Modern topographic measurements have evolved from precise measurement of angles vertically and horizontally using theodolites, in determining precise position of points on the globe using receivers of signals from satellites integrated in global positioning systems.
First-satellite system called the American- GPS (Global Positioning System) has become the generic name for topographic measurements that uses satellite signals for positioning and for this type of device.
Currently, the most used devices are the GNSS-RTK dual frequency (L1 / L2) with an increased number of channels that can connect to multiple systems of satellites to GPS, the Russian GLONASS system, or channels reserved for other systems that will appear ulterior- European Galileo system and the Chinese Compass under implementation.
If GPS systems simple frequency can be used only on measurements of static or kinematic results are to be obtained after a post-processing of data recorded in the field, GNSS-RTK dual-frequency L1 / L2 can be used both in measurements of static and kinematic and at measurements in real time, so-called RTK (real time Kinematic). To determine in real time with centimeter accuracy of the coordinates of the points needed as GPS devices GNSS RTK corrections from the stations to receive landline. This is done either by UHF radio from its own base, or using GSM modems to connect to the internet for receiving RTK corrections from permanently fixed stations, existing in many countries. Track Phone modules Internet works with GSM cards from local mobile operators.
Provided the measurements GPS-RTK is that the software controller have implemented algorithm trans calculation system WGS84 coordinate the national system of coordinates of each country (in the case of Romania – transduced – for trans calculation and projection stereographic 1970 as a national system) .
Another condition is that the area in which the measuring to be GSM signal data strong enough to connect internet, otherwise the GPS measurements RTK is required at least 2 devices (base and rover) and the opportunity to establish the connection UHF radio between them.
It is good to know !
– Not to be confused with the GSM signal data voice signal! The fact that you can talk on your mobile phone does not mean that you have Internet data stream!
– RTK GPS equipment purchased second-hand from abroad, or even in the country in most cases, have implemented programs trans calculation networks of countries of origin. Most times further implementation of grid distortion of transduced for trans calculation is not possible, or if it is possible to incur significant additional unannounced sellers.
– A manufacturer of equipment reliability can be verified and the duration and efficiency of granting guarantee in the event of failure (hardware or software) that characterize this type of equipment in general – regardless of the manufacturing company thanks to the very new technology. A delay repairs indicate a producer that has a well developed network of servicing and for whatever reason, subsequent disappearance from the market, it will bring in the position of not being able to repair the appliance.