Synchronizer Properties - General Settings

When you add the Synchronizer module, the Synchronizer 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 Synchronizer properties, such as the contributing stations and the maximum tracking rate.

Synchronization Settings category

Tracking interval: Specifies the maximum tracking interval that the Synchronizer will pass to its dependent modules. Possible selections are between 1 Hertz and 20 Hertz. Default: 1 Hz.

Selected GNSS receivers: Use the setting to select stations from all currently available GNSS Receiver modules. The Synchronizer will collect and forward only the data of the selected stations. To change the selection, click the browse button. The Select GNSS Receivers dialog appears.

Tip - If stations are added to the system after the Synchronizer has been set up, these stations are, by default, not selected and do not contribute to the processed network.

Why should stations not be included into the Synchronizer configuration? This may happen, for example, if maintenance work is done on a certain station. You may want to keep the reference station data for post-processing; therefore, you do not remove the respective GNSS Receiver module from the network. However, troubles at the station should not influence the data processing. In this case, you will exclude the station from the Synchronizer.

Handling of Delayed Receivers category

The settings of this category pertain to the usage of delayed receivers in network processing. If the Synchronizer module is used in other setups, it is safe to keep the default settings.

Two non-editable properties display the system-wide parameters that are applied for detecting whether a receiver is flagged as delayed or lost. If receiver observations arrive more than the maximum acceptable delay later than the epochs they refer to, they are flagged as delayed. If the delay exceeds the station timeout value, the respective receiver will be flagged as lost. A delayed receiver comes with a yellow, a lost receiver with a red receiver icon in the Synchronizer Status view. Some modules like the Network Processor keep a history of data of the lost receiver, so it can be used immediately, should data arrive from that receiver again in a timely manner.

Maximum acceptable delay: Not available for editing. The maximum acceptable delay for a receiver to not be flagged as delayed is 2000 milliseconds. After that period, the receiver will immediately be flagged as delayed (yellow receiver icon in the Synchronizer Status view).

Station timeout: Not available for editing. If receiver observations do not arrive for more than 60 seconds, the receiver is considered to be lost (red receiver icon in the Synchronizer Status view), for example, due to a connection issue.

Exclude delayed receivers: In a situation where data from a specific GNSS Receiver is continuously delayed (but not lost), one might want to exclude that station from being used in processing or real-time data output. With the default value No kept for the Exclude delayed receivers property, a receiver with delay will be marked as "slow" and will be excluded from synchronization, but may still be used by some modules. Additionally, some modules like the Network Processor or the RTXNet Processor keep a history of data of the lost receiver, so it can be used immediately should data arrive from that receiver again in a timely manner, that is with a delay below the maximum acceptable delay value.

If you set the Exclude delayed receivers property to Yes, two additional properties become available. Receivers that are considered delayed (but not lost!) constantly for longer than the period that is specified with the Exclude delayed receiver after property, are flagged as lost and, additionally, removed from network processing and real-time output. If the constantly delayed station should be currently used as Physical Base Station, a different station will be used as PBS. In this case, the rover connected to that PBS must re-initialize. To be considered as healthy (green), the receiver must send data in a timely manner (that is with a delay below the maximum acceptable delay value) for a given time (specified with the Add healthy receiver after property) consecutively. Then the receiver is added, as if an administrator had added it to the Synchronizer. If a receiver has been excluded or included again, an alarm is triggered.

Exclude delayed receiver after: Specifies the period [in seconds] for a receiver to be flagged as lost (red receiver icon in the Synchronizer Status view) and be considered as completely removed from the Synchronizer, if the delay is continuously larger than the Maximum acceptable delay. Default: 300 seconds.

Add healthy receiver after: Specifies the period [in seconds] a receiver send data that are not considered as delayed, before it is considered as healthy and will be fully used. Default: 60 seconds.

Comparison of the settings for the Exclude delayed receivers property

The table below compares the states and behavior of the system if either receivers are not excluded or excluded. For the comparison the following settings are assumed:

The table compares the receiver status, its symbol color in the Synchronizer Status view, and whether a receiver will be usable as PBS or not.