After collecting GNSS data, I converted the raw UBX logs to RINEX format (*.obs), and then submitted the RINEX file to the CSRS-PPP service (Precise Point Positioning) for post-processing.
I received an email containing warnings, and I’m unable to view the summary results in the CSRS-PPP report.
Do you have any idea what might be causing this issue?
I use two different programs to convert ubx to rinex. One is Emlid Studio and the other is RTK Convert. The former is more user friendly and appears to be a UI wrapper over the latter. When using RTK Convert, select the ‘Options’, in line item ‘Ant #/type’ enter ‘SFEFACET’ (or the specific antenna you have) and in line item ‘Antenna Delta H/E/N’ enter your antenna height off the ground in the ‘H’ field. Antenna Height is the sum of ground-to-bottom of the antenna PLUS the L1 or L@ or average of the L1+L2 height offsets. NOTE THA NOT ALL SPARKFUN ANTENNAS HAVE BEE VETTED BY NOAA OPUS OR THAT CANADIAN SERVICE. There are other post here discussing antennas. Emlid has provision to enter antenna info , but I don’t have that running on this computer so I can’t tell you specifically, but it’s there if you look for it.
CSRS Computing Services performs calculations for dual-frequency antennas in the high-price segment, for which vendors provide a file with corrections for antenna phase center variations. This sounds quite complicated, but it simply means that they do not have your antenna listed and cannot perform precise calculations.
Setting up your own reference base station requires determining its position.
The accuracy of determining the position of a base station depends on its application:
If your base station is to be, for example, for an agricultural machinery guidance system, its position does not have to be determined super precisely, because the rover will precisely determine its position relative to this station.
If you are going to determine a position that must be in the same coordinate system as the positions of objects on the map, e.g. plot boundary points, then you need to determine the position of the base station as precisely as possible, because you want to know the position of the rover not only in relation to the reference base station, but also in relation to other objects measured by other people.
Unfortunately, in both cases, to determine the position of your base reference station, you need to use another base reference station. It can be a neighbor’s station, but usually it is a station of a national or international operator.
It should be remembered that the positioning measurement error increases with distance from the base reference station. For example, for the ZED-F9P receiver, the specified RTK positioning accuracy is 0.01 m + 1 ppm, which means that, for example, for a measurement of 20 km from the reference base station, the accuracy is 0.01 m + 0.02 m. If you use an ANN-MB antenna for this, there is also a phase center variations error of < 0.01m.
In summary, if your base reference station will be used to determine the position only relative to this station, e.g. in agriculture, then the position of the station can be determined using RTK. If your base reference station will be used to determine the position in a specific coordinate system, then its position must be determined using a method based on a static measurement lasting several hours for example 2 hours, which can be calculated using the program https://github.com/rtklibexplorer/RTKLIB/releases/download/b34L/demo5L.zip
The static measurement consists of:
Collecting unmodified satellite data, the so-called raw satellite data, using the strsvr program demo5L. Requires a receiver setup to collect raw data.
Converting the file with collected data to RINEX format using the rtkconv program from the demo5L package.
Obtaining the position of the national operator’s base station, an observation file in the RINEX format for the measurement time, navigation files of specific constellations, e.g. GPS, Galileo for the measurement time.
Using the rtkpost program from the demo5L package to perform calculations based on the collected RINEX files, the position of the base station, determining the type of the base station antenna according to the file with the atx extension.
The solution is a graph with fix status points from which the average position can be read. The result will be in the same coordinate system that the base station coordinates were given in (provided that the coordinate system is based on the WGS84 or GRS80 ellipsoid, and most of the valid systems are).
