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Though state-of-the-art dual-frequency receivers are employed in the continuous Global Positioning System (CGPS) arrays, the CGPS coordinate time series are typically very noisy due to the effects of atmospheric biases, multipath, receiver noise, and so on, with multipath generally being considered the major noise contributor. An adaptive finite-duration impulse response filter, based on a least-mean-square algorithm, has been developed to derive a relatively noise-free time series from the CGPS results. Furthermore, this algorithm is suitable for realtime applications.Numerical simulation studies indicate that the adaptive filter is a powerful signal decomposer, which can significantly mitigate multipath effects. By applying the filter to both pseudorange and carrier phase multipath sequences derived from some experimental GPS data, multipath models have been reliably derived. It is found that the best multipath mitigation strategy is forward filtering using data on two adjacent days, which reduces the standard deviations of the pseudorange multipath time series to about one fourth its magnitude before correction and to about half in the case of carrier phase. The filter has been successfully applied to the pseudorange multipath sequences derived from CGPS data. The benefit of this technique is that the affected observable sequences can be corrected, and then these corrected observables can be used to improve the quality of the GPS coordinate results.

The thin-film morphology, degree of crystallinity, as well as the electrical properties of triisopropylsilyl ͑TIPS͒ pentacene organic thin-film transistors ͑OTFTs͒ were significantly influenced by the solvent used for spin-coating a TIPS pentacene layer. The TIPS pentacene films spin-coated from solvents having high boiling points ͑chlorobenzene and xylene͒ showed dendritelike morphology and a higher degree of crystallinity, while TIPS pentacene spin-coated from solvent having a low boiling point ͑chloroform͒ showed amorphous-like morphology and a lower degree of crystallinity. The field-effect mobility of OTFTs fabricated from chlorobenzene was 4 ϫ 10 −2 cm 2 /V s, whereas mobility of 10 −4 to 10 −5 cm 2 /V s was achieved when using chloroform. This implies that the morphology, crystallinity, as well as the electrical properties of TIPS pentacene have a strong dependence on the solvent used for spin-coating.Organic thin-film transistors ͑OTFTs͒ have attracted considerable attention in flexible electronics such as displays, 1,2 sensors, 3 and radio-frequency identification tags 4 due to their potential advantages of low-cost manufacturing, simple device architecture, and lowtemperature process. Similar to organic light-emitting diodes ͑OLEDs͒, the technologies of OTFTs can be categorized into two distinct groups based on the channel material, small molecule and polymer. Pentacene-based OTFTs have been intensively studied until recently due to their superior electrical properties such as high field-effect mobility up to 7 cm 2 /V s and high current on/off ratio. 5 Polymer-based OTFTs also have been widely investigated using polymer materials such as poly͑3-hexylthiophene͒ and poly͑9,9-dioctylfluorene-co-bithiophene͒. 6,7 However, the major problem of polymer-based OTFTs is that they exhibit a rather low field-effect mobility of 0.2 cm 2 /V s, which limits its application to low-end technologies.Although pentacene OTFT exhibits fairly good electrical characteristics, the rather poor electrical reliability may be a critical problem and may not be a proper solution for large-area applications because a rather costly vacuum deposition process is needed. Thus, in order to realize OTFTs having reasonable electrical characteristics and comparability to low-cost manufacturing, new pentacene derivatives have been suggested as channel material. 8-10 To increase the solubility of pentacene, functionalized side groups are attached to the pentacene backbone. Several works have been reported and these include triisopropylsilyl ͑TIPS͒ pentacene, 8 pentacene-N-sulfinylmethacrylamide 9 and many other derivatives. 10 In these materials, TIPS pentacene is intensively studied due to its high electrical performance.The focus of this work is to investigate the influence of solvent on the thin-film morphology, degree of crystallinity, and electrical properties of spin-coated TIPS pentacene OTFTs because these properties are closely related to each other. The thin-film morphology and degree of crystallinity of TIPS pentacene were signifi...

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This paper compares the interpolation methods used in network‐based GPS techniques, including the linear combination model, distance‐based linear interpolation method, linear interpolation method, lower‐order surface model, and least‐squares collocation. The advantages and disadvantages of each method are discussed. All of the methods use an n‐1 independent error vector generated from a network of n reference stations to model the distance‐dependent biases at the user station. General formulas for all of the methods involve first computation of the n‐1 coefficients, and then formation of an n‐1 linear combination with an n‐1 error vector from the reference stations to mitigate the spatially correlated errors for the user station(s). Test results from multiple reference stations show that all of the methods can significantly reduce the distance‐dependent biases at the GPS user station. The performance of all the methods is comparable.