Voice Alerts

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Introduction

Software release(s) 20160511 and later contain the ability to issue voice alerts. These are alerts, not commands or advice. Voice Alerts are an audio indication of local traffic and contain no advice on the action to be taken once issued. As Pilot in Command, it is your responsibility to take all necessary action. The issue of a PilotAware voice alert does not give information on all the traffic in the vicinity. It advises only on those that can be seen electronically, these being, PilotAware (P3I), ADSB, Mode-C/S and FLARM, if a FLARM mouse is connected or you are connected to an OGN-R uplink. There will be other traffic that is not being picked up so it is important to maintain your preferred visual scan.

Warning

It is vitally important that you understand and acknowledge that there are concerns that a reliance on a prompted lookout from any EC device including PilotAware could reduce the effectiveness of the visual scan.

For instance, there may be a danger that your attention will be focused on the one area prompted whether this be by voice or visually and therefore, you maybe spotting the wrong aircraft, or missing other aircraft that are outside the area prompted by PilotAware.

Some pilots may become intrigued by the information provided on local aircraft, or fixated on the display or voice commands, at the expense of maintaining their necessary visual scan.

Pilots may also incorrectly assume that all aircraft can be seen on their EC device. This is not the case for any EC device.

It must therefore be stressed that PilotAware does not replace the need for an effective visual scan which is your primary responsibility.  If at any time you feel that you are distracted by PilotAware turn it off until you are more familiar with its operation.

Voice Alert Output

The voice alert output is available from the 3.5mm jack on the PilotAware unit. It does not come from your tablet or iPhone, although some navigational systems do incorporate their own audio alerts. The output volume is adjustable and the output can be fed into your headset, intercom, communications radio or other device as you wish, using a 3.5mm male to male connecting lead.

Please note that the interface to your communications equipment will be bespoke to your requirements and to your aircraft design. Information on connecting to the more common units will no doubt be available on the PilotAware Forum forum.pilotaware.com as more installations are completed.

A direct connection to noise cancelling headsets such as Bose or Light Speed Zulu has proven most effective. Using standard David Clarke headsets may require an audio amplifier to be placed in line with the signal as these older headsets have a higher impedance. The following has been effectively used by several users.

Adjusting the Output Volume

The voice alert subroutine is always on. However, the volume can be raised or lowered as required to the maximum and minimum available. This is done by logging onto your PilotAware WiFi hotspot and typing in 192.168.1.1 and selecting Configure from the Options Menu. Midway through the table you will see the volume control. Selecting ‘+’will increase the volume
Selecting ‘-’will decrease the volume.

There is an upper limit to which the output volume can be raised. Above this further amplification will be needed if a higher output is required. The output impedance and other electrical characteristics can be found in the on-line Raspberry Pi literature. Modifications to the audio output of PilotAware Rosetta is not covered by the Warranty. As the volume is increased or decreased an announcement of “PILOTAWARE” will be made so that you can vary the output for your needs.

Types of Audio Alert
There are two types of Audio Alert given by PilotAware. Bearing and Bearingless

Voice Alerts for Targets with a Bearing
Targets with a bearing including PilotAware, FLARM, ADS-B and Mode-S/3D give positional data so they are able to accurately position in 3 dimensions, aircraft nearby to your own aircraft. This allows PilotAware to give an audio alert very similar to that which you would get from an ATC service.

This alert is in the format; Traffic, One O’clock, two hundred feet above, 9 KilometresPilotAware will always call out vertical separation in feet and distances in whole Kilometres rounded

down to the nearest Kilometre. Audio Alerts are generated when aircraft transit between 3 zones around the host aircraft.

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In the phrase Traffic, One O’clock, height, 9 Kilometres”, the reference to height will be followed by above, below or replaced by level if it is 0ft.

Voice Alerts for Targets without a Bearing (Mode-C/S)

Mode C/S transmissions are considerably less accurate in that they give no GPS positional co- ordinates. See section on Mode-S detection. From the signal that we receive we can only detect its height relative to 1013.2Mb and the signal strength of the received transmission. So, the voice commands have to be in a different format.

The signal from an approaching Mode-S transponder will increase non-linearly as it gets close to, and diminish non-linearly as it retreats from your aircraft. As it gets closer, the strength of the signal received increases exponentially. The absolute signal strength at any particular distance is not a

constant for all installations, so we can only work with relative strengths.

A voice alert is generated as the signal strength changes from one strength band to another. This results in the following voice alerts.

TRAFFIC NOTICE” – Advises you of the presence of a Mode-S contact at the maximum range for your selected detection setting.

TRAFFIC ALERT – Advises that the aircraft is continuing towards you. You should now be maximizing your visual scan guided by the relative height and also planning and possibly implementing avoiding action. e.g. climbing or descending to increase separation.

TRAFFIC DANGER- The aircraft is now in relatively close proximity and all efforts should be concentrated on a visual scan to locate it, together with any and all appropriate action to maximize separation.

Please remember that because of the significantly higher output of CAT transponders, it is possible that you will not be able to visually see the contact for which you have received a voice alert because it will be too far away. If this is happening regularly, then reduce the sensitivity as described in the Configuration Page.

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