On the spot

High technology governs all areas of our lives. Today’s navigation technology leaves nothing to chance, not even in areas such as agriculture. Modern farmers carry out several steps of a process with only one multi-purpose vehicle which performs all the necessary tasks at the same time.

Today’s navigation technology

If you take a closer look, you may even find that the farmer is not even behind the wheel! This is where satellite navigation technology comes into play, guiding the tractor to cut its swathes with centimetre-accuracy, supported by a data correction service. While the farmer cannot use the system to affect the weather when sowing his crops, it can certainly ensure an optimum return from the fields.

Any position on Earth can be determined by measuring its distance from a group of satellites. Navigation satellites regularly transmit their position to Earth to enable distances to be measured in this way. The distance from a reference point can be determined on the basis of the time these signals take to cover the distance to Earth. The sought position can then be calculated from the distances to at least four satellites. However, a position determined in this way may vary from two to 20 metres in accuracy. This lack of precision can be attributed to distortion of the satellite signals by inadequate technical equipment and by external influences.

 

Networking makes it possible to model and correct errors

The ascos services provided by AXIO-NET GmbH are able to draw on an infrastructure of over 300 reference stations distributed all over Germany, whose data are collected and networked at the AXIO-NET headquarters in Hanover. This networking makes it possible to model and correct the main errors in the satellite signals. Determining a position with ascos requires a positioning system, the ‘Rover’, and a mobile radio broadcast device which in most cases is either a mobile telephone or a modem and a mobile radio card. The satellite signals are received by the Rover, which radios its position, still inaccurate at this time, to the ascos data-processing centre. The satellite signals received by the Rover are compared with the data from the surrounding reference stations. Because the exact position of the reference stations is known, it is now possible to establish the difference between the satellite signals at the Rover and those at the base stations. The result of this calculated correction is known as the wide area augmentation parameter. The data processing centre transmits the wide area augmentation parameters back to the Rover once every second. The rover then uses the information to correct the determined position.

Tasks associated with surveying, the registration and documentation of supply networks (electricity, gas, water, district heating and telecommunications), and the initial and final surveying required for the construction of roads and railway lines can be carried out efficiently and accurately in this way.

Accessible at all times

The AXIO-NET reference stations are located in geographically stable positions to ensure that they are accessible at all times. The satellite signals are received by high-performance dual-frequency GPS and GLONASS receivers which are backed up by an uninterrupted power supply. Correction data for both satellite systems are provided via the ascos network. The use of both systems greatly improves availability even in difficult locations. Correction data will also be provided for Galileo once the European satellite navigation system’s first satellites become operational.

 

Galileo

Typical areas of application for working with ascos services include positioning, precise navigation solutions, dynamic processes with a spatial reference, and the control of machinery. In addition to the energy and utility sectors, ascos has successfully tapped new markets that include the construction industry, agriculture and forestry, and the construction of roads and railway lines.

Astrium Services is making use of its holding in ascos to further expand its strategic role as a one-stop-shop for satellite services.