vPAR QuadRadar Analog - Traffic Display
May 10, 2004
Michael Oxner


First, take a look at a screen shot of the Traffic Display.

Traffic with Aircraft on Downwind

The radar display is drawn on the left hand side, while the information boxes on the right control information about how the display is drawn, and how connections to the network (typically the internet) are managed.

The targets are drawn with a bright "slash" where the target was at last "hit", and up to ten trail spots (not user configurable) showing target trail history. Each slash will successively (and marginally) thinner and lighter in color than the previous dot. The slashes will be wider further from the display center since the targets are drawn by angular width. Also, the dots will fade slightly the longer they are on the display. This is especially noticeable on the current position dot. The Traffic Display plots targets at 5 second intervals, by default.

The boxes on the right describe the approach and touchdown area. The only parts of this information that are used in the plotting of the Traffic Display are the Latitude and Longitude pair, the Final Approach Course (in combination with the Magnetic Variation), and to a lesser extent, the GPI, or Glide Path Intercept. The center of the display is the GPI. The GPI, in turn, is determined based on the latitude and longitude of the runway threshold, and the distance along the final approach course specified in the GPI box. That will be the center of the display. More information on setting up approaches is available on the Final display's own page. While not having a map drawn in the background, the Traffic display does have a dashed line, extending from the GPI to 10 NM on final, depicting the Final Approach Course for easier vectoring. Support for a background map is not anticipated at this time. The ranges selectable are only 5, 10, 15, and 20 NM, adjusted by the Range sub-selection in the Radar Display Control box under the Approach Setup box. Changing the range in the Traffic display also changes the range on the Final display. Use the Change button next to the Range Selection buttons to toggle between the Traffic and Final displays. See the Final Display write up for more information on setting up approach values.

Every time the display is plotted, the boxes in the right are read. This means the display can be adjusted on the fly. That is, if the final approach course is a little off, you can place your cursor in the Final Approach Course box and change the value, instantly updating the screen. Also, the latitude and longitude of the display can be changed similarly. One more important point: All decimals in all fields must have a period instead of a comma to ensure that the value gets converted properly. This goes for both the "approaches.ini" file and the text boxes on the Quad Radar screen. A comma will end up truncating the value, turning "44,64334678234" into "44". This will have the effect of either not seeing the aircraft, since they will be too far away, or it will help you vector them to final nowhere near where the runway really is. If an aircraft is showing as connected in the Connection Manager at the bottom right (see the next paragraph for more info), but not showing on the screen, check the values in the boxes if you believe he is within the range being displayed but not showing up on the Traffic display.

Lastly, the Connection Manager. This is accessible regardless of which mode the Display is set to. It allows the controller to open and close the port to the network, meaning you can control the program's willingness to accept connections. It also shows a list of connected aircraft callsigns, reminding you who is connected, since you don't have "data tags" on the display itself. Also, it gives a facility to disconnect individual pilots by clicking on the callsign to highlight the aircraft's callsign and then clicking on the "Boot Pilot" button to remove his connection. Note that if a position report from the pilot's Transponder is delayed by internet traffic and is received after the boot pilot button was clicked, it may show up as being connected again, and the pilot may have to be booted again.