• Journal of Satellite, Information and Communications
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• v.3 no.2
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• pp.32-37
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• 2008

Global Navigation Satellite System (GNSS) is been developing in many countries. The satellite navigation system has the importance in economic and military fields. For utilizing satellite navigation system properly, the technology of GNSS Ground Station is needed. GNSS Ground Station monitors the signal of navigation satellite and analyzes navigation solution. This study deals with the navigation software for GNSS Ground Station. This paper will introduce the navigation solution algorithm for GNSS Ground Station. The navigation solution can be calculated by the code-carrier smoothing method, the Kalman-filter method, the least-square method, and the weight least square method. The performance of each navigation algorithm in this paper is presented.

• Journal of Advanced Navigation Technology
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• v.20 no.4
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• pp.305-313
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• 2016

International Civil Aviation Organization (ICAO) has recommended the adoption of performance-based navigation (PBN), which utilizes global navigation satellite system (GNSS). As a part of efforts to adopt PBN in South Korea, preparations have been made to implement GNSS. In Oct. 2014, Korea augmentation satellite system (KASS) was officially launched for development. A set of navigation devices need to be on-board for an airplane to utilize GNSS. GNSS navigation devices are used for different phases of flights through en-route, terminal, departure, approach and a wide variety of specification standards have been proposed for GNSS navigation. In this paper, we investigate the many proposed standards for GNSS navigation devices and their interfaces. This paper can be useful for designing procedures and flight test used in KASS implementation.

• Journal of Positioning, Navigation, and Timing
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• v.12 no.4
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• pp.335-342
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• 2023

Lunar Navigation Satellite System refers to a constellation of satellite providing PNT services on the moon. LNSS consists of main satellite and navigation satellites. Navigation satellites orbiting around the moon and a main satellite moves the area between the moon and the L2 point. The navigation satellite performs the same role as the Earth's GNSS satellite, and the main satellite communicates with the Earth for time synchronization. Due to the effect of the non-uniform shape of the moon, it is necessary to focus on the influence of the lunar gravitational field when designing the orbit simulation for navigation satellite. Since the main satellite is farther away from the moon than the navigation satellite, both the earth's gravity and the moon's gravity must be considered simultaneously when designing the orbit simulation for main satellite. Therefore, the main satellite orbit simulation must be designed through the three-body problem between the Earth, the moon, and the main satellite. In this paper, the orbit simulation tool for main satellite and navigation satellite required for LNSS was designed. The orbit simulation considers the environment characteristics of the moon. As a result of comparing long-term data (180 days) with the commercial program GMAT, it was confirmed that there was an error of about 1 m.

• Journal of Positioning, Navigation, and Timing
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• v.4 no.2
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• pp.43-55
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• 2015

In the case of satellite navigation positioning, the shielding of satellite signals is determined by the environment of the region at which a user is located, and the navigation performance is determined accordingly. The accuracy of user position determination varies depending on the dilution of precision (DOP) which is a measuring index for the geometric characteristics of visible satellites; and if the minimum visible satellites are not secured, position determination is impossible. Currently, the GLObal NAvigation Satellite system (GLONASS) of Russia is used to supplement the navigation performance of the Global Positioning System (GPS) in regions where GPS cannot be used. In addition, the European Satellite Navigation System (Galileo) of the European Union, the Chinese Satellite Navigation System (BeiDou) of China, the Quasi-Zenith Satellite System (QZSS) of Japan, and the Indian Regional Navigation Satellite System (IRNSS) of India are aimed to achieve the full operational capability (FOC) operation of the navigation system. Thus, the number of satellites available for navigation would rapidly increase, particularly in the Asian region; and when integrated navigation is performed, the improvement of navigation performance is expected to be much larger than that in other regions. To secure a stable and prompt position solution, GPS-GLONASS integrated navigation is generally performed at present. However, as available satellite navigation systems have been diversified, finding the minimum satellite constellation combination to obtain the best navigation performance has recently become an issue. For this purpose, it is necessary to examine and predict the navigation performance that could be obtained by the addition of the third satellite navigation system in addition to GPS-GLONASS. In this study, the current status of the integrated navigation performance for various satellite constellation combinations was analyzed based on 2014, and the navigation performance in 2020 was predicted based on the FOC plan of the satellite navigation system for each country. For this prediction, the orbital elements and nominal almanac data of satellite navigation systems that can be observed in the Korean Peninsula were organized, and the minimum elevation angle expecting signal shielding was established based on Matlab and the performance was predicted in terms of DOP. In the case of integrated navigation, a time offset determination algorithm needs to be considered in order to estimate the clock error between navigation systems, and it was analyzed using two kinds of methods: a satellite navigation message based estimation method and a receiver based method where a user directly performs estimation. This simulation is expected to be used as an index for the establishment of the minimum satellite constellation for obtaining the best navigation performance.

• The Bulletin of The Korean Astronomical Society
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• v.34 no.1
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• pp.159-159
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• 2009

• Journal of Aerospace System Engineering
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• v.8 no.2
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• pp.40-48
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• 2014

In this paper, a prototype of GPS jammer localization system for precise landing is developed. The jammer localization system consists of the four jamming signal receivers for collecting RF signal, one central tracking station for estimating jammer position, and one monitoring station for displaying estimated position on the map. In order to estimate jammer location TDOA and AOA algorithm are introduced, and the function and design parameters of the developed prototype are proposed. CW, DSSS, Swept CW jamming signals were generated and used. From the results, it can be confirmed that developed system meets the performance goal.

• Journal of Satellite, Information and Communications
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• v.7 no.1
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• pp.108-115
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• 2012

Many studies relating the satellite navigation has been done by a relatively small research community in Korea. Most of domestic research has been focused on the application of the satellite navigation technology, but recently the topics of the next generation satellite navigation system are emphasized for its importance. Even opinions suggesting a future Korea's own satellite navigation system are not that uncommon. Due to the geographic, economic, and technological reasons, it is not widely discussed yet. However, a development technical roadmap regarding the Korea's own navigation satellite was established on the Korea Space Development Plan in general term. Currently four global navigation satellite systems are operating or being deployed. Several regional navigation satellite systems are in planning and development phase. Particularly in Asia, China has launched several satellites to complete their own global navigation satellite system, COMPASS until 2020. Japan launched one satellite and has planned to launch rest of set until 2013. It is proper time to develop Korea's own navigation satellite system to acquire the domestic space development technology and the security of navigational infrastructure. In this study, the validity or the feasibility of the Korea's own satellite navigation system is not discussed; rather the possibility and suitability of the additional information to the current operational navigation message is main target. For the first payload of the future Korea's satellite navigation satellite, a regional augmented system is more likely. This study also is focused on that aspect.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.2
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• pp.27-31
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• 2006

With the fast developing pace, the Galileo system is entering the navigation stage with high profile. At the same time, U.S. is accelerating his GPS modernization schedule, and Russian also begins to resuscitate their GLONASS. Moreover, Chinese Beidou system has also joined the satellite navigation family with low profile already. And of course Japanese QZSS even moves forward. Along with the bitter competition in technology, finance, market and even military affairs, all these systems will firmly benefit each other and massively extend the role of civil satellite navigation industry in the future. The Global Navigation Satellite Systems (GNSS) would be almost certain to include above major satellite navigation systems. Thus how to utilize the navigation satellite resource for world peace and promote the progress of mankind should be the key issue of this century.

• Journal of Positioning, Navigation, and Timing
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• v.11 no.4
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• pp.333-339
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• 2022

The satellite navigation system was developed for the purpose of calculating the location of local users, starting with the Global Positioning System (GPS) in the 1980s. Advanced countries in the space industry are operating Global Navigation Satellite System (GNSS) that covers the entire earth, such as GPS, GLONASS, Galileo, and BeiDou, by establishing satellite navigation systems for each country. Regional Navigation Satellite Systems (RNSS) such as QZSS and NavIC are also in operation. In the early 2010s, only GPS and GLONASS could calculate location using a single system for location determination. After 2016, the EU and China also completed the establishment of GNSS such as Galileo and BeiDou. As a result, satellite navigation users can benefit from improved availability of GNSS. In addition, before Galileo and BeiDou's Full Operational Capability (FOC) declaration, they used combined navigation algorithms to calculate the user's location by adding another satellite navigation system to the GPS satellites. Recently, it may be possible to calculate a user's location for each navigation system using the resources of a single system. In this paper, we evaluated the performance of single system navigation and combined navigation solutions of GPS, GLONASS, Galileo, BeiDou and QZSS individual navigation systems using high-performance GNSS receivers.

• Journal of Positioning, Navigation, and Timing
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• v.1 no.1
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• pp.23-27
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• 2012

Recently, devices like Personal Privacy Devices (PPD) are being employed to avoid the detection of one's location by GPS, and most PPD transmits swept CW signals. However, signals transmitted from PPD may interfere a precise location system based on GPS. Accordingly, in order to reduce interferences by PPD, a technique to locate an interferer is needed. In order to locate an interferer AOA method and TDOA method are generally used, TDOA method is known to be more accurate than AOA method. Unfortunately, TDOA method has a problem of ambiguity in obtaining measurements of swept CW interference. Thus, this paper design a localization algorithm based on TDOA method that can accurately locate an interferer transmitting swept CW signals by resolving problem of ambiguity. In addition, feasibility of the designed algorithm has been verified by simulation results.