TERMIUM Plus^®

Record 1,  Textual support,  French

Record 1,  Textual support,  Spanish

Record 2,  Textual support,  English

Record number: 2, Textual support number: 1 CONT

The gyros are used to maintain the platform’s inertial orientation by sensing rotations of the platform caused by vehicle-rotation-induced friction at the gimbal pivot points ... One gyro - called the vertical gyro - is oriented so its input axes are aligned with the X and Y platform axes; its input axes provide IMU [Inertial Measurement Unit] platform roll and pitch stabilization. The second gyro is oriented so that one input axis lies along the platform’s Z axis and the other lies in the X-Y plane. This gyro - the azimuth gyro - provides platform yaw stabilization with the Z input axis, while the second input axis is used as a platform rate detector for built-in test equipment.  3, record 2, English, - azimuth%20gyroscope

Record number: 2, Textual support number: 2 CONT

The sensors for angular velocity are vibrating gyroscopes(3 axes, to detect rotation and pitch/roll pendulations of the payload). An error signal is obtained differencing the signal from the azimuth gyroscope and a constant level settable from the telemetry, which controls the speed of rotation. Such error signal drives an analog PID [Proportional Integral Differential] circuit; the output of the PID is connected to the PWM [Pulse Width Modulation] driver supplying current to the pivot azimuth motors.  3, record 2, English, - azimuth%20gyroscope

Record number: 2, Textual support number: 3 CONT

azimuth gyro: term used at Natural Resources Canada - Earth Sciences Sector.  4, record 2, English, - azimuth%20gyroscope

Record number: 2, Textual support number: 1 PHR

Azimuth gyro drift rate.  5, record 2, English, - azimuth%20gyroscope

Record 2,  Textual support,  French

Record number: 2, Textual support number: 1 CONT

La plate-forme stabilisée [...] Trois gyroscopes sont utilisés : (a) Un gyroscope d'azimut qui, n'ayant aucun degré de liberté dans l'axe vertical, détecte tout déplacement de la plate-forme en azimut. (b) Deux gyroscopes d'inclinaison [...]  3, record 2, French, - gyroscope%20d%27azimut

Record number: 2, Textual support number: 1 OBS

gyroscope d'azimut : terme en usage à Ressources naturelles Canada - Secteur des sciences de la Terre.  4, record 2, French, - gyroscope%20d%27azimut

Record number: 2, Textual support number: 1 PHR

Vitesse de dérive du gyroscope d'azimut.  5, record 2, French, - gyroscope%20d%27azimut

Record 2,  Textual support,  Spanish

Record 3,  Textual support,  English

Record number: 3, Textual support number: 1 DEF

Describes the method of error checking in which data written to an optical disk during one disk rotation is read for accuracy on the subsequent rotation. Recorded data on an optical disk may be read immediately after writing(recording) ;no processing is required. This allows error free recording in a single pass because whenever a written sector of data contains errors it is immediately rewritten.  3, record 3, English, - direct%20read%20after%20write

Record number: 3, Textual support number: 2 DEF

A laser-based technology for recording data on a videodisk.  4, record 3, English, - direct%20read%20after%20write

Record 3,  Textual support,  French

Record number: 3, Textual support number: 1 OBS

Cette lecture s'effectue aux fins de contrôle.  3, record 3, French, - contr%C3%B4le%20en%20cours%20d%27enregistrement

Record 3,  Textual support,  Spanish

Record number: 3, Textual support number: 1 DEF

Operación en que los datos registrados en un disco de video se leen inmediatamente después de registrarse de modo que puedan detectarse los errores; los errores no se pueden borrar ni sobrescribir en esta clase de disco, pero los datos pueden corregirse y volverse a escribir en una nueva ubicación. Entonces se dirige a la computadora (ordenador) a dicha nueva ubicación de modo que se ignore la sección que contiene el error.  1, record 3, Spanish, - lectura%20directa%20despu%C3%A9s%20de%20la%20escritura

Record 4,  Textual support,  English

Record number: 4, Textual support number: 1 DEF

The error resulting from angular displacements of gimbals from their reference positions such that gimbal pick offs do not measure the true angular motion of the case about the input reference axis.  2, record 4, English, - gimbal%20error

Record number: 4, Textual support number: 1 CONT

Any rotation of the outer gimbal(of a directional gyro) changes the relative position of the compass card and the pointer, resulting in an erroneous reading.... This error is called gimbal error.  3, record 4, English, - gimbal%20error

Record 4,  Textual support,  French

Record number: 4, Textual support number: 1 CONT

Il y a une erreur de transmission des rotations relatives de l'axe du gyro à la rose des caps due à la cinématique de la suspension à la cardan [...] Cette erreur, variable selon le cap de l'avion [...] est dite erreur de cardan.  2, record 4, French, - erreur%20de%20cardan

Record number: 4, Textual support number: 1 OBS

erreur de cardan : terme uniformisé par le Comité d'uniformisation de la terminologie aéronautique (CUTA) - opérations aériennes.  3, record 4, French, - erreur%20de%20cardan

Record 4,  Textual support,  Spanish

Record 5,  Textual support,  English

Record number: 5, Textual support number: 1 CONT

SYLLABUSes OF EXAMINATIONS... Gyro Compass. Properties of the free gyroscope; relationship between applied force and precession; effect of the earth's rotation on a free gyroscope, drift and tilt; errors associated with gyro compasses; latitude, course and speed error, ballistic deflection, rolling error; latitude, course and speed correction; fundamental classes of gyro compass...  2, record 5, English, - roll%20error

Record 5,  Textual support,  French

Record number: 5, Textual support number: 1 CONT

Programme des examens [...] Compas gyroscopiques : Les propriétés du gyroscope libre, la relation entre la force appliquée et la précession, l'effet de la rotation de la Terre sur un gyroscope libre, la dérive et l'inclinaison les erreurs associées aux compas gyroscopiques, l'erreur de latitude, de route et de vitesse, la déflexion balistique et l'erreur de roulis, la correction des erreurs de latitude, de route et de vitesse, les principales catégories de compas gyroscopiques [...]  2, record 5, French, - erreur%20de%20roulis

Record 5,  Textual support,  Spanish

Record 6,  Textual support,  English

Record number: 6, Textual support number: 1 CONT

The vacuum-drive heading indicator is the simplest of many types of gyro-controlled directional indicators designed to provide stable heading reference.... Errors. The chief cause of precession, causing the card to creep or drift, is bearing friction. Normal movement of the gimbal rings produces friction, which is increased if the bearings are worn, dirty, or improperly lubricated. Other sources of precession error include unbalanced gyro components and the effect of the earth's rotation. The latter effect depends upon the position of the instrument in relation to the earth, and is not appreciable unless a flight involves considerable change in latitude.  1, record 6, English, - unbalanced

Record number: 6, Textual support number: 2 CONT

Unsymmetrical gyroscope.  2, record 6, English, - unbalanced

Record number: 6, Textual support number: 1 OBS

mass unbalance: The characteristic of a gyro resulting from lack of coincidence of the center of supporting forces and the center of mass. It gives rise to torques caused by linear accelerations that lead to acceleration-sensitive drift rates.  2, record 6, English, - unbalanced

Record 6,  Textual support,  French

Record number: 6, Textual support number: 1 CONT

Garde-cap. Il s'agit d'un gyroscope que l'on maintient horizontal et qui définit une direction fixe dans le plan horizontal à sa dérive près. Le gyroscope est monté à la Cardan comme dans le cas du compas mais il n'est pas balourdé. Un détecteur d'horizon monté sur la caisse de tore délivre un signal proportionnel à l'inclinaison du moment cinétique; ce signal est traité et est envoyé dans un moteur couple d'axe cd qui crée un couple vertical ramenant le moment cinétique horizontal.  3, record 6, French, - balourd%C3%A9

Record number: 6, Textual support number: 2 CONT

Gyroscope balourdé.  4, record 6, French, - balourd%C3%A9

Record number: 6, Textual support number: 1 OBS

balourd : Mauvaise répartition des masses d'une pièce ou d'un ensemble tournant, qui fait que son centre de gravité n'est pas sur l'axe de rotation.  5, record 6, French, - balourd%C3%A9

Record 6,  Textual support,  Spanish

Record 7,  Textual support,  English

Record number: 7, Textual support number: 1 CONT

Where positioning accuracy is concerned, it may seem surprising that the accuracy provided by the gyros has more impact than that of the accelerometers... This is due to the fact that navigation in fact occurs on a sphere, the Earth. It will therefore be readily understood that traveling along a straight line on the Earth comes down in fact to a rotation, and that rotation is detected by the gyros. In practice, gyros are subject to a zero-error known as gyro bias : When there is no rotation, a gyro should indicate zero, but in fact measures something that is the bias value. When an inertial navigation system is immobile, the gyros measure bias values that are integrated by the calculator and the unit thinks that it is rotating, and therefore advancing across the surface of the terrestrial globe, which generates a position error. It will be understood that position error shows linear growth over time and there is a direct relationship between the accuracy of a gyro and position drift.  1, record 7, English, - zero%2Derror

Record 7,  Textual support,  French

Record number: 7, Textual support number: 1 CONT

Les erreurs de mesure des gyromètres laser peuvent être représentées par des modèles mathématiques beaucoup plus simples que ceux intervenant dans l'étude des gyromètres classiques. Cela résulte essentiellement de l'insensibilité des gyromètres laser aux accélérations. La description de l'erreur d'un gyromètre laser fait intervenir : a) une erreur de zéro, due à des différences de propriétés physiques pour les ondes circulant en sens inverse dans le mélange gazeux ionisé; [...] b) une erreur imputable au blocage [...] c) une erreur de facteur d'échelle [...]  2, record 7, French, - erreur%20de%20z%C3%A9ro

Record number: 7, Textual support number: 2 CONT

Performances et précisions des mesures (gyroscopes et gyromètres) [...] erreurs de zéro : nécessite un recalage par GPS toutes les 30 h .  3, record 7, French, - erreur%20de%20z%C3%A9ro

Record 7,  Textual support,  Spanish

Record 8,  Textual support,  English

Record number: 8, Textual support number: 1 CONT

Gyro Scale Factor Error : This is an indication of the angular error which occurs during rotation. E. g. with 300 ppm scale factor error(=0. 03%) the angular error is in the area of 0. 1 degree after one revolution.  2, record 8, English, - scale%20factor%20error

Record number: 8, Textual support number: 2 CONT

A gyro’s accuracy and performance can be judged by its output errors; for rate sensors the most important are: bias; scale factor error; noise... The scale factor error is the linear deviation of the measured rate from the true rate (normally given as a percentage of full scale).  3, record 8, English, - scale%20factor%20error

Record 8,  Textual support,  French

Record number: 8, Textual support number: 1 CONT

Les erreurs de mesure des gyromètres laser peuvent être représentées par des modèles mathématiques beaucoup plus simples que ceux intervenant dans l'étude des gyromètres classiques. Cela résulte essentiellement de l'insensibilité des gyromètres laser aux accélérations. La description de l'erreur d'un gyromètre laser fait intervenir : a) une erreur de zéro [...] b) une erreur imputable au blocage [...] c) une erreur de facteur d'échelle, beaucoup plus faible que dans le cas des gyromètres mécaniques, due à une stabilité imparfaite des propriétés physiques des éléments de l'appareil.  1, record 8, French, - erreur%20de%20facteur%20d%27%C3%A9chelle

Record 8,  Textual support,  Spanish

Record 9,  Textual support,  English

Record number: 9, Textual support number: 1 CONT

... for a mechanically dithered RLG [ring laser gyro], non-linearities(sidebands) appear in the input-output scale factor curve for an input rotation rate which is a harmonic of the dither frequency... There are two disadvantages to dithering. One is that the rotation rate periodically passes through zero where lock-in occurs. This results in a "random walk" angular position error. The other is that the vibration of the gyro body may affect other components or the gyro may be affected by other vibration sources. The laser gyro need not be mechanically dithered. The same result may be achieved by optical devices.  1, record 9, English, - mechanically%20dithered

Record number: 9, Textual support number: 1 OBS

dither: To periodically tilt from side to side.  2, record 9, English, - mechanically%20dithered

Record 9,  Textual support,  French

Record 9,  Textual support,  Spanish

Record 10,  Textual support,  English

Record number: 10, Textual support number: 1 CONT

... for a mechanically dithered RLG [ring laser gyro], non-linearities(sidebands) appear in the input-output scale factor curve for an input rotation rate which is a harmonic of the dither frequency... There are two disadvantages to dithering. One is that the rotation rate periodically passes through zero where lock-in occurs. This results in a "random walk" angular position error. The other is that the vibration of the gyro body may affect other components or the gyro may be affected by other vibration sources. The laser gyro need not be mechanically dithered. The same result may be achieved by optical devices.  1, record 10, English, - mechanically%20dithered%20RLG

Record number: 10, Textual support number: 1 OBS

dither: To periodically tilt from side to side.  4, record 10, English, - mechanically%20dithered%20RLG

Record 10,  Textual support,  French

Record 10,  Textual support,  Spanish

Record 11,  Textual support,  English

Record number: 11, Textual support number: 1 OBS

Orientation errors in letters: vertical rotation errors (as in d for b), horizontal rotation errors (as in b for p) or depth axis rotation errors (as in d for p). All except a very small proportion of rotation errors are vertical axis rotations (that is, reversals).  1, record 11, English, - rotation%20error

Record 11,  Textual support,  French

Record number: 11, Textual support number: 1 OBS

Inversions des lettres elles-mêmes, c'est-à-dire la confusion des lettres symétriques, par exemple b et d, q et p, etc.  1, record 11, French, - inversion%20statique

Record 11,  Textual support,  Spanish