All the current GPS Interface Control Documents can be downloaded from <a href="https://www.gps.gov" target="_blank">GPS.gov</a>, the official U.S. Government webpage for GPS.
\li GPS L1 and L2C: Global Positioning System Directorate, <a href="https://www.gps.gov/technical/icwg/IS-GPS-200H.pdf" target="_blank"><b>Interface Specification IS-GPS-200 Revision H</b></a>. September, 2013.
\li GPS L1C (available with first Block III launch): Global Positioning System Directorate, <a href="https://www.gps.gov/technical/icwg/IS-GPS-800D.pdf" target="_blank"><b>Interface Specification IS-GPS-800 Revision D</b></a>. September, 2013.
\li GPS L5 (first Block IIF satellite launched on May, 2010): Global Positioning System Directorate, <a href="https://www.gps.gov/technical/icwg/IS-GPS-705D.pdf" target="_blank"><b>Interface Specification IS-GPS-705 Revision D</b></a>. September, 2013.
\li Standard Accuracy (ST) signals at L1 and L2: Russian Institute of Space Device Engineering, Global Navigation Satellite System GLONASS. <a href="http://facility.unavco.org/data/docs/ICD_GLONASS_5.1_(2008)_en.pdf" target="_blank"><b>Interface Control Document. Navigational radiosignal in bands L1, L2. Edition 5.1</b></a>, Moscow, Russia, 2008
Check the <a href="https://ec.europa.eu/enterprise/policies/satnav/galileo/index_en.htm" target="_blank">Galileo website of the European Commission</a> and the
<a href="https://www.esa.int/Our_Activities/Navigation/The_future_-_Galileo/What_is_Galileo" target="_blank">Galileo website of the European Space Agency</a>.
There is a website with <a href="http://igs.org/mgex/Status_GAL.htm" target="_blank">Galileo constellation status information</a> from the International GNSS Service.
\li Galileo E5, E6, and E1: European GNSS (Galileo) Open Service. <a href="http://www.gsc-europa.eu/system/files/galileo_documents/Galileo_OS_SIS_ICD.pdf" target="_blank"><b>Signal In Space Interface Control Document. Ref: OS SIS ICD, Issue 1.2</b></a>, European Commission, Nov. 2015.
\li European GNSS (Galileo) Open Service <a href="" target="_blank"><b>Signal-In-Space Operational Status Definition</b></a>, European Commission, Sept. 2015.
The European Commission is granting free access to the technical information on the future Galileo open service signal, i.e. the specifications manufacturers
and developers need to process data received from satellites. This document informs receiver manufacturers, application developers and service providers on how
\li <a href="http://www2.unb.ca/gge/Resources/beidou_icd_english_ver2.0.pdf" target="_blank"><b>BeiDou Navigation Satellite System Signal In Space Interface Control Document</b></a>.
Open Service Signal (Version 2.0). China Satellite Navigation Office, December 2013.
\li <a href="http://www2.unb.ca/gge/Resources/beidou_open_service_performance_standard_ver1.0.pdf" target="_blank"><b>BeiDou Navigation Satellite System Open Service Performance Standard</b></a>. (Version 1.0). China Satellite Navigation Office, December 2013.
\subsection sbas Satellite Based Augmentation Systems (SBAS)
\li <b>Minimum Operational Performance Standards for Global Positioning System/Wide Area Augmentation System Airborne Equipment, DO-229D</b>, RTCA, Washington, DC, Dec. 13, 2006. The 'RTCA MOPS DO229D - appendix A' is the reference standard for WAAS/EGNOS application development. RTCA is an advisory committee of the US federal government, and issues standards for civil airborne equipment, among other duties. One such standard is MOPS 229D (Minimum Operational Performance Standards for Global Positioning System/Wide Area Augmentation System Airborne Equipment version D), which describes the implementation of satellite-based augmentation services (SBAS) for receivers designed for civil aviation use. An annex to DO229D contains the specifications for the SBAS signal and message. The RTCA provides regular updates to these standards. MOPS 229D is available for a fee from the <a href="http://rtca.org/onlinecart/product.cfm?id=396" target="_blank">RTCA website</a>.
\li <a href="http://www.gps.gov/technical/ps/2008-WAAS-performance-standard.pdf" target="_blank"><b>Global Positioning System Wide Area Augmentation System (WAAS) Performance Standard, 1st Edition</b></a>, Department of Transportation and Federal Aviation Administration, Oct. 31, 2008. This document defines the levels of performance the U.S. Government makes available to users of the GPS SPS augmented by the Wide Area Augmentation System.
\li <a href="http://egnos-portal.eu/sites/default/files/EGNOS-open-service-sdd.PDF" target="_blank"><b>EGNOS Open Service (OS) Service Definition Document. Ref: EGN-SDD OS, Revision 2.2</b></a>, European GNSS Agency (GSA), Feb. 12, 2015. This is a complementary document to the RTCA DO229D, mentioned above. It describes the scope of services provided by the EGNOS Open Service to be used by end-users or Application Specific Service Providers. It details the general conditions relating to the use of the EGNOS service, a technical description of the Signal-in-Space (SIS), the reference receiver, environmental conditions, the service performance achieved and aspects relating to service provision.
\li <a href="http://egnos-user-support.essp-sas.eu/new_egnos_ops/sites/default/files/library/official_docs/egnos_sol_sdd_in_force.pdf" target="_blank"><b>EGNOS Safety of Life Service Definition Document. Ref: EGN-SDD SoL, Revision 3.0</b></a>, European GNSS Agency (GSA), Sep. 22, 2015. The EGNOS Safety of Life (SoL) Service is provided openly and is freely accessible without any direct charge and is tailored to safety-critical transport applications in various domains, in particular for aviation applications. The service is thus compliant with the aviation APV-I (Approach with Vertical Guidance) requirements, as defined by ICAO in Annex 10, but may support also applications in other SoL domains.
More information about EGNOS can be found through the <a href="https://egnos-user-support.essp-sas.eu/new_egnos_ops/index.php" target="_blank">EGNOS Portal</a>.
The final output of a navigation receiver is usually its position, speed or other related physical quantities. However, the calculation of those quantities
are based on a series of measurements from one or more satellite constellations. Although receivers calculate positions in real time, in many cases it is
interesting to store intermediate measures for later post-processing. RINEX is the standard format that allows the management and disposal of the measures
\li The most common version at present is <a href="http://igscb.jpl.nasa.gov/igscb/data/format/rinex211.txt" target="_blank"><b>RINEX: The Receiver Independent Exchange Format Version 2.11</b></a>, which enables storage of measurements from pseudorange, carrier-phase and Doppler systems for GPS or GLONASS,
along with data from EGNOS and WAAS satellite based augmentation systems (SBAS).
\li The most recent version is <a href="ftp://igscb.jpl.nasa.gov/igscb/data/format/rinex301.pdf" target="_blank"><b>RINEX: The Receiver Independent Exchange Format Version 3.01</b></a> published in June, 2009.
It includes Galileo and improves the handling of multi-constellation data files.
\li There is also available the <a href="ftp://igscb.jpl.nasa.gov/igscb/data/format/rinex_clock302.txt " target="_blank"><b>RINEX Extensions to Handle Clock Information</b></a>, published in September, 2010.
The <a href="http://www.nmea.org" target="_blank">National Marine Electronics Association </a> released the NMEA 0183 Interface Standard, which defines electrical signal requirements, data transmission protocol and time,
and specific sentence formats for a 4800-baud serial data bus. The standard is <a href="http://www.nmea.org/store/index.asp?show=cprd&cid=8" target="_blank">available for purchase</a>.
KML is an XML language focused on geographic visualization, including annotation of maps and images. Geographic visualization includes not only the presentation of graphical data on the globe, but also the control of the user's navigation in the sense of where to go and where to look.
Google submitted KML (formerly Keyhole Markup Language) to the Open Geospatial Consortium (OGC) to be evolved within the OGC consensus process with the following goal: KML Version 2.2 has been adopted as an OGC implementation standard.
\li Open Geospatial Consortium, Inc., <a href="http://portal.opengeospatial.org/files/?artifact_id=27810" target="_blank"><b>OGC KML Version 2.2.0</b></a>, April 2008.
In 1998, the C++ standards committee (the <a href="http://www.open-std.org/JTC1/SC22/WG21/" target="_blank">ISO/IEC JTC1/SC22/WG21 working group</a>)
standardized C++ and published the international standard ISO/IEC 14882:1998 (informally known as C++98). A technical corrigendum was approved in 2003,
In 2005, a technical report, called the <a href="http://www.open-std.org/JTC1/SC22/WG21/docs/papers/2005/n1836.pdf" target="_blank">Library Technical Report 1</a>
(often known as TR1 for short), was released. While not an official part of the standard, it specified a number of extensions to the standard library,
which were expected to be included in the next version of C++. The linked document is officially a draft, but that is due only to procedural issues;
the content did not change. Scott Meyers provides more <a href="http://www.aristeia.com/EC3E/TR1_info.html" target="_blank">TR1 information</a>.
Some ISO/IEC standards are publicly available, for instance: <a href="http://standards.iso.org/ittf/PubliclyAvailableStandards/c043351_ISO_IEC_TR_18015_2006(E).zip" target="_blank">ISO/IEC TR 18015:2006 Technical Report on C++ Performance</a>.
The standard for the next version of the language (previously known as C++0x) was finally
published with the name of <a href="https://en.wikipedia.org/wiki/C%2B%2B11" target="_blank">C++11</a> in September, 2011, as the ISO/IEC 14882:2011 Standard. GCC, the GNU Compiler Collection,
\li The most recent public draft of the <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2011/n3242.pdf" target="_blank"><b>Standard for Programming Language C++</b></a> was published in Feb. 2011.
\subsection protocols Positioning protocols in wireless communication networks
Cellular industry location standards first appeared in the late 1990s, with the <a href="http://www.3gpp.org/index.php" target="_blank">3rd generation partnership project (3GPP)</a> radio resource location services protocol (RRLP) technical specification 44.031 positioning protocol for GSM networks.
Today, RRLP is the de facto standardized protocol to carry GNSS assistance data to GNSS-enabled mobile devices, and the term "3GPP specification" now covers all GSM (including GPRS and EDGE),
W-CDMA and LTE (including LTE-A) specifications. Precisely, the label "LTE-A" is applied to networks compliant with LTE Release 10 and beyond, which fulfill the requirements issued by
the <a href="http://www.itu.int/en/ITU-R/Pages/default.aspx" target="_blank">International Telecommunication Union Radiocommunication Sector (ITU-R)</a> in the global standard for international mobile telecommunications (IMT Advanced, also referred to as 4G)
\li Open Mobile Alliance (OMA), <a href="http://member.openmobilealliance.org/ftp/Public_documents/LOC/Permanent_documents/OMA-AD-SUPL-V1_0-20070615-A.zip" target="_blank"><b>Secure User Plane Location Architecture Version 1 (SUPL 1.0)</b></a>, June 2007.
\li Open Mobile Alliance (OMA), <a href="http://member.openmobilealliance.org/ftp/Public_documents/LOC/Permanent_documents/OMA-AD-SUPL-V2_0-20120417-A.zip" target="_blank"><b>Secure User Plane Location Architecture Version 2 (SUPL 2.0)</b></a>, April 2012.
LTE Release 9 introduced extension hooks in LPP messages, so that the bodies external to 3GPP could extend the LPP feature set. OMA LPP extensions (LPPe), supported in SUPL 3.0, build on top of the 3GPP LPP reusing its procedures and data types.
Check the <a href="http://technical.openmobilealliance.org/Technical/LOC.aspx" target="_blank">OMA Location Working Group (WG) webpage</a> for updated information about LPP Extensions (LPPe) Specification.
\li The <a href="http://technical.openmobilealliance.org/Technical/release_program/mlp_v31.aspx" target="_blank"><b>OMA Mobile Location Protocol (MLP) V3.1</b></a> is an application-level protocol for getting the position of mobile stations (mobile phones, wireless personal digital assistants, etc.) independent
of underlying network technology. The MLP serves as the interface between a Location Server and a Location Services (LCS) Client.
