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The tracking performance of a Phase Lock Loop (PLL) is affected by the influence of several error sources. In addition to thermal noise and dynamic stress error, oscillator phase noise can cause significant phase jitter which degrades the tracking performance. Oscillator phase noise is usually caused by two different effects: Allan deviation phase noise is caused by frequency instabilities of the receiver's reference oscillator and the satellite's frequency standard. It can be termed as system-inherent phase noise and is relevant for both static and dynamic applications. “External” phase noise, however, is caused by vibration and is a major problem for dynamic applications. In the context of this paper, both types of phase noise will be modeled and the resulting integrals will be evaluated for PLLs up to the third order. Besides, phase jitter induced by thermal noise and signal dynamics will also be discussed, thus providing all necessary formulas for analyzing the performance of a phase lock loop in case of different forms of stress. Since the main focus is centered on the effects of oscillator phase noise, the overall PLL performance is graphically illustrated with and without consideration of oscillator phase noise. © 2002 Wiley Periodicals, Inc. 相似文献
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Christian Tiberius Thomas Pany Bernd Eissfeller Peter Joosten Sandra Verhagen 《GPS Solutions》2002,6(1-2):96-99
In this short contribution it is demonstrated how integer carrier phase cycle ambiguity resolution will perform in near future,
when the US GPS gets modernized and the European Galileo becomes operational. The capability of ambiguity resolution is analyzed
in the context of precise differential positioning over short, medium and long distances. Starting from dual-frequency operation
with GPS at present, particularly augmenting the number of satellites turns out to have beneficial consequences on the capability
of correctly resolving the ambiguities. With a 'double' constellation, on short baselines, the confidence of the integer ambiguity
solution increases to a level of 0.99999999 or beyond.
Electronic Publication 相似文献
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The location requirements for emergency callers outside urban areas can hardly be fulfilled without global navigation satellite
systems (GNSS). Consequently, interest in positioning techniques based on use of a GNSS such as GPS or on the cellular network
infrastructure itself is growing rapidly in the mobile-telephone community. Moreover, the increasing demand for commercial
location-based services (LBS) has driven cellular-phone and network manufacturers to focus on positioning solutions which
are even more accurate than the regulatory mandates for positioning of emergency callers. One example of these upcoming LBS
is our PARAMOUNT project, which aims at improving user-friendly info-mobility services for hikers and mountaineers by combining
wireless communications (GMTS), satellite navigation (GNSS) and geographic information systems (GIS), based on a mobile client/server
architecture. The availability of mobile phones or PDAs with combined GNSS and cellular network-based wireless communication
on a high integration level is one primary demand of such LBS applications. Based on this, we will give some initial answers
to the question of whether mobile handset architecture synergies exist for the combination of GNSS with wireless location
in CDMA cellular wireless networks. In order to identify synergies, we will outline similarities and differences between wireless
communication and satellite navigation. In this respect, we pay particular attention to the so-called RAKE receiver architecture
employed in mobile CDMA cellular handsets. Our initial investigations will show that the RAKE receiver architecture, on which
mobile CDMA cellular handsets are based, will most likely be the one most suitable for achieving synergies between the two
positioning techniques within the same mobile handset architecture. Consequently, several receiver components could be used
to handle both types of signals (navigation and communications), resulting in a reduction of manufacturing costs and in a
decrease in energy consumption.
Electronic Publication 相似文献
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Bernd Eissfeller 《Journal of Geodesy》1996,70(9):539-545
Linear gravity field state space models are still a useful tool to model the anomalous gravity field in vector gravimetry, airborne gravimetry, inertial geodesy and navigation. This paper deals with an idea ofJordan and Heller (1978) to solve analytically the upward continuation problem of Markov gravity models.In contrary to the standard Markov shaping filter approach the height dependency of the covariance function, i.e. variance factor and correlation length as function of height, is strictly introduced in state space and not neglected. Using some basic integral transforms, a general upward continuation integral is derived for the n-th order Markov process. The upward continuation integral is solved for the special and practically important case of 2nd order Markov process in very detail. This leads to the introduction of the special sine and cosine integral functions into the the mathematical covariance model. The features of the covariance model are analyzed analytically and the height dependency is discussed numerically. 相似文献
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In contrast to continuous global considerations of time dependent boundary value problems an attempt is made to define4D-linear observation equations in the framework of integrated geodesy for discrete, more or less regional and local applications
(deformation analysis) where time variations in position and in the gravity field have to be considered. The derivation is
a strict analogue and extension of the3D integrated approach. In addition the construction of time dependent covariance functions is discussed, which are necessary
to solve for unknown displacements and changes in the gravity potential in the generalized least squares collocation model. 相似文献
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