This standard shall be the basis for establishing World Land Speed Records under the authority of the World Land Speed Racing Association®.
Preface
A standard set in the early 1900’s and used currently for gauging vehicle land speed records says one must establish the time it takes to traverse one mile, then traverse and time the mile the opposite direction within an hour. The two velocities are then averaged. This method somewhat cancels-out any affect from prevailing wind, but leaves plenty of room to question the absolute accuracy of the speed calculation due to human error and environmental factors.
The days of timing lights and questionable accuracy are no longer necessary. Global Navigation Satellite System (GNSS) – based timing is the methodology embraced by the World Land Speed Racing Association® (WLSRA®), is state of the art, and is being used on the North American Eagle™ land speed record challenger project. Hopefully this will become a globally-accepted standard soon. GNSS absolute positional accuracy can be within 5 millimeters, but point-to point velocities calculated from differential data is proving to have much higher resolution than even this high positional accuracy would suggest. With GNSS, several things are achieved that traditional methods are not able to capture. These include: ease of implementation, universality, permanent multiple-redundant datasets in RINEX (Receiver Independent Exchange) format, a self-compensating data acquisition rate-dependent accuracy guarantee, and what is considered the most attractive aspect with a direct impact on safety – the ability to capture the fastest mile within the entire length of each run.
Understanding measurement uncertainty, being able to quantify the gap between observations and reality, ensures error-free conclusions. Often we think of this gap as being a range of unmeasurable quantity centered about the absolute truth. In land speed racing, there is no prize for going slower than the next person, and in the world of fishing, no one lies by reporting a fish smaller than it was. To ensure absolute integrity in the interpretation of data supporting the speed of land speed vehicles, the method established as the standard must guarantee uncertainty favors the smallest fish possible and the staunchest competitor must not be able to question the timing conclusion. From now and into the future, the requirement is that one must be able to say “We went at least _____.”
The WLSRA® timing method provides an elegant solution to this requirement that dynamically compensates for uncertainty based upon the data acquisition rate, which makes the conclusions reached now will be as valid as those made with advanced systems in the future. The history behind developing this standard is an engaging story of desperation, limited resources, and serendipitous circumstances.
1.0 Definitions
| Global Navigation Satellite System (GNSS) |
The collective of components required to collect data regarding position and velocity of the vehicle and that of the Static Reference Station.
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| Differential Global Navigation Satellite System |
(DGNSS) A method by which position is determined by calculating the position of a kinematic GNSS station against that of a fixed or static GNSS. This method eliminates error such as that created by atmospheric affects.
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| Data |
Cartesian or straight-line velocities between individual localizations of the antenna mounted to the vehicle.
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| Vehicle Antenna |
The antenna that receives signals from GPS and GLONASS or equivalent satellites, mounted in a fixed position on the vehicle.
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| Reference Antenna |
The antenna that receives signals from GPS and GLONASS or equivalent satellites, mounted in a stationary position on the ground.
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| Continuously Operating Reference System (CORS) |
Any of a multitude of satellite tracking stations established in fixed positions on the ground, typically maintained by government authority that provide an open database for GNSS calculations.
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| Static Reference Station |
A GNSS component that provides satellite transmission data from a fixed reference position.
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| Vehicle Average Speed (Va) |
The Velocity average of V1 and V2 as determined by the distance traveled by the Vehicle Antenna between T1, T2, and T3, T4 respectively.
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| Variables | D1 Distance between T1 and T2, (>/= 1 mile) D2 Distance between T3 and T4, (>/= 1 mile) T1 Absolute time, Run 1, determines D1 start T2 Absolute time, Run 1, determines D1 end T3 Absolute time, Run 2, determines D2 start T4 Absolute time, Run 2, determines D2 end V1 Average Velocity, in miles per hour between T1 and T2. V2 Average Velocity, in miles per hour between T3 and T4. Va Average of V1 and V2 |
2.0 Rules
| 2.1 |
WLSRA® records and certified timing shall be approved by the WLSRA™ board. The board, at its discretion, may require independent evaluation of data and/or calculations to validate a WLSRA™ Record and/or Certification. Each WLSRA™ Record or Certification shall bear the original signature of the WLSRA™ Timing Official.
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| 2.2 |
The Land Speed Record, shall be determined by Va and applies to a single vehicle in its vehicle class and shall be held to the vehicle and driver until exceeded by a WLSRA® record in the same vehicle class. This represents the World Record time achieved for a vehicle in its class.
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| 2.3 |
Land Speed Certification applies to a single vehicle in its vehicle class and shall be held to the vehicle and the driver forever. This does not represent a world record under WLSRA® authority, but is a WLSRA® - certified average speed (Va).
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| 2.4 |
Va shall be determined by a Differential Global Navigation Satellite System and the movement of a single receiving antenna mounted in a fixed position upon the vehicle. The reference or static station may be one or more local GNSS’s in fixed position, or by use of CORS data from the closest available CORS station.
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| 2.5 |
The course is comprised of two parallel straight-line paths of unlimited length by which the vehicle travels, each with opposite headings +/- 5 degrees.
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| 2.6 |
T3 shall not exceed T1 by 60 minutes if prevailing wind speed exceeds 15 miles per hour. The lengths of travel (D1 and D2) by which velocities (V1 and V2) are established, approaches but shall not exceed one mile. Since an exact mile is impossible to resolve between precise points in time, the closest points that encompass an exact mile shall be used for T1, T2, and T3, T4 respectively. The WLSRA® Timing Protocol ensures increased accuracy as distance approaches but does not exceed one mile. As technology advances to provide DGNSS capability with faster acquisition rates, the closer to one mile D1 and D2 can be.
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| 2.7 |
The faster the acquisition rate for velocity is, the shorter the distance is traveled between data points. D1 and D2 may be determined by integration of individual straight-line velocities between data points. Accumulation of error through integration shall be avoided by calculating the exact distance between T1, T2, and T3, T4 localizations respectively.
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| 2.8 |
To eliminate potential velocity errors introduced by vehicle dynamics, averaging of velocities between data points shall not be the basis of calculating Va. Va shall be calculated and expressed to the 4th decimal place. (6.3362miles/hour)
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| 2.9 |
Time format for data is GMT, and shall not be corrected for local time zone. Time stamps shall be from original GPS /GLONASS, or equivalent satellite data feeds.
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| 2.10 |
Original data sets shall be retained by the WLSRA®. The data format may be in a common industry format such as RTCM or proprietary formats such as TPS, LB2, and RT17
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| 2.11 |
Records certified by the WRLSA® may be appealed based solely upon re-evaluation of the original data set and at the discretion of the WLSRA® board.
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3.0 Formulas Va = (V1+V2) /2 V1 = D1/(T2-T1) V2 = D2/(T4-T3) D1= distance between T1 and T2 D2 = distance between T3 and T4 |