4.6. Mark Co-location Definition

The Mark Co-location Definition defines how data files are associated with user marks. The definition, as shown in Fig. 4.8, can only be modified prior to session processing. Two options are available:

Mark Co-location Definition Settings

Fig. 4.8 Mark Co-location Definition Settings

Mark ID: if the first four characters of a RINEX file correctly identifies a unique user mark in your project (see Section 5), there should be no co-location problem: OP will group the RINEX files by their respective four-character IDs. However, if the names of GNSS observation files subsequently uploaded to OPUS do not start with a four-character ID unique to each user mark, OP will group the observation files by their position.

Caution

Co-location by Mark ID is only meant to help organize files in OP. Ultimately, files are arranged by coordinates (positions), even if Mark ID was initially selected. In addition, observations can be manually associated to specific user marks after loading. See “Manage Data Files” in Section 7.3.10.

Position: this is the default setting for OP. GNSS observations files are grouped by the positions (latitude/longitude) given in their respective OPUS solutions. Data files whose OPUS solution positions fall within the Maximum Position Difference specified (1 m is the new project default, but this can be changed) will be grouped together. OP will attempt to name each user mark uniquely. If all the data files associated with a user mark, and only the data files associated with that mark, use the same first four characters in their file names, the user mark will be given that four-character name, even if the co-location definition is selected as “Position.” Otherwise, a name will be automatically generated starting with “a001.” If “a001” is already in use, the numeric portion will be incremented until a unique name is created (e.g. a002, a003, etc.).

Caution

Most GNSS receiver software will automatically name observation files starting with the serial number of the receiver (or at least its last four digits). If receivers are used on different marks throughout the project, this will result in OP assigning sequential codes to each mark name. To avoid this, make sure the RINEX file names start with the corresponding four-character mark ID.