transmit the computed position back to the user segment monitor the satellites'orbits and status

.the space segment consists of a notional constellation of 24 operational satellites .they are orbiting the earth in orbits inclined 55° to the plane of the equator in a nearly circular orbit of the earth at an altitude of 20 200 km 10 900 nm .each satellite broadcasts ranging signals on two uhf frequencies l1 and l2 providing for suitable receivers signals to determine time position and velocity exemple 379 transmit signals which can be used, by suitable receivers, to determine time, position and velocity.transmit signals which can be used, by suitable receivers, to determine time, position and velocity.

In civil aviation the height value computed by the receiver of the satellite ?

Question 187-25 : Height above the wgs 84 ellipsoid geometric height above ground height above mean sea level msl flight level

.the geodetic reference datum used is wgs 84.in the civil aviation field altitudes and flight levels are.defined in terms of atmospheric pressure points on the ground are defined by their planimetric coordinates and by their orthometric height or altitude which use as their reference the geoid corresponding to mean sea level.the heights derived from gnss systems use the wgs 84 ellipsoid as their reference and are thus different from the values of the orthometric height at the same point.the height difference between the ellipsoid gnss height reference and the geoid orthometric height reference is called the undulation of the geoid this value thus defines the distance of the geoid above positive undulation of the geoid or below negative undulation of the geoid the reference ellipsoid .this gives us the relationship.undulation of the geoid = ellipsoidal height orthometric height altitude.the aeronautical information service publishes the values of the undulation of the geoid for each ifr aerodrome .this value conventionally designated gund is expressed in feet it will be shown on the charts as and when they are amended exemple 383 height above the wgs-84 ellipsoid.height above the wgs-84 ellipsoid.

In relation to the satellite navigation system navstar/gps the term ?

Question 187-26 : Orbital plane and the equatorial plane horizontal plane at the location of the receiver and the direct line to a satellite orbital plane and the earth's axis horizontal plane at the location of the receiver and the orbital plane of a satellite

. 2606.the orbital planes of the satellite navigation system navstar/gps are inclined 55° to the equatorial plane exemple 387 orbital plane and the equatorial plane.orbital plane and the equatorial plane.

How long does it take a navstar/gps satellite to orbit the earth ?

Question 187-27 : Approximately 12 hours one day 12 days 365 days because the satellites are located in a geostationary orbit

. 2607.the 24 satellites that make up the gps space segment are orbiting the earth about 12 000 miles above us they are constantly moving making two complete orbits in less than 24 hours these satellites are travelling at speeds of roughly 7 000 miles an hour.the orbital period is exactly one half a sidereal day 11 hours and 58 minutes so that the satellites pass over the same locations or almost the same locations every day exemple 391 approximately 12 hours.approximately 12 hours.

At what approximate height above the wgs 84 ellipsoid are navstar/gps ?

Question 187-28 : 20200 km 10900 km 36000 km 19500 km

.the satellites are in a nearly circular orbit of the earth at an altitude of 20 200 km 10 900 nm .the gps satellites are orbiting the earth in orbits inclined 55° to the plane of the equator .it consists of a notional constellation of 24 operational satellites the satellites are distributed in 6 orbital planes with at least 4 satellites in each .the orbital period is exactly one half a sidereal day 11 hours and 58 minutes so that the satellites pass over the same locations or almost the same locations every day exemple 395 20200 km.20200 km.

In which frequency bands are the l1 and l2 frequencies used by the satellite ?

Question 187-29 : Uhf vhf ehf shf

.the navigation message contains . almanac data. ephemeris. satellite clock correction parameters. utc parameters. ionospheric model. satellite health data..each gps satellite transmits data on two uhf frequencies l1 1575 42 mhz and l2 1227 6 mhz .l1 is a standard accuracy signal designed for civil users world wide and l2 is a high accuracy signal modulated by a special code for authorised user only exemple 399 uhf.uhf.

In relation to the satellite navigation system navstar/gps which of the ?

Question 187-30 : Prn is a code used for the identification of the satellites and the measurement of the time taken by the signal to reach the receiver prn is the atmospheric jamming that affects the signals transmitted by the satellites prn describes the continuous electro magnetic background noise that exists in space prn occurs in the receiver it is caused by the signal from one satellite being received from different directions multipath effect

.the c/a code is a pseudo random noise prn code sequence repeating every millisecond each c/a code is unique and provides the mechanism to identify each satellite.for information .gps receiver is able to determine the distance to a satellite by determining the difference between the time of transmission by satellite and the time of reception the initial distance calculated to the satellites is called pseudo range because the difference between the gps receiver and the satellite time references initially creates an erroneous range exemple 403 prn is a code used for the identification of the satellites and the measurement of the time taken by the signal to reach the receiver.prn is a code used for the identification of the satellites and the measurement of the time taken by the signal to reach the receiver.

Which of the following navstar/gps satellite navigation system codes can be ?

Question 187-31 : C/a ppp c/a and p p and y

.this question also appears at the exam under the following statement .'unauthorised civilian users of navstar gps can access.the c/a code'.gps system satellites transmit their signals on two carrier wave l1 and l2 .l1 is a standard accuracy signal designed for civil users world wide and l2 is a high accuracy signal modulated by a special code for authorised user only .c/a code coarse acquisition clear access or civil access is modulated on the l1 carrier only the p code precise or protected is modulated on both carriers.l1 1575 42 mhz.l2 1227 6 mhz..l1 is the higher frequency .l1 is modulated with the p and c/a code exemple 407 c/a.c/a.

Almanac data stored in the receiver of the satellite navigation system ?

Question 187-32 : Fast identification of received signals coming from visible satellites recognition whether selective availability sa is operative assignment of received prn codes pseudo random noise to the appropriate satellite correction of receiver clock error

.the gps almanac is a set of data that every gps satellite transmits and it includes information about the state health of the entire gps satellite constellation and coarse data on every satellite's orbit .when a gps receiver has current almanac data in memory it can acquire satellite signals and determine initial position more quickly exemple 411 fast identification of received signals coming from visible satellites.fast identification of received signals coming from visible satellites.

How does a navstar/gps satellite navigation system receiver recognise which of ?

Question 187-33 : Each satellite transmits its signal on common frequencies with an individual pseudo random noise code the doppler shift is unique to each satellite the receiver detects the direction from which the signals are received and compares this information with the calculated positions of the satellites each satellite transmits its signal on a separate frequency

exemple 415 each satellite transmits its signal, on common frequencies, with an individual pseudo random noise code.each satellite transmits its signal, on common frequencies, with an individual pseudo random noise code.

Which of the following data in addition to the pseudo random noise prn code ?

Question 187-34 : Almanac data satellite status information time positions of the satellites data to correct receiver clock error almanac data time data to impair the accuracy of the position fix

.the 'navigation message' provides all the necessary information to allow the user to perform . the positioning service ephemeris parameters needed to compute the satellite coordinates with enough accuracy the time parameters and clock corrections to compute satellite clock offsets and time conversions . the service parameters with satellite health information used to identify the navigation data set exemple 419 almanac data; satellite status information.almanac data; satellite status information.

What is the time taken to receive the complete navigation message complete set ?

Question 187-35 : 12 5 minutes = 30 seconds per data frame 12 hours = period of the satellites orbit 25 seconds = 1 second per data frame 24 seconds = 1 second per data frame

exemple 423 12.5 minutes (= 30 seconds per data frame).12.5 minutes (= 30 seconds per data frame).

Which of the following statements concerning the l1 and l2 navstar/gps ?

Question 187-36 : The higher frequency is used to transmit both the c/a and p codes c/a and p codes are transmitted at different times on both frequencies the higher frequency is only used to transmit the p code the lower frequency is used to transmit both the c/a and p codes

.gps system satellites transmit their signals on two carrier wave l1 and l2 .l1 is a standard accuracy signal designed for civil users world wide and l2 is a high accuracy signal modulated by a special code for authorised user only .c/a code coarse acquisition clear access or civil access is modulated on the l1 carrier only the p code precise or protected is modulated on both carriers.l1 1575 42 mhz.l2 1227 6 mhz..l1 is the higher frequency .l1 is modulated with the p and c/a code exemple 427 the higher frequency is used to transmit both the c/a and p codes.the higher frequency is used to transmit both the c/a and p codes.

Which one of the following errors can be compensated for by a navstar/gps ?

Question 187-37 : Ionospheric delay multipath tropospheric receiver noise

.this question also appears at exams with the following wording 'gps receivers using both gps frequencies l1 and l2 can nearly eliminate .ionospheric propagation delay'.ionospheric delay can be compensated by a navstar/gps . 2608.influenced propagation of radio waves through the earth's atmosphere.while radio signals travel with the velocity of light in the outer space their propagation in the ionosphere and troposphere is slower.in the ionosphere in a height of 80 400 km a large number of electrons and positive charged ions are formed by the ionizing force of the sun the electrons and ions are concentrated in four conductive layers in the ionosphere d e f1 and f2 layers these layers refract the electromagnetic waves from the satellites resulting in an elongated runtime of the signals.these errors are mostly corrected by the receiver by calculations the typical variations of the velocity while passing the ionosphere for low and high frequencies are well known for standard conditions theses variations are taken into account for all calculations of positions exemple 431 ionospheric delay.ionospheric delay.

Concerning the navstar/gps satellite navigation system what is the meaning of ?

Question 187-38 : It is a technique by which a receiver ensures the integrity of the navigation information it is the ability of the gps satellites to check the integrity of the data transmitted by the monitoring stations of the ground segment it is a method whereby a receiver ensures the integrity of the pseudo random noise prn code transmitted by the satellites it is a technique whereby the receivers of the world wide distributed monitor stations ground segment automatically determines the integrity of the navigation message

.raim is a technique whereby a receiver processor determines the integrity of the navigation signals.raim is achieved by consistency check among pseudo range measurements.basic raim requires 5 satellites a 6th is for isolating a faulty satellite from the navigation solution.for information when a gps receiver uses barometric altitude as an augmentation to raim the number of satellites needed for the receiver to perform the raim function may be reduced by one exemple 435 it is a technique by which a receiver ensures the integrity of the navigation information.it is a technique by which a receiver ensures the integrity of the navigation information.

What is the inclination to the equatorial plane of the satellite's orbit in the ?

Question 187-39 : 55° 45° 35° 65°

. 2606.the orbital planes of the satellite navigation system navstar/gps are inclined 55° to the equatorial plane exemple 439 55°.55°.

In respect of the use of gnss dilution of precision dop is a loss of accuracy ?

Question 187-40 : Relative position of the visible satellites ionospheric effects use of satellites at low altitudes multi path signals from some satellites

.the position dilution of precision pdop is the geometric effect resulting from satellites being too close together satellites that appear farther apart in the sky provide a more accurate position solution than ones close together in the latter case the position accuracy is degraded in a similar fashion to when position lines from ground based navaids navigational aids are less than 45° since the ephemeris of each satellite is known by the gps global positioning system receiver it is possible to calculate which combination of gps satellites provides the best geometry at a given time this is translated into a figure called the position dilution of precision pdop since the satellites move across the sky relative to the user the pdop is always changing a low pdop is better a pdop of 4 to 6 is considered good position solutions calculated when the pdop is from 6 to 10 should be used cautiously because they may have significant error a pdop that is above 10 indicates unacceptable error . /com en/com062 646 jpg.the icao international civil aviation organization states that a pdop of less than 6 is required for en route navigation with a pdop of 3 or less required for nonprecision approaches i e not ils types exemple 443 relative position of the visible satellites.relative position of the visible satellites.

~

Exclusive rights reserved. Reproduction prohibited under penalty of prosecution.

7439 Free Training Exam