Data Analysis Fundamentals: GPS Coordinates and Timing Beacons
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GPS Coordinates and Timing Beacons
05.46
| 00:00 | - It should go without saying that one of the key aspects of any logging system is the recording of an accurate lap time. |
| 00:07 | The two common ways of doing this are by using a lap timing beacon which is a physical infrared transmitter placed on the track side that triggers a receiver in the car or by using GPS. |
| 00:21 | We will discuss these options as well as their pros and cons in detail in the next section of modules but for now, we need to deal with the setup of either system so that we have accurate lap times. |
| 00:33 | We'll start by dealing with timing beacons since for the most part are pretty simple. |
| 00:37 | The system consists of a transmitter and a receiver and we simply need to locate the transmitter on the side of the racetrack where it can be seen by the receiver in the car. |
| 00:48 | Often these transmitters will be placed on the top of a pit wall which usually gets them approximately at the right height to trigger the receiver. |
| 00:56 | The other popular technique is to fit a transmitter to a tripod which provides more adjustability. |
| 01:02 | The next consideration is where you choose to locate the transmitter since this will then become the start/finish line for the purposes of lap timing and the track map. |
| 01:12 | It might seem to be a bit of a redundant question since the obvious spot would be directly on the start/finish line however that might not be quite so simple. |
| 01:22 | At many large race meetings, you're likely to have multiple competitors with timing beacons and they can't all be at the same spot. |
| 01:29 | At some racetracks it's simply not possible to put the transmitter on the actual start/finish line due to obstructions on the pit wall. |
| 01:37 | While having your transmitter right on the start/finish line is ideal, it's not the end of the world if you're a little way off. |
| 01:45 | However the bigger issue is consistently using the same spot when you return to a given racetrack. |
| 01:51 | If you're using varying locations for your transmitter then it can make it harder to overlay your data in a meaningful way from different visits to the same track. |
| 02:00 | This sort of discrepancy can be accounted for inside your analysis package by offsetting the data but this is just one more task you need to complete. |
| 02:09 | Try to choose a position for your beacon that can be easily replicated each time you visit that track. |
| 02:16 | This might mean lining up the beacon with a specific crack in the concrete wall, a section of the safety fence or any other reference that's unlikely to change over time. |
| 02:25 | Since it's common for multiple transmitters to be used at a racetrack simultaneously, there obviously needs to be some method of pairing the transmitter to your beacon so that it doesn't trigger off every available beacon. |
| 02:38 | The technique and options will depend on the system you're using however as an example, the MoTeC BTX transmitter has three internal dials that can be used to set a unique identifier. |
| 02:51 | The receiver in the car will pick up the signal from every transmitter and then send them to the logger which is programmed to look for a specific unique identifier. |
| 03:01 | Often you may find that the higher level race series will require a control logging package and the entire series may then operate off a single transmitter that is run by the series managers. |
| 03:14 | This obviously makes things easier from the competitor's point of view and all you need to do is to program your logger to receive the correct identifier. |
| 03:22 | Since the transmitter is battery powered, the biggest potential failure point is a dead battery. |
| 03:29 | And even though the battery use of the transmitter shouldn't be high, this is a real concern. |
| 03:33 | GPS is easily the most popular timing system at the club and enthusiast level. |
| 03:38 | Purely due to the simplicity and low cost. |
| 03:42 | It's not without a few shortcomings though which we will detail later. |
| 03:47 | In order for the logger to be able to provide lap times, it's necessary to program the logger with the GPS coordinates of the start/finish line. |
| 03:55 | While many loggers will come preconfigured with the GPS coordinates for popular tracks around the world, this isn't always the case and even when they are, I found occasionally they're wrong. |
| 04:06 | That's not the end of the world though as we can teach the logger where the start/finish line is. |
| 04:11 | Typically this can be done in two ways. |
| 04:14 | The first is to drive the car around the track and push a button as you cross the start/finish line. |
| 04:20 | There's no doubt this can be effective but if you're on track in a busy practice session, it can be hard to do this accurately while keeping control of the car and avoiding other traffic. |
| 04:30 | The second option is to use a GPS receiver and find the coordinates for the start/finish line. |
| 04:36 | This doesn't need to be as daunting as it sounds as these days we all carry a cellphone that can use GPS for location. |
| 04:44 | All you'll need is a GPS location map and a search of your app store should find several for free. |
| 04:51 | Once you've got a suitable app, you're going to need to make sure you're expressing your GPS coordinate in the correct format. |
| 04:58 | GPS coordinates can be expressed as decimal degrees or degrees, minutes and seconds. |
| 05:06 | You're most likely going to need to enter the coordinates in decimal degrees into your logger. |
| 05:12 | Once you've got that set up, you can just go and stand in the centre of the start line and record the coordinates. |
| 05:17 | Obviously it goes without saying that doing this in the middle of a race is probably going to end poorly. |
| 05:24 | So apply some common sense. |
| 05:26 | I usually do this as soon as I arrive at the track in the morning before the track has been opened to race traffic. |
| 05:33 | One advantage of GPS lap timing is that once the coordinates are set these will be stored for a particular racetrack so you don't need to do it each time you come back to that track. |
