Formula One Telemetry
When Plextek was approached in
1998 to develop a new telemetry system in conjunction with Pi Group for Formula
One motor racing it soon became clear that a standard's based solution was
not going to be a viable option.
Systems such as GSM, DECT
and Bluetooth were never designed to support
the data rates required or operate in this radio environment. The only
solution was to develop a custom radio system.
The starting point in the design
of a custom communications system is to address the first key question:-
What are the requirements of the
system?
Considerations of a wide variety
of parameters including the required data rates, acceptable latency, quality
of service, countries of operation, hardware size, cost, power consumption
and more are all required.
Once an initial definition of the
requirements has been produced consideration of the radio system can commence.
The first consideration is often what frequency band can be used for the system.
Radio frequency spectrum is a rare resource and is managed by international
regulation. In general the allocation of radio spectrum will either be:-
- as a dedicated frequency band
allocated by a national authority
- a frequency band dedicated to
a specific function on a shared basis
- or a frequency band open to
a wide number of users with different applications
The
selection of a suitable frequency band is a complex issue. In order to ensure
maximum interworking between multiple users and multiple systems legal constraints
are imposed on the performance characteristics of the radio equipment that
can be used in each band. This can typically be limitations on maximum output
power, acceptable modulation schemes, installation locations and the applications
served. The regulations vary from country to country although the process
within the EU is now quite well harmonised.
Using our experience of radio system
design and knowledge of world-wide radio spectrum allocation we are able to
identify likely suitable frequency bands that could potentially be utilised
by specific systems. From theoretical analysis of the likely radio link budget,
potential data rates, fading characteristics and possible sources of interference
it is possible to begin to outline a proposed system.
For a high performance system it
will then usually be necessary to perform specific measurements in the intended
environment to allow an accurate characterisation of the radio performance
to be made. Typically this will involve the use of our survey vehicle and
equipment, including a proprietary high performance channel sounder. The objectives
of the surveying being to measure:-
-
Path loss and time domain characteristics
of the specific radio channel
- Background noise levels and
characteristics
From the radio survey data it is
possible for our engineers to begin to produce computer models of the radio
channel characteristics using packages such as Simulink and Matlab to further
develop the proposed system.
For the Formula One motor racing
telemetry system measurements were undertaken at the Silverstone, Hockenheim,
Nurbergring and Barcelona circuits to allow models of a number of different
environments to be produced. From the measured data the proposed system design
can be developed and tested to produce coverage estimates showing the likely
performance of the system. This approach allows an early check on whether
the initial objectives of the system are likely to be achieved prior to thedesign
of the equipment.
The Formula One motor racing telemetry
system developed by Plextek and Pi Group raced into first place in the San
Marino Grand Prix at Imola on Easter Sunday 2001 when the Williams-BMW Team
notched up the first victory of their two-year partnership.
In the gap between the 2001 and 2002 season, Pi came back to Plextek for
a software upgrade program. These system
improvements allowed a fully acknowledged handshake protocol. The new
software also provided a data downlink channel to the car, which was
illegal under the old 2001 FIA rules but has been relaxed from 2002.
The new Plextek software allowed the teams to receive error free transfers
of data from the cars, and reliably send command information to the
cars to tune performance during the race.
The upgraded telemetry system was installed on four Formula One team
cars including Williams-BMW, Jaguar and Arrows.
