Day 6: The wake-up call. Follow Sagar’s adventures as he hangs around the Netherlands in the days leading up to the Grand Cooperative Driving Challenge .
The day started off with good news and bad news. The good news is that we will get access to the DAF test track to do platooning and run our tests. Finally, we have a decent track to do our tests. The bad news is that the track will only be available from 6am to 8am. Yes, you heard that right, 6am. So we need to assemble at TNO at 5am, which means that we need to leave the Hotel at 4:30am. Wow, talk about getting an early start!
Today we implemented one of the ‘bright ideas’ we had yesterday involving some processing on the RADAR signal. It worked quite well and Dennis went on to implement a slightly more sophisticated prediction model for estimating other vehicles’ data, even if we lose their signal for a short period of time. This needs to be tested however.. perhaps on the test track tomorrow.
Today we also calibrated and verified certain system constants that we had earlier roughly approximated. Among other things, I needed to figure out the radius of the earth at Netherlands. This is needed to calculate distance based on GPS coordinates. However, in order to do the distance calculation the Right Way(tm) I dived into the theory of Geodesics. Learned about the various approximations of the earth surface (spherical, ellipsoidal, geoid ..), types of ellipsoidic approximations, the mercaptor projection and so on. Ultimately, I used a method that guarantees a theoretical accuracy of <15nm (yes, nano-meters) for the terrestrial ellipsoid 🙂 Of course, this is soundly impractical, but it did give a pretty good reference value that we could compare other approaches with. In the end, since we are engineers, we just approximated the earth to a spehere (not a spheroid. In geodesics, there is a difference..) and verified that the resulting simplified estimate was within +/- 1% accuracy 🙂 In the end, Dennis was quite pissed that I spent nearly 3 hours on doing things the Right Way(tm), instead of just using an engineering hack. But I learned something new, and we got an unbeatably good reference value to validate the engineering hack we ultimately used.
An important issue we came up with today is the fact that if the TNO lead vehicle (which will be at the head of both platoons) drops communication even for a few milliseconds, the results could be quite disastrous. However, since wireless is inherently untrustworthy, we asked TNO to reduce the impact of a communications drop by fixing RADAR reflectors on either side of the lead vehicle. This way, even if we lose the vehicle on air, there is a chance that we might catch it with RADAR and thereby avoid accelerating into it. TNO agreed with this idea and are investigating ways to get it done by the competition dates.
Today we also had a “social evening” and TNO took us to the DAF museum in Eindhoven. This is a small but impressive place and there were many, many DAF automobile models. I could actually cover the DAF museum in a separate post, so I won’t say more here. We had dinner in the museum itself and returned to TNO by 21:30.
Now we call it an early night, since Dennis, Simon, Henrik and I will have to be up by 04:15 tomorrow morning. This is one of those times that we need to remind ourselves that this is fun and that is why we are choosing to do it. But we hope to have a productive two hours on the test track tomorrow morning. We MUST, because after tomorrow, we get just 2 more hours for actually testing stuff prior to the competition.