Targa Florio Rules and Stages

Unlike many rally events, Targa Florio has few rules or restrictions on the equipment that can be used in the vehicle. Once a vehicle qualifies under a number of categories, the main rule is to complete the stage in a given time. The other rule that applies to PM's is that a vehicle speed monitored at secret locations. Hence time management, navigation, safety and occupants are the main other areas of attention in the rules.

Starting Procedures.

PM's are commenced from a stationary position.

While PC's (Time Trials) can be commenced at any speed. In these stages, start time is measured by a pneumatic tube which activates a timer.

PC Stages Mode 1

The Mode 1 in PC stages is basically a simple timer. The stage is started with a press of the Select button or Reliability switch and a preset countdown timer starts to run. No tones are sounded but a countdown clock is displayed for the navigator. When half the stage time has elapsed, PAVAS commences to emit tone indicating the time until the end. At the five second point a warble is sounded for one second and then the count down resumes.

PAVAS Techniques in PC stages Mode 2

PC stage timing is critical and is exacerbated by the short stage lengths that are used. There are two problems with using a mechanical switch in the vehicle to time the stage. The first of these is the operator's reaction time. This can be simply measured in a configuration parameter mode. The second problem, in mode 2, is the distance travelled during the reaction time. This is more complicated and depends on the vehicle speed. PAVAS corrects for this distance by logging the distance traveled from an arbitrary point every 100 milliseconds and stores it in memory. The memory structure rotates so that the First In memory value is the First Out memory value (FIFO). This memory is 6.4 seconds deep. When the switch contact is finally recognized, the software retrieves the distance value prior to the reaction time and uses this value as the start distance.

The same method is used at the BUT when the operator presses the switch again. PAVAS uses the rotating memory to calculate the distance prior to the reaction time. Since the start distance is known, the outbound leg distance can be calculated. So the total distance of the stage can be calculated which is the outbound leg, plus the inbound leg and the BUT distance. Now the time prescribed for the stage is known so the required average speed can be calculated. This is then used as the requested speed for the TSD algorithm. PAVAS then uses Null Tone Guidance to direct the driver. To keep the driver aware of the navigators progress, a beep tone is sounded when the switch closure is recognized.

It should be noted that switch closures are subject to contact bounce, therefore the activation time is finite and typically 50 milliseconds. The PAVAS software debounces the contact closure to ensure a reliable signal and this time is accounted for in the reaction time measurements. If the Select button or Reliability switch is closed as the finish line is crossed, PAVAS indicates the time taken.

PAVAS Techniques in PC stage Mode 3

In Mode 3, the outbound distance is provided. The menu system allows for this value is to added after the mode is selected and prior to the start which is indicated by a Select button or a Reliability switch closure. The rotating memory is used as in the Mode 2 description above. The stage distance is immediately calculated and so the Null Tone Guidance commences immediately and provides feedback to the driver. The navigator only has to provide the start indication. At the five second time, a warble is sounded for one second. Then the tones revert to Null Guidance. If the Select button or Reliability switch is closed as the finish line is crossed, PAVAS indicates the time taken.