Post Processing Engine Properties

When you add the Post Processing Engine module, the Post Processing Engine Properties dialog appears with this tab.

If you select the module in the Tree view after you have added the module, the categories and settings of this tab appear in the Properties view.

Use the General Settings tab to view and edit the Post Processing Engine properties, such as the processing mode, the selected stations and session, and file location as well as the outlier filtering and processing parameters.

Processing Mode category

Processing mode: Only available for editing, when you add the module. Specifies whether the Post Processing Engine works in kinematic or static mode. Default: Static.

Note - Since kinematic post processing results in a high number of values and is a memory-consuming process, the module internally sets limits to the number of stations and the session duration, if the kinematic processing mode is selected.

Maximum number of threads: When first scanning the data folders for files or when processing baselines, the processing load generated by the Post Processing Engine module can get very high, depending on the processing power (mainly the number of CPU cores) of your computer system, and on the number of processes performed concurrently in multiple threads. On the other hand, the more folders are scanned or baselines are processed concurrently, the faster the result will be available. That means: The more CPU cores the computer running the Post Processing Engine module has, the more processes are safe to be run concurrently. Use the Maximum number of threads setting to specify the maximum number of processes (that is either file scanning or baseline processing) run concurrently that best fits with the processing power of your computer system. The minimum allowed number of concurrently running processes is 1, which is also the default.

File Type category

Base folder: Specifies the path to the root folder, where the observation data files reside in. To select or change the destination, set the focus into the value field and click the browse button. The Folder Browser dialog appears.

Note - To use files from another computer than the local one, use a UNC path pointing to the remote folder.

Option	File location	Folder names depend on…
Plain	All files will be stored into one folder.	- Storage path setting.
Enhanced month	An enhanced data folder structure is applied to the data. This option writes all files generated within a month into the monthly folder.	- Storage path setting. - Year and month. For example: C:\Refdata.YY\Month.MMM\.
Enhanced day	An enhanced data folder structure is applied to the data. For each day a folder is created and files are written into the daily folder.	- Storage path setting. - Year, month, and day. For example: C:\Refdata.YY\Month.MMM\ Day.DD\.
CORS	An enhanced data folder structure is applied to the data. Below the root, for each file type a folder is created, which then contains folders for the year, day, and reference station.	- Storage path setting. - File type, year, day, and station. All characters in lower case. The station is characterized by a four character site ID. For example: C:\rinex\YYYY\DDD\SITE\.

Note - Both, the automatically created file names and the file contents refer to the measurement date and time, based on system time. With an enhanced folder structure, the files are located in folders whose structure also depends on GPS time.

Note - The folder structure must not be enhanced by the station code. That means, when storing data, the Add station code to folder structure setting must not be set to Yes.

File type: Specifies the format of the observation files to be used for processing. The selected file types are also taken from ZIP files within the specified folders. Available selections are:

Station Definition category

Selected stations: Specifies the (sub-)network of station(s) to be post processed. By default, no stations are selected. To select all or individual stations for processing, set the focus into the value field and click the browse button. The Station Selection dialog appears.

Session category

Start time: First parameter to specify the time segment of the processing data. Specifies the date and time of the data for which the first post processing session should be started. Following sessions always start after the last session has finished; sessions do not overlap.

Session duration: Second parameter to specify the time segment of the processing data. Specifies the duration of all sessions. By adding this value repeatedly to the Start time, the Post Processing Engine determines the following sessions. Selectable values are between one minute and up to two weeks. Default: 1 hour.

Note - Make sure that session durations are not less than the maximum file length of selected data files. For example, if you want to process a session of 1 hour, the selected file(s) must not contain more than 60 minutes of data. Of course, they may contain less.

After processing, the processing result is written into the database and passed on to other modules with an event time, which is set to the end of the session period.

Session delay: Delays the start of processing for a specific time after the last epoch of the time segment - specified by Start time and Session duration - has been written. Thus, the Storage modules will have finished data writing before the Post Processing Engine module starts processing. Selectable values are between no delay (select Immediately) and up to four weeks. Default: 10 minutes.

Advanced category

Elevation cutoff: The processor discards satellites with an elevation below the value specified here. Default: 10°.

Processing interval: Specifies how many epochs are used for processing. If the observations in one or more of the files used for processing have been stored with a lower update rate, the Post Processing Engine internally adjusts the processing interval to the file with the least data. Depending on the selected Processing mode the interval values available for selection differ.

Maximum baseline length: This parameter steers the definition and selection of baselines from given station positions. Baselines are created from station positions only if the baseline length is less than the value set here. Default: 70 km.

Use redundant baselines: If set to No, the Post Processing Engine connects each station once by a baseline to the nearest processed station. With Yes selected, the processor takes all possible information in the network into account and connects all stations positioned within the distance limits. Default: No.

Use float solution: If set to Yes, float solutions are also accepted for postprocessing. For short and moderately long baselines (< 70 km) postprocessing allows fixing ambiguities. Ambiguity fixing provides higher accuracies with shorter observation time, for example sessions of 1 hour. Fixed solutions might not be possible on baselines longer than 100 km. Default: No.

Note - Trimble recommends to use the float solution in sessions longer than 12 hours only.

Minimum baseline length: Use the setting to limit the use of float solutions, if no fixed solutions are available, to baselines of a minimum length. For baselines shorter than this limit, float solutions will be discarded.

Outlier Filtering category

The median is the middle value in a list ordered from smallest to largest. Using a median filtering technique you can smooth the data (offsets to coordinates) and remove outliers from the data, while preserving significant changes within curves ("edges"). The technique applied uses a sliding time window over either 3 or 5 epochs (selectable) and a minimum definition for outliers. If the value of the central epoch exceeds the user-defined offset threshold, the filter replaces this value by the median of the samples in the window. Thus, one outlier (with a window size of three epochs) or two consecutive outliers (with a window size of five epochs) will be removed, while a jump in the values will be kept.

Use median filter: If set to Yes, a median filter will be applied. Default: Yes.

Sliding time window size: Specifies the size in epochs of the sliding time window used by the median filtering method. The sliding time window always includes the last available epoch and the epochs before. A larger window filters more outliers, but also increases the epoch delay. With 3 epochs selected, a single outlier will be detected and removed; two consecutive outliers will stay in the data. With 5 epochs selected, two consecutive outliers will be removed and thus, a jump in the data might be detected one epoch later.