We can start with the base station, mobile station and data link of RTK system to understand the problem of no fixed solution in measurement.
01. Base station
Therefore, when there is no fixed solution, it may be related to the satellite signal difference received by the base station. The following aspects can be obtained from the working principle of the base station:
First, the base station did not receive enough satellites (the number of satellites is less than 5);
Second, the base station receives satellite signals with strong interference;
Third, the base station receives satellite signals reflected by signal reflectors.
The base station should be set up in a place with good visual-to-air condition, and must be far away from various strong electromagnetic interference sources (such as high-voltage lines, TV stations, mobile phone signal towers, etc.). Because the data chain of RTK adopts UHF (ultrahigh) electromagnetic waves, therefore, the antenna of the radio station should be set at a distance of more than 2 meters from the base station as far as possible, and the influence of the multi-path effect should be reduced at the same time. There is no large-area signal reflection around the base station (such as large-area water areas, large buildings, etc.).
02. Mobile station
When there is no fixed solution in RTK measurement, it may be that the mobile station cannot determine the unknown number in the whole week, that is, initialization. There are several main factors:
First, the receiver observes the number of satellites;
II. The distance from the mobile station to the benchmark station.
Reduce the use of RTK under some special circumstances, such as the measurement area with strong interference and limited visual space conditions, and try not to move the station more than 10 kilometers away from the base station.
03. Data Link
It has a considerable relationship with data transmission, and there are mainly the following points:
1. Transmission distance.
II. Data transmission format.
Because the measuring area cannot be changed, place the antenna of the radio station at a high place where the terrain is relatively bad and the electromagnetic wave transmission is poor, increase the transmitting power of the radio station, and choose the data format with smaller data transmission.