Feature: Telemetry - radio ga ga.

What is Telemetry?

Telemetry is data transmitted by radio wave - more specifically microwave - from a Formula 1 car to the pits. This data contains information on car performance (chassis and engine), driver inputs, speeds, gear shifts... you name it, it's monitored by one sensor or another, or a combination of sensors. Back in the garage it is analysed by engineers, rack runners (control systems engineers) and drivers alike to help understand and optimise the performance of the car.

On the chassis side alone the Lucky Strike BAR Honda team broadcast over two hundred channels of data, collated from 70 to 80 sensors and a further 50-60 monitored switches. And that's in race trim. When the team go testing, there are even more sensors to contend with.

You gotta have a system...

Each team has their own way of working with their telemetry. Lucky Strike BAR Honda use a Pi Systems set-up as the basis of their operation, but it has been heavily customised to suit the specific requirements of the team.

"Pi are closely connected with Jaguar Racing, so we try to keep what we're doing quite separate," explains Rob Reeve, BAR's chief engineer of electronics. No one in Formula 1 wants to give secrets away, and telemetry boffins are no exception.

It's Rob and his team's job to decide which sensors to put on the car, which variables to measure, which channels to broadcast, how frequently the data is sent and so on.

The Lucky Strike BAR Honda garage receives data from the 006 in three different ways:

1. Real time telemetry - live data broadcast as the car moves around the track; gives a general overview of how the car is operating and what the driver is doing at any one moment.

2. End of lap 'burst' - the data is buffered up on board the car over the course of a lap, then 'dumped' as the car passes the start finish beacon. The burst is a summary of the entire previous lap's data; very useful for the engineers in quickly assessing the general behaviour of the car. Each burst contains around 800-900KB of data. The resolution is not high enough to facilitate in-depth analysis, but gives an overview that can help the engineers direct their attention where it is needed when the car comes back to the garage.

3. Hard-wire download - much more data is logged on the car than can be broadcast. When the car pulls into the garage, the engineers hook it up to their computers via a cable and download all the data stored on board. This data is of a much higher resolution; after a short practice run of four to five laps, the files downloaded amount to around 25-30MB. While not strictly telemetry (because it is not being broadcast), the download data is basically a more in depth version of the live and burst telemetry.

So, what's it for?

The telemetry data a car produces has a part to play at every stage of a grand prix weekend, although exactly how and what depends on the particular session. The four basic functions of telemetry are: systems monitoring; driver analysis; set-up analysis and switch pragmatics.

1. Systems monitoring

Telemetry is absolutely key in providing an early warning when systems on the car, such as hydraulics or fuel injection, are not running as expected.

The rack runners monitor every aspect of car performance in real time. On a race weekend there are three rack runners on the chassis side, each with a double-screen computer display. One monitors systems on Jenson Button's car, another Takuma Sato's and the third Anthony Davidson's or the T-Car. When neither the T-car nor Anthony's car are running, the third rack runner assists the monitoring of Jenson and Taku's. There is a fourth person monitoring specifically gearbox systems, plus further rack runners on the Honda side of things monitoring engine systems.

The most important thing for a team at any stage over a grand prix weekend is to keep the car running. During free practice, this involves calling the car in when a problem is spotted, and not letting it leave before the problem is fixed.

"In a practice session, if the telemetry wasn't working we probably wouldn't let the car out; it's that important," explains Reeve. "If the gearbox is losing oil pressure, for example, we will spot it immediately in the telemetry. You can then pull the car in, save the gearbox and, crucially, save the time. You won't have a broken car sat out on the track for half an hour until the end of the session. You can fix the problem and get back out."

In a race situation, rather than pulling the car into the garage, keeping it running involves informing the driver of any corrective action - back-up modes or settings - that can be taken to get the car to the end. For example, when Jenson Button nursed his car home for his first ever podium in Malaysia this year, he had been informed over the radio to switch his engine oil pump to a manual mode to prolong its life.

Craig Wilson, BAR's chief race engineer, explains how problems are communicated during the race:

"The rack runners are constantly looking for error warnings or any issues cropping up. They then inform us on the pitwall of the problem and any potential action we can take. We then decide if we have the facilities to fix the problem - a back-up mode or setting change. If we do, we'll inform the driver in a fairly direct manner: 'go to this mode' and so on."

During the race the engineers are very busy assessing the on-track situation and working out strategy, while the drivers are even busier doing the actual racing. With so much data coming off the car every lap, communication between rack runners, engineers and drivers is done on a need-to-know basis. Hence, if a rack runner comes on the radio the engineers know it is something serious. (One of the BAR mechanics calls Rob Reeve 'The Doominator'.)

However, as Rob is keen to point out, an alarm going off on a rack runner's display doesn't always spell disaster:

"Ours is probably the worst job in the pit lane - because generally we're the first to know if we're not going to finish. But there are grands prix where, say, on lap four you think 'there's no way we're going to finish', but you do. Equally, though, sometimes you get failures where you don't see anything. For example, in Malaysia, we had a few worries on Jenson's car, but Takuma's looked perfect. Then Taku just stopped."

Despite that lingering element of unpredictability, the incredible reliability displayed by modern F1 cars is thanks, at least in part, to telemetry. Although pit-to-car telemetry is now banned by the FIA, car-to-pit still allows problems to be spotted and checked before they develop into anything more serious.

Systems monitoring also has a vital safety role to play. In fact, when the FIA recently discussed scrapping telemetry altogether, most teams complained on safety grounds. If critical sensors fail, such as brake pressure sensors, the team can call the driver in and avoid endangering him unnecessarily. There is no doubt that telemetry has prevented serious accidents that would have occurred had failures not been spotted.

2. Driver Analysis

The team record every control input (steering, throttle, brake, gear change) the driver makes, as well as speed traces each lap. Different drivers vary in the amount that they look at and analyse their own driving technique from telemetry. Out of the three Lucky Strike BAR Honda drivers, Takuma Sato does it the most.

"Taku lives by his telemetry," says BAR's third driver Anthony Davidson. "I do it more by feel than actually looking on the computer screen. But I'll look at it if I have a genuine question to ask, like 'I wonder if those tyres were better at the beginning of the lap than the end'."

Nevertheless, Anthony admits that even the most feel-dependent driver finds telemetry useful in his never-ending quest for speed.

"Comparing yourself against other drivers is always interesting. If you're struggling around one section of the circuit, you might just have a look at their data. Seeing their steering input, throttle application and brake pressure can be really helpful."

3. Set up analysis

While telemetry alone cannot tell the engineers the best way to set the car up, it serves two very important functions in the process.

First it confirms the driver's own feedback about the car's handling, supplementing his information on where the car is oversteering or understeering, how the traction control is operating, what the ride heights are like and so on.

Second it provides an important early indication system while the car is out on the track as to where the engineers need to focus their attention when the car comes back into the garage.

Again, different drivers place different emphasis on their own feedback against the telemetry data. Takuma is very interested in the data in making set up decisions; Jenson prefers to talk in more general terms with his engineers. It is Craig Wilson's job as chief race engineer to ensure a healthy combination of both approaches is used.

"Without the data, you would limit your fine-tuning of the set-up and your analysis of the performance gains around the track; you'd have to be much more reliant on the driver," Craig explains.

"Then again you need both to get the full picture. For example, the data may show the car has some understeer, but the driver might say the main problem is entry oversteer, which is causing the mid-corner understeer you're seeing in the data."

Even in the technologically advanced world of Formula 1, there is no replacement for the human element. Telemetry is invaluable, but only when paired with an able driver and the brains of his engineers.

4. Switch pragmatics

One of live telemetry's most basic functions is also one of its most useful. The human element still being a factor, it is quite possible for drivers to make selection errors with the switches on their steering wheel, which control things such as the diff, traction control and fuel mixture settings. So the rack runners monitor the status of every switch on the car.

When a driver adjusts a switch setting, the rack runner will call out the changes, so that the race engineers are aware of the changes and can note them, for future reference when deciding on adjustments to make to the car or for discussion with the driver over the car issues.

And finally...

Not just anyone can broadcast telemetry: you need a special licence from the local radio authority. In some countries this is fairly simple and cheap; a licence at Silverstone costs just ?480 for the right to use radios and telemetry. At other races, where interference with local TV broadcasters on similar frequencies is a problem, it can be much more difficult and expensive; at Monza or Imola in Italy the same license costs the team ?6,500.

So vital is telemetry, however, that it's worth every penny.

Feature courtesy of the BAR Lucky Tribe media site.