Message Transmission Delay Analyze

Introduction

The message transmission delay analyze tool is used to calculate delay time during transmission from surveilliance sensor to receiver.

System will compare the timestamp encoded in ASTERIX message, which is the sensor transmission time (Tx), and the timestamp encoded in data packet, which is the receiving time (Rx). The difference between Rx and Tx is considered as transmission delay.

When the calculated is greater than a warning level, a message will be shown in log.

When the calculated is greater than a disgard level, or is less than zero, it will not be used for further statistic, and a message will be shown in log.

Preparation

To generate a correct delay time, it requires:

  • A valid Rx time is included in data packet
  • A valid Tx time is included in ASTERIX data
  • Both Rx and Tx time must be UTC time, or in a same timezone
  • Both Rx and Tx clock must be synchronized with a common time source, normally GPS

The timestamp in the following dataitems will be used as Tx time:

  • I002/030 - Time of Day
  • I034/030 - Time of Day

User Interface

The main window of message transmission dealy analyze tool is as below.

delay_ui.png
Main Window

Before starting analyze, it's necessary to open the configuration window by clicking on Settings button.

delay_config.png
Configuration Window

The meaning of each parameter is listed below.

P**arameter** Description
SAC/SIC SAC and SIC of sensor
UAP UAP of sensor data
Frame Type Frame of sensor data
Verify SAC/SIC If selected, only data match SAC and SIC will be processed. If not selected, all data will be processed.
Warning threadhold If calculated delay is greater than this value, a log message will be printed
Maximum allowed delay If calculated delay is greater than this value, a log message will be printed, and this delay will not be used in statistic
Recording File Recording file for analyze, support rex and rei file

When all parameters are set, analyze can be started by clicking on Start button; and process can be interrupted by clicking on Stop button.

During the process, if any message match the warning or disgard thredhold, a log message will be printed.

When analyze finish, statistic information will be printed, and a delay chart will be shown in the Chart table.

delay_log.png
Process Log
delay_chart.png
Delay Chart