Bouncing into and out of the High Speed Zone to set the most accurate average speed.
PAVAS – Null Guidance Technique
This is an audible tone based system to guide the driver to an average speed. This is used in TSD Regularity and Targa Florio stages. This method greatly simplifies conveying the speed information to the driver and it is easily assimilated.
The first part is that if the driver is less than the desired speed, a low tone of 800 hertz is used. If the speed is greater than the desired speed, a tone of 2000 hertz is used. Now as the speed approaches the desired speed, the mark to space ratio of the tone decreases. If the speed is 30 kph away from the desired speed, then the mark to space ratio is 1.0 which results in a solid tone. As the range decreases so does the mark to space ratio with a minimum of 0.1 which results in a short “pip” sound. In both situations of under or over speed, the driver can tell he is getting closer and what he has to do to reach the desired speed.
The Dead Zone
On the under speed condition, if the vehicle gets very close to the desired speed, the the tone does not sound. This called the Dead Zone. If the vehicle is over speed, there will always be a higher pitch tone. When a stage starts that uses Null Guidance, two test tones of the low and high frequency are sounded to help the driver memorize the pitch.
The Dead Zone is located in the higher speed of the Low Speed Zone. As the vehicle proceeds through the rally stage, the ASS effect becomes predominate and, though the Dead Zone is decreased, it is finite and so the vehicle speed cannot be precisely determined. Since the high speed region now borders on the Dead Zone, the best driving technique is increase the speed until the high frequency pips are heard and then reduce the speed to fall back into the Dead Zone. This technique can be applied to ensure the vehicle is extremely close to the desired average speed. The basis of this technique is that from the audible tones both the High Speed Zone and the Dead Zone are easily recognized.
Bouncing
into and out of the High Speed Zone to set the most accurate average
speed.
2020-12-05