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111-600: The AN/PSN-13 Defense Advanced GPS Receiver ( DAGR ; colloquially, " dagger ") is a handheld GPS receiver used by the United States Department of Defense and select foreign military services. It is a military-grade, dual-frequency receiver, and has the security hardware necessary to decode the encrypted P(Y)-code GPS signals . Manufactured by Rockwell Collins , the DAGR entered production in March 2004, with
222-478: A federal structure with two overlapping power centers so that each citizen as an individual is subject to the powers of state government and national government. To protect against abuse of power, each branch of government – executive, legislative, and judicial – had a separate sphere of authority and could check other branches according to the principle of the separation of powers . Furthermore, there were checks and balances within
333-408: A moving map display , or recorded or used by some other system, such as a vehicle guidance system. Although usually not formed explicitly in the receiver processing, the conceptual time differences of arrival (TDOAs) define the measurement geometry. Each TDOA corresponds to a hyperboloid of revolution (see Multilateration ). The line connecting the two satellites involved (and its extensions) forms
444-592: A "driving force in American government" and a "remarkably resilient institution". Congress is the "heart and soul of our democracy", according to this view, even though legislators rarely achieve the prestige or name recognition of presidents or Supreme Court justices ; one wrote that "legislators remain ghosts in America's historical imagination." One analyst argues that it is not a solely reactive institution but has played an active role in shaping government policy and
555-521: A GPS receiver known as the "Polaris Guide", that looks like a DAGR, but uses only the civilian C/A code signals. These units are labelled as "SPS", for " Standard Positioning Service ", and may be possessed by non-military users. GPS The Global Positioning System ( GPS ), originally Navstar GPS , is a satellite-based radio navigation system owned by the United States Space Force and operated by Mission Delta 31 . It
666-472: A Senate and House of Representatives." The House and Senate are equal partners in the legislative process – legislation cannot be enacted without the consent of both chambers. The Constitution grants each chamber some unique powers. The Senate ratifies treaties and approves presidential appointments while the House initiates revenue -raising bills. The House initiates impeachment cases, while
777-705: A deliberate error introduced into the GPS data that military receivers could correct for. As civilian GPS usage grew, there was increasing pressure to remove this error. The SA system was temporarily disabled during the Gulf War , as a shortage of military GPS units meant that many US soldiers were using civilian GPS units sent from home. In the 1990s, Differential GPS systems from the US Coast Guard , Federal Aviation Administration , and similar agencies in other countries began to broadcast local GPS corrections, reducing
888-450: A directive making GPS freely available for civilian use, once it was sufficiently developed, as a common good. The first Block II satellite was launched on February 14, 1989, and the 24th satellite was launched in 1994. The GPS program cost at this point, not including the cost of the user equipment but including the costs of the satellite launches, has been estimated at US$ 5 billion (equivalent to $ 10 billion in 2023). Initially,
999-517: A full complement of 24 satellites in 2027. The GPS project was launched in the United States in 1973 to overcome the limitations of previous navigation systems, combining ideas from several predecessors, including classified engineering design studies from the 1960s. The U.S. Department of Defense developed the system, which originally used 24 satellites, for use by the United States military, and became fully operational in 1993. Civilian use
1110-429: A liaison. The U.S. Department of Defense is required by law to "maintain a Standard Positioning Service (as defined in the federal radio navigation plan and the standard positioning service signal specification) that will be available on a continuous, worldwide basis" and "develop measures to prevent hostile use of GPS and its augmentations without unduly disrupting or degrading civilian uses". USA-203 from Block IIR-M
1221-563: A manageable level to permit accurate navigation. During Labor Day weekend in 1973, a meeting of about twelve military officers at the Pentagon discussed the creation of a Defense Navigation Satellite System (DNSS) . It was at this meeting that the real synthesis that became GPS was created. Later that year, the DNSS program was named Navstar. Navstar is often erroneously considered an acronym for "NAVigation System using Timing And Ranging" but
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#17327805364331332-461: A minimum, four satellites must be in view of the receiver for it to compute four unknown quantities (three position coordinates and the deviation of its own clock from satellite time). Each GPS satellite continually broadcasts a signal ( carrier wave with modulation ) that includes: Conceptually, the receiver measures the TOAs (according to its own clock) of four satellite signals. From the TOAs and
1443-444: A powerful effect of waking up a somewhat dormant Congress which investigated presidential wrongdoing and coverups; the scandal "substantially reshaped" relations between the branches of government, suggested political scientist Bruce J. Schulman . Partisanship returned, particularly after 1994; one analyst attributes partisan infighting to slim congressional majorities which discouraged friendly social gatherings in meeting rooms such as
1554-431: A receiver start-up situation. Most receivers have a track algorithm , sometimes called a tracker , that combines sets of satellite measurements collected at different times—in effect, taking advantage of the fact that successive receiver positions are usually close to each other. After a set of measurements are processed, the tracker predicts the receiver location corresponding to the next set of satellite measurements. When
1665-524: A revised constitution with a two-chamber or bicameral Congress. Smaller states argued for equal representation for each state. The two-chamber structure had functioned well in state governments. A compromise plan, the Connecticut Compromise , was adopted with representatives chosen by population (benefiting larger states) and exactly two senators chosen by state governments (benefiting smaller states). The ratified constitution created
1776-582: A state's at-large representation to the federal government by senators. Most incumbents seek re-election, and their historical likelihood of winning subsequent elections exceeds 90 percent. The historical records of the House of Representatives and the Senate are maintained by the Center for Legislative Archives, which is a part of the National Archives and Records Administration . Congress
1887-519: A two-year term , commencing every other January. Elections are held every even-numbered year on Election Day . The members of the House of Representatives are elected for the two-year term of a Congress. The Reapportionment Act of 1929 established that there be 435 representatives, and the Uniform Congressional Redistricting Act requires that they be elected from single-member constituencies or districts . It
1998-497: Is also required that the congressional districts be apportioned among states by population every ten years using the U.S. census results, provided that each state has at least one congressional representative. Each senator is elected at-large in their state for a six-year term, with terms staggered , so every two years approximately one-third of the Senate is up for election. Each state, regardless of population or size, has two senators, so currently, there are 100 senators for
2109-693: Is directly responsible for the governing of the District of Columbia , the current seat of the federal government. The First Continental Congress was a gathering of representatives from twelve of the Thirteen Colonies . On July 4, 1776, the Second Continental Congress adopted the Declaration of Independence , referring to the new nation as the "United States of America". The Articles of Confederation in 1781 created
2220-440: Is elected and gives each House the power to create its own structure. Section Seven lays out the process for creating laws, and Section Eight enumerates numerous powers. Section Nine is a list of powers Congress does not have, and Section Ten enumerates powers of the state, some of which may only be granted by Congress. Constitutional amendments have granted Congress additional powers. Congress also has implied powers derived from
2331-493: Is essentially charged with reconciling our many points of view on the great public policy issues of the day. Congress is constantly changing and is constantly in flux. In recent times, the American South and West have gained House seats according to demographic changes recorded by the census and includes more women and minorities . While power balances among the different parts of government continue to change,
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#17327805364332442-433: Is extraordinarily sensitive to public pressure. Several academics described Congress: Congress reflects us in all our strengths and all our weaknesses. It reflects our regional idiosyncrasies, our ethnic, religious, and racial diversity, our multitude of professions, and our shadings of opinion on everything from the value of war to the war over values. Congress is the government's most representative body ... Congress
2553-462: Is one of the global navigation satellite systems (GNSS) that provide geolocation and time information to a GPS receiver anywhere on or near the Earth where there is an unobstructed line of sight to four or more GPS satellites. It does not require the user to transmit any data, and operates independently of any telephone or Internet reception, though these technologies can enhance the usefulness of
2664-527: Is owned and operated by the United States government as a national resource. The Department of Defense is the steward of GPS. The Interagency GPS Executive Board (IGEB) oversaw GPS policy matters from 1996 to 2004. After that, the National Space-Based Positioning, Navigation and Timing Executive Committee was established by presidential directive in 2004 to advise and coordinate federal departments and agencies on matters concerning
2775-808: Is unhealthy For a more complete list, see List of GPS satellites On February 10, 1993, the National Aeronautic Association selected the GPS Team as winners of the 1992 Robert J. Collier Trophy , the US's most prestigious aviation award. This team combines researchers from the Naval Research Laboratory, the U.S. Air Force, the Aerospace Corporation , Rockwell International Corporation, and IBM Federal Systems Company. The citation honors them "for
2886-529: The tabloidization of media coverage. Others saw pressure to squeeze a political position into a thirty-second soundbite. A report characterized Congress in 2013 as unproductive, gridlocked, and "setting records for futility". In October 2013, with Congress unable to compromise, the government was shut down for several weeks and risked a serious default on debt payments, causing 60% of the public to say they would "fire every member of Congress" including their own representative. One report suggested Congress posed
2997-544: The Board of Education . Congress began reasserting its authority. Lobbying became a big factor despite the 1971 Federal Election Campaign Act . Political action committees or PACs could make substantive donations to congressional candidates via such means as soft money contributions. While soft money funds were not given to specific campaigns for candidates, the money often benefited candidates substantially in an indirect way and helped reelect candidates. Reforms such as
3108-541: The Commerce Clause , the enumerated power to regulate commerce, in rulings such as McCulloch v. Maryland , have effectively widened the scope of Congress's legislative authority far beyond that prescribed in Section Eight. Constitutional responsibility for the oversight of Washington, D.C. , the federal district and national capital, and the U.S. territories of Guam , American Samoa , Puerto Rico ,
3219-587: The Congress of the Confederation , a unicameral body with equal representation among the states in which each state had a veto over most decisions. Congress had executive but not legislative authority, and the federal judiciary was confined to admiralty and lacked authority to collect taxes, regulate commerce, or enforce laws. Government powerlessness led to the Convention of 1787 which proposed
3330-609: The Conservative Coalition . Democrats maintained control of Congress during World War II . Congress struggled with efficiency in the postwar era partly by reducing the number of standing congressional committees. Southern Democrats became a powerful force in many influential committees although political power alternated between Republicans and Democrats during these years. More complex issues required greater specialization and expertise, such as space flight and atomic energy policy. Senator Joseph McCarthy exploited
3441-503: The Doppler effect , they could pinpoint where the satellite was along its orbit. The Director of the APL gave them access to their UNIVAC I computer to perform the heavy calculations required. Early the next year, Frank McClure, the deputy director of the APL, asked Guier and Weiffenbach to investigate the inverse problem: pinpointing the user's location, given the satellite's. (At the time,
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3552-523: The Northern Mariana Islands . These six members of Congress enjoy floor privileges to introduce bills and resolutions, and in recent Congresses they vote in permanent and select committees, in party caucuses and in joint conferences with the Senate. They have Capitol Hill offices, staff and two annual appointments to each of the four military academies. While their votes are constitutional when Congress authorizes their House Committee of
3663-580: The United States Capitol in Washington, D.C. Members are chosen through direct election , though vacancies in the Senate may be filled by a governor 's appointment. Congress has 535 voting members: 100 senators and 435 representatives. The vice president of the United States , as President of the Senate, has a vote in the Senate only when there is a tie. The House of Representatives has six non-voting members . Congress convenes for
3774-504: The navigation equations gives the position of the receiver along with the difference between the time kept by the receiver's on-board clock and the true time-of-day, thereby eliminating the need for a more precise and possibly impractical receiver based clock. Applications for GPS such as time transfer , traffic signal timing, and synchronization of cell phone base stations , make use of this cheap and highly accurate timing. Some GPS applications use this time for display, or, other than for
3885-449: The second-wave feminism movement , when activists moved into electoral politics. Beginning in the 1970s, donors and political action committees like EMILY's List began recruiting, training and funding women candidates. Watershed political moments like the confirmation of Clarence Thomas and the 2016 presidential election created momentum for women candidates, resulting in the Year of
3996-484: The "biggest risk to the U.S. economy" because of its brinksmanship , "down-to-the-wire budget and debt crises" and "indiscriminate spending cuts", resulting in slowed economic activity and keeping up to two million people unemployed. There has been increasing public dissatisfaction with Congress, with extremely low approval ratings which dropped to 5% in October 2013. In 2009, Congress authorized another delegate for
4107-439: The 1960s opened the possibility for Black, Asian American, Latina and other non-white women candidates to run for Congress. Racially polarized voting, racial stereotypes and lack of institutional support still prevent women of color from reaching Congress as easily as white people . Senate elections, which require victories in statewide electorates, have been particularly difficult for women of color. Carol Moseley Braun became
4218-846: The 2002 Bipartisan Campaign Reform Act limited campaign donations but did not limit soft money contributions. One source suggests post-Watergate laws amended in 1974 meant to reduce the "influence of wealthy contributors and end payoffs" instead "legitimized PACs" since they "enabled individuals to band together in support of candidates". From 1974 to 1984, PACs grew from 608 to 3,803 and donations leaped from $ 12.5 million to $ 120 million along with concern over PAC influence in Congress. In 2009, there were 4,600 business, labor and special-interest PACs including ones for lawyers , electricians , and real estate brokers . From 2007 to 2008, 175 members of Congress received "half or more of their campaign cash" from PACs. From 1970 to 2009,
4329-600: The 40,000th unit delivered in September 2005. It was estimated by the news source Defense Industry Daily that, by the end of 2006, the USA and various allies around the world had issued almost $ 300 million worth of DAGR contracts, and ordered almost 125,000 units. The DAGR replaced the Precision Lightweight GPS Receiver (PLGR), which was first fielded in 1994. Rockwell Collins also manufactures
4440-410: The 50 states. Article One of the U.S. Constitution requires that members of Congress be at least 25 years old for the House and at least 30 years old for the U.S. Senate, be a U.S. citizen for seven years for the House and nine years for the Senate, and be an inhabitant of the state which they represent. Members in both chambers may stand for re-election an unlimited number of times. The Congress
4551-518: The American response as a "police action". According to Time magazine in 1970, "U.S. presidents [had] ordered troops into position or action without a formal congressional declaration a total of 149 times." In 1993, Michael Kinsley wrote that "Congress's war power has become the most flagrantly disregarded provision in the Constitution," and that the "real erosion [of Congress's war power] began after World War II." Disagreement about
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4662-401: The Congress has started and ended at noon on the third day of January of every odd-numbered year. Members of the Senate are referred to as senators; members of the House of Representatives are referred to as representatives, congressmen, or congresswomen. Scholar and representative Lee H. Hamilton asserted that the "historic mission of Congress has been to maintain freedom" and insisted it was
4773-462: The Constitution's Necessary and Proper Clause . Congress has authority over financial and budgetary policy through the enumerated power to "lay and collect Taxes, Duties, Imposts and Excises, to pay the Debts and provide for the common Defence and general Welfare of the United States". There is vast authority over budgets, although analyst Eric Patashnik suggested that much of Congress's power to manage
4884-524: The Earth's center) and the offset of the receiver clock relative to the GPS time are computed simultaneously, using the navigation equations to process the TOFs. The receiver's Earth-centered solution location is usually converted to latitude , longitude and height relative to an ellipsoidal Earth model. The height may then be further converted to height relative to the geoid , which is essentially mean sea level. These coordinates may be displayed, such as on
4995-664: The GPS and related systems. The executive committee is chaired jointly by the Deputy Secretaries of Defense and Transportation. Its membership includes equivalent-level officials from the Departments of State, Commerce, and Homeland Security, the Joint Chiefs of Staff and NASA . Components of the executive office of the president participate as observers to the executive committee, and the FCC chairman participates as
5106-411: The GPS positioning information. It provides critical positioning capabilities to military, civil, and commercial users around the world. Although the United States government created, controls, and maintains the GPS system, it is freely accessible to anyone with a GPS receiver. The GPS project was started by the U.S. Department of Defense in 1973. The first prototype spacecraft was launched in 1978 and
5217-668: The GPS service, including new signals for civil use and increased accuracy and integrity for all users, all the while maintaining compatibility with existing GPS equipment. Modernization of the satellite system has been an ongoing initiative by the U.S. Department of Defense through a series of satellite acquisitions to meet the growing needs of the military, civilians, and the commercial market. As of early 2015, high-quality Standard Positioning Service (SPS) GPS receivers provided horizontal accuracy of better than 3.5 meters (11 ft), although many factors such as receiver and antenna quality and atmospheric issues can affect this accuracy. GPS
5328-740: The Global Positioning System (GPS) its 60th Anniversary Award, nominated by IAF member, the American Institute for Aeronautics and Astronautics (AIAA). The IAF Honors and Awards Committee recognized the uniqueness of the GPS program and the exemplary role it has played in building international collaboration for the benefit of humanity. On December 6, 2018, Gladys West was inducted into the Air Force Space and Missile Pioneers Hall of Fame in recognition of her work on an extremely accurate geodetic Earth model, which
5439-604: The Government of the United States, or in any Department or Officer thereof". Article Four gives Congress the power to admit new states into the Union. One of Congress's foremost non-legislative functions is the power to investigate and oversee the executive branch. Congressional oversight is usually delegated to committees and is facilitated by Congress's subpoena power. Some critics have charged that Congress has in some instances failed to do an adequate job of overseeing
5550-546: The House expanded delegates, along with their powers and privileges representing U.S. citizens in non-state areas, beginning with representation on committees for Puerto Rico's resident commissioner in 1970. In 1971, a delegate for the District of Columbia was authorized, and in 1972 new delegate positions were established for U.S. Virgin Islands and Guam . In 1978, an additional delegate for American Samoa were added. In
5661-477: The House of Representatives have equal legislative authority, although only the House may originate revenue and appropriation bills . Congress has an important role in national defense , including the exclusive power to declare war, to raise and maintain the armed forces , and to make rules for the military. Some critics charge that the executive branch has usurped Congress's constitutionally defined task of declaring war. While historically presidents initiated
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#17327805364335772-625: The Jeffersonian Republican Party and began the era of the First Party System . In 1800, Thomas Jefferson 's election to the presidency marked a peaceful transition of power between the parties. John Marshall , 4th chief justice of the Supreme Court , empowered the courts by establishing the principle of judicial review in law in the landmark case Marbury v. Madison in 1803, effectively giving
5883-480: The Navy TRANSIT system were too slow for the high speeds of Air Force operation. The Naval Research Laboratory (NRL) continued making advances with their Timation (Time Navigation) satellites, first launched in 1967, second launched in 1969, with the third in 1974 carrying the first atomic clock into orbit and the fourth launched in 1977. Another important predecessor to GPS came from a different branch of
5994-582: The Navy was developing the submarine-launched Polaris missile, which required them to know the submarine's location.) This led them and APL to develop the TRANSIT system. In 1959, ARPA (renamed DARPA in 1972) also played a role in TRANSIT. TRANSIT was first successfully tested in 1960. It used a constellation of five satellites and could provide a navigational fix approximately once per hour. In 1967,
6105-604: The SLBM situation. In 1960, the Air Force proposed a radio-navigation system called MOSAIC (MObile System for Accurate ICBM Control) that was essentially a 3-D LORAN System. A follow-on study, Project 57, was performed in 1963 and it was "in this study that the GPS concept was born". That same year, the concept was pursued as Project 621B, which had "many of the attributes that you now see in GPS" and promised increased accuracy for U.S. Air Force bombers as well as ICBMs. Updates from
6216-581: The Senate decides impeachment cases. A two-thirds vote of the Senate is required before an impeached person can be removed from office. The term Congress can also refer to a particular meeting of the legislature. A Congress covers two years; the current one, the 118th Congress , began on January 3, 2023, and will end on January 3, 2025. Since the adoption of the Twentieth Amendment to the United States Constitution ,
6327-635: The Supreme Court a power to nullify congressional legislation. The Civil War , which lasted from 1861 to 1865, which resolved the slavery issue and unified the nation under federal authority but weakened the power of states' rights . The Gilded Age (1877–1901) was marked by Republican dominance of Congress. During this time, lobbying activity became more intense, particularly during the administration of President Ulysses S. Grant in which influential lobbies advocated for railroad subsidies and tariffs on wool. Immigration and high birth rates swelled
6438-524: The TOTs, the receiver forms four time of flight (TOF) values, which are (given the speed of light) approximately equivalent to receiver-satellite ranges plus time difference between the receiver and GPS satellites multiplied by speed of light, which are called pseudo-ranges. The receiver then computes its three-dimensional position and clock deviation from the four TOFs. In practice the receiver position (in three dimensional Cartesian coordinates with origin at
6549-607: The U.S. Navy developed the Timation satellite, which proved the feasibility of placing accurate clocks in space, a technology required for GPS. In the 1970s, the ground-based OMEGA navigation system, based on phase comparison of signal transmission from pairs of stations, became the first worldwide radio navigation system. Limitations of these systems drove the need for a more universal navigation solution with greater accuracy. Although there were wide needs for accurate navigation in military and civilian sectors, almost none of those
6660-442: The U.S. Secretary of Defense, William Perry , in view of the widespread growth of differential GPS services by private industry to improve civilian accuracy. Moreover, the U.S. military was developing technologies to deny GPS service to potential adversaries on a regional basis. Selective Availability was removed from the GPS architecture beginning with GPS-III. Since its deployment, the U.S. has implemented several improvements to
6771-416: The US government announced that the next generation of GPS satellites would not include the feature at all. Advances in technology and new demands on the existing system have now led to efforts to modernize the GPS and implement the next generation of GPS Block III satellites and Next Generation Operational Control System (OCX) which was authorized by the U.S. Congress in 2000. When Selective Availability
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#17327805364336882-512: The United States military. In 1964, the United States Army orbited its first Sequential Collation of Range ( SECOR ) satellite used for geodetic surveying. The SECOR system included three ground-based transmitters at known locations that would send signals to the satellite transponder in orbit. A fourth ground-based station, at an undetermined position, could then use those signals to fix its location precisely. The last SECOR satellite
6993-554: The White House a little more in favor of the executive branch", according to one account. Past presidents, including Ronald Reagan , George H. W. Bush , Bill Clinton , and George W. Bush , have made public statements when signing congressional legislation about how they understand a bill or plan to execute it, and commentators, including the American Bar Association , have described this practice as against
7104-504: The Whole votes, recent Congresses have not allowed for that, and they cannot vote when the House is meeting as the House of Representatives. On January 6, 2021, the Congress gathered to confirm the election of Joe Biden, when supporters of the outgoing president Donald Trump attacked the building . The session of Congress ended prematurely, and Congress representatives evacuated. Trump supporters occupied Congress until D.C police evacuated
7215-552: The Woman and the election of members of The Squad , respectively. Women of color faced additional challenges that made their ascension to Congress even more difficult. Jim Crow laws , voter suppression and other forms of structural racism made it virtually impossible for women of color to reach Congress prior to 1965. The passage of the Voting Rights Act that year , and the elimination of race-based immigration laws in
7326-662: The area. The event was the first time since the Burning of Washington by the British during the War of 1812 that the United States Congress was forcefully occupied. Various social and structural barriers have prevented women from gaining seats in Congress. In the early 20th century, women's domestic roles and the inability to vote forestalled opportunities to run for and hold public office. The two party system and
7437-451: The axis of the hyperboloid. The receiver is located at the point where three hyperboloids intersect. It is sometimes incorrectly said that the user location is at the intersection of three spheres. While simpler to visualize, this is the case only if the receiver has a clock synchronized with the satellite clocks (i.e., the receiver measures true ranges to the satellites rather than range differences). There are marked performance benefits to
7548-570: The basic position calculations, do not use it at all. United States Congress Minority (49) Minority (212) Vacant (3) [REDACTED] [REDACTED] The United States Congress is the legislature of the federal government of the United States . It is bicameral , composed of a lower body, the United States House of Representatives , and an upper body, the United States Senate . It meets in
7659-417: The budget has been lost when the welfare state expanded since "entitlements were institutionally detached from Congress's ordinary legislative routine and rhythm." Another factor leading to less control over the budget was a Keynesian belief that balanced budgets were unnecessary. The Sixteenth Amendment in 1913 extended congressional power of taxation to include income taxes without apportionment among
7770-416: The case of the latter, the lack of affiliation with a political party does not mean that such members are unable to caucus with members of the political parties. Members can also switch parties at any time, although this is quite uncommon. Article One of the United States Constitution states, "All legislative Powers herein granted shall be vested in a Congress of the United States, which shall consist of
7881-648: The clocks on GPS satellites, as observed by those on Earth, run 38 microseconds faster per day than those on the Earth. The design of GPS corrects for this difference; because without doing so, GPS calculated positions would accumulate errors of up to 10 kilometers per day (6 mi/d). When the Soviet Union launched its first artificial satellite ( Sputnik 1 ) in 1957, two American physicists, William Guier and George Weiffenbach, at Johns Hopkins University 's Applied Physics Laboratory (APL) monitored its radio transmissions. Within hours they realized that, because of
7992-496: The distance from the satellite to the ground station. With the distance information collected from multiple ground stations, the location coordinates of any satellite at any time can be calculated with great precision. Each GPS satellite carries an accurate record of its own position and time, and broadcasts that data continuously. Based on data received from multiple GPS satellites , an end user's GPS receiver can calculate its own four-dimensional position in spacetime ; However, at
8103-451: The distance traveled between two position measurements drops below or near the random error of position measurement. GPS units can use measurements of the Doppler shift of the signals received to compute velocity accurately. More advanced navigation systems use additional sensors like a compass or an inertial navigation system to complement GPS. GPS requires four or more satellites to be visible for accurate navigation. The solution of
8214-612: The early years as political parties became pronounced. With the passage of the Constitution and the Bill of Rights , the anti-federalist movement was exhausted. Some activists joined the Anti-Administration Party that James Madison and Thomas Jefferson were forming about 1790–1791 to oppose policies of Treasury Secretary Alexander Hamilton ; it soon became the Democratic-Republican Party or
8325-407: The effect of both SA degradation and atmospheric effects (that military receivers also corrected for). The U.S. military had also developed methods to perform local GPS jamming, meaning that the ability to globally degrade the system was no longer necessary. As a result, United States President Bill Clinton signed a bill ordering that Selective Availability be disabled on May 1, 2000; and, in 2007 ,
8436-487: The electorate. Lame duck reforms according to the Twentieth Amendment reduced the power of defeated and retiring members of Congress to wield influence despite their lack of accountability. The Great Depression ushered in President Franklin Roosevelt and strong control by Democrats and historic New Deal policies. Roosevelt 's election in 1932 marked a shift in government power towards
8547-425: The exclusive power of removal , allowing impeachment and removal of the president, federal judges and other federal officers. There have been charges that presidents acting under the doctrine of the unitary executive have assumed important legislative and budgetary powers that should belong to Congress. So-called signing statements are one way in which a president can "tip the balance of power between Congress and
8658-595: The executive branch. Numerous New Deal initiatives came from the White House rather initiated by Congress. President Roosevelt pushed his agenda in Congress by detailing Executive Branch staff to friendly Senate committees (a practice that ended with the Legislative Reorganization Act of 1946). The Democratic Party controlled both houses of Congress for many years. During this time, Republicans and conservative southern Democrats formed
8769-463: The extent of congressional versus presidential power regarding war has been present periodically throughout the nation's history. Congress can establish post offices and post roads, issue patents and copyrights , fix standards of weights and measures, establish Courts inferior to the Supreme Court , and "make all Laws which shall be necessary and proper for carrying into Execution the foregoing Powers, and all other Powers vested by this Constitution in
8880-564: The fear of communism during the Second Red Scare and conducted televised hearings. In 1960, Democratic candidate John F. Kennedy narrowly won the presidency and power shifted again to the Democrats who dominated both chambers of Congress from 1961 to 1980, and retained a consistent majority in the House from 1955 to 1994. Congress enacted Johnson's Great Society program to fight poverty and hunger. The Watergate Scandal had
8991-412: The first woman of color to reach the Senate in 1993. The second, Mazie Hirono , won in 2013. In 2021, Kamala Harris became the first female President of the Senate , which came with her role as the first female Vice President of the United States . Article One of the Constitution creates and sets forth the structure and most of the powers of Congress. Sections One through Six describe how Congress
9102-428: The full constellation of 24 satellites became operational in 1993. After Korean Air Lines Flight 007 was shot down when it mistakenly entered Soviet airspace, President Ronald Reagan announced that the GPS system would be made available for civilian use as of September 16, 1983; however, initially this civilian use was limited to an average accuracy of 100 meters (330 ft) by use of Selective Availability (SA),
9213-407: The highest-quality signal was reserved for military use, and the signal available for civilian use was intentionally degraded, in a policy known as Selective Availability . This changed on May 1, 2000, with U.S. President Bill Clinton signing a policy directive to turn off Selective Availability to provide the same accuracy to civilians that was afforded to the military. The directive was proposed by
9324-402: The internal structure of Congress is important to understand along with its interactions with so-called intermediary institutions such as political parties , civic associations , interest groups , and the mass media . The Congress of the United States serves two distinct purposes that overlap: local representation to the federal government of a congressional district by representatives and
9435-486: The lack of term limits favored incumbent white men, making the widow's succession – in which a woman temporarily took over a seat vacated by the death of her husband – the most common path to Congress for white women. Women candidates began making substantial inroads in the later 20th century, due in part to new political support mechanisms and public awareness of their underrepresentation in Congress. Recruitment and financial support for women candidates were rare until
9546-430: The late 20th century, the media became more important in Congress's work. Analyst Michael Schudson suggested that greater publicity undermined the power of political parties and caused "more roads to open up in Congress for individual representatives to influence decisions". Norman Ornstein suggested that media prominence led to a greater emphasis on the negative and sensational side of Congress, and referred to this as
9657-488: The law. Generally militia forces are controlled by state governments, not Congress. Congress also has implied powers deriving from the Constitution's Necessary and Proper Clause which permit Congress to "make all laws which shall be necessary and proper for carrying into Execution the foregoing Powers, and all other Powers vested by this Constitution in the Government of the United States, or in any Department or Officer thereof". Broad interpretations of this clause and of
9768-441: The legislature since there were two separate chambers. The new government became active in 1789. Political scientist Julian E. Zelizer suggested there were four main congressional eras, with considerable overlap, and included the formative era (1780s–1820s), the partisan era (1830s–1900s), the committee era (1910s–1960s), and the contemporary era (1970–present). Federalists and anti-federalists jostled for power in
9879-543: The most significant development for safe and efficient navigation and surveillance of air and spacecraft since the introduction of radio navigation 50 years ago". Two GPS developers received the National Academy of Engineering Charles Stark Draper Prize for 2003: GPS developer Roger L. Easton received the National Medal of Technology on February 13, 2006. Francis X. Kane (Col. USAF, ret.)
9990-440: The new measurements are collected, the receiver uses a weighting scheme to combine the new measurements with the tracker prediction. In general, a tracker can (a) improve receiver position and time accuracy, (b) reject bad measurements, and (c) estimate receiver speed and direction. The disadvantage of a tracker is that changes in speed or direction can be computed only with a delay, and that derived direction becomes inaccurate when
10101-487: The nuclear triad, also had requirements for a more accurate and reliable navigation system. The U.S. Navy and U.S. Air Force were developing their own technologies in parallel to solve what was essentially the same problem. To increase the survivability of ICBMs, there was a proposal to use mobile launch platforms (comparable to the Soviet SS-24 and SS-25 ) and so the need to fix the launch position had similarity to
10212-584: The other branches of government. In the Plame affair , critics including Representative Henry A. Waxman charged that Congress was not doing an adequate job of oversight in this case. There have been concerns about congressional oversight of executive actions such as warrantless wiretapping , although others respond that Congress did investigate the legality of presidential decisions. Political scientists Ornstein and Mann suggested that oversight functions do not help members of Congress win reelection. Congress also has
10323-524: The precision needed for GPS. The design of GPS is based partly on similar ground-based radio-navigation systems, such as LORAN and the Decca Navigator System , developed in the early 1940s. In 1955, Friedwardt Winterberg proposed a test of general relativity —detecting time slowing in a strong gravitational field using accurate atomic clocks placed in orbit inside artificial satellites. Special and general relativity predicted that
10434-597: The process for going to war, they asked for and received formal war declarations from Congress for the War of 1812 , the Mexican–American War , the Spanish–American War , World War I , and World War II , although President Theodore Roosevelt 's military move into Panama in 1903 did not get congressional approval. In the early days after the North Korean invasion of 1950 , President Truman described
10545-703: The ranks of citizens and the nation grew at a rapid pace. The Progressive Era was characterized by strong party leadership in both houses of Congress and calls for reform; sometimes reformers said lobbyists corrupted politics. The position of Speaker of the House became extremely powerful under leaders such as Thomas Reed in 1890 and Joseph Gurney Cannon . By the beginning of the 20th century, party structures and leadership emerged as key organizers of Senate proceedings. A system of seniority, in which long-time members of Congress gained more and more power, encouraged politicians of both parties to seek long terms. Committee chairmen remained influential in both houses until
10656-652: The reason for the ultra-secrecy at that time. The nuclear triad consisted of the United States Navy's submarine-launched ballistic missiles (SLBMs) along with United States Air Force (USAF) strategic bombers and intercontinental ballistic missiles (ICBMs). Considered vital to the nuclear deterrence posture, accurate determination of the SLBM launch position was a force multiplier . Precise navigation would enable United States ballistic missile submarines to get an accurate fix of their positions before they launched their SLBMs. The USAF, with two thirds of
10767-408: The reference atomic clocks at the ground control stations; any drift of the clocks aboard the satellites from the reference time maintained on the ground stations is corrected regularly. Since the speed of radio waves ( speed of light ) is constant and independent of the satellite speed, the time delay between when the satellite transmits a signal and the ground station receives it is proportional to
10878-504: The reforms of the 1970s. Important structural changes included the direct popular election of senators according to the Seventeenth Amendment , ratified on April 8, 1913. Supreme Court decisions based on the Constitution's commerce clause expanded congressional power to regulate the economy. One effect of popular election of senators was to reduce the difference between the House and Senate in terms of their link to
10989-413: The several States, and without regard to any census or enumeration. The Constitution also grants Congress the exclusive power to appropriate funds, and this power of the purse is one of Congress's primary checks on the executive branch. Congress can borrow money on the credit of the United States, regulate commerce with foreign nations and among the states, and coin money. Generally, the Senate and
11100-736: The spirit of the Constitution. There have been concerns that presidential authority to cope with financial crises is eclipsing the power of Congress. In 2008, George F. Will called the Capitol building a "tomb for the antiquated idea that the legislative branch matters". The Constitution enumerates the powers of Congress in detail. In addition, other congressional powers have been granted, or confirmed, by constitutional amendments. The Thirteenth (1865), Fourteenth (1868), and Fifteenth Amendments (1870) gave Congress authority to enact legislation to enforce rights of African Americans, including voting rights , due process , and equal protection under
11211-403: The user carrying a clock synchronized with the satellites. Foremost is that only three satellites are needed to compute a position solution. If it were an essential part of the GPS concept that all users needed to carry a synchronized clock, a smaller number of satellites could be deployed, but the cost and complexity of the user equipment would increase. The description above is representative of
11322-579: Was allowed from the 1980s. Roger L. Easton of the Naval Research Laboratory , Ivan A. Getting of The Aerospace Corporation , and Bradford Parkinson of the Applied Physics Laboratory are credited with inventing it. The work of Gladys West on the creation of the mathematical geodetic Earth model is credited as instrumental in the development of computational techniques for detecting satellite positions with
11433-420: Was concerned with the curving of the paths of radio waves ( atmospheric refraction ) traversing the ionosphere from NavSTAR satellites. After Korean Air Lines Flight 007 , a Boeing 747 carrying 269 people, was shot down by a Soviet interceptor aircraft after straying in prohibited airspace because of navigational errors, in the vicinity of Sakhalin and Moneron Islands , President Ronald Reagan issued
11544-551: Was created by the U.S. Constitution and first met in 1789, replacing the Congress of the Confederation in its legislative function. Although not legally mandated, in practice since the 19th century, members of Congress are typically affiliated with one of the two major parties , the Democratic Party or the Republican Party , and only rarely with a third party or independents affiliated with no party. In
11655-490: Was destroyed in a launch failure). The effect of the ionosphere on radio transmission was investigated in a geophysics laboratory of Air Force Cambridge Research Laboratory , renamed to Air Force Geophysical Research Lab (AFGRL) in 1974. AFGRL developed the Klobuchar model for computing ionospheric corrections to GPS location. Of note is work done by Australian space scientist Elizabeth Essex-Cohen at AFGRL in 1974. She
11766-703: Was discontinued, GPS was accurate to about 5 meters (16 ft). GPS receivers that use the L5 band have much higher accuracy of 30 centimeters (12 in), while those for high-end applications such as engineering and land surveying are accurate to within 2 cm ( 3 ⁄ 4 in) and can even provide sub-millimeter accuracy with long-term measurements. Consumer devices such as smartphones can be accurate to 4.9 m (16 ft) or better when used with assistive services like Wi-Fi positioning . As of July 2023 , 18 GPS satellites broadcast L5 signals, which are considered pre-operational prior to being broadcast by
11877-625: Was inducted into the U.S. Air Force Space and Missile Pioneers Hall of Fame at Lackland A.F.B., San Antonio, Texas, March 2, 2010, for his role in space technology development and the engineering design concept of GPS conducted as part of Project 621B. In 1998, GPS technology was inducted into the Space Foundation Space Technology Hall of Fame . On October 4, 2011, the International Astronautical Federation (IAF) awarded
11988-626: Was launched in 1969. With these parallel developments in the 1960s, it was realized that a superior system could be developed by synthesizing the best technologies from 621B, Transit, Timation, and SECOR in a multi-service program. Satellite orbital position errors, induced by variations in the gravity field and radar refraction among others, had to be resolved. A team led by Harold L. Jury of Pan Am Aerospace Division in Florida from 1970 to 1973, used real-time data assimilation and recursive estimation to do so, reducing systematic and residual errors to
12099-549: Was never considered as such by the GPS Joint Program Office (TRW may have once advocated for a different navigational system that used that acronym). With the individual satellites being associated with the name Navstar (as with the predecessors Transit and Timation), a more fully encompassing name was used to identify the constellation of Navstar satellites, Navstar-GPS . Ten " Block I " prototype satellites were launched between 1978 and 1985 (an additional unit
12210-455: Was seen as justification for the billions of dollars it would cost in research, development, deployment, and operation of a constellation of navigation satellites. During the Cold War arms race , the nuclear threat to the existence of the United States was the one need that did justify this cost in the view of the United States Congress. This deterrent effect is why GPS was funded. It is also
12321-529: Was ultimately used to determine the orbit of the GPS constellation. On February 12, 2019, four founding members of the project were awarded the Queen Elizabeth Prize for Engineering with the chair of the awarding board stating: "Engineering is the foundation of civilisation; ...They've re-written, in a major way, the infrastructure of our world." The GPS satellites carry very stable atomic clocks that are synchronized with one another and with
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