Real-time surveying is calculating distances from a base station using a GPS signal. This method uses either a single or dual frequency. Once the range reaches ten kilometers, the survey equipment transitions to the L1 carrier phase. This system has its limitations, which are related to the range and the frequency of the receiver. However, it is incredibly effective and efficient.
GNSS RTK
Real-time kinematic (RTK) systems provide positional accuracy faster than the carrier phase of GPS. They work by observing satellites simultaneously. The advantage of this method is that it yields more accurate positions with fewer measurements. A standard RTK system has at least five satellites and a single roving receiver.
Another advantage of GNSS RTK systems is their low cost and high accuracy. This technology is beneficial for large-scale construction sites and remote construction areas. However, it has a few limitations. For example, it cannot be used in obstructed lands or areas with heavy radio interference. Additionally, the system requires a survey assistant and a base station to work.
To use GNSS RTK systems, you must install a ground-fault circuit interrupter (GFCI) before you begin working in a wet area. Then, you must ensure that your base station antenna is mounted on a fixed point five meters above ground level. Generally, RTK provides an accuracy of up to 50 cm horizontally and 1.5 cm vertically. However, the precision varies depending on the number of satellites and receivers and their geometry.
RTK-GPS systems improve convenience by enabling multiple rover stations to work together at the same time. The system can also be used for multiple purposes. The main advantage of this type of system is that a single base station can control a plurality of rover stations at one time. This system also improves security and communications speed.
RTK systems require a real-time wireless connection between the base station and the rovers. The positioning of the transmitter antenna is crucial as it determines the system’s performance. Ideally, the antenna is mounted as high as possible to cover the whole area. Additionally, the longer the antenna, the better.
Improvements in RTK technology
RTK technology has advanced significantly over the past several years. It began as a military technology but has been used by surveyors and other industries since its introduction.
RTK drones can now provide centimeter-level positioning accuracy. It represents a significant improvement over satellite data.
RTK is also helpful for disaster relief, as it can rapidly provide information on the damage’s extent and the survivors’ location. It can also significantly reduce the time and cost of data collection. Its accuracy makes it possible to conduct accurate surveying work even if no terrestrial reference system exists.
RTK systems can also be integrated with robotic stations, allowing a more flexible approach to construction staking. In addition, RTK systems are also used in the salt harvesting industry. Rahco International was one of the first to introduce RTK technology into this industry. The primary benefit of RTK is its pinpoint location accuracy. It is more accurate than satellite data and corrects inaccuracies and discrepancies.
As the industry evolves, RTK will continue to evolve. While many companies may adopt different solutions, the basic principles remain the same. Many manufacturers recognize this and are working to improve their solutions to meet industry needs.
Limitations of RTK systems
One of the limitations of RTK systems in surveying is their lack of accuracy. They are inefficient in areas with obstructions or in lands where satellite communications may be interrupted. Moreover, RTK requires a base station with known coordinates. These factors prevent the use of technology in some areas.
Another limitation of RTK is the need for permanent base stations. The location of the base station is critical to survey accuracy. Furthermore, security concerns and power supply issues are involved in setting up a permanent base station. Another limitation is that RTK systems require a clear line of sight between the drone and the base station. This limitation makes them minimally tolerant of signal drops.
Another limitation of RTK systems is the distance between the roving receiver and the base station. It can be hundreds of feet or even thousands of feet. As a result, it is vital to know the distance between the roving and base receiver before deciding on the best surveying solution.
Cost
RTK GPS systems cost between $2000 and $15,000 and consist of a moving GPS receiver, a base station, and differential correction software. The cost of these systems varies, and the exact price will depend on your needs. The cost is higher for new systems, but used ones are usually cheaper.
An RTK GPS systems by Bench Mark USA uses an orbiting satellite system in an orbital control network. The satellites transmit corrections along with the GPS signal. It eliminates about three-quarters of the bias associated with GPS coordinates. The second-largest contributor to the GPS error budget is the ionosphere.
An RTK system with more than 800 channels is an ideal piece of equipment for those who need a high-precision RTK system for surveying. Its accuracy and versatility make it an excellent choice for surveying projects, as it can perform precise surveying under any type of sky, including low-signal areas. In this way, surveyors can improve their accuracy and productivity. They can also perform more detailed work with more accurate data.
