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The increases in the nucleation density and the crystal growth rate and change of morphology of the diamond thin films synthesized by DC-plasma CVD (Chemical Vapor Deposition) under the hypergravity condition are confirmed. To explain the reason for these effects, in-situ plasma diagnostics that enables to identify the active species in the plasma is studied.

This paper discusses the implementation of a modified IEEE 802.11 transceiver that is employed to enhance the positioning capabilities of a traditional vehicle on-board navigation unit (OBU). In this paper, we propose to use the current wireless local access network (WLAN) as enhancing infrastructure for ubiquitous localisation and positioning. We describe the architecture of a localisation receiver built around a FPGA that is capable of measuring the signal round trip time and thus distance between itself and visible WiFi access points. The proposed system has great potentials to enhance the performance of traditional hardware solutions often based on GNSS plus INS traditionally used as fundamental component in an intelligent transportation system. The proposed system offers vehicle-to-vehicle communication and ranging capabilities using the current IEEE 802.11 standard. This paper describes the details of the WLAN ranging estimation method, possible integration approaches with a GPS plus INS system and an analysis of the proposed system’s positioning performance in a crowded urban environment., Peer Reviewed, Preprint

This dissertation presents a novel satellite timekeeping system which does not require on-board atomic clocks as used by existing navigation satellite systems such as GPS, GLONASS or the planned GALILEO system. This concept is differentiated by the employment of a synchronization framework combined with lightweight steerable on-board clocks which act as transponders re-broadcasting the precise time remotely provided by the time synchronization network located on the ground. This allows the system to operate optimally when satellites are in direct contact with the ground station, making it suitable for a system like the Japanese Quasi-Zenith Satellite System, QZSS. Low satellite mass and low satellite manufacturing and launch cost are significant advantages of this novel system. Two possible implementations of the time synchronization network for QZSS are presented. Additionally, the problem of satellite communication interruption is analyzed and a solution is presented. Finally a positioning and timing quality analysis, aimed to provide understanding of the actual timing quality requirements for QZSS, is presented.

We have developed a new control method for the quasi-zenith satellite (QZS) remote synchronization system for the onboard crystal oscillator (RESSOX). The new method utilizes L1 and L2 positioning signals of the QZS system. We have proved that precise orbit prediction or estimation of delays such as those caused by the ionosphere and troposphere is not necessary to realize RESSOX technology. L1/L2/Ku-band signal delay caused by the ionosphere and other sources is calculated separately using RESSOX feedback control. The results of Ku-band delay are used to generate the appropriate control signal. The results show that synchronization within 2 ns between the ground-site atomic clock and the QZS site is achievable. We also confirmed that the crystal oscillator that has the same specifications as the actual onboard crystal oscillator could be controlled by the same method as the prototype in the test bed., See also ADM002029. Presented at the Annual Precise Time and Time Interval (PTTI) Meeting (38th), held in Reston, VA, on 5-7 Dec 2006. Published in the proceedings of the meeting, p153-174, 2007. Prepared in cooperation with University of Tokyo, Japan; Space Engineering Development Company, Japan; and University of New South Wales, Australia. The original document contains color images.

A positioning performance analysis of the RESSOX synchronizationnetwork for the Japanese Quasi-Zenith Satellite System, QZSS, is presented.A hardware-in-the-loop experiment setup has been developed to studyconcrete effects on positioning when a real space-born OCXO is employedin the atomic clock-less RESSOX architecture. This study focuses on apositioning performance analysis of QZSS used in conjunction with GPS.Particular focus is given to the effects of faulty synchronization onpositioning, specifically when, because of unavoidable communicationinterruptions, the QZSS satellite clock has to function without remotecontrol. Results show that the recently proposed RESSOX phase errorcompensation method can guarantee enough time accuracy even forcommunication interruptions of the order of one hour. The relationshipbetween QZSS plus GPS positioning accuracy and QZSS clock quality isdiscussed.