3.4.8.3. Kinematic surveying

Kinematic surveying uses differential carrier phase tracking to record observations simultaneously. It is used in most surveying applications where the base receiver remains stationary and placed at the known point, while the rover receiver will visit the unknown points for a very short time.

Kinematic surveying is a technique where two GNSS receivers are used. One receiver, known as the base, stays in a fixed location, and another receiver, called the rover, moves to different locations. The base receiver constantly tracks satellite signals and sends correction information to the rover. This allows the rover to accurately determine its position quickly, even if it only stays in one spot for a short time.

Think of it like using a GPS to find your way while hiking. You have a GPS device at a base camp (the base receiver) that knows exactly where it's located. As you hike (the rover), your device can use the information from the base camp to quickly and accurately determine your location, even if you stop to look at a map for just a moment.

The recording interval for static observations could be 10 sec., for rapid static observations 5-10 sec, and for kinematic observations 0.2 sec or more. Kinematic GNSS can use multiple bases and/or multiple rovers in the same survey, if necessary.

In kinematic surveying, data is collected at very short intervals, sometimes as quick as every 0.2 seconds. This fast collection allows for high accuracy even while moving. Additionally, multiple receivers (bases and rovers) can be used simultaneously to gather data over a larger area or to improve accuracy further, depending on the requirements of the survey.

Imagine you're filming a fast-moving race. To capture every important moment clearly, you need to shoot at a high frame rate (like the 0.2 seconds in kinematic surveying). Similarly, using more than one camera (multiple rovers) allows you to cover the entire race, ensuring that all angles are recorded without missing action, enhancing the final result.

Kinematic GNSS surveying is generally suitable for any type of surveying or mapping in areas with no high rise buildings, overhanging trees, dense forest, over-passes or such structures in rover’s route.

For kinematic surveying to work effectively, the area where the rover moves should be free from obstacles that block satellite signals. High buildings, trees, and dense structures can interfere with the satellite signals that the rover needs to determine its position accurately. It’s essential for clear signals to maintain the accuracy of measurements.

Think of it like trying to use a walkie-talkie in a forest. If you're standing in an open area, the signal is clear and strong. But if you're surrounded by tall trees, the signal might get blocked or weak. Similarly, in kinematic surveying, obstacles can disrupt the signals needed to find accurate locations.

Possible errors in kinematic surveying could be; (i) antenna height may change between points, especially if a prism pole with a sliding mechanism is used, and (ii) improper centering the antenna over the point.

Errors in kinematic surveying can occur due to changes in the height of the antenna as the rover moves, particularly if there are any adjustable mounting devices. Additionally, if the antenna is not perfectly centered over the point being surveyed, this misalignment can lead to inaccuracies in measurement. Both of these factors can affect the precision of the data collected.

Imagine trying to take a precise measurement of a piece of fabric while holding the measuring tape at different heights or angles. If the tape is not straight or if your measurement point shifts, you might end up with incorrect measurements. The same principle applies to kinematic surveying—accurate setup is crucial for precise data.

This method is undergoing rapid improvement, and OTF-AR (On-The-Fly–Ambiguity Resolution) is making it ideal for surveys, such as road centre line survey, topographic survey, hydrographic survey, airborne applications and many more.

Kinematic surveying is rapidly evolving, with advancements like On-The-Fly–Ambiguity Resolution (OTF-AR) allowing for immediate data collection without long setup times. This makes it particularly useful for various surveying applications, including mapping roads, detailed topographic surveys, and even underwater surveys (hydrographic surveys). These applications benefit from the quick and reliable measurements that kinematic surveying provides.

Think of kinematic surveying as using a GPS during a road trip where you need to quickly find your way through unfamiliar streets (road center line survey). The technology helps you navigate and make quick decisions, ensuring you stay on track despite potential obstacles or detours. It’s about getting accurate directions efficiently.

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