Interview Questions for Electronic Navigation Equipment Proficiency

GPS, or the Global Positioning System, relies on a constellation of satellites orbiting Earth. These satellites transmit precise timing signals. A GPS receiver on the ground (or on a vessel) receives these signals from at least four satellites. By measuring the time it takes for these signals to reach the receiver, and knowing the satellite’s precise location, the receiver can triangulate its own position using a technique called trilateration. Think of it like finding a point on a map by measuring the distance to three known points—the intersection of the circles defines your location. The use of four satellites accounts for any clock errors in the receiver and allows for three-dimensional positioning (latitude, longitude, and altitude).

Each satellite continuously broadcasts a signal containing its precise location and time. These messages include details on satellite health, ephemeris data (precise satellite orbital information), and almanac data (less precise but more general orbital information). The receiver uses this data to calculate its position.

For example, a ship’s captain uses GPS to determine the vessel’s exact location to ensure safe navigation, avoiding hazards and following designated routes. Similarly, an aircraft pilot relies on GPS for precise navigation.

Electronic charts come in various formats, each with its own capabilities. The most common types include:

• Raster Charts: These are digital images of traditional paper charts. They are visually familiar but lack the data integration capabilities of vector charts. Imagine a scanned copy of a paper map—all the visual information is there, but you can’t easily extract individual data points.
• Vector Charts: These charts are built using lines, points, and polygons. This allows for better data management and manipulation—zoom in and out without losing quality. This is akin to having a computer-generated map where every element is defined individually and can be updated easily.
• ENCs (Electronic Navigational Charts): ENCs are a special type of vector chart that conforms to international standards. They contain official chart data and have integrated safety features like highlighting dangers and providing warnings. ENCs are essential for ECDIS systems.

The choice of chart depends on the navigation system and the level of detail required. ENCs are preferred for professional navigation due to their safety features and compliance standards.

GPS, despite its accuracy, has certain limitations:

• Atmospheric Effects: The ionosphere and troposphere can delay GPS signals, leading to errors in position calculation. Advanced receivers incorporate methods to correct for these effects.
• Multipath Errors: Signals can bounce off objects (buildings, water) before reaching the receiver, causing inaccurate readings. Signal processing techniques help mitigate these.
• Satellite Geometry: The relative positions of the satellites can influence the accuracy of the position fix; a poor geometry (e.g., satellites clustered together) leads to greater uncertainty. The receiver indicates the quality of the satellite geometry through its PDOP (Position Dilution of Precision) value.
• Obstructions: Buildings, foliage, or even a bridge can block GPS signals, leading to loss of reception. This can be countered by using multiple receivers or by supplementing GPS with other navigation systems.
• Intentional Interference (Spoofing/Jamming): GPS signals can be intentionally jammed or spoofed (simulated) which results in inaccurate data and potentially dangerous situations. The best solution is to use a combination of different navigation systems to validate the GPS data.

These limitations are mitigated by using techniques like differential GPS (DGPS), which corrects for atmospheric errors using reference stations, or by integrating GPS with other navigation systems such as inertial navigation systems (INS) or radar.

An Inertial Navigation System (INS) uses accelerometers and gyroscopes to measure the vessel’s movement (acceleration and rotation). By integrating this information over time, it calculates its position and orientation. Imagine a sophisticated mechanical system that continuously monitors changes in motion and uses those to estimate current location. It does not require external reference points, making it useful in environments where GPS might be unavailable (e.g., under dense foliage or inside a tunnel).

Accelerometers measure changes in velocity, while gyroscopes measure changes in orientation (rotation). The INS computer continuously integrates these measurements to track position and heading. However, these measurements accumulate errors over time (drift), so INS systems are often augmented with other navigational inputs (like GPS) to improve accuracy. The system calculates the speed in each axis and integrates it to determine the distance traveled in each direction. It uses this information and its initial position and orientation to determine its current location.

An Automatic Radar Plotting Aid (ARPA) is a radar system that automatically tracks and displays targets, such as other vessels, buoys, or landmasses. It enhances the safety of navigation by providing valuable information about the relative motion of targets. It goes beyond simply showing radar echoes and actively analyzes the movement of each contact to provide information such as:

• Target Range and Bearing: The distance and direction to each target.
• Target Course and Speed: The direction and speed the target is moving.
• CPA (Closest Point of Approach): The closest point the target will pass to your vessel.
• TCPA (Time to Closest Point of Approach): The time until the target is at its closest point to your vessel.

Think of an ARPA as a sophisticated assistant that constantly monitors surrounding vessels, alerting the navigator to potential collision risks and giving them time to take preventative action. This allows mariners to anticipate and avoid collisions, increasing safety at sea, particularly in congested waters or during poor visibility.

Gyrocompass calibration is a crucial process to ensure its accuracy. It involves several steps aimed at minimizing errors:

• Leveling: The gyrocompass must be precisely leveled to ensure accurate readings. This often involves adjusting leveling screws until bubble indicators in the compass show the system is perfectly horizontal.
• Setting the Latitude: The gyrocompass needs its latitude set, as the Earth’s rotation rate varies with latitude. This is usually done using input from another positioning system, like GPS.
• Compass Error Correction: Gyrocompasses are subject to various errors such as precession, which causes the gyrocompass to align slowly with the local magnetic meridian. Calibration helps minimize these errors. Several tests and adjustments are performed to minimize deviations from the true north.
• Comparison with a Reference: The gyrocompass’s heading is often compared to a reference source, such as a known geographic landmark or a highly accurate GPS system, to verify accuracy. This allows for the detection and correction of systematic errors.
• Regular Maintenance: Regular maintenance checks on the gyrocompass are essential to ensure its continued accuracy and reliability, covering aspects like component wear, power supply, and environmental factors.

A well-calibrated gyrocompass provides an accurate and reliable heading reference crucial for safe navigation.

An Electronic Chart Display and Information System (ECDIS) is a sophisticated navigation system integrating electronic charts with other navigation data. Key features include:

• Electronic Chart Display: Displays vector-based ENCs. The ECDIS will dynamically update the chart to show the vessel’s position and other relevant navigational information.
• Integrated Navigation Data: Combines GPS, gyrocompass, speed log, and other sensor data to provide a comprehensive picture of the vessel’s position, course, and speed.
• Route Planning and Monitoring: Allows for route planning and monitoring, with alerts for deviations from the planned course or proximity to hazards. The system might even sound alarms if the vessel is about to stray from its planned course.
Safety Features: Includes safety features such as automatic alarms for proximity to hazards (shoals, rocks, etc.), and checks for conflicts with other vessels or structures.
• Data Management: ECDIS systems allow for the management of various electronic navigational data like charts, route plans, and other navigational information.
• Integration with other Systems: The ECDIS can often be integrated with other shipboard systems, such as the automatic identification system (AIS), weather systems, and radar for a comprehensive navigational picture.

ECDIS provides a significant enhancement to navigational safety, reducing the risk of accidents. It’s now standard on many commercial vessels.

The Automatic Identification System (AIS) is a crucial technology for maritime safety and traffic management. It’s essentially a system that allows vessels to automatically broadcast their identification, position, course, and other information to other nearby vessels and shore stations. Think of it as a ‘ship-to-ship’ and ‘ship-to-shore’ communication system, but instead of voices, it uses digital data.

Here’s how it works:

• Transmitting Data: Each AIS-equipped vessel transmits its data at regular intervals (typically every 2-10 seconds) using VHF radio frequencies. This data includes its Maritime Mobile Service Identity (MMSI) number (a unique identifier like a phone number for ships), position (latitude and longitude), course, speed, heading, and other relevant information.
• Receiving Data: Other vessels and shore-based AIS receivers can pick up these broadcasts, decode the data, and display it on their Electronic Chart Display and Information Systems (ECDIS) or other navigation equipment. This allows mariners to see the positions and movements of other ships in real-time, greatly enhancing situational awareness and reducing the risk of collisions.
• Data Processing: The received AIS data is typically processed and displayed on a screen showing icons representing vessels, with information about each ship displayed upon selection. The system can also be integrated with radar for enhanced visualization.

For example, imagine two large container ships approaching each other in dense fog. AIS allows both captains to see each other’s positions and predicted courses well in advance, allowing them to take appropriate evasive maneuvers and avoid a potentially disastrous collision. It’s a powerful tool for improving maritime safety.

Differential GPS (DGPS) enhances the accuracy of standard GPS by correcting for systematic errors in the satellite signals. Standard GPS signals can have errors due to atmospheric conditions and satellite clock inaccuracies. DGPS mitigates these errors significantly.

It works by using a network of ground-based reference stations. These stations know their exact location using very precise surveying techniques. They receive the same GPS signals as any GPS receiver. By comparing the received signals with their known position, the reference stations can calculate the errors in the GPS signals.

These error corrections are then broadcast to GPS receivers via radio signals (usually on a specific frequency). The GPS receiver uses these corrections to adjust its calculated position, resulting in a much more accurate location fix. The accuracy improvement can be from several meters to just centimeters depending on the system used.

Imagine trying to measure something with a slightly inaccurate ruler. DGPS is like having a calibrator for your GPS – refining the measurements for better precision. It is especially useful in areas where high accuracy is critical, such as surveying, harbor navigation, and precision agriculture.

Navigation errors can stem from many sources, broadly categorized as:

• Satellite-Related Errors: These include errors in the satellite clocks, orbital predictions, and atmospheric delays (ionospheric and tropospheric).
• Receiver-Related Errors: These are due to limitations of the GPS receiver itself, including multipath effects (signals reflecting off buildings or water before reaching the receiver), noise interference, and antenna imperfections.
• User-Related Errors: This includes incorrect antenna placement, inaccurate data entry, and human errors in interpreting the navigation data.
• Environmental Factors: Atmospheric conditions like ionospheric storms can affect signal propagation. Obstructions like buildings or trees can block signals or cause multipath errors.

For example, a multipath error can occur when a GPS signal reflects off a large building before reaching the receiver. This reflected signal might reach the receiver slightly later than the direct signal, causing an error in the position calculation. Understanding these different error sources is crucial for mitigating their impact and ensuring reliable navigation.

Several types of radar are used in navigation, each with its own strengths and weaknesses:

• X-band Radar: This is the most common type used on ships. It operates at a higher frequency, providing better resolution and detail for smaller targets. It works well in closer ranges, but its signals are more susceptible to weather interference (rain, sea spray).
• S-band Radar: Operating at a lower frequency, S-band radar has better penetration in heavy weather and longer range capabilities. However, its resolution is generally lower than X-band.
• High-Frequency (HF) Radar: HF radar is a surface-wave radar used to track sea currents, wave height, and wind direction. It is less commonly used for direct ship navigation, but can be useful for coastal surveillance and weather forecasting.
• ARPA (Automatic Radar Plotting Aid): While not a specific type of radar itself, ARPA is a system that automatically tracks targets detected by the radar, predicting their future positions to assist with collision avoidance.

The choice of radar depends on the specific needs of the user. A coastal vessel might prioritize higher resolution X-band radar, while a long-range cargo ship may prefer the better weather penetration of S-band radar. ARPA is nearly universal on larger vessels for its collision avoidance features.

Maintaining accurate navigation data is paramount for safe and efficient operation. Inaccurate navigation data can lead to collisions, groundings, delays, and other serious consequences. This is especially crucial in areas with high traffic density or challenging environmental conditions.

Accuracy depends on many factors, from the quality of the navigation equipment to the proper maintenance and calibration of instruments, and to the correct input and use of data. For instance, a small error in position can be amplified over time if not corrected, leading to substantial deviations from the intended course. Accurate charts and navigational aids are equally crucial. Furthermore, regular checks and updates of navigational software and data sources are vital to ensure accuracy.

Imagine a pilot relying on an outdated or faulty chart. They might unknowingly steer their ship into a previously unknown hazard, with potentially catastrophic results. Maintaining accuracy is not just about precision; it’s about preventing potentially fatal consequences and safeguarding both vessels and the environment.

Troubleshooting a malfunctioning GPS receiver involves a systematic approach. Here’s a step-by-step process:

1. Check for Obstructions: Ensure that the antenna has a clear view of the sky, free from obstructions like trees, buildings, or other physical barriers that could impede signal reception.
2. Verify Power Supply: Confirm that the receiver is receiving adequate power. Check connections and fuses.
3. Examine Antenna Connections: Inspect the antenna cable and connector for any damage, corrosion, or loose connections. Reseat any connections carefully.
4. Check for Interference: Identify any potential sources of radio frequency interference (RFI) near the receiver. Other electronic devices or metal objects could interfere with signal reception.
5. Test in a Known Good Location: Move the receiver to an area with excellent GPS reception to test its functionality. If it functions correctly in this area but not in its usual location, it indicates a problem with the original location, such as signal interference.
6. Software/Firmware Update: Check for available software or firmware updates from the receiver’s manufacturer. Outdated software might contain bugs or compatibility issues.
7. Consult Documentation: Review the receiver’s technical manual for troubleshooting steps and error codes. The manual might provide specific solutions for specific error messages.
8. Contact Support: If the problem persists, contact the manufacturer or a qualified technician for professional assistance.

This systematic approach helps isolate the problem quickly and efficiently. Remember that documenting each step is important for effectively diagnosing and resolving the issue.

The Loran-C system (Long Range Navigation) was a terrestrial-based radio navigation system that provided long-range, relatively accurate position fixes. While largely replaced by GPS, it played a critical role in navigation for many years, especially in areas where GPS coverage was poor or unreliable.

Loran-C worked by transmitting synchronized radio signals from a network of ground-based transmitters. A Loran-C receiver on a vessel would receive these signals from multiple transmitters and measure the time differences between their arrivals. These time differences were then used to calculate the vessel’s position using hyperbolic lines of position. It was particularly useful in coastal areas and for long-range navigation in conditions where GPS signals were not readily available.

Though largely obsolete, its legacy underscores the importance of redundant navigation systems. The development of Loran-C reflected the necessity for robust navigation regardless of technological advancements or the availability of other systems. GPS’s reliability should not entirely replace the value of understanding older systems and techniques.

Radio navigation systems use radio waves to determine a vessel’s or aircraft’s position. Different systems employ various techniques to achieve this. Here are a few key examples:

• VOR (Very High Frequency Omnidirectional Range): A ground-based system that transmits radio signals in all directions. Receivers on board the aircraft measure the bearing to the VOR station, allowing for accurate determination of direction. Think of it like a lighthouse emitting a directional signal, telling you the direction to the lighthouse itself.

• DME (Distance Measuring Equipment): Used in conjunction with VOR or other navigational aids, DME measures the distance to a ground station. Combining the bearing from a VOR and the distance from a DME provides a precise position fix.

• ILS (Instrument Landing System): A precision approach system used during landings, providing guidance along the localizer (lateral guidance) and glide slope (vertical guidance) to the runway. Imagine a precisely guided path, helping pilots land safely even in low visibility.

• GPS (Global Positioning System): A satellite-based system that provides three-dimensional position, velocity, and time information worldwide. It uses signals from multiple satellites to triangulate the user’s location – like having several points of reference in space to precisely pin down your position on Earth.

• GNSS (Global Navigation Satellite System): This is a broader term encompassing GPS, GLONASS (Russia), Galileo (Europe), and BeiDou (China). These systems offer increased redundancy and accuracy through the use of multiple constellations.

A magnetic compass works by aligning itself with the Earth’s magnetic field. A magnetized needle, freely pivoting, points towards magnetic north. However, this is not the same as true north (geographic north). The difference is called magnetic variation or declination.

Limitations include:

• Magnetic Deviation: Local magnetic fields from metallic objects on board the vessel or aircraft can affect compass readings. This requires compensation using deviation cards or electronic correction.

• Magnetic Variation: The difference between magnetic north and true north varies geographically and over time. Charts provide information on this variation, requiring correction to determine true bearings.

• Heaving and Rolling: On a moving vessel, the compass needle can be sluggish to respond to changes in heading, leading to inaccurate readings during rough weather.

• Latitude Error: As one moves closer to the poles, the magnetic field lines become increasingly steeper, leading to larger errors in compass readings.

Dead reckoning (DR) is a method of estimating one’s current position based on the known starting position, course, speed, and elapsed time. It’s essentially a calculation – think of it as estimating where you’ll be based on how fast and in what direction you’re moving.

For instance, if you start at point A, travel at 10 knots for one hour on a heading of 090 degrees, you would estimate your position to be approximately 10 nautical miles east of point A. DR is a valuable tool, but it’s crucial to understand its limitations. It assumes constant speed and course, which is rarely the case in reality. Therefore, DR positions should always be cross-checked with other navigational information.

Inaccurate navigation data can have severe safety implications, potentially leading to:

• Collisions: Misjudging position relative to other vessels or obstacles can result in collisions, with potentially catastrophic consequences.

• Groundings: An incorrect assessment of depth or proximity to land could lead to grounding, causing damage to the vessel and potentially endangering crew and passengers.

• Missed Approaches: In aviation, inaccurate data can result in pilots misjudging their approach to a runway, leading to a missed approach or even an accident.

• Search and Rescue Difficulties: Inaccurate position reporting makes search and rescue operations significantly more challenging, potentially delaying assistance and reducing the chances of survival.

Regular calibration, cross-checking of data from multiple sources, and careful attention to detail are critical to mitigating these risks.

Updating electronic charts (ENCs) is crucial for maintaining safe navigation. ENCs are updated regularly by the relevant hydrographic offices. The process generally involves:

• Checking for Updates: The chart system should have a built-in update mechanism or provide a method to check for new chart data.

• Downloading Updates: Updates are usually downloaded electronically via a computer connected to the internet. The updates could be incremental, updating only changed chart data.

• Installing Updates: The downloaded data must then be correctly installed onto the chart plotter or navigation system. This may involve following specific instructions provided by the chart system’s manufacturer.

• Verification: After installing the update, it is essential to verify that the chart data is correctly loaded and the system is functioning properly.

Note that updates are crucial. Outdated chart data can be dangerously inaccurate.

Regular maintenance of navigation equipment is paramount for safe and efficient operations. Neglecting maintenance can lead to equipment failure, inaccurate readings, and ultimately, safety hazards. A maintenance schedule should include:

• Calibration: Regular calibration checks ensure that the equipment provides accurate readings within acceptable tolerances.

• Inspections: Visual inspections for damage, corrosion, or loose connections help identify potential problems early.

• Software Updates: Keeping the navigation system’s software up-to-date ensures compatibility, access to new features, and bug fixes that enhance performance and reliability.

• Functional Tests: Regularly testing all features and functionalities ensures that the entire system is working correctly.

• Documentation: Maintaining comprehensive records of all maintenance activities is essential for traceability and compliance.

Preventative maintenance is far more cost-effective than dealing with equipment failure during crucial operations.

Interpreting navigational data from different sources requires a systematic approach. This process involves:

• Data Correlation: Compare data from multiple sources (e.g., GPS, radar, ENCs) to identify any discrepancies. If inconsistencies exist, investigate the potential reasons.

• Understanding Limitations: Recognize the limitations and error sources associated with each data source. For instance, GPS can be affected by atmospheric conditions, while magnetic compasses are susceptible to deviation.

• Prioritization: Prioritize data sources based on their accuracy and reliability in the specific context. For instance, in areas with good satellite coverage, GPS would be prioritized over other less reliable sources.

• Situational Awareness: Integrate navigational data with other information, such as weather conditions, traffic density, and environmental factors, to create a comprehensive understanding of the situation.

• Critical Evaluation: Always critically evaluate the data. Do not blindly trust any single data source. A combination of sources creates a more robust and reliable understanding.

This approach will promote safety and prevent misinterpretations of data.

Several satellite navigation systems provide global positioning capabilities. The most widely known is the Global Positioning System (GPS), operated by the United States. GPS uses a constellation of satellites orbiting the Earth to pinpoint a receiver’s location. Other prominent systems include:

• GLONASS (Globalnaya Navigatsionnaya Sputnikovaya Sistema): Russia’s equivalent to GPS, offering similar functionality.
• Galileo: A European Union system designed for high accuracy and reliability, offering improved performance in challenging environments.
• BeiDou (BeiDou Navigation Satellite System): China’s global navigation satellite system, providing positioning, navigation, and timing services.

Each system uses a slightly different approach in terms of satellite signals and the algorithms used for position calculation, but the basic principle remains the same: triangulation based on the signals received from multiple satellites.

True north refers to the geographical North Pole, the Earth’s actual axis of rotation. Magnetic north, on the other hand, is the direction indicated by a compass needle, which points towards the Earth’s magnetic north pole. These two points are not the same and the difference between them is called magnetic variation or declination.

Think of it like this: imagine a giant bar magnet inside the Earth. The magnetic north pole is where the ‘north’ end of this imaginary magnet points. However, the Earth’s axis of rotation and its magnetic axis are not aligned, resulting in a difference between true north and magnetic north. This difference varies geographically and changes over time.

Navigators must account for magnetic variation when using a compass to determine true direction by consulting navigational charts that provide the current declination value for the specific location.

Course Over Ground (COG) is the actual direction of movement of a vessel or aircraft over the Earth’s surface, expressed as an angle relative to true north. It’s the track the vessel or aircraft is actually following, taking into account the effects of currents, winds, or other external forces. It’s different from the heading, which is the direction the vessel or aircraft is pointed.

For example, a ship might be heading 090 degrees (due east), but if a strong current pushes it slightly north, its COG might be 095 degrees. Electronic navigation systems calculate COG using various data sources, such as GPS, and display it along with other vital navigational information.

Voyage planning using electronic navigation systems involves several steps:

1. Destination and Route Planning: Identify the departure and arrival points and determine the optimal route, considering factors such as weather, water depth, and traffic. Electronic charts (ECDIS) significantly aid this process by visualizing navigational hazards and suggesting safe routes.
2. Waypoints Creation: Establish waypoints along the planned route. Waypoints act as navigational checkpoints, providing guidance to the vessel or aircraft.
3. Data Input and Verification: Enter the planned route, waypoints, and other relevant information into the electronic navigation system. Ensure all data is accurate and consistent.
4. Route Monitoring: During the voyage, continuously monitor the position, COG, and speed to ensure the vessel or aircraft is following the planned route. Automatic alerts can be set up to warn of deviations or potential hazards.
5. Contingency Planning: Develop alternative routes or plans to handle unexpected events, such as bad weather or equipment malfunctions.

Modern systems often incorporate features like route optimization algorithms, automatic identification systems (AIS) integration, and weather forecasting data to aid in comprehensive voyage planning.

Conflicting navigational data from different sources is a potential issue. The key is to prioritize reliable sources and understand the limitations of each.

Here’s how to handle such situations:

1. Source Assessment: Evaluate the reliability of each data source. GPS data is generally considered highly reliable, but other sources like radar or electronic charts may have limitations.
2. Data Cross-Referencing: Compare data from multiple sources. If there are discrepancies, investigate the reasons. For instance, a GPS receiver might be temporarily affected by atmospheric conditions.
3. Prioritization: Prioritize data from more reliable sources. For example, in case of conflicting data from a GPS and a compass, it is generally safer to rely on GPS data. However, always be aware of the possible limitations of any single source.
4. Manual Checks: Always employ basic navigational skills such as visual observation and celestial navigation (where applicable) to verify electronic readings and gain confidence in the overall situation.
5. Professional Judgment: Ultimately, the navigator’s professional judgment and experience play a vital role in interpreting and resolving conflicting data. If in doubt, always take the safest course of action.

Advancements in electronic navigation equipment are constantly improving safety and efficiency. Recent developments include:

• Improved GPS Accuracy: Techniques like Real Time Kinematic (RTK) GPS provide centimeter-level accuracy, crucial for applications requiring precise positioning.
• Integrated Navigation Systems: Systems combining GPS, inertial navigation systems (INS), and other sensors provide improved reliability and accuracy, especially in challenging environments where GPS signals might be weak or unavailable.
• Advanced Chart Display and Information Systems (ECDIS): ECDIS systems integrate electronic charts with other navigational data, offering improved situational awareness and enhanced safety features.
• Automated Identification System (AIS): AIS is a critical safety feature enabling vessels to share their position and other information, reducing the risk of collisions.
• Augmented Reality (AR) Navigation: Overlaying navigational information onto the real-world view through AR devices offers an intuitive and immersive navigational experience.

These advancements contribute to increased safety, efficiency, and decision-making in various sectors such as marine, aviation and road transportation.

Electronic position fixing relies on the principles of trilateration and triangulation. These methods use signals from known locations to determine the position of a receiver.

Trilateration uses the distances from at least three known points (e.g., satellites in GPS) to pinpoint a location. Each satellite transmits a signal indicating its precise position and the time the signal was sent. By measuring the time it takes for the signal to reach the receiver, the distance can be calculated. The receiver then uses these distances from three or more satellites to calculate its coordinates through complex mathematical processes (mostly done automatically by the navigation system).

Triangulation uses the angles from known points to determine a position. It is often used in conjunction with range information. For example, a ship might determine its position by measuring the angle to two known landmarks, using their bearings to create intersecting lines that pinpoint its location. Modern systems often use a combination of trilateration and triangulation for high-precision positioning.

Both methods use mathematical algorithms to solve for the position coordinates (latitude and longitude).