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Research paper : How car navigation systems have been put into practical use (H. Ikeda et al.)−285−Synthesiology - English edition Vol.3 No.4 (2011) practical scope of applications. We selected CD-ROMs even though the media was seldom used in vehicles at that time. In employing CD-ROMs, we introduced CD drive suppliers to an oil damper developed by Tokai Rubber Industries, an affiliate of Sumitomo Electric, so that CD drives could withstand vibrations in the vehicle.Furthermore, ROM was selected as program memory to store programs up to 1 Mbyte. For map operation memory, we selected DRAM, although it was also rarely used for automotive purposes. We employed these devices with automotive environmental testing and reliability considerations in mind.The United States started refining the GSP for military purposes in around 1988, and the system has been permitted to be used by civilians with intentionally reduced accuracy. GPS made it possible to determine the current location without the aforementioned sensors in vehicles, only requiring the provision of a receiver. In around 1990, GPS NAVS emerged on the market, which were mostly off-the-shelf NAVS because they were easy to install. At first, since there were not a sufficient number of satellites in the sky required for positioning, GPS NAVS became useless in tunnels and in the shade of buildings where no satellite was in view. In around 1995, however, GPS NAVS became almost practically useful. When the effect of accuracy degradation was removed in 2001, they easily reached the practical level.3.6 Promoting sales to customersSumitomo Electric developed digital road maps of Osaka and the surrounding areas, tested the NAVS and began appealing to automakers six months after we independently started developing the NAVS in 1983. Our project was highly regarded by Nissan. Mass production of map-matching NAVS incorporating wheel speed sensors, a magnetic field sensor and a 1:2500 map commenced in 1989 with a planned monthly output of 1000 units for the Cima and Cedric, although the unit needed to improve in positioning accuracy. In 1991, we offered optical fiber gyro-equipped NAVS for the Cedric and Cima. Subsequently, however, Nissan founded Xanavi Informatics Corporation jointly with Hitachi as an attempt to develop NAVS in-house. Thereafter, although our systems were selected by customers excluding Toyota, a substantial amount of man-hours required to meet customized requirements resulted in huge deficits, and this became problematic in terms of business operations.Meanwhile, audio manufacturers and other suppliers began offering aftermarket NAVS, which gradually became predominant. Although we speculated that OEM NAVS would go mainstream as a driving assist system in the future, we entered into a competition in the aftermarket against the will of some of our employees because we considered that gaining a reputation in the aftermarket was indispensable to our survival in the business. While many GPS NAVS displayed current locations away from roads or even on a lake according to GPS-detected coordinates, our positioning accuracy and quick route computation, achieved with OEM onboard NAVS, were well-received.4 NAVS business: development and withdrawal4.1 Development cost burden and business profitability As we worked on NAVS hardware development, along with improvements in location detection, view for the map, route computation and route guidance, and paying costs of nationwide map development and updating, it was impossible to continue the NAVS business without successful prospects for business profitability. To recover these costs, required NAVS sales were at least 20,000 units per month.Vehicles equipped with an OEM NAVS at that time numbered some thousands per month at each automaker, although the number was very large at Toyota, to which Sumitomo Electric was not shipping. We received orders totaling less than 10,000 units per month even during busy periods. At that time, we thought that the NAVS market would explode and our sales volume would soon reach a profitable level. Contrary to our expectations the market growth halted after the burst of the bubble economy, and our business was constantly underperforming. One cause of the failure of our NAVS business model was that we could not develop a scheme in which automakers would pay the heavy costs of map data and software development.Consequently, to somehow improve profitability, we collaborated with our competitors in map database construction and even in NAVS development.4.2 Onboard NAVS software development problemsAfter entering the aftermarket, we still worked with multiple automakers on developing OEM NAVS. With them it was necessary to enable audio and air conditioner controls to be displayed on the same screen. Different vehicle families came with different instrument panel designs and the number of switches installable on the instrument panel would also change. The presence or absence of one switch necessitated a substantial software revision, as in the case where use of a different cell phone model entails a substantially changed feel of operation. After 1995, in addition to adapting the NAVS to different vehicle families, we implemented novel major software features such as VICS reception and access to the Internet. In order to launch new features such as VICS support and Internet connections ahead of competitors in such a period it was important to standardize the software so that the functions could be simply expanded.To ensure that the above-mentioned adaptation and launch of new features met multiple automakers’ requests, we needed

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