vPAR (Virtual Precision Approach Radar) March 1, 2005 By Michael Oxner

About vPAR:

The idea for vPAR was born by accident just after Christmas 2001. I had recently attended an online "fly-in" using VatSim where PARs (also known as Ground Controlled Approaches, or GCA) were being done. These were being conducted using ProController, a basic radar client. This interface encounters a couple of major issues when trying to conduct a PAR or GCA for a pilot.

The VatSim server software is designed to provide position updates roughly every 5 seconds and a software re-write would be required for them to provide more frequent updates. This was not likely to occur given the scope of such an ordeal. Talking about it with Jonathan Bjornson, an active member of VatSim both flying and controlling, he inadvertently sparked the idea of building a pair of programs that would obtain and transfer data outside of VatSim. Simple enough, it seemed. With some guidance from Ken Greenwood, a former military ATC now in the civilian world and actively involved in VatSim, I began working on designing the new pieces of software. My programming guru, Al Mitchell, was patient enough with me to help me solve some major issues that sprung up during development.

The QuadRadar program was written for the controller, but there had to be a way to get data to it. I knew nothing about how to work with VatSim's servers, and they couldn't provide position updates as quickly as I needed for vPAR to be a success. So another program had to be written to pair up with the QuadRadar for faster interogation. The design evolved quickly to a simple little applet that would run next to Flight Simulator, connected to the QuadRadar program on the controller's desktop through the internet. The program would report Flight Simulator's position and altitude when asked by the controller host. Since this operation is similar in context to real-world radar and transponder (except the transponder in the real-world doesn't actually know where it is -- it's the radar's job to calculate that), the name Transponder got attached to this side of things.

Now that we were free to send our own data differently, we had to process it differently, too. This gave rise to many opportunities to draw the data in a more useful way. Enter the PAR display. With the help of a real world PAR controller in Greenwood, NS, I set out to develop my PAR program's appearance. I modeled the original program after the real world scope in use at Greenwood, and kept the interface very simple. The Traffic display, the familiar "top down" screen, was overly simplified, but useable. The more I worked with it, the more inspired I was to develop a new version, but I had nothing to work with and "developer's block" set in. Marcel Ritzema, from the Netherlands, came to my rescue without realizing it by sending me an image that, although small and difficult to discern any real detail, was good enough to start the ideas rolling once again. Now we have the new, albeit fictitious, interface which should provide the virtual PAR controllers with more features to play with and a lot more flexibility in customization.

And that's basically it. There was a major development for the name of the program in late 2003, delaying the release of this version. I inadvertently gave it a name that I am not allowed to repeat, since it is a trademark infringement with DiamlerChrysler's MOPAR autoparts division. I came by the name honestly, in that I used my initials with the term 'PAR'. When I realized the connection with the name, I contacted Chrysler. They let me off the hook (graciously), provided I ceased use of the name and removed all materials associated with it. So, this pair of programs, which was meant to be V2.0, ended up taking on a new name. There were plenty of new features and a lot of the core code from the original releases were reworked to accomodate them, so I decided to start fresh with V1.0 with the new name.

All of this has culminated in the release of vPAR. I'm considering this an open beta, as I did with the last program. I hope people will drop me an e-mail to let me know where they're using it (I always like to know where my works make it in the world, even if they're not big name items) and provide any comments, good or bad. Please report any bugs. This is freeware and I won't make a promise of fixing any of them and not within any given time frame. With the success of the old PAR programs behind me, I will certainly look at fixing my mistakes if people enjoy this version as much as they did the last. Enough of this. On with the show!