Misplaced Pages

#766233

110-500: DGPSs consist of networks of fixed position, ground-based reference stations. Each reference station calculates the difference between its highly accurate known position and its less accurate satellite-derived position. The stations broadcast this data locally—typically using ground-based transmitters of shorter range. Non-fixed (mobile) receivers use it to correct their position by the same amount, thereby improving their accuracy. The United States Coast Guard (USCG) previously ran DGPS in

220-515: A single device. In the 1990s when even handheld receivers were quite expensive, some methods of quasi-differential GPS were developed, using the receiver in quick turns of positions or loops of 3-10 survey points . United States Coast Guard The United States Coast Guard ( USCG ) is the maritime security , search and rescue , and law enforcement service branch of the United States Armed Forces and one of

330-536: A "system of cutters," each ship operated under the direction of the customs officials in the port to which it was assigned. Several names, including "Revenue-Marine," were used as the service gradually becoming more organized. Eventually it was officially organized as the United States Revenue Cutter Service . In addition to its regular law enforcement and customs duties, revenue cutters and their crews were used to support and supplement

440-540: A Coast Guard Reserve Officer. Lawyers, engineers, intelligence officers, military aviators holding commissions in other branches of the U.S. Armed Forces requesting interservice transfers to the Coast Guard, graduates of maritime academies, and certain other individuals may also receive an officer's commission in the Coast Guard through the Direct Commission Officer (DCO) program. Depending on

550-696: A GPS fix is due to transmission delays in the ionosphere , which could also be measured and corrected for in the broadcast. This offered an improvement to about 5 metres (16 ft) accuracy, more than enough for most civilian needs. The US Coast Guard was one of the more aggressive proponents of the DGPS, experimenting with the system on an ever-wider basis throughout the late 1980s and early 1990s. These signals are broadcast on marine longwave frequencies, which could be received on existing radiotelephones and fed into suitably equipped GPS receivers. Almost all major GPS vendors offered units with DGPS inputs, not only for

660-757: A branch of the armed forces of the United States at all times. The Coast Guard shall be a service in the Department of Homeland Security, except when operating as a service in the Navy." Coast Guard organization and operation is as set forth in Title 33 of the Code of Federal Regulations . On 25 November 2002, the Homeland Security Act was signed into law by U.S. President George W. Bush, designating

770-572: A combat environment. The squadron operated divisions in three separate areas during the period of 1965 to 1970. Twenty-six Point-class cutters with their crews and a squadron support staff were assigned to the U.S. Navy with the mission of interdicting the movement of arms and supplies from the South China Sea into South Vietnam by Viet Cong and North Vietnam junk and trawler operators. The squadron also provided 81mm mortar naval gunfire support to nearby friendly units operating along

880-463: A departure from the Navy conventions, all petty officers E-6 and below wear red chevrons and all chief petty officers wear gold. The U.S. Coast Guard Academy is a four-year service academy located in New London, Connecticut . Approximately 200 cadets graduate each year, receiving a Bachelor of Science degree and a commission as an ensign in the Coast Guard. Graduates are obligated to serve

990-540: A fraction of the cost. The accuracy inherent in the SA however, was too poor to make this realistic. The military received multiple requests from the Federal Aviation Administration (FAA) , United States Coast Guard (USCG) and United States Department of Transportation (DOT) to set SA aside to enable civilian use of GNSS, but remained steadfast in its objection on grounds of security. Throughout

1100-617: A gold Coast Guard Shield in lieu of a line star or staff corps officer insignia. Highly qualified enlisted personnel in pay grades E-6 through E-9 with a minimum of eight years' experience can compete each year for appointment as warrant officers (WO). Successful candidates are chosen by a board and then commissioned as chief warrant officer two (CWO2) in one of twenty-one specialties. Over time, chief warrant officers may be promoted to chief warrant officer three (CWO3) and chief warrant officer four (CWO4). The ranks of warrant officer (WO1) and chief warrant officer five (CWO5) are not currently used in

1210-572: A lack of LW on new consumer receivers, increasing interference levels, the energy inefficiency of AM and high electricity costs at transmitters. In 2014 and 2015 Russia closed all of its LW broadcast transmitters. As of 2024 more than half of LW frequencies are unoccupied and some of the remaining services are scheduled for closure. BBC Radio 4 (UK) announced that it will stop distinct programming for LW broadcasts in 2024 in an effort to transition listeners to other means of listening. A closure date for LW broadcasts has not yet been announced. With

SECTION 10

#1732780961767

1320-467: A minimum of five years on active duty. Most graduates are assigned to duty aboard Coast Guard cutters immediately after graduation, either as Deck Watch Officers (DWOs) or as Engineer Officers in Training (EOITs). Smaller numbers are assigned directly to flight training at Naval Air Station Pensacola , Florida or to shore duty at Coast Guard Sector , District, or Area headquarters units. In addition to

1430-458: A separate DGPS system, but discontinued its use on December 15, 2022. Other countries have their own DGPS. A similar system which transmits corrections from orbiting satellites instead of ground-based transmitters is called a Wide-Area DGPS (WADGPS) satellite-based augmentation system . When GPS was first being put into service, the US military was concerned about the possibility of enemy forces using

1540-678: A separate federal agency, also within the Treasury Department, with fulltime paid crews. In 1915 these two agencies, the Revenue Cutter Service and the Lifesaving Service, were merged to create the modern United States Coast Guard. The Lighthouse Service and the Bureau of Marine Inspection and Navigation were absorbed by the Coast Guard 1939 and 1942 respectively. In 1967, the Coast Guard moved from

1650-636: A service of the Department of the Navy . This arrangement has a broad historical basis, as the Coast Guard has been involved in wars as diverse as the War of 1812 , the Mexican–American War , and the American Civil War , in which the cutter Harriet Lane fired the first naval shots attempting to relieve besieged Fort Sumter . The last time the Coast Guard operated as a whole within the Navy

1760-509: A staff job, or an operations ashore billet. OCS is the primary channel through which the Coast Guard enlisted grades ascend to the commissioned officer corps. Unlike the other military services, the Coast Guard does not have a Reserve Officers' Training Corps (ROTC) program. However, the Coast Guard does have the Select Reserve Direct Commission, an officer program for prospective candidates interested serving as

1870-411: A summary table of the authorities of the Coast Guard's 192 special agents and 3,780 maritime law enforcement boarding officers. Coast Guardsmen have the legal authority to carry their service-issued firearms on and off base. This is rarely done in practice, however; at many Coast Guard stations, commanders prefer to have all service-issued weapons in armories when not in use. Still, one court has held in

1980-437: A total workforce of 87,569. The formal name for a uniformed member of the Coast Guard is "Coast Guardsman", irrespective of gender. "Coastie" is an informal term commonly used to refer to current or former Coast Guard personnel. In 2008, the term "Guardian" was introduced as an alternative but was later dropped. Admiral Robert J. Papp Jr. stated that it was his belief that no Commandant had the authority to change what members of

2090-465: Is a humanitarian and security service. It protects the United States ' borders and economic and security interests abroad; and defends its sovereignty by safeguarding sea lines of communication and commerce across U.S. territorial waters and its Exclusive Economic Zone . Due to ever-expanding risk imposed by transnational threats through the maritime and cyber domains, the U.S. Coast Guard

2200-399: Is at any given time deployed to and operating on all seven continents and in cyberspace to enforce its mission. Like its United States Navy sibling, the U.S. Coast Guard maintains a global presence with permanently-assigned personnel throughout the world and forces routinely deploying to both littoral and blue-water regions. The U.S. Coast Guard's adaptive, multi-mission "white hull" fleet

2310-542: Is essentially the same, a single constant shift forward from the time coded in the signal can compensate for all long-wave signals received at any one location from the same time signal station. The militaries of the United Kingdom, Russian Federation, United States, Germany, India and Sweden use frequencies below 50 kHz to communicate with submerged submarines . In the ITU Radio Regulations

SECTION 20

#1732780961767

2420-412: Is leveraged as a force of both diplomatic soft power and humanitarian and security assistance over the more overtly confrontational nature of "gray hulled" warships. As a humanitarian service, it saves tens of thousands of lives a year at sea and in U.S. waters, and provides emergency response and disaster management for a wide range of human-made and natural catastrophic incidents in the U.S. and throughout

2530-698: Is mainly for marine navigation, broadcasting its signal on the long-wave band; another is used for land surveys and land navigation, and has corrections broadcast on the Commercial FM radio band. The third at Sydney airport is currently undergoing testing for precision landing of aircraft (2011), as a backup to the Instrument Landing System at least until 2015. It is called the Ground Based Augmentation System . Corrections to aircraft position are broadcast via

2640-527: Is managed and used by the Coast Guard for tracking pollution and safety incidents in the nation's ports. The National Maritime Center (NMC) is the merchant mariner credentialing authority for the USCG under the auspices of the Department of Homeland Security . To ensure a safe, secure, and environmentally sound marine transportation system, the mission of the NMC is to issue credentials to fully qualified mariners in

2750-541: Is no longer deemed a necessity owing to the removal of selective availability in 2000 and also the introduction of newer generation of GPS satellites . The Canadian system was similar to the US system and was primarily for maritime usage covering the Atlantic and Pacific coast as well as the Great Lakes and Saint Lawrence Seaway . It was discontinued as a service December 15, 2022. Australia runs three DGPSes: one

2860-532: Is often considered a medium wave sub-band. Swedish station SAQ, located at the Varberg Radio Station facility in Grimeton, is the last remaining operational Alexanderson alternator long-wave transmitter. Although the station ended regular service in 1996, it has been maintained as a World Heritage Site , and makes at least two demonstration transmissions yearly, on 17.2 kHz. Longwave

2970-603: Is on the grounds of the former St. Elizabeths Hospital in the Anacostia section of Southeast Washington, across the Anacostia River from former Coast Guard headquarters. The fiscal year 2016 budget request for the U.S. Coast Guard was $ 9.96 billion. The Coast Guard's current district organization is divided into 9 districts. Their designations, district office and area of responsibility are as follows: Shore establishment commands exist to support and facilitate

3080-469: Is the main mode in the longwave band. The attenuation of signal strength with distance by absorption in the ground is lower than at higher frequencies, and falls with frequency. Low frequency ground waves can be received up to 2,000 kilometres (1,200 mi) from the transmitting antenna. Very low frequency waves below 30 kHz can be used to communicate at transcontinental distances, can penetrate saltwater to depths of hundreds of feet, and are used by

3190-554: Is the oldest continuously operating naval service of the United States. As Secretary of the Treasury, Hamilton headed the Revenue-Marine, whose original purpose was collecting customs duties at U.S. seaports. By the 1860s, the service was known as the U.S. Revenue Cutter Service and the term Revenue-Marine gradually fell into disuse. The modern U.S. Coast Guard was formed by a merger of the U.S. Revenue Cutter Service and

3300-573: Is used for broadcasting only within ITU Region 1. The long-wave broadcasters are located in Europe, North Africa and Mongolia . Typically, a larger geographic area can be covered by a long-wave broadcast transmitter compared to a medium-wave one. This is because ground-wave propagation suffers less attenuation due to ground conductivity at lower frequencies. Many countries have stopped using LW for broadcasting because of low audience figures,

3410-610: The Department of the Treasury from its inception until 1967. A congressional authority transfer to the Navy has only happened once: in 1917, during World War I . By the time the U.S. entered World War II in December 1941, the U.S. Coast Guard had already been transferred to the Navy by President Franklin Roosevelt . Created by Congress as the Revenue-Marine on 4 August 1790 at the request of Alexander Hamilton , it

Differential GPS - Misplaced Pages Continue

3520-788: The Federal Highway Administration , the Federal Railroad Administration and the National Geodetic Survey appointed the United States Coast Guard as the maintaining agency for the U.S. Nationwide DGPS network (NDGPS). The system is an expansion of the previous Maritime Differential GPS (MDGPS), which the Coast Guard began in the late 1980s and completed in March 1999. MDGPS covered only coastal waters,

3630-866: The IALA Recommendation on the Performance and Monitoring of DGNSS Services in the Band 283.5–325 kHz cite the United States Department of Transportation 's 1993 estimated error growth of 0.67 metres per 100 kilometres (3.5  ft/100 mi ) from the broadcast site but measurements of accuracy across the Atlantic, in Portugal, suggest a degradation of just 0.22  m/100 km (1.2  ft/100 mi ). DGPS can refer to any type of Ground-Based Augmentation System (GBAS). There are many operational systems in use throughout

3740-528: The Isle of Man and the Commissioners of Irish Lights , covering the whole of Ireland . Transmitting on the 300-kHz band, the system underwent testing and two additional transmitters were added before the system was declared operational in 2002. Effective Solutions provides details and a map of European Differential Beacon Transmitters. The United States Department of Transportation , in conjunction with

3850-415: The U.S. Department of the Treasury to the newly formed U.S. Department of Transportation , an arrangement that lasted until it was placed under the U.S. Department of Homeland Security in 2003 as part of legislation designed to more efficiently protect American interests following the terrorist attacks of 11 September 2001 . In times of war, the Coast Guard or individual components of it can operate as

3960-515: The U.S. Life-Saving Service on 28 January 1915, under the Department of the Treasury. In 1939, the U.S. Lighthouse Service was also merged into the U.S. Coast Guard. As one of the country's six armed services, the U.S. Coast Guard and its predecessor have participated in every major U.S. war since 1790, from the Quasi-War with France to the Global War on Terrorism . As of December 2021,

4070-610: The United States Army Corps of Engineers (USACE) sought comments on a planned phasing-out of the U.S. DGPS. In response to the comments received, a subsequent 2016 Federal Register notice announced that 46 stations would remain in service and "available to users in the maritime and coastal regions". In spite of this decision, USACE decommissioned its remaining 7 sites and, in March 2018, the USCG announced that it would decommission its remaining stations by 2020. As of June 2020, all NDGPS service has been discontinued as it

4180-463: The radio spectrum with wavelengths longer than what was originally called the medium-wave broadcasting band. The term is historic, dating from the early 20th century, when the radio spectrum was considered to consist of longwave (LW), medium-wave (MW), and short-wave (SW) radio bands. Most modern radio systems and devices use wavelengths which would then have been considered 'ultra-short' (i.e. VHF , UHF , and microwave ). In contemporary usage,

4290-436: The 160–190 kHz band a transmitter / amplifier output power to the antenna of at most 1 watt, with an antenna at most 15 meters (49 feet) high; this is called Low Frequency Experimental Radio (LowFER). The 190–435 kHz band is used for navigational beacons . Frequencies from 472–479 kHz are available to licensed amateurs as the new 630 m band , part of the now-defunct maritime band , but this

4400-528: The 1970s, some long-wave stations in northern and eastern Europe and the Soviet Union operated on frequencies as high as 433 kHz. Some radio broadcasters, for instance Droitwich transmitting station in the UK, derive their carrier frequencies from an atomic clock , allowing their use as frequency standards . Droitwich also broadcasts a low bit-rate data channel, using narrow-shift phase-shift keying of

4510-566: The Academy, prospective officers, who already hold a college degree, may enter the Coast Guard through Officer Candidate School (OCS), also located at the Coast Guard Academy. OCS is a 17-week course of instruction that prepares candidates to serve effectively as officers in the Coast Guard. In addition to indoctrinating students into a military lifestyle, OCS provides a wide range of highly technical information necessary to perform

Differential GPS - Misplaced Pages Continue

4620-530: The Coast Guard and Maritime Transportation Act of 2006, upon the declaration of war and when Congress so directs in the declaration, or when the President directs, the Coast Guard operates under the Department of Defense as a service in the Department of the Navy . As members of the military, Coast Guardsmen on active and reserve service are subject to the Uniform Code of Military Justice and receive

4730-473: The Coast Guard are called as the term Coast Guardsman is found in Title 14 USC which established the Coast Guard in 1915. "Team Coast Guard" refers to the four components of the Coast Guard as a whole: Regular, Reserve, Auxiliary, and Coast Guard civilian employees. Commissioned officers in the Coast Guard hold pay grades ranging from O-1 to O-10 and have the same rank structure as the Navy. Officers holding

4840-651: The Coast Guard as the federal agency responsible for maritime SAR operations, and the United States Air Force as the federal agency responsible for inland SAR. Both agencies maintain rescue coordination centers to coordinate this effort, and have responsibility for both military and civilian search and rescue. The two services jointly provide instructor staff for the National Search and Rescue School that trains SAR mission planners and coordinators. Previously located on Governors Island, New York,

4950-452: The Coast Guard is frequently lauded for its quick responsiveness and adaptability in a broad range of emergencies. In a 2005 article in Time magazine following Hurricane Katrina , the author wrote, "the Coast Guard's most valuable contribution to [a military effort when catastrophe hits] may be as a model of flexibility, and most of all, spirit." Wil Milam, a rescue swimmer from Alaska told

5060-535: The Coast Guard joined with the U.S. Navy and U.S. Marine Corps to adopt a new maritime strategy called A Cooperative Strategy for 21st Century Seapower that raised the notion of prevention of war to the same philosophical level as the conduct of war. This new strategy charted a course for the Navy, Coast Guard and Marine Corps to work collectively with each other and international partners to prevent regional crises, man-made or natural, from occurring, or reacting quickly should one occur to avoid negative impacts to

5170-543: The Coast Guard operate under Department of the Navy operational control while other Coast Guard units remain under the Department of Homeland Security . The Deployable Operations Group (DOG) was a Coast Guard command established in July 2007. The DOG established a single command authority to rapidly provide the Coast Guard, Department of Homeland Security, Department of Defense, Department of Justice and other interagency operational commanders adaptive force packages drawn from

5280-423: The Coast Guard to be placed under the U.S. Department of Homeland Security . The transfer of administrative control from the U.S. Department of Transportation to the U.S. Department of Homeland Security was completed the following year, on 1 March 2003. The U.S. Coast Guard reports directly to the civilian Secretary of Homeland Security. However, under 14 U.S.C.   § 3 as amended by section 211 of

5390-547: The Coast Guard's deployable specialized force units. The DOG was disestablished on 22 April 2013 and reorganized into Deployable Specialized Forces (DSF) units were placed under the control of the Atlantic and Pacific Area Commanders. The planning for the unit began after the terrorist attacks of 11 September 2001, and culminated with its formation on 20 July 2007. Its missions included maritime law enforcement, anti-terrorism , port security , pollution response, and diving operations . There were over 25 specialized units within

5500-509: The Coast Guard. Chief warrant officers may also compete for the Chief Warrant Officer to Lieutenant Program. If selected, the warrant officer will be promoted to lieutenant (O-3E). The "E" designates over four years' active duty service as a warrant officer or enlisted member and entitles the member to a higher rate of pay than other lieutenants. Enlisted members of the Coast Guard have pay grades from E-1 to E-9 and also follow

5610-482: The DGPS corrections generally fell with distance, and large transmitters capable of covering large areas tend to cluster near cities. This meant that lower-population areas, notably in the midwest and Alaska, would have little coverage by ground-based GPS. As of November 2013 the USCG's national DGPS consisted of 85 broadcast sites which provide dual coverage to almost the entire US coastline and inland navigable waterways including Alaska, Hawaii, and Puerto Rico. In addition

SECTION 50

#1732780961767

5720-828: The Deployable Operations Group including the Maritime Security Response Team , Maritime Safety and Security Teams , Law Enforcement Detachments, Port Security Units , the National Strike Force , and Regional Dive Lockers. The DOG also managed Coast Guard personnel assigned to the Navy Expeditionary Combat Command and was involved in the selection of Coast Guard candidates to attend Navy BUD/S and serve with Navy SEAL Teams . The new Department of Homeland Security headquarters complex

5830-466: The GPS post-processing software. The software computes baselines using simultaneous measurement data from two or more GPS receivers. The baselines represent a three-dimensional line drawn between the two points occupied by each pair of GPS antennas. The post-processed measurements allow more precise positioning, because most GPS errors affect each receiver nearly equally, and therefore can be cancelled out in

5940-662: The Great Lakes, and the Mississippi River inland waterways, while NDGPS expands this to include complete coverage of the continental United States. The centralized Command and Control unit is the USCG Navigation Center, based in Alexandria, VA. There are currently 85 NDGPS sites in the US network, administered by the U.S. Department of Homeland Security Navigation Center. In 2015, the USCG and

6050-466: The L1 frequency ( 1575.42 MHz ) was deliberately degraded by offsetting its clock signal by a random amount, equivalent to about 100 metres (330  ft ) of distance. This technique, known as Selective Availability , or SA for short, seriously degraded the usefulness of the GPS signal for non-military users. More accurate guidance was possible for users of dual-frequency GPS receivers which also received

6160-531: The L2 frequency ( 1227.6 MHz ), but the L2 transmission, intended for military use, was encrypted and was available only to authorized users with the decryption keys. This presented a problem for civilian users who relied upon ground-based radio navigation systems such as LORAN , VOR and NDB systems costing millions of dollars each year to maintain. The advent of a global navigation satellite system (GNSS) could provide greatly improved accuracy and performance at

6270-526: The Navy in various armed conflicts including the American Civil War . A separate federal agency, the U.S. Life-Saving Service , developed alongside the Revenue-Marine. Prior to 1848, there were various charitable efforts at creating systems to provide assistance to shipwrecked mariners from shore-based stations, notably by the Massachusetts Humane Society . The federal government began funding lifesaving stations in 1848 but funding

6380-940: The South Vietnamese coastline and assisted the U.S. Navy during Operation Sealords . Coast Guard Squadron Three , was a combat unit formed by the United States Coast Guard in 1967 for service during the Vietnam War . Placed under the operational control of the United States Navy and based in Pearl Harbor . It consisted of five USCG High Endurance Cutters operating on revolving six-month deployments. A total of 35 High Endurance Cutters took part in operations from May 1967 to December 1971, most notably using their 5-inch guns to provide naval gunfire support missions. Often units within

6490-568: The Southern Positioning Augmentation Network (SouthPAN) offers higher accuracy positioning for GNSS users. Post-processing is used in Differential GPS to obtain precise positions of unknown points by relating them to known points such as survey markers . The GPS measurements are usually stored in computer memory in the GPS receivers, and are subsequently transferred to a computer running

6600-635: The Treasury Alexander Hamilton lobbied Congress to fund the construction of ten cutters , which it did on 4 August 1790 (now celebrated as the Coast Guard's official birthday). Until the re-establishment of the Navy in 1798, these "revenue cutters" were the only naval force of the early United States. As such, the cutters and their crews frequently took on additional duties, including combating piracy, rescuing mariners in distress, ferrying government officials, and even carrying mail. Initially not an organized federal agency at all, merely

6710-405: The U.S. Coast Guard is the second smallest of the U.S. military service branches in terms of membership, the service by itself is the world's 12th largest naval force. The Coast Guard carries out three basic roles, which are further subdivided into eleven statutory missions. The three roles are: With a decentralized organization and much responsibility placed on even the most junior personnel,

SECTION 60

#1732780961767

6820-572: The U.S. Coast Guard's authorized force strength is 44,500 active duty personnel and 7,000 reservists. The service's force strength also includes 8,577 full-time civilian federal employees and 31,000 uniformed volunteers of the U.S. Coast Guard Auxiliary . The service maintains an extensive fleet of roughly 250 coastal and ocean-going cutters , patrol ships, buoy tenders, tugs, and icebreakers; as well as nearly 2,000 small boats and specialized craft. It also maintains an aviation division consisting of more than 200 helicopters and fixed-wing aircraft. While

6930-421: The U.S. Navy , as well as officers from the U.S. Public Health Service Commissioned Corps are assigned to the Coast Guard to perform chaplain-related functions and medical-related functions, respectively. These officers wear Coast Guard uniforms but replace the Coast Guard insignia with that of their own service. The Navy and Coast Guard share identical officer rank insignia except that Coast Guard officers wear

7040-556: The USCG and FAA sponsored systems, a number of vendors have created commercial DGPS services, selling their signal (or receivers for it) to users who require better accuracy than the nominal 15 meters GPS offers. Almost all commercial GPS units, even hand-held units, now offer DGPS data inputs, and many also support WAAS directly. To some degree, a form of DGPS is now a natural part of most GPS operations. A reference station calculates differential corrections for its own location and time. Users may be up to 200 nautical miles (370 km) from

7150-578: The USCG signals, but also aviation units on either VHF or commercial AM radio bands. "Production quality" DGPS signals began to be sent out on a limited basis in 1996, and the network was rapidly expanded to cover most US ports of call, as well as the Saint Lawrence Seaway in partnership with the Canadian Coast Guard . Plans were put into place to expand the system across the US, but this would not be easy. The quality of

7260-574: The USCG's ground-based DGPS networks, and there has been some argument that the latter will be turned off as WAAS becomes fully operational. By the mid-1990s it was clear that the SA system was no longer useful in its intended role. DGPS would render it ineffective over the US, where it was considered most needed. Additionally, during the Gulf War of 1990–1991 SA had been temporarily turned off because Allied troops were using commercial GPS receivers. This showed that leaving SA turned off could be useful to

7370-534: The United States maritime jurisdiction. The six uniformed services that make up the U.S. Armed Forces are defined in Title 10 of the U.S. Code : "The term "armed forces" means the Army, Marine Corps, Navy, Air Force, Space Force, and Coast Guard." The Coast Guard is further defined by Title 14 of the United States Code : "The Coast Guard as established January 28, 1915, shall be a military service and

7480-538: The United States on longwave radio frequencies between 285 kHz and 325 kHz near major waterways and harbors. It was discontinued in March 2022. The USCG's DGPS was known as NDGPS (Nationwide DGPS) and was jointly administered by the Coast Guard and the Army Corps of Engineers . It consisted of broadcast sites located throughout the inland and coastal portions of the United States including Alaska, Hawaii and Puerto Rico. The Canadian Coast Guard (CCG) also ran

7590-435: The United States. During the launch of the new U.S. maritime strategy at the International Seapower Symposium at the U.S. Naval War College in 2007, Coast Guard Commandant Admiral Thad Allen said the new maritime strategy reinforced the time-honored missions the service has carried out in the United States since 1790. "It reinforces the Coast Guard maritime strategy of safety, security and stewardship, and it reflects not only

7700-429: The United States. In 2000, an executive order by President Bill Clinton turned it off permanently. Nevertheless, by this point DGPS had evolved into a system for providing more accuracy than even a non-SA GPS signal could provide on its own. There are several other sources of error which share the same characteristics as SA in that they are the same over large areas and for "reasonable" amounts of time. These include

7810-438: The adoption of the Geneva Frequency Plan of 1975 , long-wave carrier frequencies are exact multiples of 9 kHz; ranging from 153 to 279 kHz. One exception was a French-language station, Europe 1 in Germany, which retained its prior channel spacing until the long-wave service was terminated in 2019. Other exceptions are all Mongolian transmitters, which are 2 kHz above the internationally recognized channels. Until

7920-445: The authority to: (1) carry a firearm; (2) execute and serve any order, warrant, subpoena, summons, or other process issued under the authority of the United States; (3) make an arrest without a warrant for any offense against the United States committed in the officer's presence or for a felony, cognizable under the laws of the United States committed outside the officer's presence if the officer has reasonable grounds to believe that

8030-474: The aviation VHF band. The marine DGPS service of 16 ground stations covering the Australian coast was discontinued effective July 1, 2020. Improved multichannel GPS capabilities, and signal sources from multiple providers (GPS, GLONASS , Galileo and BeiDou ) was cited as providing better navigational accuracy than could be obtained from GPS + DGPS. An Australian Satellite-Based Augmentation System (SBAS),

8140-438: The band 135.7–137.8 kHz is allocated (on a secondary basis) to Amateur radio worldwide, subject to a power limit of 1 watt EIRP. Many countries' regulators license amateurs to use it. In North America during the 1970s, the frequencies 167, 179, and 191 kHz were assigned to the short-lived Public Emergency Radio of the United States . Nowadays, in the United States, Part 15 of FCC regulations allow unlicensed use of

8250-472: The calculations. Differential GPS measurements can also be computed in real time by some GPS receivers if they receive a correction signal using a separate radio receiver, for example in Real Time Kinematic (RTK) surveying or navigation . The improvement of GPS positioning doesn't require simultaneous measurements of two or more receivers in any case, but can also be done by special use of

8360-408: The carrier, for Radio Teleswitch Services . Because long-wave signals can travel very long distances, some radio amateurs and shortwave listeners engage in an activity called DXing . DXers attempt to listen in to far away transmissions, and they will often send a reception report to the sending station to let them know where they were heard. After receiving a report, the sending station may mail

8470-404: The case of People v. Booth that Coast Guard boarding officers are qualified law enforcement officers authorized to carry personal firearms off-duty for self-defense. The Coast Guard traced its roots to the small fleet of vessels maintained by the United States Department of the Treasury beginning in the 1790s to enforce tariffs (an important source of revenue for the new nation). Secretary of

8580-718: The communications and operations center for the National Response Team, the NRC maintains agreements with a variety of federal entities to make additional notifications regarding incidents meeting established trigger criteria. The NRC also takes Maritime Suspicious Activity and Security Breach Reports. Details on the NRC organization and specific responsibilities can be found in the National Oil and Hazardous Substances Pollution Contingency Plan. The Marine Information for Safety and Law Enforcement (MISLE) database system

8690-448: The country's eight uniformed services . The service is a maritime, military, multi-mission service unique among the United States military branches for having a maritime law enforcement mission with jurisdiction in both domestic and international waters and a federal regulatory agency mission as part of its duties. It is the largest coast guard in the world, rivaling the capabilities and size of most navies . The U.S. Coast Guard

8800-410: The duties of a Coast Guard officer. Graduates of OCS are usually commissioned as ensigns, but some with advanced graduate degrees may enter as lieutenants (junior grade) or lieutenants . Graduating OCS officers entering active duty are required to serve a minimum of three years, while graduating reserve officers are required to serve four years. Graduates may be assigned to a cutter, flight training,

8910-554: The early to mid 1980s, a number of agencies worked to develop a solution to the SA "problem". Since the SA signal was changed slowly, the effect of its offset on positioning was relatively fixed – that is, if the offset was "100 meters to the east", that offset would be true over a relatively wide area. This suggested that broadcasting this offset to local GPS receivers could eliminate the effects of SA, resulting in measurements closer to GPS's theoretical performance, around 15 metres (49 ft). Additionally, another major source of errors in

9020-477: The global reach of our maritime services but the need to integrate and synchronize and act with our coalition and international partners to not only win wars ... but to prevent wars," Allen said. Title 14 USC, section 2 authorizes the Coast Guard to enforce U.S. federal laws. This authority is further defined in 14 U.S.C.   § 522 , which gives law enforcement powers to all Coast Guard commissioned officers, warrant officers, and petty officers. Unlike

9130-450: The globally available GPS signals to guide their own weapon systems. Originally, the government thought the "coarse acquisition" (C/A) signal would give only about 100- metre (330  ft ) accuracy, but with improved receiver designs, the actual accuracy was 20 to 30 metres (66 to 98  ft ). Starting in March 1990, to avoid providing such unexpected accuracy, the C/A signal transmitted on

9240-403: The ionospheric effects mentioned earlier, as well as errors in the satellite position ephemeris data and clock drift on the satellites. Depending on the amount of data being sent in the DGPS correction signal, correcting for these effects can reduce the error significantly, the best implementations offering accuracies of under 10 centimetres (3.9 in). In addition to continued deployments of

9350-476: The magazine, "In the Navy, it was all about the mission. Practicing for war, training for war. In the Coast Guard, it was, take care of our people and the mission will take care of itself." The eleven statutory missions as defined by law are divided into homeland security missions and non-homeland security missions: The U.S. Coast Guard Search and Rescue (CG-SAR) is one of the Coast Guard's best-known operations. The National Search and Rescue Plan designates

9460-464: The military to communicate with submerged submarines . Low frequency waves can also occasionally travel long distances by reflecting from the ionosphere (the actual mechanism is one of refraction ), although this method, called skywave or "skip" propagation, is not as common as at higher frequencies. Reflection occurs at the ionospheric E layer or F layers . Skywave signals can be detected at distances exceeding 300 kilometres (190 mi) from

9570-564: The mission of the sea and air assets and Coastal Defense . U.S. Coast Guard Headquarters is located in Southeast Washington, D.C. Examples of other shore establishment types are Coast Guard Sectors (which may include Coast Guard Bases), Surface Forces Logistics Center (SFLC), Coast Guard Stations , Coast Guard Air Stations , and the United States Coast Guard Yard . Training centers are included in

9680-868: The other branches of the United States Armed Forces , which are prevented from acting in a law enforcement capacity by 18 U.S.C.   § 1385 , the Posse Comitatus Act , and Department of Defense policy, the Coast Guard is exempt from and not subject to the restrictions of the Posse Comitatus Act. Further law enforcement authority is given by 14 U.S.C.   § 703 and 19 U.S.C.   § 1401 , which empower U.S. Coast Guard active and reserve commissioned officers, warrant officers, and petty officers as federal customs officers . This places them under 19 U.S.C.   § 1589a , which grants customs officers general federal law enforcement authority, including

9790-660: The person to be arrested has committed or is committing a felony; and (4) perform any other law enforcement duty that the Secretary of Homeland Security may designate. The U.S. Government Accountability Office Report to the House of Representatives , Committee on the Judiciary on its 2006 Survey of Federal Civilian Law Enforcement Functions and Authorities, identified the Coast Guard as one of 104 federal components that employed law enforcement officers . The report also included

9900-534: The radio spectrum (30–300 kHz). The "Longwave Club of America" ( United States ) is interested in "frequencies below the AM broadcast band" (i.e., all frequencies below 520 kHz). Because of their long wavelength , radio waves in this frequency range can diffract over obstacles like mountain ranges and travel beyond the horizon, following the contour of the Earth. This mode of propagation, called ground wave ,

10010-460: The range that transmit coded time signals to radio clocks. For example: Radio-controlled clocks receive their time calibration signals with built-in long-wave receivers. They use long-wave, rather than short-wave or medium-wave , because long-wave signals from the transmitter to the receiver always travel along the same direct path across the surface of the Earth , so the time delay correction for

10120-564: The rank of ensign (O-1) through lieutenant commander (O-4) are considered junior officers, commanders (O-5) and captains (O-6) are considered senior officers, and rear admirals (O-7) through admirals (O-10) are considered flag officers. The Commandant of the Coast Guard and the Vice Commandant of the Coast Guard are the only members of the Coast Guard authorized to hold the rank of admiral. The Coast Guard does not have medical officers or chaplains of its own. Instead, chaplains from

10230-821: The same pay and allowances as members of the same pay grades in the other uniformed services. The service has participated in every major U.S. conflict from 1790 through today, including landing troops on D-Day and on the Pacific Islands in World War II , in extensive patrols and shore bombardment during the Vietnam War , and multiple roles in Operation Iraqi Freedom . Maritime interception operations, coastal security, transportation security, and law enforcement detachments have been its major roles in recent conflicts in Iraq . On 17 October 2007,

10340-545: The same rank structure as the Navy. Enlisted members in pay grades of E-4 and higher are considered petty officers and follow career development paths very similar to those of Navy petty officers. Petty officers in pay grade E-7 and higher are chief petty officers and must attend the Coast Guard Chief Petty Officer Academy , or an equivalent Department of Defense school, in order to be advanced to pay grade E-8. The basic themes of

10450-440: The school are: Enlisted rank insignia is also nearly identical to Navy enlisted insignia. The Coast Guard shield replacing the petty officer's eagle on collar and cap devices for petty officers or enlisted rating insignia for seamen qualified as a "designated striker" . Group Rate marks (stripes) for junior enlisted members (E-3 and below) also follow Navy convention with white for seaman, red for fireman, and green for airman. In

10560-582: The school is now located at Coast Guard Training Center Yorktown at Yorktown, Virginia. Operated by the Coast Guard, the National Response Center (NRC) is the sole U.S. Government point of contact for reporting all oil , chemical , radiological , biological , and etiological spills and discharges into the environment, anywhere in the United States and its territories. In addition to gathering and distributing spill/incident information for Federal On Scene Coordinators and serving as

10670-794: The shore establishment commands. The military college for the USCG is called the United States Coast Guard Academy which trains both new officers through a four year program and enlisted personnel joining the ranks of officers through a 17 week program called Officer Candidate School (OCS). Abbreviated TRACEN, the other Training Centers include Training Center Cape May for enlisted bootcamp, Training Center Petaluma and Training Center Yorktown for enlisted "A" schools and "C" schools, and Coast Guard Aviation Technical Training Center and Coast Guard Aviation Training Center Mobile for aviation enlisted "A" school, "C" schools, and pilot officer training. The Coast Guard has

10780-482: The signal travel time from the transmitting station to the receiver is always the same for any one receiving location. Longwaves travel by groundwaves that hug the surface of the Earth, unlike mediumwaves and shortwaves . Those higher-frequency signals do not follow the surface of the Earth beyond a few kilometers, but can travel as skywaves , ' bouncing ' off different layers of the ionosphere at different times of day. These different propagation paths can make

10890-444: The specific program and the background of the individual, the course is three, four or five weeks long. The first week of the five-week course is an indoctrination week. The DCO program is designed to commission officers with highly specialized professional training or certain kinds of previous military experience. Longwave In radio, longwave , long wave or long-wave , and commonly abbreviated LW , refers to parts of

11000-423: The start of the medium wave broadcast band at 520 kHz. In Europe, Africa, and large parts of Asia ( International Telecommunication Union Region 1 ), where a range of frequencies between 148.5 and 283.5  kHz is used for AM broadcasting in addition to the medium-wave band, the term longwave usually refers specifically to this broadcasting band, which falls wholly within the low frequency band of

11110-462: The station, however, and some of the compensated errors vary with space: specifically, satellite ephemeris errors and those introduced by ionospheric and tropospheric distortions. For this reason, the accuracy of DGPS decreases with distance from the reference station. The problem can be aggravated if the user and the station lack "inter visibility"—when they are unable to see the same satellites. The United States Federal Radionavigation Plan and

11220-583: The system provided single or dual coverage to a majority of the inland portion of United States. Instead, the FAA (and others) started studying broadcasting the signals across the entire hemisphere from communications satellites in geostationary orbit. This led to the Wide Area Augmentation System (WAAS) and similar systems, although these are generally not referred to as DGPS, or alternatively, "wide-area DGPS". WAAS offers accuracy similar to

11330-658: The system was implemented as a maritime navigation aid to fill the gap left by the demise of the Decca Navigator System in 2000. With a network of 12 transmitters sited around the coastline and three control stations, it was set up in 1998 by the countries' respective General Lighthouse Authorities (GLA) — Trinity House covering England , Wales and the Channel Islands , the Northern Lighthouse Board covering Scotland and

11440-525: The term longwave is not defined precisely, and its intended meaning varies. It may be used for radio wavelengths longer than 1,000 m i.e. frequencies up to 300  kilohertz (kHz), including the International Telecommunication Union's (ITU's) low frequency (LF, 30–300 kHz) and very low frequency (VLF, 3–30 kHz) bands. Sometimes the upper limit is taken to be higher than 300 kHz, but not above

11550-411: The time lag different for every signal received. The delay between when the long-wave signal was sent from the transmitter (when the coded time was correct) and when the signal is received by the clock (when the coded time is slightly late) depends on the overland distance between the clock and the transmitter and the speed of light through the air , which is also very nearly constant. Since the time lag

11660-480: The transmitting antenna. Non-directional beacons transmit continuously for the benefit of radio direction finders in marine and aeronautical navigation. They identify themselves by a callsign in Morse code . They can occupy any frequency in the range 190–1750 kHz. In North America, they occupy 190–535 kHz. In ITU Region 1 the lower limit is 280 kHz. There are institutional broadcast stations in

11770-653: The world, according to the US Coast Guard, 47 countries operate systems similar to the US NDGPS (Nationwide Differential Global Positioning System). A list can be found at the World DGPS Database for Dxers. European DGPS network has been developed mainly by the Finnish and Swedish maritime administrations in order to improve safety in the archipelago between the two countries. In the UK and Ireland,

11880-421: The world. The U.S. Coast Guard operates under the U.S. Department of Homeland Security during peacetime. During times of war, it can be transferred in whole or in part to the U.S. Department of the Navy under the Department of Defense by order of the U.S. President or by act of Congress . Prior to its transfer to Homeland Security, it operated under the Department of Transportation from 1967 to 2003 and

11990-518: Was in World War II , in all some 250,000 served in the Coast Guard during World War II. Coast Guard Squadron One , was a combat unit formed by the United States Coast Guard in 1965 for service during the Vietnam War . Placed under the operational control of the United States Navy, it was assigned duties in Operation Market Time . Its formation marked the first time since World War II that Coast Guard personnel were used extensively in

12100-406: Was inconsistent and the system still relied on all-volunteer crews. In 1871, Sumner Increase Kimball was appointed chief of the Treasury Department's newly created Revenue Marine Division, and began the process of organizing the Revenue-Marine cutters into a centralized agency. Kimball also pushed for more funding lifesaving stations and eventually secured approval to create the Lifesaving Service as

#766233