Voice ATIS

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Voice ATIS

Voice ATIS makes it possible for the pilot to listen to the actual information of the departure or arrival airport also on an audio channel, rather than just reading it in the form of text lines that are being display when tuning in to a new controller's frequency. This is a major step forward in bringing the simulation closer to real life. EuroScope is supporting this feature from the beginning.

To enable a second voice channel connection that can be tuned-in by pilots you need a second VATSIM connection with its our air (primary) frequency. Before setting up a voice ATIS station, make sure to read the relevant part of VATSIM's Code of Conduct (see part A8 and C11). This second connection is rather restricted. You cannot specify your callsign freely. The callsign must have the format xxxx_ATIS, where xxxx is the airport's ICAO code (e.g. LHBP_ATIS). EuroScope enforces this requirement by letting you only specify the airport's ICAO code for the voice ATIS connection. EuroScope automatically appends the _ATIS suffix and also checks that this airport is defined in the current sector file. After you have established the voice ATIS connection, you will see your own connection in the controller list as *_ATIS.

To set the radio frequency of your voice ATIS connection, go to the Voice Communication Setup dialog and add the appropriate definition as ATIS frequency. Here you also enter the voice server address and voice channel name. There is one more restriction: The channel name must be the same as your voice ATIS callsign. So if you are going to serve LHBP with voice ATIS, then be sure to define a connection with LHBP_ATIS as channel name.

By the way, EuroScope automatically blocks incoming audio on the voice ATIS channel to protect you from any disturbances.

Operating Modes

There are two principal ways in which you can compile an ATIS message:

  • Single-Recording Mode: In this mode you perform a single, uninterrupted recording of the entire ATIS message, much like you do on your answering machine at home. This mode is what you know from other radar clients like VRC. It provides the best audio quality and the highest flexibility. The disadvantage, however, is that you have to re-record the entire message every hour, or in times of rapid weather change, twice an hour. In addition you have to type the message in text form in the message area, because by the rules of VATSIM Code of Conduct you always have to publish the same ATIS message also in text form.
  • Multiple-Recording Mode: This mode is based on the idea synthesized speech. All the data that go into an ATIS message are known to EuroScope in digital. So, why not attempt to create the audio representation by concatenating recordings of word fragments. We pre-record those fragments and then only need to tell EuroScope which fragments to glue together. So whenever we want to change our ATIS message, we edit the fragment list and are done. This works a lot faster than re-recording the entire message. Another advantage is that the audio fragment list can serve at the same time as our text ATIS.

A difficult part in this process is to interpret a METAR report and convert it into a word-list for the ATIS. Fortunately, there are web-base services around which do exactly that. By combining all these techniques we arrive at a fully automated ATIS system - a true innovation brought about by EuroScope. A new ATIS is now created in a two step process, both of which run without human interaction:

  1. EuroScope compiles a request to an ATIS Maker web service. This request contains the airport ICAO code, the current METAR, runways in use, approach type, ATIS letter, and departure frequency. The answer returned by the ATIS Maker service is a fully compiled ATIS message in text form, or in other words: The audio fragment list for our ATIS message.
  2. EuroScope generates the voice ATIS message by concatenating the audio fragments of that list and thereby forms the audible ATIS message. As the fragment list is also a readable text, it also serves as the text form of the ATIS.

The ATIS messages generated in this way sound a little more mechanical than the recordings done in a single run. On the other hand, this mode reduces the workload of the controller significantly. Once setup correctly it takes care of the entire ATIS message generation.

The following sections will cover the two modes in detail. We start with the voice ATIS dialog, which is laid out so general that it fits both modes.

Dialog Fields

Image:VoiceAtis1.jpg

Before we delve into the fields and buttons of this dialog, we need to cover one general topic: How EuroScope stores audio recordings. EuroScope expects all voice recordings in one file directory, which you can configure. In addition, this directory contains a single descriptor file, which is a text file that serves as lookup table for all the recordings. This file associates logical names of audio fragments with the file names of the corresponding .wav files. When working in multiple-recording mode, these audio fragment names are used to tell EuroScope, which fragments to combine to a message. At the same time these names are used for the text representation of the ATIS.

For example: You decide that you want to have a fragment that contains the sound for "runway 07L and 07R in use". In that case, this same text should be used as the name of the audio fragment. When you later want to use it as part of your ATIS, you put the name enclosed in square brackets [...] into the desired place of the Text Atis and multiple record ATIS edit box. That tells EuroScope which fragment to play when it reaches that position and for text-users a readable text appears on their screen, with the brackets removed.

Now we take a look at the top-most field of the dialog:

  • ATIS file descriptor - The full path specification of the index file. EuroScope expects the audio fragment files in the same directory as the index file. Of course you can have multiple such directories if you want to experiment with different setups. By pressing the Browse button next to to the field you can browse and select a descriptpor file and thereby also define, which directory the audio fragment files will be retrieved from.
When you start the system for the first time, it is possible that you receive the error message that the ATISdescriptor file can not be opened. In this case create an empty folder and create the descriptor file there.

The voice ATIS setup is an exemption to the rule that changes are only saved when explicitly requested. Any click in this dialog, any change in any data will be saved immediately to the descriptor file.

  • Records list
    The top list contains your audio fragments, that is: your recordings. The amount of recordings you need depends on the way you would like to use the voice ATIS facility. In single-recording mode you typically have only one or very few recordings, which you regularly overwrite. In the multiple-recordings mode you will typically have several dozens to several hundreds of fragments that will be combined to the final message.
  • Record content
    This edit box reflects the name of the presently selected recording in the list above. You can edit the name or enter a new name to create a new recording. Note that in multiple-recording mode this name serves at the same time as representation in the text form of the ATIS. The name is not case-sensitive.
  • File name edit
    The name of the corresponding audio file. If the file extension is .wav then it will not be modified, otherwise a .atis extension will be appended automatically.
  • New button
    If you press this button a new recording will be added to the list. Both the recording name and the file name must entered before you hit this button.
  • Delete button
    It simply deletes the selected recording from the recordings list. It also deletes the associated audio file.
  • Modify button
    It changes the selected entry in the recordings list by the content of the edit boxes.
  • Start recording/Stop recording button
    When you have an item selected in the recordings list, this buttons starts a new recording on the selected audio file. The button text changes to Stop recording. Pressing the button a second time finishes your recording.
  • Start single record playback
    Starts the presently selected recording as a playback loop. This button actually starts the playback in single-recording mode. As long as you don't press this button, nothing will be heard on your voice ATIS channel.
  • Unlock button
  • To avoid accidentally overwriting a recording, EuroScope locks all recordings when you leave the dialog. To unlock an existing recording, press the Unlock button.
  • ATIS airport
    With this field you can ask for a METAR of a station. Type the station name here. At the same time, this field configures your ATIS callsign. EuroScope automatically appends the _ATIS suffix and tries to active the corresponding voice channel when you press the Connect button and if such a channel has been defined in your Voice Communication settings.
  • Connect ATIS button
    This button is used to create your ATIS connection to the VATSIM server and to the voice server. This ATIS connection is a completely separate connection; VATSIM regulations restrict the use of such a second connection for the use as ATIS channel. The button is enabled only when you have a live, direct connection to VATSIM. The ICAO code that you entered in the ATIS airport field will be used to form the callsign of that connection. EuroScope will find the air frequency of this connection by looking the callsign up in your Voice Communication settings. There it will automactically check mark the ATIS check box and the RCV and XMT voice check boxes.
  • Disconnect ATIS button
    Use it to disconnect the ATIS connection. It is enabled only when you are connected.
  • ATIS connect status
    Just next to the Disconnect ATIS button there is a status field. It shows the current status of the voice ATIS connection.
  • Get METAR button
    This button requests the METAR of the selected ATIS airport. When you press it the first time, it may happen that nothing is displayed momentarily as it may take a short time to receive the METAR information. If necessary, press it a second time some seconds later.
  • Current ATIS info and + and - buttons
    By pressing the + and - buttons you can change the current ATIS letter. The current ATIS letter is also displayed in the toolbar of the main window. These buttons also change the ATIS letter in the Text ATIS and multiple record ATIS box. EuroScope looks for the ATIS letter in that box by searching for a space-letter-space combination and replaces all such occurrences of the old ATIS letter by the new one.
  • Start multiple record playback
    Starts the fragment list defined in the Text ATIS and multiple record ATIS box as a playback loop. This button actually starts the playback of multiple-recording mode. As long as you don't press it, nothing will be heard on your voice ATIS channel.
  • Stop ATIS playback
    It stops the current ATIS playback.
  • Listen playback check-box
    If you check this box the current playback is looped back to your secondary output. Thereby you can monitor what is being sent to the voice server connection.

Single-Recording Mode

This mode is the simpler of the two modes. You make a single recording of the ATIS and let it playback in a loop.

To create the recording, enter a recording name (called record content in the dialog) and a file name in the two edit boxes. In the example below, both the recording name and file name are "MyAtis". Then press the New button to create that entry in the descriptor file. The corresponding line appears in the top list box and is selected.

Image:VoiceAtis0.jpg

Step-By-Step Procedure

Chances are that after a fresh installation of EuroScope you see a lot of recording entries in the top list, as the installer sets up a multi-recoding mode example. For your first experiments you might want to create your own empty directory. For example, create a directory named "SingleRecATIS" under the EuroScope working directory. Then create an empty text file in there, named for example "descriptor.txt". Finally, press the Browse button in the Voice ATIS dialog, navigate to your new directory and select the empty descriptor file. Now the top list box should look empty and ready for your experiments.

Before you start recording it is advisable to write your entire ATIS text down in the lower big box, titled Text ATIS and multiple record ATIS. So you only have to read it off from there when you are recording. And this text will also appear as the text form of the ATIS for pilots who just want to read your ATIS.

Also take a quick look at the ATIS airport field, it should contain the ICAO code of the airport you are providing the ATIS for. And then select an ATIS info letter. If you are taking over a controller position from someone else, it is a good idea to continue with the letter of your predecessor or the next letter in the alphabet.

Now press the Start recording button and read the ATIS slowly and clearly. Consider that pilots will be listening and making notes.

When done press the same button again, which in the meantime has changed its label to Stop recording. If you are not satisfied with your recording you can repeat it as often as you want.

Before you set your recording online you might want to listen to your recording. To do that, press the Start single record playback button and click the check box Listen playback. Now you hear your recording exactly like the pilots will hear them later. When done, just click the Listen playback check box off, but let the playback loop continue. Do not press Stop ATIS playback -- otherwise your pilots will only hear silence.

Before connecting the ATIS to the VATSIM and voice servers you must make sure that your voice communication setup contains an entry with the appropriate callsign. For example, if you are providing an ATIS for the LHBP airport, you should have an entry LHBP_ATIS in your communications setup with the appropriate frequency, voice server and voice channel settings.

Finally, to set your recording online, press the Connect ATIS button. The status box to the right should now say Connected to VATSIM. When you now take a look at the communications setup, you should see a green check mark in the ATIS checkbox of your ATIS channel and both the XMT and RCV voice boxes checked. Don't worry, you won't be disturbed by anyone talking to that channel, as EuroScope automatically suppresses voice input from that channel.

As final check, look at the menu bar of the main window and you should see there the ATIS identification letter as you have set it in the Voice ATIS dialog and next to it the air frequency. That is the frequency of your ATIS channel. If you see ---.--- something in your setup has gone wrong. This is always a good final check that your voice ATIS is online, connected to the voice server and performing the playback loop.

Advanced Techniques

When you enter the text form of the ATIS, you can simplify things a little by using functions. EuroScope has a couple of built-in functions that are particularly useful in the ATIS text, for example:

$atisairport - airport code of your ATIS airport
$altim(<airport-code>) - the altimeter setting
$deprwy(<airport-code>) - active departure runways
$arrrwy(<airport-code>) - active arrival runways
$wind(<airport-code>) - wind from current METAR of this airport

But working with these built-in functions in the ATIS text has the disadvantage that it will be more difficult for you to read the ATIS text while you are recording, as you can't see what the functions expand to.

Here is another little trick: When you come back after an hour to record the next ATIS message, you don't need to stop the playback loop. Playback and recording can work in parallel. When you are done recording the new message, stop the playback and restart it. That way you can almost provide an uninterrupted service.

Multiple-Recording Mode

Instead of using a single recording for your ATIS, this mode allows you to build your voice ATIS from multiple pieces that are being concatenated. Typically, these pieces are single words or short phrases and we call them fragments. In the lower edit box you program the sequence of fragments that you want to play. EuroScope uses two special constructs in this edit box:

  1. Square brackets [ ] enclose the names of fragments; e.g. [clouds] plays the recording with the name clouds
  2. Braces { } enclose numbers that are going to be pronounced in aviation phraseology, e.g. {2500} plays as two thousand five hundred. That of course requires that you have recorded the fragments with names 2, thousand, 5, and hundred.

All letters or digits that are not enclosed in square brackets or braces will be spelled out as single letters or digits in aviation phraseology, e.g. AB9 will play as alpha-bravo-niner.

Here is a more complete example of what your fragment list might look like:

[Heathrow][information]J[time]1450Z[clouds][few]{2300}[broken]{4800}

This will play back as: Heathrow information juliet time one four five zero zulu clouds few two-thousand-three-hundred broken four-thousand-eight-hundred.

When a pilot requests the text ATIS of that channel he will see:

  • Heathrow information J time 1450Z clouds few 2300 broken 4800

thus he will see your fragment list, except that all the special characters have been removed.

Here is an example of a full ATIS as it looks in the dialog:

Image:VoiceAtis1.jpg

Recording the Framgments

To use this mode you need of course the recordings for all the fragments you are going to use. That list includes at the bare minimum:

  • The digits from 0 to 9 - [0], [1],
  • The numbers [10], [11], ... [18], [19].
  • The numbers [20], [30], ... [80], [90].
  • Hundred and thousand - [hundred], [thousand].
  • The word and - [and].
  • The full alphabet
  • All words that might appear in an ATIS, for example: wind, degrees, knots, clouds, cavok, clear, few, scattered, broken, overcast, temperature, dew point, QNH, visibility, kilometers, trend, nosig, ...

EuroScope can record fragments, but is not the most preferable tool to do so many recordings. It does not give you enough control about the trimming of the fragments, and trimming is important if you want the fragments later run smoothly into each other. The tool of choice for the recording is a good audio editor, for example the free program Audacity. In an audio editor you can speak all these framgments in a single recording and then cut them out very precisely. When recording and storing the fragments you should use the format 7350 Hz sampling rate, 16-bit signed PCM and use the .wav extension in the file names.

Note: The recordings done by EuroScope itself are not stored in this format, but a proprietary one. So don't try to import recordings from EuroScope into Audacity.

Warning: Some sound editors re-configure your Windows audio settings and might thereby accidentally turn-off your microphone. In your next EuroScope session that might catch you at surprise, because no pilot will be able to hear you. In that case check your Windows audio settings. On a Windows XP system that means:

  1. Right-click the loudspeaker symbol in the right corner of the task bar and select Audio properties
  2. In the upcoming dialog, click the Audio tab
  3. In the middle box Sound Recording press the Volumes button
  4. Now you see the mixer panel for all your audio sources; make sure the check box Select on the microphone section is checked.

Of course you might also be able get a ready-made set of audio fragments from your vACC, so you might search their website for it and save yourself a lot of work. EuroScope also comes with an example set of fragments in its ATIS_demo sub-directory, which is designed for use with the vacchun.hu/td/esmetar.php ATIS interpreter (see below).

Just as an inofficial hint: Members of VATGER use mostly the following ATIS sound set: http://edmm.flyiar.com/atis.rar, which was created by Lukas Kulik.

Compiling an ATIS

To build the fragment list that comprises your current ATIS you can use the Insert item button. Just select a row in the upper box and press Insert item, or press ENTER or double-click the row. The selected audio fragment will be inserted in the fragment list and automatically enclosed in square brackets. The focus is thereby shifted to the fragment list and you can continue typing in the fragment list. To shift the focus back to the upper box, press the TAB key and then select the next fragment. You can easily find a fragment by typing the first letters or digits.

Once you have completed your fragment list, press the Start multiple record playback button to start the playback. To monitor the compiled audio message, click the Listen playback check box. If the playback didn't start, you might want to take a look at the message log. If EuroScope has problems interpreting the contents of your fragment list, it leaves error messages in the message log, which probably will tell you very quickly, what's wrong.

To make your voice ATIS audible to the pilots, press the Connect button and follow the same steps as in the previous section. Note that you must keep the playback running and do not hit the Stop ATIS playback button, as this will also stop the playback for your external listeners. Un-check the Listen playback check box instead to stop monitoring your ATIS.

External ATIS Interpreter

If it was just for the functionality described up to this point, the multiple-recording mode would not be a real time saver. Putting all the fragments together to form a complete ATIS might even take longer than doing a single recording of the entire ATIS. The real clue comes in by automatically building the segment list from the current METAR and all the things EuroScope knows about active runways and the ATIS-letter you have chosen in the dialog. This is in fact not a trivial task considering the complexity of the METAR message. EuroScope has not yet built that functionality in, but can make use of external web services that accomplish the task instead.

To configure the use of such an external ATIS interpreter, we use the ATIS maker URL field. Enter here the web address of the service you want to use and all the parameters that the service needs to perform its task.

At present there are at least two ATIS interpreter services available:

  • The VACCHUN interpreter - It was built by Attila Ábrahám. You can find a complete set of wave files and also a complete reference manual in the atis_demo folder of your EuroScope installation. Of course the wave files are limited to LHBP only, but you are free to adapt them for your area.
  • UNIAtis by Sami Ylismäki - This is a widely configurable ATIS interpreter. Currently it supports full METAR decoding with the exception of remarks, and every field can be customized to support a wide variety of formats. It includes support for semi-freely customized fields in the ATIS. If you would like to join him and make your own area specification contact him via the forum of UNIAtis at http://www.uniatis.net/.

The parameters that must be specified in the ATIS maker URL are dependent on the service you use. For the VACCHUN service, the included documentation describes nicely which parameters you should specify. Here is an example (split artificially into multiple lines):

http://vacchun.hu/td/esmetar.php?
tlcond=100,1013,110&metar=$metar(LHBP)&arr=$arrrwy(LHBP)&dep=$deprwy(LHBP)
&app=ILS&par=1&info=$atiscode&lvp=2

An example for the UNIAtis service looks very similar:

http://uniatis.net/atis.php?
depfreq=120.800&metar=$metar($atisairport)&arr=$arrrwy($atisairport)
&dep=$deprwy($atisairport)&apptype=ILS&info=$atiscode

Note how both examples make use of the built-in functions of EuroScope to transfer the METAR information, the settings of departure and arrival runways, and the ATIS letter to web service. Some new built-in functions have been added particularly for this purpose:

$atisairport - airport code of your ATIS airport
$altim(<airport-code>) - the altimeter setting
$deprwy(<airport-code>) - active departure runways
$arrrwy(<airport-code>) - active arrival runways
$metar(<airport-code>) - the METAR in its long form
$atiscode - the current ATIS letter as set in the control above

After you have setup your ATIS maker URL, press the Test URL button and observe two things happening:

  • In the field Extracted URL you see how EuroScope has expanded the built-in function calls in your URL; that is the exact web request as is is being sent out to the external service. Originally more thought of as a debugging tool, it is a nice instrument to see what exactly is being sent.
  • In the fragment list you see the result that came back from the external web service, namely a complete fragment list for your new ATIS. You can edit this result by hand, although in most cases the returned result will be totally satisfactory.

If you have checked the Automatically generate new ATIS using the URL check box, EuroScope will automatically update the ATIS for every new METAR report that is being received. It also increases the ATIS letter automatically at that time. In order to let neighboring controllers know that the ATIS code has changed, EuroScope sends a text message to all other EuroScope clients in range, containing the new ATIS letter and airport code. If a neighboring controller has specified the same ATIS airport, the ATIS letter in his client is automatically updated and immediately visible in the menu bar.

By the combination of all these techniques, the entire ATIS preparation process has been fully automated -- a great achievement when you are controlling as a one-man-show and rarely finding the time to record a new ATIS.


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