A free Premium account on the FCL.055 website! Read here
Sign up to unlock all our services and 15164 corrected and explained questions.
Question 209-1 : What are the effects, if any, of shadowing by parts of the aircraft e.g. wing on the reception of signals from navstar/gps satellites ? [ Exam pilot ]
It may prevent the reception of signals.
.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.
Question 209-2 : Which of the following geometric satellite constellations provides the most accurate navstar/gps position fix ?
3 satellites with a low elevation above the horizon and an azimuth of 120° from each other together with a fourth directly overhead.
. 2605
Question 209-3 : In relation to the navstar/gps satellite navigation system, what is involved in the differential technique d gps ?
Fixed ground stations compute position errors and transmit correction data to a suitable receiver on the aircraft.
Question 209-4 : Which of the following statements about the accuracy that can be obtained with the differential technique d gps of the satellite navigation system navstar/gps is correct ?
The nearer a receiver is situated to a d gps ground station, the more accurate the position fix.
Question 209-5 : How does a receiver of the navstar/gps satellite navigation system determine the elevation and azimuth data of a satellite relative to the location of the antenna ?
It calculates it by using almanac data transmitted by the satellites.
Question 209-6 : In relation to the navstar/gps satellite navigation system, search the sky is a ?
Procedure that starts after switching on a receiver if there is no stored satellite data available.
Question 209-7 : Which of the following, if any, is a prerequisite if a receiver of a navstar/gps satellite navigation system is to be used in combination with a multi sensor system ?
The prescribed ifr equipment must be installed and operational.
Question 209-8 : Which of the following is the datum for altitude information when conducting flights under ifr conditions on airways using the navstar/gps satellite navigation system ?
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.
Question 209-9 : Which of the following statements about the visibility of navstar/gps satellites is correct ?
It varies, depending on the time and observer's location.
Question 209-10 : How many operational satellites are required for full operational capability foc of the satellite navigation system navstar/gps ?
24.
Question 209-11 : Which of the following satellite navigation systems has full operational capability foc and is approved for specified flights under ifr conditions in europe ?
Navstar/gps.
.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.
Question 209-12 : Gps system satellites transmit their signals on two carrier waves 1575 mhz and 1227 mhz and supply two possible codes accessible according to user civil or military..commercial aviation uses ?
Only the 1575 mhz carrier wave and one 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.
Question 209-13 : Which statement about dilution of precision dop is correct ?
The value of dop depends upon the geometry and number of satellites in view.
.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.
Question 209-14 : The different segments of the satellite navigation system navstar/gps are the ?
Control, space and user.
. 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.
Question 209-15 : One of the tasks of the control segment of the satellite navigation system navstar/gps is to ?
Monitor the status of the satellites.
. 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.
Question 209-16 : The main task of the user segment receiver of the satellite navigation system navstar/gps is to calculate receiver position by ?
Selecting appropriate satellites automatically, to track the signals and to measure the time taken by signals from the satellites to reach the receiver.
. 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.
Question 209-17 : One of the tasks of the space segment of the satellite navigation system navstar/gps is to ?
Transmit signals which can be used, by suitable receivers, to determine time, position and velocity.
.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.
Question 209-18 : In civil aviation, the height value computed by the receiver of the satellite navigation system navstar/gps is the ?
Height above the wgs 84 ellipsoid.
.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.
Question 209-19 : In relation to the satellite navigation system navstar/gps, the term inclination denotes the angle between the ?
Orbital plane and the equatorial plane.
. 2606.the orbital planes of the satellite navigation system navstar/gps are inclined 55° to the equatorial plane.
Question 209-20 : How long does it take a navstar/gps satellite to orbit the earth ?
Approximately 12 hours.
. 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.
Question 209-21 : At what approximate height above the wgs 84 ellipsoid are navstar/gps satellites circling the earth ?
20200 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.
Question 209-22 : In which frequency bands are the l1 and l2 frequencies used by the satellite navigation system navstar/gps for transmission of the navigation message ?
Uhf.
.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.
Question 209-23 : In relation to the satellite navigation system navstar/gps, which of the following statements correctly describes the term pseudo random noise prn signal ?
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.
.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.
Question 209-24 : Which of the following navstar/gps satellite navigation system codes can be processed by unauthorised civil aviation receivers ?
C/a.
.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.
Question 209-25 : Almanac data stored in the receiver of the satellite navigation system navstar/gps is used for the ?
Fast identification of received signals coming from visible satellites.
.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.
Question 209-26 : How does a navstar/gps satellite navigation system receiver recognise which of the received signals belongs to which satellite ?
Each satellite transmits its signal, on common frequencies, with an individual pseudo random noise code.
Question 209-27 : Which of the following data, in addition to the pseudo random noise prn code, forms part of the so called 'navigation message' transmitted by navstar/gps satellites ?
Almanac data satellite status information.
.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.
Question 209-28 : What is the time taken to receive the complete navigation message complete set of data from all satellites ?
12.5 minutes = 30 seconds per data frame.
Question 209-29 : Which of the following statements concerning the l1 and l2 navstar/gps transmission frequencies and codes is correct ?
The higher 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.
Question 209-30 : Which one of the following errors can be compensated for by a navstar/gps receiver comparing l1 and l2 frequencies ?
Ionospheric delay.
.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.
Question 209-31 : Concerning the navstar/gps satellite navigation system, what is the meaning of the term receiver autonomous integrity monitoring raim ?
It is a technique by which a receiver ensures the integrity of the navigation information.
.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.
Question 209-32 : What is the inclination to the equatorial plane of the satellite's orbit in the navstar gps constellation ?
55°.
. 2606.the orbital planes of the satellite navigation system navstar/gps are inclined 55° to the equatorial plane.
Question 209-33 : In respect of the use of gnss, dilution of precision dop is a loss of accuracy due to ?
Relative position of the visible 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.
Question 209-34 : Which one of the following is an advantages of a multi sensor system using inputs from a global navigation satellite system gnss and an inertial reference system irs ?
The gnss can be used to update the fms position from a drifting irs.
.what is a multi sensor system in aviation, it's a fmc flight management computer..informations received from a gnss are well more accurate than an ins, while computing our position from different sources, the fmc can use gnss position to continuously correct the information received from the ins. we will not correct physically the drift.
Question 209-35 : What type of clock is used in navstar gps satellites ?
Atomic.
Question 209-36 : How many clocks are installed in each navstar gps satellite ?
4.
Question 209-37 : What is egnos european global navigation overlay system ?
Wide area differential gps wadgps.
. egnos european geostationary navigation overlay service consists of 3 geostationary inmarsat satellites which broadcast gps look alike signals...egnos is designed to improve accuracy to 1 2m horizontally and 3 5 m vertically..integrity and safety are improved by alerting users within 6 seconds if a gps malfunction occurs up to 3 hrs gps alone... wadgps is an acronym for wide area differential gps. it's a general term for solutions used to enhance gps accuracy over large areas e.g., north america or europe...wadgps solutions usually use a network of ground based stations that compare their precisely known location with locations calculated from gps satellite signals. any differences found can be used to create correction data that's broadcast from satellites....satellite based augmentation systems include. egnos in western europe and the mediterranean. waas in usa. msas in japan. gagan in india
Question 209-38 : In accordance with icao annex 10 the navstar/gps global average 95% position accuracy in sps should be ?
13 m horizontally.
.the us department of defense has released the new gps performance standard in october, 2001 taking into account the new levels of performance achievable without sa selective availability. according to the revised performance standard for gps sps standard positioning service , positioning accuracy standards are given as dod, 2001 ..global average positioning domain accuracy..= or < 13 meters 95% all in view horizontal error signal in space only..= or < 22 meters 95% all in view vertical error signal in space only
Question 209-39 : In relation to the satellite navigation system navstar/gps, all in view is a term used when a receiver ?
Is tracking more than the required 4 satellites and can instantly replace any lost signal with another already being monitored.
Question 209-40 : The gps control segment consists of ?
A master control station, monitor stations and ground antennas.
.the control segment permits to ensure that the transmitted data of the satellites is controlled and updated from time to time by ground stations... main tasks of the control segment are. managing sps performance. navigation data upload. monitoring satellites..the control segment comprises. a master control station. ground antenna. monitoring stations..for information.the space segment consists of a notional constellation of 24 operational satellites...the user segment is the gps receiver side.
~
Exclusive rights reserved. Reproduction prohibited under penalty of prosecution.
