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66-419: Instead of sailing directly toward a windward mark, the helmsman chooses a point of sail towards the direction of the wind that maximizes velocity made good (either towards the destination - or towards better winds). To actually reach a mark, the boat needs to alternate between courses ( tacks ) where the wind approaches from alternating sides. The helmsman uses VMG to find exactly what the optimum angle against

132-637: A SiRFstarIII chip and are comparable to their commercial counterparts. Other chips and software implementations are also available. An automotive navigation system takes its location from a GNSS system and, depending on the installed software, may offer the following services: Aviators use Satnav to navigate and to improve safety and the efficiency of the flight. This may allow pilots to be independent of ground-based navigational aids, enable more efficient routes and provide navigation into airports that lack ground-based navigation and surveillance equipment. There are now some GPS units that allow aviators to get

198-643: A built-in Satnav system . In 1991, Mitsubishi introduced Satnav car navigation on the Mitsubishi Debonair (MMCS: Mitsubishi Multi Communication System). In 1997, a navigation system using Differential GPS was developed as a factory-installed option on the Toyota Prius . In 2000, the Clinton administration removed the military use signal restrictions, thus providing full commercial access to

264-611: A laptop , some phones can provide localisation services to a laptop as well. Software companies have made available GPS navigation software programs for in-vehicle use on laptop computers. Benefits of GPS on a laptop include larger map overview, ability to use the keyboard to control GPS functions, and some GPS software for laptops offers advanced trip-planning features not available on other platforms, such as midway stops, capability of finding alternative scenic routes as well as only highway option. Palms and Pocket PC 's can also be equipped with GPS navigation. A pocket PC differs from

330-581: A clearer look in areas where the satellite is augmented to be able to have safe landings in bad visibility conditions. There have now been two new signals made for GPS, the first being made to help in critical conditions in the sky and the other will make GPS more of a robust navigation service. Many aviator services have now made it a required service to use a GPS. Commercial aviation applications include GNSS devices that calculate location and feed that information to large multi-input navigational computers for autopilot , course information and correction displays to

396-419: A combination of satellite data and cell tower data to shorten the time to first fix , reduce the need to download a satellite almanac periodically and to help resolve a location when satellite signals are disturbed by the proximity of large buildings. When out of range of a cell tower the location performance of a phone using A-GPS may be reduced. Phones with an A-GPS based hybrid positioning system can maintain

462-412: A commercial reality. The Macrometer Interferometric Surveyor was the first commercial GNSS-based system for performing geodetic measurements. In 1989, Magellan Navigation Inc. unveiled its Magellan NAV 1000, the world's first commercial handheld GPS receiver. These units initially sold for approximately US$ 2,900 each. In 1990, Mazda 's Eunos Cosmo was the first production car in the world with

528-488: A data connection. Consequently, almost any smartphone now qualifies as a personal navigation assistant . The use of mobile phones as navigational devices has outstripped the use of standalone GNSS devices. In 2009, independent analyst firm Berg Insight found that GNSS-enabled GSM/WCDMA handsets in the USA alone numbered 150 million units, against the sale of only 40 million standalone GNSS receivers. Assisted GPS (A-GPS) uses

594-444: A dedicated navigation device as it has an own operating system and can also run other applications. Other GPS devices need to be connected to a computer in order to work. This computer can be a home computer , laptop , PDA , digital camera , or smartphones . Depending on the type of computer and available connectors, connections can be made through a serial or USB cable, as well as Bluetooth , CompactFlash , SD , PCMCIA and

660-414: A feature called " text to speech ". Manufacturers include: Almost all smartphones now incorporate GNSS receivers . This has been driven both by consumer demand and by service suppliers. There are now many phone apps that depend on location services, such as navigational aids, and multiple commercial opportunities, such as localised advertising. In its early development, access to user location services

726-470: A fee. User privacy may be compromised if Satnav equipped handheld devices such as mobile phones upload user geo-location data through associated software installed on the device. User geo-location is currently the basis for navigational apps such as Google Maps, location-based advertising , which can promote nearby shops and may allow an advertising agency to track user movements and habits for future use. Regulatory bodies differ between countries regarding

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792-603: A few centimeters. GPS maps and directions are occasionally imprecise. Some people have gotten lost by asking for the shortest route, like a couple in the United States who were looking for the shortest route from South Oregon to Jackpot, Nevada . In August 2009 a young mother and her six-year-old son became stranded in Death Valley after following Satnav directions that led her up an unpaved dead-end road. When they were found five days later, her son had died from

858-409: A location fix when GPS signals are inadequate by cell tower triangulation and WiFi hotspot locations. Most smartphones download a satellite almanac when online to accelerate a GPS fix when out of cell tower range. Some, older, Java -enabled phones lacking integrated GPS may still use external GPS receivers via serial or Bluetooth ) connections, but the need for this is now rare. By tethering to

924-463: A navigation software suite. Also, software modules are significantly cheaper than complete stand-alone systems (around € 50 to €100). The software may include maps only for a particular region, or the entire world, if software such as Google Maps are used. Some hobbyists have also made some Satnav devices and open-sourced the plans. Examples include the Elektor GPS units. These are based around

990-479: A navigational error, President Ronald Reagan made the navigation capabilities of the existing military GPS system available for dual civilian use. However, civilian use was initially only a slightly degraded " Selective Availability " positioning signal. This new availability of the US military GPS system for civilian use required a certain technical collaboration with the private sector for some time, before it could become

1056-545: A set of standard steering commands, responses by the helmsman, and acknowledgment by the conning officer are widely recognized in the maritime industry. The helmsman repeats any verbal commands to demonstrate that the command is heard and understood. The International Convention on Standards of Training, Certification and Watchkeeping for Seafarers (STCW) requires that a helmsman be able to understand and respond to helm orders in English. The proliferation of autopilot systems and

1122-749: A steering stand with a ship's wheel. Such simulators incorporate magnetic and gyro compasses (or repeaters) for steering. Moreover, a rudder angle indicator that responds appropriately to the helm is part of the configuration. However technology also allows for a multitude of smaller workstations in a classroom setting. Administrators network student workstations so that the instructor can launch individual scenarios at each station. Computer models are used to accurately simulate conditions such as wind, seas, and currents. Moreover, shallow-water effects or other hydrodynamic forces, such as ships passing close to each other, can also be depicted. A computer application records training sessions, complete with voice commands issued by

1188-419: A tree canopy or inside a structure, such as in a building, garage or tunnel. Today, most standalone Satnav receivers are used in automobiles. The Satnav capability of smartphones may use assisted GNSS (A-GNSS) technology, which can use the base station or cell towers to provide a faster Time to First Fix (TTFF), especially when satellite signals are poor or unavailable. However, the mobile network part of

1254-544: A variety of hazards, including man-made obstacles, land formations, grounding in shallow waters, and the threat of collision with other vessels. In addition, powerful sea tides and river currents encountered in seaports heighten navigation dangers, as a ship's ability to stop is severely limited. Helmsmen of merchant and military ships that are underway stand watch at the helm for a set period of time before being relieved by another watchstander. The person being relieved will complete any course change or other critical maneuver that

1320-417: A variety of ship sizes and environmental conditions. Scenarios depicted in 3-D graphics range from making course corrections in open waters to maneuvering in port, rivers, or other shallow waters. Cost compared to a real vessel is low. Mariners learn responses to dangerous situations, such as steering failure, in the safety of a virtual environment. Land-based ship simulators may feature a full-scale replica of

1386-459: A week because their Satnav shows a street through his property. John and Starry Rhodes, a couple from Reno, Nevada were driving home from Oregon when they started to see there was a lot of snow in the area but decided to keep going because they were already 30 miles down the road. But the Satnav led them to a road in the Oregon forest that was not plowed and they were stuck for 3 days. Mary Davis

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1452-404: Is ergonomical , their screens are small, and some do not show color, in part to save power. Some use transflective liquid-crystal displays , allowing use in bright sunlight. Cases are rugged and some are water-resistant. Other receivers, often called mobile are intended primarily for use in a car, but have a small rechargeable internal battery that can power them for an hour or two away from

1518-551: Is in hand, rudder amidships, steering off the port pump." The officer on watch will usually reply with "very well." GPS navigation device A satellite navigation device or satnav device , also known as a satellite navigation receiver or satnav receiver or simply a GPS device , is a user equipment that uses satellites of the Global Positioning System (GPS) or similar global navigation satellite systems (GNSS). A satnav device can determine

1584-422: Is in progress before handing over the helm. The helmsman handing over the helm will inform the relief helmsman of any rudder commands in place and pertinent conditions. "Steering 180. We have oncoming traffic two points on the starboard" for example. In addition, the current helmsman should inform the relief if there are any peculiarities affecting steerage. Similarly, the helmsman will also point out if he or she

1650-408: Is steering a ship in a harbor or seaport when reduced speeds slow a ship's response to the rudder. For it is during ship arrivals and departures, when most ship collisions or groundings occur. Clear communication, then, between the officer of the bridge and the helmsman is essential for safe operations. The officer or harbor pilot relies upon the helmsman to flawlessly execute steering commands to avoid

1716-480: Is steering on a landmark, range, or navigational light. The relief helmsman is obligated to repeat the course being steered or other rudder command in order to demonstrate an understanding of the situation at the helm. On merchant ships, it is taught at the various maritime academies that the proper way to relieve the helm is for the helmsman being relieved to call out loudly the ship's course per gyro, course per standard magnetic compass, steering mode, rudder angle, and

1782-430: Is the speed component in the direction of a mark. If the course deviation is θ {\textstyle \theta } and speed over ground V o {\textstyle V_{o}} , the speed component toward a mark: V M C , y ^ = V o c o s θ {\displaystyle VMC,{\hat {y}}=V_{o}cos\theta } If

1848-436: The helm is usually an able seaman , particularly during ship arrivals, departures, and while maneuvering in restricted waters or other conditions requiring precise steering. An ordinary seaman is commonly restricted to steering in open waters. Moreover, military ships may have a seaman or quartermaster at the helm. A professional helmsman maintains a steady course, properly executes all rudder orders, and communicates to

1914-522: The A-GNSS technology would not be available when the smartphone is outside the range of the mobile reception network, while the satnav aspect would otherwise continue to be available. As with many other technological breakthroughs of the latter 20th century, the modern GNSS system can reasonably be argued to be a direct outcome of the Cold War of the latter 20th century. The multibillion-dollar expense of

1980-773: The American GPS was the first satellite navigation system to be deployed on a fully global scale, and to be made available for commercial use, this is not the only system of its type. Due to military and other concerns, similar global or regional systems have been, or will soon be deployed by Russia, the European Union, China, India, and Japan. GNSS devices vary in sensitivity, speed, vulnerability to multipath propagation , and other performance parameters. High-sensitivity receivers use large banks of correlators and digital signal processing to search for signals very quickly. This results in very fast times to first fix when

2046-454: The Earth. By the time the signals arrive at the user's receiver, they are typically as weak as −160  dBW , equivalent to 100 attowatts (10  W) . This is well below the thermal noise level in its bandwidth. Outdoors, GPS signals are typically around the −155 dBW level (−125  dBm ). Conventional GPS receivers integrate the received GPS signals for the same amount of time as

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2112-555: The US Satnav satellite system. As GNSS navigation systems became more and more widespread and popular, the pricing of such systems began to fall, and their widespread availability steadily increased. Several additional manufacturers of these systems, such as Garmin (1991), Benefon (1999), Mio (2002) and TomTom (2002) entered the market. Mitac Mio 168 was the first PocketPC to contain a built-in GPS receiver. Benefon's 1999 entry into

2178-576: The US and Russian programs was initially justified by military interest. In contrast, the European Galileo was conceived as purely civilian. In 1960, the US Navy put into service its Transit satellite-based navigation system to aid in naval navigation. The US Navy in the mid-1960s conducted an experiment to track a submarine with missiles with six satellites and orbiting poles and was able to observe satellite changes. Between 1960 and 1982, as

2244-514: The United States Navy and United States Coast Guard: Rudder Heading Steering a ship effectively requires skills gained through training and experience. An expert helmsman has a keen sense of how a particular ship will respond to the helm or how different sea conditions impact steering. For instance, experience teaches a helmsman the ability to correct the rudder in advance of a ship substantially falling off course. This requires

2310-598: The accuracy of a number of GNSS. A satellite navigation device can retrieve location and time information from one or more GNSS systems in all weather conditions, anywhere on or near the Earth's surface. Satnav reception requires an unobstructed line of sight to four or more GNSS satellites, and is subject to poor satellite signal conditions. In exceptionally poor signal conditions, for example in urban areas, satellite signals may exhibit multipath propagation where signals bounce off structures, or are weakened by meteorological conditions. Obstructed lines of sight may arise from

2376-496: The benefits were shown, the US military consistently improved and refined its satellite navigation technology and satellite system. In 1973, the US military began to plan for a comprehensive worldwide navigational system which eventually became known as the GPS (Global Positioning System). In 1983, in the wake of the tragedy of the downing of Korean Air Lines Flight 007 , an aircraft which was shot down while in Soviet airspace due to

2442-443: The boat, which allows it to move with greater speed, but less directly toward the wind (or mark). As an example, assume a boat wants to go north in a wind coming from the north. Assume also on a heading of 60 degrees (NE) the speed of the boat is 5.0 knots. Falling off to 65 degrees NE accelerates the boat to 5.2 knots. Turning up into the wind to a heading of 55 degrees NE causes the boat speed to drop to 4.0 knots. These data indicate

2508-412: The building materials or reflected as in multipath . Given that high-sensitivity GPS receivers may be up to 30  dB more sensitive, this is sufficient to track through 3 layers of dry bricks, or up to 20 cm (8 inches) of steel-reinforced concrete, for example. Examples of high-sensitivity receiver chips include SiRFstarIII and MediaTek ʼs MTK II. A sequential GPS receiver tracks

2574-407: The capacity to anticipate the delay between when the helm is applied and when the ship responds to the rudder. Similarly, a skilled helmsman will avoid overcompensating for a ship's movement caused by local conditions, such as wind, swells, currents, or rough seas. Computer-based ship simulators provide a training environment for learning skills to steer a ship. Training can be programmed to replicate

2640-624: The car. Special purpose devices for use in a car may be permanently installed and depend entirely on the automotive electrical system. Many of them have touch-sensitive screens as input method. Maps may be stored on a memory card . Some offer additional functionality such as a rudimentary music player , image viewer , and video player . The pre-installed embedded software of early receivers did not display maps; 21st-century ones commonly show interactive street maps (of certain regions) that may also show points of interest , route information and step-by-step routing directions, often in spoken form with

2706-400: The course is directly towards a mark, VMC will be identical to speed over ground (SOG). An ordinary GPS unit will, if it indicates a VMG measurement, of necessity be velocity made good on course. Measurement of wind speed and direction, in addition to boat speed and heading, is required to calculate a real VMG reading. If a mark is exactly currently in the direction of the wind, VMC will be

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2772-659: The duration of a complete C/A code cycle which is 1 ms. This results in the ability to acquire and track signals down to around the −160 dBW level. High-sensitivity GPS receivers are able to integrate the incoming signals for up to 1,000 times longer than this and therefore acquire signals up to 1,000 times weaker, resulting in an integration gain of 30 dB. A good high-sensitivity GPS receiver can acquire signals down to −185 dBW, and tracking can be continued down to levels approaching −190 dBW. High-sensitivity GPS can provide positioning in many but not all indoor locations . Signals are either heavily attenuated by

2838-493: The effects of heat and dehydration . In May 2012, Japanese tourists in Australia were stranded when traveling to North Stradbroke Island and their satnav instructed them to drive into Moreton Bay . In 2008 Satnav routed a softball team bus into a 9 ft tunnel, which sliced off the top of the bus and hospitalized the whole team. Brad Preston, Oregon claims that people are routed into his driveway five to eight times

2904-404: The helmsman learns to relax and take into account the vessel's natural rhythm in order to avoid oversteering whatever the maritime environment. Consequently, more accurate steering is attained with less rudder. Applying the minimal rudder required to steer a course reduces drag of the ship, thereby favorably impacting the ship's speed and operating costs. One of the helmsman's most important duties

2970-407: The helmsman may vary: on small vessels such as fishing vessels and yachts , the functions of the helmsman are combined with that of the skipper ; on larger vessels, there is a separate officer of the watch who is responsible for the safe navigation of the ship and gives orders to the helmsman, who physically steers the ship in accordance with those orders. In the merchant navy , the person at

3036-460: The increased computerization of operations on a ship's bridge lessen the need for helmsmen standing watch in open waters. Helm orders or commands fall into two categories: rudder commands and heading commands. A rudder command dictates changing the angle of the rudder, which is a single-event action, whereas steering a heading is a comparatively long event and will require ongoing or continuous rudder adjustments. The following are helm orders used in

3102-417: The instructor which are received by the students via a headset. On-the-job training at sea is critical to a helmsman developing ability to "sense" or anticipate how a ship will respond in different conditions. The experienced helmsman uses measured responses to sea conditions, even when encountering heavy weather that may cause a ship to pitch and roll as it pounds its way through oncoming waves. Subsequently,

3168-412: The market also presented users with the world's first phone based GPS navigation system. Later, as smartphone technology developed, a GPS chip eventually became standard equipment for most smartphones. To date, ever more popular satellite navigation systems and devices continue to proliferate with newly developed software and hardware applications. It has been incorporated, for example, into cameras. While

3234-460: The military had access to the full accuracy of GPS. Consumer devices were restricted by selective availability (SA), which was scheduled to be phased out but was removed abruptly by President Clinton. Differential GPS is a method of cancelling out the error of SA and improving GPS accuracy, and has been routinely available in commercial applications such as for golf carts. GPS is limited to about 15 meter accuracy even without SA. DGPS can be within

3300-713: The necessary satellites by typically using one or two hardware channels. The set will track one satellite at a time, time tag the measurements and combine them when all four satellite pseudoranges have been measured. These receivers are among the least expensive available, but they cannot operate under high dynamics and have the slowest time-to-first-fix (TTFF) performance. Consumer GNSS navigation devices include: Dedicated devices have various degrees of mobility. Hand-held , outdoor , or sport receivers have replaceable batteries that can run them for several hours, making them suitable for hiking , bicycle touring and other activities far from an electric power source. Their design

3366-405: The newer ExpressCard . Some PCMCIA/ExpressCard GPS units also include a wireless modem . Devices usually do not come with pre-installed GPS navigation software , thus, once purchased, the user must install or write their own software. As the user can choose which software to use, it can be better matched to their personal taste. It is very common for a PC-based GPS receiver to come bundled with

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3432-454: The officer on the bridge using navigational terms relating to ship's heading and steering. A helmsman relies upon visual references, a magnetic and gyrocompass , and a rudder angle indicator to steer a steady course. The mate or other officer on the bridge directs the helmsman aboard merchant or navy ships. Clear and exact communication between the helmsman and officer on the bridge is essential to safe navigation and ship handling. Consequently,

3498-486: The optimal VMG is obtained on a heading of 60 degrees from the true wind (60 degrees NE or 300 degrees NW). Turning up into the wind (more towards the mark) makes less progress towards the mark because the boat slows down too much. Turning downwind speeds up the boat, but yields a course that leads too far away from the mark for the increased speed to be a benefit. Velocity made good is often confused with velocity made good on course (VMC), and often used interchangeably. VMC

3564-507: The pilots, and course tracking and recording devices. Military applications include devices similar to consumer sport products for foot soldiers (commanders and regular soldiers), small vehicles and ships, and devices similar to commercial aviation applications for aircraft and missiles. Examples are the United States military's Commander's Digital Assistant and the Soldier Digital Assistant . Prior to May 2000 only

3630-488: The pump the vessel is steering off of. The relief helmsman will then take the helm and repeat all the information to ensure that he/she knows what to steer while on watch. An example of this would be: Helmsman: "Helm is being relieved... steering two-four-eight per gyro, checking two-four-five per standard. Helm is in hand, rudder amidships, steering off the port pump." Relief: "Helm has been relieved... steering two-four-eight per gyro, checking two-four-five per standard. Helm

3696-428: The same as VMG. As the direction towards a mark deviates with the direction of the wind, VMC will deviate from true VMG, and will be less useful to use for the purpose of optimizing sailing performance. Helmsman A helmsman or helm (sometimes driver or steersman ) is a person who steers a ship , sailboat , submarine , other type of maritime vessel, airship , or spacecraft . The rank and seniority of

3762-486: The same technique to geo-fence their customers to the areas they have paid for, charging additional fees for violations. In 2010, New York Civil Liberties Union filed a case against the Labor Department for firing Michael Cunningham after tracking his daily activity and locations using a Satnav device attached to his car. Private investigators use planted GPS devices to provide information to their clients on

3828-440: The signals are at their normal levels, for example, outdoors. When signals are weak, for example, indoors, the extra processing power can be used to integrate weak signals to the point where they can be used to provide a position or timing solution. GNSS signals are already very weak when they arrive at the Earth's surface. The GPS satellites only transmit 27 W (14.3 dBW) from a distance of 20,200 km in orbit above

3894-547: The trade-off between speed and progress toward the upwind mark (to the north in this case). Finding the heading that moves the boat most quickly towards the mark requires basic trigonometry . The northward component of the boat's velocity vector is found by multiplying the boat speed (V B ) by the cosine of the angle between the true wind direction (north) and the sailboat's heading. V M G = V B   c o s θ {\displaystyle VMG=V_{B}\ cos\theta } In this case,

3960-428: The treatment of geo-location data as privileged or not. Privileged data cannot be stored, or otherwise used, without the user's consent. Vehicle tracking systems allow employers to track their employees' location raising questions regarding violation of employee privacy. There are cases where employers continued to collect geo-location data when an employee was off duty in private time. Rental car services may use

4026-495: The user's geographic coordinates and may display the geographical position on a map and offer routing directions (as in turn-by-turn navigation ). As of 2023 , four GNSS systems are operational: the original United States' GPS, the European Union's Galileo , Russia's GLONASS , and China's BeiDou Navigation Satellite System. The Indian Regional Navigation Satellite System (IRNSS) will follow and Japan's Quasi-Zenith Satellite System ( QZSS ) scheduled for 2023 will augment

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4092-410: The wind angle towards the wind is on opposite sides of the boat. On a tack , the sailor might start by pointing the sailboat as close into the wind as possible while still keeping the winds blowing across the sails in a manner that provides aerodynamic lift which then propels the boat. The sailor can then turn slightly away from the wind to create more forward wind pressure on the sails and better balance

4158-450: The wind is. At the optimum boat speed and angle to the wind, VMG is maximized, steering closer to the direction of the wind will reduce boat speed, while steering further away from the direction of the wind might give a higher boat speed, but at the cost of a larger deviation in heading, so less progress towards a mark. For reaching marks that are towards the direction of the wind, sailboats need to alternate between headings, "tacks", where

4224-527: Was a very good chance that they could have had a fatality on their hands. Other hazards involve an alley being listed as a street, a lane being identified as a road, or rail tracks as a road. Obsolete maps sometimes cause the unit to lead a user on an indirect, time-wasting route, because roads may change over time. Smartphone Satnav information is usually updated automatically, and free of additional charge. Manufacturers of separate Satnav devices also offer map update services for their merchandise, usually for

4290-643: Was driven by European and American emergency services to help locate callers. All smartphone operating systems offer free mapping and navigational services that require a data connection; some allow the pre-purchase and downloading of maps but the demand for this is diminishing as data connection reliant maps can generally be cached anyway. There are many navigation applications and new versions are constantly being introduced. Major apps include Google Maps Navigation , Apple Maps and Waze , which require data connections, iGo for Android, Maverick and HERE for Windows Phone, which use cached maps and can operate without

4356-399: Was driving in an unfamiliar place when her Satnav told her to make a right turn onto a train track while there was a train coming down. Mary was lucky there was a local police officer who noticed the situation and urged her quickly to get out of the car as fast as she could. Mary was lucky enough to get out of the car leaving it for the train to hit and total it. The officer commented that there

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