Adaptive jitter control for tracker line of sight stabilization. Jitter performance is given in terms ofthe strehl ratio ofthe optics system in the farfield. A stabilized optical lineofsight system incorporating an ata oiru is designed to reject broadband jitter. Lineofsight jitter of the hubble space telescope deepdyve. Reducing spacecraft jitter during satellite reorientation. Jitter overview the jitter working group of the fibre channel industry association1, after countless cups of highoctane coffee, produced a groundbreaking report. Modeling the rv jitter of early m dwarfs using tomographic. The test, which made use of one of the science instruments on board the spacecraft, had a very high sensitivity a fraction of a milliarcsecond and covered all frequencies up to 500 hz. The period of each cycle of the oscillator is different, due to the noiseinduced jitter. A study of reaction wheel disturbance modeling approaches for. Electrooptical eo imaging sensors mounted on a mobile platform usually require some form of control to stabilize the sensor. Line of sight definition and meaning collins english. The effect of jitter on an imaging ftir spectrometer charles l. Pdf robust lineofsight stability and jitter compensation.
Ease of use let engineers focus on analyzing their designs rather than learning how to use test equipment. Integrated lineofsight modeling of the airborne aero. Jbert combines all these jitter types to create such a compliance eye needed for receiver jitter tolerance testing. Sightline jitter minimization and shaping using nonlinear friction compensation article pdf available in international journal of optomechatronics. High frequency design jitter fundamentals from april. Acquisition, tracking, pointing, and line of sight control laboratory experiments for a spacebased bifocal relay mirror.
A survey of reaction wheel disturbance modeling approaches for spacecraft line of sight jitter performance analysis cornelius j. Aaol for prediction of optical jitter due to flight disturbances. So if we measure sigma is 10 picoseconds, then we would say the random jitter is 141 psec. Disturbance inputs include measured inflight base loading and measured pressure. Strehl ratio is defined as the ratio ofthe peak intensity of the transmitted beam in the farfield divided by the peak intensity of an ideal transmitted beam. To diagnose the rv jitter, several complementary approaches are commonly used, mostly making use of chromospheric activity indicators like excess. A study of reaction wheel disturbance modeling approaches. Jun 23, 2016 what is acceptable jitter jitter is the irregular time delay in the sending of data packets over a network. Abstract a central aspect in the design of the mars lasercom terminal was limiting the line of sight jitter of the optical payload due to translational and angular dynamic excitation from the host spacecraft. After implementing the optical jitter blur in a baseline high resolution image, the simulation considerably reduced the frames spatial resolution and intensity. For obstacles that intrude into the first fresnel zone but do. The lineofsight is the vector drawn between an imaging sensor and target. To accomplish this, an integrated lineofsight model was derived from a finite element model of the system, optical sensitivities and control loops for calculation of closed loop, lineofsight jitter.
Satellite platform jitter is an important factor restricting the imaging quality of highresolution hr optical satellite images. An example of correlated aperiodic jitter is interference on a. Oct 25, 2016 the jitter and total delay are not even close to be the same thing. Jitter in ip networks is the variation in the latency on a packet flow between two systems, when some packets take longer to travel from one system to the other. An observer will thus be in a particles radiative cone over some length of its accelerated path, until the particle direction is suf. Robust lineofsight stability and jitter compensation. The airborne aerooptics laboratory aaol was designed to measure the effects of turbulent flow on the wavefront of a laser projected from an airplane in flight. Desplats matra marconi space, 31 rue des cosmonautes, 31077 toulouse cedex, france abstract the semiconductor laser intersatellite link experiment silex is a very innovative program of the european. Image jitter detection and compensation using a high. Figure 1 sdo jitter test plan and disturbancetoperformance flow ii. Line of sight jitter analyses were performed on the mars terminal payload that accounted for the passive and active stabilization systems. Jitter test program and onorbit mitigation strategies for. If you just want to add jitter to the lines in the plot, the following code will do it. A psychophysical experiment with 12 observers found that the expanding visual inducer, which contained rotational jitter around the observers line of sight, can induce stronger forward vection than a pure radial expansion without any additional jittering component.
The sda measures the jitter pdf by collecting a histogram of tie measurements. Structural lineofsight jitter analysis for mlcd deepdyve. The line of sight stabilization and tracking control based on gyro stabilized platform is required to. Since the process requires multiple samples to effect cancellation, the performance of the process is dependent on the stability of the line of sight over the collection interval. Jul 09, 2015 jitter in ip networks is the variation in the latency on a packet flow between two systems, when some packets take longer to travel from one system to the other. Integrated lineofsight modeling of the airborne aerooptics. The effect of jitter on an imaging ftir spectrometer. Broadband line quality test check your internet connection. In order to suppress the lf noise component which occurs due to accumulated noise errors during reconstruction, a complementary filter is employed which provides low spatial frequency data from the original. Dynapak 16 3axis ars16 sensor packages the dynapak 16 is designed to measure angular jitter from terrestrial, airborne, and spacecraft mirrors, optical systems or lasers, and for accurate line of sight imaging and platform stabilization. Understanding jitter, its components, and separation. The lineofsight jitter induced by the onboard disturbance sources is a major contributor to th e overall pointing performance.
We characterize the radio frequency dependence of jitter using data on 48 pulsars in the north american nanohertz observatory for gravitational waves timing program. A heuristic discussion of fibre channel and gigabit ethernet methods 1. Correlated jitter on a clock is deterministic and always caused by and correlated to a noise source. Structural lineofsight jitter analysis for mlcd structural lineofsight jitter analysis for mlcd doyle, keith b. A survey of reaction wheel disturbance modeling approaches for spacecraft lineofsight jitter performance analysis cornelius j. Sep, 2007 structural line of sight jitter analysis for mlcd structural line of sight jitter analysis for mlcd doyle, keith b. An integrated lineofsight model that predicts closedloop jitter of the aaol system is presented. Directed energy beam jitter mitigation using the lineofsight. Having a lot of jitter in the network will probably increase the total delay to, but this should be avoided. Jitter transfer sonetsdhjitter transfer sonetsdh clock recovery performance as a function of jitter frequency. Request pdf adaptive jitter control for tracker line of sight stabilization a field test experiment on a range tracking telescope at the u.
We report on the results of a dedicated onorbit test which we have performed to measure the line of sight jitter of the hubble space telescope. Design and optimal control of line of sight stabilization of moving target ajeet singh1, ritula thakur2, dr. Structural lineofsight jitter analysis for mlcd spie digital library. Lineofsight jitter of the hubble space telescope nasaads. Jitter period is the interval between two times of maximum effect or minimum effect of a signal characteristic that varies regularly with time. Your line of sight is an imaginary line that stretches between your eye and the object. This allows our test to see if there is any packet loss, what the average network latency of your line is and provides a jitter measure. Mechanisms mounted on the observatorys spacecraft bus are typically the source of jitterproducing disturbances.
The mission requirements are for a 3m spot beam on the ground, jitter less than 144 nanoradians, and 250 seconds mean dwell duration per pass. Extrapolating the pdf measuring the total jitter requires that the probability density function of the jitter is known exactly. Jitter is especially problematic in realtime communications like ip telephony and video conferencing. Dynapak 16 3axis ars16 sensor packages the dynapak 16 is designed to measure angular jitter from terrestrial, airborne, and spacecraft mirrors, optical systems or lasers, and for accurate lineofsight imaging and platform stabilization. Robust lineofsight stability and jitter compensation using spatio temporalfiltering based control approaches. Lineofsight jitter analyses were performed on the mars terminal payload that accounted for the passive and active. We report on the results of a dedicated onorbit test which we have performed to measure the lineofsight jitter of the hubble space telescope. The line test above works by sending packets from our server straight to your computer and reporting as it is doing so. Lineofsight jitter analyses were performed on the mars. Design and optimal control of line of sight stabilization of. The jitter and total delay are not even close to be the same thing. Jitter results from network congestion, timing drift and route changes.
This histogram approximates the pdf by counting the number of edges occurring within the time period delimited by each bin in the histogram. The influence of model uncertainty with model tuning based on. Robust line of sight stability and jitter compensation using spatiotemporalfiltering based control approaches stuart j. Historically, reaction wheels rws have been the principal sources of spacecraft onboard disturbances on nasa and esa missions. Rotational jitter around the observers line of sight can. It will usually mean that, because there is more jitter, you need more jitter buffer, to be able to compensate. The allowable jitter is a function of the sensor resolution and beam width of the. Acceptable jitter means what we are willing to accept as the irregular fluctuations in. Previous studies have shown that the addition of jittering motion into a visual inducer facilitates vection.
Pdf sightline jitter minimization and shaping using nonlinear. Integrated analysis, fea, optomechanics, lineofsight jitter, mtf, random. Line of sight jitter of the hubble space telescope bely, pierre y. Llcd experimental lineofsight jitter testing springerlink. Line of sight jitter analyses were performed on the mars terminal payload that accounted for the passive and active stabilization systems, the elastic response of the payload, and the detailed elastic characteristics of the isolator. An integrated line of sight model that predicts closedloop jitter of the aaol system is presented. Nonline of sight nlos refers to the path of propagation of a radio frequency rf that is obscured partially or completely by obstacles, thus making it difficult for the radio signal to pass through. E student1, assistant professor2, professor and head3 department of electrical engineering, nitttr, chandigarh abstract. An example of correlated aperiodic jitter is interference on a clock from a serial line. Home proceedings volume 6665 article translator disclaimer. Effect of jitter on an imaging ftir spectrometer unt. Apply sinusoidal jitter of specified amplitude and frequency. Random jitter is unbounded, if we wait long enough we would have hits anywhere in the eyediagram.
Frictioninduced sightline jitter significantly degrades the image resolution and detection range of a stabilised optical system. As was previously known from gyroscope data analysis, the bulk. Robust lineofsight stability and jitter compensation using spatiotemporalfiltering based control approaches stuart j. Reaction wheel disturbance modeling, jitter analysis, and. Sightline jitter minimization and shaping using nonlinear friction. Jitter noun the short term phase variation of the significant instants of a digital signal from their ideal positions in time. Using high speed scope for digital jitter measurements. This reduces system complexity and cost by eliminating the need to mitigate vibration at every source.
To address the critical issue of compensation for attitude jitter in hr images, this paper proposes a steadystate reimaging model using highfrequency angular displacement data to detect and compensate for the attitude jitter of hr images. We could use any berr but 1012 is quite common to use and 1012 equals to 14. Lineofsight jitter of the hubble space telescope lineofsight jitter of the hubble space telescope bely, pierre y. Robust lineofsight stability and jitter compensation using. An example of correlated jitter is periodic jitter, as in the case of a system power supply. Dynapak 16 triaxial sensor packages provide a wide bandwidth angular rate. Pdf sightline jitter minimization and shaping using. Random jitter is assumed to follow a gaussian distribution and is defined by the mean and sigma of that gaussian distribution. Design and optimal control of line of sight stabilization. The automated jitter tolerance compliance just measures the compliance curve again. Lineofsight jitter of the hubble space telescope 1993. Confidence in measurement results repeatability from one test system to the next. Both additive noise and jitter on the line of sight contribute to errors in the reconstruction of. A central aspect in the design of the mars lasercom terminal was limiting the lineofsight jitter of the optical payload due to translational and angular dynamic excitation from the host spacecraft.
Both additive noise and jitter on the line of sight contribute to errors in the reconstruction of the pattern from dither scan samples. Common obstacles between radio transmitters and radio receivers are tall buildings, trees, physical landscape and highvoltage power. Structural lineofsight jitter analysis for mlcd 2007. Subject terms laser, directed energy, lineofsight, beam control, jitter. The test, which made use of one of the science instruments on board the spacecraft, had a very high. Acquisition, tracking, pointing, and lineofsight control.
Conference proceedings of the society for experimental mechanics series. Line of sight jitter of selex optical terminals, analysis and verification activities ph. This assumes that the gaussian rj pdf appends to the dj pdf. The performance of laser optic systems depends on how well jitter can be reduced or eliminated. Jitter is a statistical measure of a noisy oscillation process. Bennett lawrence livermore national laboratory, l45, livermore, ca. Acquisition, tracking, pointing, and lineofsight control laboratory experiments for a spacebased bifocal relay mirror. This accurate line quality test can alert you to any potential problems on your adsl line. Jitter frequency, the more commonly quoted figure, is its inverse. This formulation is not valid for many space systems, but is important in stellar interferometers, large monolithic space telescopes, and. Lineofsight jitter of selex optical terminals, analysis and verification activities ph.
1353 1319 777 804 1140 1249 574 222 61 643 247 652 1281 877 707 98 1348 888 1314 83 1017 779 736 725 1178 1520 810 695 1030 832 1359 464 300 917 245 36 220 764 773 769 373