New iRTK5 Makes Cadastral SurveyingFaster and Easier in Xinjiang, China

By Adin Li,

Marketing Department of Hi-Target International

Case backgroundSurvey and register the lands and real estate properties can help to resolve the land dispute, manage the total land usage and better development plan.This project went off in Aksu, Xinjiang, China, where is an important agricultural base. More than 5,200 pieces of land need to be registered properly in a short period of time while the accuracy required to be better than 5cm for the coordinates.Accuracy of the cadastral survey is very vital and sensitive to the land owners and administration agencies as it provides the essential elements of the land maps, coordinates. It is required that accuracies of all the boundary marks, evaluated by root mean square error value, should be less than 5 cm according to the National Cadastral Survey Standards of China when the mapping scale is 1:500.Project challengesWhen doing the digital mapping work, total station is the traditional device that acquiring the precise data. Before doing that, measuring a station point and a direction reference point by any means is necessary, which takes some time.Below are the challenges:1. The efficiency of total station remains uncertain due to the man power status and the mechanical stability and performance of the products. That is a threat to finishing the project.2. The uncertainty cannot always be solved because of the limited budget and period of project closing time.3. Using normal GNSS RTK receiver can be faster than total station, but it would be interfered by the signal blocking and radius of the antenna easily, resulting in lower reliability.4. To make the result more reliable in the corner and the place which covered by the roof, surveyors need to climb the building, where the safety and efficiency are greatly threaten.  Therefore, finding a way to boost the efficiency without sacrificing the accuracy and surveyors’ safety is an urgent calling to the service providers.SolutionThe new iRTK5, with a built-in IMU, can provide 2 cm accuracy within 30 degree tilt, while there is no need for calibration at all. Thus, by using the new iRTK5, surveyors can go and pick without leveling the pole every time surveying points, no matter it is in a plane region, or a complicated area where man cannot access directly, the real coordination can be measured swiftly.Step 1: Setting up the GNSS RTK receiver base and the transmission methods, get fixed solution and activate the IMU function.Step 2: Verify the accuracy and reliability of the new iRTK5 in tilt survey mode with a total station on a boundary mark.

Step 3: Go and pick. Using Hi-Survey software and using AR stake out when the direction confused. Quickly survey and collect all the boundary points then export to office software.

All the work had been done in a short time, the efficiency boost almost 2X according to the clients experience while less man power had been used at the same time.

Since total station’s accuracy can be good within 2 mm error, these coordinates can be recognized as real coordinates. Here attached the comparison of the results between precise total station and Hi-Target iRTK5 in tilt mode. As the test shows, most of the errors between real coordinates and coordinates provided by iRTK5 are less than 2 cm.

BenefitsThe new iRTK5 with built-in IMU function, providing calibrating-free tilt survey in any magnetic circumstances, can greatly improve the efficiency and accessibility, even the safety can be enhanced in some certain occasion. Here are the key benefits of using the new iRTK5 GNSS receiver:1.With precise tilt survey function, surveyors can map the special places like roof of the building, building corner where the survey pole cannot stand up straightly, objects that beneath the obstacles like vehicles and machines…Therefore, the accessibility can be hugely improved.2.There is no longer necessary for surveyors to climb, wich will put themselves in danger. So the safety is guaranteed.3.It is not necessary for surveyors to level the survey pole any more, just activate the tile mode, pick and go. The efficient work had greatly reduced the man power (2 times in this case) and project period (20% time less), saved the budget and satisfied the users as well.