DOCSLIB.ORG

Effectiveness of the Quasi-Zenith Satellite System in Ubiquitous Positioning

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Effectiveness of the Quasi-Zenith Satellite System in Ubiquitous Positioning View metadata, citation and similar papers at core.ac.uk brought to you by CORE SCIENCE & TECHNOLOGY TRENDS QUARTERLY REVIEW No.16 / July 2005 7 Effectiveness of the Quasi-Zenith Satellite System in Ubiquitous Positioning TERUHISA TSUJINO General Unit information systems will show you the local area 1 Introduction map, and other systems will provide interesting related information. Recently, a variety of research is underway The Ministry of Internal Affairs and targeted at “ubiquitous positioning” in many Communications (MIAC) has launched a research countries including U.S.A., U.K., France and project, scheduled to be completed by April of Australia. In Japan, for instance, a study on the 2007, to build a high-performance infrastructure, application of ubiquitous positioning to the providing police, fire fighting agencies and distribution of goods has been carried out by maritime safety agencies with enhanced University of Tokyo. “Ubiquitous” means “existing emergency calls capabilities for improved safety at any place, at any time” or “omnipresent.” and freedom from care. Swift localization of the In a future information society, methods for transmitter has been a longstanding challenge measuring precisely where you are will be as in mobile phone emergency calls. Mobile important and matter-of-course as ubiquitous terminals with automatic positional information hardware devices such as wearable computers transmission capability using GPS will enable and IC tags. This trend is heralded by the police to reach the spot much more quickly. fact that millions of mobile phone users have However, GPS positioning is often unavailable signed up for positional information services. in areas without a clear skyline, such as Although the positional accuracy currently mountainous terrain and densely populated areas, available from mobile phone services is still because sufficient GPS satellites are not in sight. low, even sometimes giving wrong information, This has been often pointed out as major blind the mainstream will shift to utilization of the side in GPS utilization. Global Positioning System (GPS) for much The Quasi-Zenith Satellite System (QZSS), higher accuracy. You can calculate your exact which will be complementary and augmentative position using time signals from more than four with GPS, will be the most effective in solving GPS satellites simultaneously. GPS has already this problem. System development will be carried established itself as one of the key components of out through cooperative effort between the nation-level infrastructure and has been used in a public sector and governmental organizations, variety of social activities. including the MIAC, the Ministry of Education, In ordinary life, time is expressed in terms Culture, Sports, Science and Technology (MEXT), of hours, minutes and seconds. In ubiquitous the Ministry of Economy, Trade and Industry positioning, your location is expressed in (METI) and the Ministry of Land, Infrastructure terms of degrees, minutes and seconds to the and Transportation (MLIT), Japan's original precision of one tenth second in both longitude satellites system will also provide substantial and latitude*1. Linking positional information impetus and business opportunities to the with other sources of information will also aerospace industry. be a commonplace application; geographical This articles gives an overall picture of 88 89 SCIENCE & TECHNOLOGY TRENDS QUARTERLY REVIEW No.16 / July 2005 many aspects paving the way to ubiquitous (low-earth-orbit) and geosynchronous orbit. positioning, including the status of the U.S. GPS With its orbital inclination angle of 55° and high satellite system and its inherent blind side, an altitude, the system is able to cover almost all the overview of the emergency calls enhancement earth’s surface except a part of the polar regions. project initiated by the MIAC, the architecture The Department of Defense (DoD) started and role of the Quasi-Zenith Satellite System, investigation into satellite-aided positioning and research trends in enhanced positioning systems in the 1960s. After several stages of cut technology undertaken by ministries and and try technical development, DoD launched the research organizations. Quasi-Zenith Satellites first NAVSTAR satellite in 1978. can be multipurpose entities: they can be used, As shown in Table 1, the NAVSTAR constellation depending on the instruments they carry, for started steady operation in 1990 (Block 2 and communications, broadcasting and monitoring 2A) after completion of the validation phase as well as their original purpose of positioning. (Block 1). Due to the life of these satellites, they However, it is apparent that priority lies in are in a process that started in 1997 of being positioning (complementation and augmentation replaced by new satellites (Block 2R), and Block of the existing GPS system) over other missions 2RM (the additional M stands for “Modernized”) such as communications and broadcasting. satellites with enhanced performance and an I therefore propose that the role of the first additional time signal for private sector use QZSS system concentrate on complementing are scheduled to be launched shortly. Block 2F and augmenting the GPS system. I also propose satellites with a newly added third time signal establishing a governmental organization that for private sector use are being constructed; the presides over the entire project for the early first one in this series is scheduled for launch implementation of a ubiquitous positioning in 2006. Furthermore, conceptual development system using the Quasi-Zenith Satellites. for next-next generation satellites, or Block 3, is currently independently underway by 2 GPS satellites system Figure 1 : NAVSTAR satellites and six orbital planes [1] 2-1 Trends in GPS satellite development The term GPS satellite (or navigation satellite) generally refers to the 24 NAVSTAR satellites operated by the U.S. Air Force (currently, five backup satellites have been added to a total of 29). As shown in Figure 1, the basic design of the system allocates 4 satellites in each of the 6 orbital planes. In addition, several backup satellites orbit the earth in preparation for malfunction or failure. Each satellite circles the earth in approx. 12 hours at an altitude of 20,200 km, roughly at midpoint between LEO Table 1 : Global Positioning satellites launched by U.S.A. Block Manufacturer Launched Number Orbital inclination Weight (kg) Design life Power 1 1978-1985 11 63° 759 5 years 0.41kW 2 Rockwell International 1989-1990 9 55° 1,660 7.5 years 0.71kW 2A 1990-1997 19 55° 1,816 7.5 years 0.71kW 2R 12 2R Lockheed Martin 1997-2006 55° 2,032 10 years 1.14kW 2RM 7 2F Boeing 2006-2012 33 55° 2,160 15 years 2.44kW 3 Lockheed Martin/Boeing Undecided (201?-) Undecided Undecided Undecided Undecided Undecided 88 89 SCIENCE & TECHNOLOGY TRENDS QUARTERLY REVIEW No.16 / July 2005 Lockheed-Martin and Boeing. DoD will soon as China, India, Israel and Brazil have decided to decide the main contractor for development and become partners in the project. It is planned that manufacturing Block 3 satellites between these a constellation of 30 positioning satellites, GNSS, two manufacturers. be launched within a few years. When the project enters the deployment phase, 8 satellites will 2-2 Functional aspects of GPS satellites be launched at a time using an Ariane V launch The current workhorses of the NAVSTAR vehicle. constellation, Block 2A and 2R, carry two types China has launched three “Beidou” geostationary of atomic clocks and constantly broadcast the positioning satellites of its own, and they are precise time base signals according to their own mainly used for traffic control and car-theft clock and orbital elements once every second. monitoring. India is also planning to launch a They are capable of sending time base signals GPS augmentation satellite, “Gagan (sky).” The practically to a precision of 10 -9 to ground GPS geostationary satellite is positioned at a high angle receivers. of elevation near the zenith over India's southern A technical specification common to all blocks high-tech industrial area including Bangalore. is the frequency of the transmitted signal. Current These regions will enjoy full geographical GPS satellites use two frequencies: L1 centered advantage for ubiquitous positioning by having a at 1575.42 MHz and L2 at 1227.6 MHz. These GPS complementation satellite just above them. frequencies should not be changed even in the future, as this is prerequisite for the continuous 2-4 GPS complementary and GPS augmentative use of ground receivers. Note, however, a plan In locations without major obstructions, to add a new frequency (L5: centered at 1176 the position of the receiver can be easily and MHz) that will be open for private sector use accurately determined using GPS signals. This (proposed for use as a civilian safety-of-life is essentially the case with the U.S. forces: the signal) is underway for implementation in Block main areas in which they use the NAVSTAR are 2F satellites. This proposal has been approved in open sky and sea, enabling them to exploit by the International Telecommunication Union - the full potential of the system. In civil use, Radio Communication Sector (ITU-R). however, there is a possibility of the signal path being obstructed by the jungle of high-rise 2-3 Non-U.S. positioning satellites buildings in densely populated area or canyons Russia has deployed the Global Navigation in mountainous terrain, meaning the required Satellite System (GLONASS) using its proprietary number of signals for accurate localization cannot positioning satellites. Due to the dwindling be received. “Availability” is the term used to number of normally operating satellites, represent the probability that you can use GPS Russia plans to launch about 10 replenishment services properly in a particular place. Many satellites starting in 2005. Although it has urban areas in Japan have availability somewhere limited usefulness due to the sparsely populated between 30 to 40%. A survey conducted in constellation, the signal from GLONASS is the West Shinjuku area (Shibasaki Laboratory, available in Japan.
Load more

Recommended publications
  • GLONASS System As a Tool for Space Weather Monitoring
    GLONASS System as a tool for space weather monitoring V.V. Alpatov, S.N. Karutin, А.Yu. Repin Institute of Applied Geophysics, Roshydromet TSNIIMASH, Roscosmos BAKU-2018 PLAN OF PRESENTATION General information about GLONASS Goals Organization and Management Technical information about GLONASS Space Weather Effects On Space Systems On Ground based Systems Possible Opportunities of GLONASS for Monitoring Space Weather Effects Russian Monitoring System for Monitoring Space Weather Effects with Use Opportunities of GLONASS 2 GENERAL INFORMATION ABOUT GLONASS NATIONAL SATELLITE NAVIGATION POLICY AND ORGANIZATION Presidential Decree of May 17, 2007 No. 638 On Use of GLONASS (Global Navigation Satellite System) for the Benefit of Social and Economic Development of the Russian Federation Federal Program on GLONASS Sustainment, Development and Use for 2012-2020 – planning and budgeting instrument for GLONASS development and use Budget planning for the forthcoming decade – up to 2030 GLONASS Program governance: Roscosmos State Space Corporation Government Contracting Authority – Program Coordinator Government Contracting Authorities Program Scientific and Coordination Board GLONASS Program Goals: Improving GLONASS performance – its accuracy and integrity Ensuring positioning, navigation and timing solutions in restricted visibility of satellites, interference and jamming conditions Enhancing current application efficiency and broadening application domains 3 CHARACTERISTICS IMPROVEMENT PLAN Accuracy Improvement by means of: . Ground Segment
    [Show full text]
  • AVL Systems for Bus Transit
    T R A N S I T C O O P E R A T I V E R E S E A R C H P R O G R A M SPONSORED BY The Federal Transit Administration TCRP Synthesis 24 AVL Systems for Bus Transit A Synthesis of Transit Practice Transportation Research Board National Research Council TCRP OVERSIGHT AND PROJECT TRANSPORTATION RESEARCH BOARD EXECUTIVE COMMITTEE 1997 SELECTION COMMITTEE CHAIRMAN OFFICERS MICHAEL S. TOWNES Peninsula Transportation District Chair: DAVID N. WORMLEY, Dean of Engineering, Pennsylvania State University Commission Vice Chair: SHARON D. BANKS, General Manager, AC Transit Executive Director: ROBERT E. SKINNER, JR., Transportation Research Board, National Research Council MEMBERS SHARON D. BANKS MEMBERS AC Transit LEE BARNES BRIAN J. L. BERRY, Lloyd Viel Berkner Regental Professor, Bruton Center for Development Studies, Barwood, Inc University of Texas at Dallas GERALD L. BLAIR LILLIAN C. BORRONE, Director, Port Department, The Port Authority of New York and New Jersey (Past Indiana County Transit Authority Chair, 1995) SHIRLEY A. DELIBERO DAVID BURWELL, President, Rails-to-Trails Conservancy New Jersey Transit Corporation E. DEAN CARLSON, Secretary, Kansas Department of Transportation ROD J. DIRIDON JAMES N. DENN, Commissioner, Minnesota Department of Transportation International Institute for Surface JOHN W. FISHER, Director, ATLSS Engineering Research Center, Lehigh University Transportation Policy Study DENNIS J. FITZGERALD, Executive Director, Capital District Transportation Authority SANDRA DRAGGOO DAVID R. GOODE, Chairman, President, and CEO, Norfolk Southern Corporation CATA DELON HAMPTON, Chairman & CEO, Delon Hampton & Associates LOUIS J. GAMBACCINI LESTER A. HOEL, Hamilton Professor, University of Virginia. Department of Civil Engineering SEPTA JAMES L.
    [Show full text]
  • The Navy Navigation Satellite System (Transit)
    ROBERT J. DANCHIK THE NAVY NAVIGATION SATELLITE SYSTEM (TRANSIT) This article provides an update on the status of the Navy Navigation Satellite System (TRANSIT). Some insights are provided on the evolution of the system into its current configuration, as well as a discussion of future plans. BACKGROUND sign goal was never achieved for long in those early In 1958, research scientists at APL solved the orbit days because the satellites had short operational life­ of the first Russian satellite, Sputnik-I, by analysis of times. The failures largely resulted from inadequate the observed Doppler shift of its transmitted signal. component quality and the large number of wiring in­ This led immediately to the concept of satellite navi­ terconnections. However, after OSCAR 2 10 and OS­ gation and the development of the U.S. Navy Navi­ CAR 12 were launched in 1966 and 1967, respectively, gation Satellite System (TRANSIT) by APL, under the enough data on the failure mechanisms became avail­ sponsorship of the Navy's Special Projects Office, to able to APL to achieve the desired advances in reli­ provide position fixes for the Fleet Ballistic Missile ability. The integrated circuit introduced in OSCAR Weapon System submarines. (The articles in Ref. 1, 10 significantly extended the satellite lifetime by im­ a previous issue of the fohns Hopkins APL Techni­ proving component reliability and reducing the num­ cal Digest devoted to TRANSIT, give the principles ber of interconnections. Subsequently, the last major of operation and early history of the system.) Now, design change made to the solar cell interconnections, 26 years after its conception, the system is mature.
    [Show full text]
  • ABAS), Satellite-Based Augmentation System (SBAS), Or Ground-Based Augmentation System (GBAS
    Current Status and Future Navigation Requirements for Mexico City New Airport New Mexico City Airport in figures: • 120 million passengers per year; • 1.2 million tons of shipping cargo per year; • 4,430 Ha. (6 times bigger tan the current airport); • 6 runways operating simultaneously; • 1st airport outside Europe with a neutral carbon footprint; • Largest airport in Latin America; • 11.3 billion USD investment (aprox.); • Operational in 2020 (expected). “State-of-the-art navigation systems are as important –or more- than having world class civil engineering and a stunning arquitecture” Air Navigation Systems: A. In-land deployed systems - Are the most common, based on ground stations emitting radiofrequency signals received by on-board equipments to calculate flight position. B. Satellite navigation systems – First stablished by U.S. in 1959 called TRANSIT (by the time Russia developed TSIKADA); in 1967 was open to civil navigation; 1973 GPS was developed by U.S., then GLONASS, then GALILEO. C. Inertial navigation systems – Autonomous navigation systems based on inertial forces, providing constant information on the position of the flight and parameters of speed and direction (e.g. when flying above the ocean and there are no ground segments to provide support). Requirements for performance of Navigation Systems: According to the International Civil Aviation Organization (ICAO) there are four main requirements: • The accuracy means the level of concordance between the estimated position of an aircraft and its real position. • The availability is the portion of time during which the system complies with the performance requirements under certain conditions. • The integrity is the function of a system that warns the users in an opportune way when the system should not be used.
    [Show full text]
  • GPS Standard Positioning Service Signal Specification
    GLOBAL POSITIONING SYSTEM STANDARD POSITIONING SERVICE SIGNAL SPECIFICATION 2nd Edition June 2, 1995 June 2, 1995 GPS SPS Signal Specification TABLE OF CONTENTS SECTION 1.0 The GPS Standard Positioning Service.....................................1 1.1 Purpose ..............................................................................................................................1 1.2 Scope.................................................................................................................................. 1 1.3 Policy Definition of the Standard Positioning Service.........................................................2 1.4 Key Terms and Definitions.................................................................................................. 3 1.4.1 General Terms and Definitions ................................................................................. 3 1.4.2 Peformance Parameter Definitions........................................................................... 4 1.5 Global Positioning System Overview.................................................................................. 5 1.5.1 The GPS Space Segment.........................................................................................5 1.5.2 The GPS Control Segment .......................................................................................6 SECTION 2.0 Specification of SPS Ranging Signal Characteristics.............9 2.1 An Overview of SPS Ranging Signal Characteristics.........................................................9
    [Show full text]
  • Beidou Navigation Satellite System Signal in Space Interface Control Document
    BeiDou Navigation Satellite System Signal In Space Interface Control Document Open Service Signal B1C (Version 1.0) China Satellite Navigation Office December, 2017 2017 China Satellite Navigation Office Table of Contents 1 Statement .......................................................................................................... 1 2 Scope ................................................................................................................ 1 3 BDS Overview ................................................................................................. 1 3.1 Space Constellation ................................................................................. 1 3.2 Coordinate System ................................................................................... 2 3.3 Time System ............................................................................................ 3 4 Signal Characteristics ...................................................................................... 3 4.1 Signal Structure ........................................................................................ 3 4.2 Signal Modulation ................................................................................... 4 4.2.1 Modulation ..................................................................................... 4 4.2.2 B1C Signal ..................................................................................... 5 4.3 Logic Levels ...........................................................................................
    [Show full text]
  • GNSS-Based Radio Tomographic Studies of the Ionosphere at Different Latitudes
    GNSS-Based Radio Tomographic Studies of the Ionosphere at Different Latitudes Vyacheslav E. Kunitsyn1,2, Elena S. Andreeva1,2, Ivan A. Nesterov1,2, Yulia S. Tumanova1,2 and Yuri N. Fedyunin3 1Lomonosov Moscow State University, Moscow, Russia 2Instutite of Solar-Terrestrial Physics, Irkutsk, Russia 3Merchant Marine Academy, New York, USA ABSTRACT We present the results of ionospheric imaging by the radio tomographic (RT) methods based on the Navigation Satellite Systems (GNSS). GNSS include the first-generation low orbiting (LO) systems (Tsikada, Transit, etc.) and second-generation high orbiting (HO) systems (GPS and GLONASS, which have been put in operation, and Galileo, BeiDou, and QZSS systems, which are currently under development in Europe, China, and Japan). The GNSS constellations and the networks of ground receivers are suitable for probing the ionosphere along different rays and processing the obtained data by tomographic inversion procedures. The results discussed in this work are obtained by the methods of low orbiting and high orbiting radio tomography (LORT and HORT, respectively). We present the examples of tomographic images of the subequatorial, midlatitude, subauroral, and auroral ionosphere in different regions of the world. The RT images of the Arctic ionosphere demonstrate different structures (characteristic circumpolar ring structures, ionization patches, tongues of ionization (TOIs), etc.) The GNSS RT methods are suitable for imaging the ionospheric disturbances caused by the tsunami wave propagation. We analyze the ionospheric disturbances after the strongest Tohoku earthquake in Japan (March 11, 2011). The RT reconstructions are compared to the measurements by the ionosondes and Global Ionospheric Maps (GIM). 1. INTRODUCTION The existing GNSS constellations and the corresponding networks of ground receivers make it possible to probe the ionosphere along different directions and to apply the RT methods to reconstruct the spatial distributions of electron concentration in the ionosphere.
    [Show full text]
  • GNSS History
    GNSS History 1 Disclaimer The views and opinions expressed herein do not necessarily reflect the official policy or position of any government agency 2 Satellite Navigation in the 1950s 1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 4 Oct 1957 Dec 1958 Sputnik I The U.S. Launched Navy Navigation Satellite System (Transit) Approved and Funded 3 Satellite Navigation in the 1960s (1 of 3) 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 13 April 1960 First Successful 5 Dec 1963 Jan 1964 Other Successful July 1967 Transit First Transit Experimental Transit Experimental Operational Became Satellites: Released Satellite (1B) Satellite Operational 2A, 22 Jun 1960 for 3B, 21 Feb 1961 Commercial 4A, 29 Jun 1961 Use 4B, 15 Nov 1961 ---- Establishing U.S. Dual Use SatNav Policy Operational Transit Satellite 4 Satellite Navigation in the 1960s (2 of 3) 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1964 1968 World’s First Surface Ship World’s First Satellite Navigator Portable Satellite 1969 AN/SRN-9 (XN-5) Doppler Geodetic World’s First Surveyor Commercial AN/PRR-14 Oceanographic Geoceiver Navigator 5 Satellite Navigation in the 1960s (3 of 3) 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1969 First Steps Toward GPS; Air Force 621B Program; World’s First Spread Spectrum Navigation Receiver, MX-450 6 Satellite Navigation in the 1970s 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1978 GPS Launches April 1973 22 Feb, 13 May, Formation of the GPS 7 Oct, 11 Dec Joint Program Office (JPO) 1971 First Timation Receiver 1975 for the Naval Research
    [Show full text]
  • GPS Success (1962 – 1978)
    True Origins and Major Original Challenges for GPS Success (1962 – 1978) A Tribute to the “almost forgotten” who labored and sacrificed to make it happen! * Brad Parkinson Stanford University 10/22/09 Stanford CPNT October 2009 1 GPtS – the Stealth Utility • Pre-History and GPS Design • The Key Innovation • 5 Engineering Frontiers • GPS Applications Enabled Note: t = TIME “Success has a thousand Fathers, failure is an orphan.“ -- Unknown Author 10/22/09 Stanford CPNT October 2009 2 Today, GPS Serves over 600 Million Users 10/22/09 Stanford CPNT October 2009 3 Summary – The GPS Concept Four or more Passive Ranging Satellite signals to solve for 4D (3 Shown for clarity) Question: How did we come up with this design in 1973? And Where did we push the Technology/ Engineering Frontiers? Big Point: Eliminates the need for accurate clocks in the user equipment. But Leaves the major Issue: from P. Enge, Scientific American What is the form of the signal? 10/22/09 Stanford CPNT October 2009 4 The Dawn of Satellite Navigation • 4 October 1957 - Sputnik • US Failures and success (31 January 1958) • William Guier and George Weiffenbach (APL) – Doppler Signature Unique – Single Pass Orbit Determination 10/22/09 Stanford CPNT October 2009 5 The Eras of Satellite Navigation 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015 2020 Pioneers -Transit 10/22/09 Stanford CPNT October 2009 6 The World in 1966 • There were no: – PCs – CDs and DVDs • And– Cell there Phones/Text was no Monday night Football!!! • NorMessaging was there a GPS – but – Satellite TV – ThereInternet was an existing Satellite-based • Google Navigation System… • Facebook – eMail – iPODS – HDTV 10/22/09 Stanford CPNT October 2009 7 Navy’s Transit • Developed by Dick Kirschner - APL • Doppler (Frequency-based) system • Polar Orbits at 1075 km.
    [Show full text]
  • NAVIGATION from LEO Current Capability and Future Promise by David Lawrence, H
    WITH RICHARD B. LANGLEY NAVIGATION FROM LEO Current Capability and Future Promise BY David Lawrence, H. Stewart Cobb, Greg Gutt, Michael O’Connor, Tyler G.R. Reid, Todd Walter and David Whelan ith the advent of smartphones, there are now more than four billion devices GPS that make use of GNSS. These satellite Wnavigation systems provide not just the blue dot representing location on our phones, but also support the critical infrastructure we rely upon. The U.S. Iridium Department of Homeland Security recognizes that all 16 sectors of U.S. critical infrastructure depend on GPS — 13 of which have critical dependence. A recent report by London Economics estimates the cost of a GNSS outage to the U.K. alone would be over 1B per day.With autonomous systems on the rise, our reliance on GNSS will only be increasing. As we become more dependent on this technology, we become vulnerable to its limitations. One major shortcoming !" is signal strength. Designed to work in an open-sky environment, GNSS is severely limited in deep attenuation FIGURE 1 The 66-satellite Iridium constellation in low Earth orbit and 31-satellite environments, with little or no service in dense cities or GPS constellation in medium Earth orbit. indoors. Furthermore, we are susceptible to jamming where a 20-watt GNSS jammer can deny service over a city block. features of these signals are also used to reliably validate The proximity of low Earth orbit (LEO) has the potential GNSS PNT solutions in real time to help mitigate potential to provide much stronger signals than the distant GNSS spoofing.
    [Show full text]
  • Beidou Navigation Satellite System Signal in Space Interface Control Document Open Service Signal B2b (Version 1.0)
    China Satellite Navigation Office 2020 BeiDou Navigation Satellite System Signal In Space Interface Control Document Open Service Signal B2b (Version 1.0) China Satellite Navigation Office July, 2020 China Satellite Navigation Office 2020 TABLE OF CONTENTS 1 Statement ····························································································· 1 2 Scope ·································································································· 2 3 BDS Overview ······················································································· 3 3.1 Space Constellation ········································································· 3 3.2 Coordinate System ·········································································· 3 3.3 Time System ················································································· 4 4 Signal Characteristics ··············································································· 5 4.1 Signal Structure ·············································································· 5 4.2 Signal Modulation ··········································································· 5 4.3 Logic Levels ·················································································· 6 4.4 Signal Polarization ·········································································· 6 4.5 Carrier Phase Noise ········································································· 6 4.6 Spurious ·······················································································
    [Show full text]
  • The Transit Satellite Geodesy Program
    S. M. YIONOULIS The Transit Satellite Geodesy Program Steve M. Yionoulis The satellite geodesy program at APL began in 1959 and lasted approximately 9 years. It was initiated as part of a major effort by the Laboratory to develop a Doppler navigation satellite system for the U.S. Navy. The concept for this system (described in companion articles) was proposed by Frank T. McClure based on an experiment performed by William H. Guier and George C. Weiffenbach. Richard B. Kershner was appointed the head of the newly formed Space Development Division (now called the Space Department), which was dedicated solely to the development of this satellite navigation system for the Navy. This article addresses the efforts expended in improving the model of the Earth’s gravity field, which is the major force acting on near-Earth satellites. (Keywords: Doppler navigation, Earth gravity field, Navy Navigation Satellite System, Satellite geodesy, Spherical harmonics, Transit Navigation System.) INTRODUCTION In a recent article, William H. Guier and George C. On October 4, 1957, the Russians launched the 4 Earth’s first artificial satellite (Sputnik I). From an Weiffenbach reminisced about those early days after analysis of the Doppler shift on the transmitted signals the launch of Sputnik I. (Their article is reprinted in this from this satellite, Guier and Weiffenbach1,2 demon- issue.) The article provides an interesting glimpse into strated that the satellite’s orbit could be determined the excitement of that time and the working environ- using data from a single pass of the satellite. During ment of the Applied Physics Laboratory in those days.
    [Show full text]