Innovative Timing Systems

Let's talk about the accuracy of RFID race timing systems. I'll share our story.

Periodically I see comments in Facebook groups about how RFID can't be accurate to anything better than perhaps 4 to 5 feet. The writers of these messages will proclaim engineering expertise in the field and state categorically that RFID chips are not fast enough, engineered for accurate reads, prone to communications failures due to something called collisions, etc. However, while their race timing system may not be that accurate, Jaguar is truly off the charts when it comes to accuracy and read success rate.

When I invented the Jaguar RFID system 18 years ago, I already had 30+ years of deep experience in RF engineering, antenna design, communications design, propagation expertise, and a solid understanding of hardware and software. It seemed to me that accuracy could be accomplished if a system was designed to maximize a number of crucial design elements. This would require a fast reader with an incredible turnover rate, fast antenna port switching, high sensitivity, and enough horse power to process complex waveforms that are often distorted. Add to that the need to use antennas that were specifically designed to provide high gain, outstanding front-to-back ratios, low VSWR, and the ability to reduce noise while still capturing the signal coming from a 75 cent chip on a runner crossing a finish line! To say it would be easy would be foolish. It was not.

I spent two years working 60 hours a week on the reader engineering, meaning firmware optimizations, sensitivity adjustments, speed of code ex*****on, and so much more. Even more challenging...I knew I had to design an antenna that would optimize the receive portion of the signal coming back from the chip, while not picking up more signals from Wi-Fi routers, cell phones, ham radios, etc. I also needed it to be highly directional so that we could use various techniques to pinpoint the chip location. There's an entire field of mathematics that covers these concepts, but suffice to say that trilateration is crucial if you want to achieve accuracy. By the way, this is nearly impossible for any system that uses mats or ramps on the ground. This is why Jaguar started out with antennas overhead and to the side. Today we produce a ground antenna, but it took us 12 years to figure out a design that would be very accurate. Let's look back now at more of the details behind the design of the Jaguar Race Timing System.

When I first began working on Jaguar, we selected Alien Technology readers and worked closely with them to perfect their technology for racing. It worked quite well and we started seeing remarkable performance. In our second year of operation, our new 7000 antenna became available and it had some incredible engineering baked into it and its performance was amazing. For those of you who love this technical stuff, the 7000 antenna could pickup up signals from 900 to 930 MHz with an SWR of 1.05 to 1.10. It also had a tightly defined axial ratio of 42 degrees. If you know...you know...that's so very difficult to achieve, but doing so allowed us to perfect our read zones.

Every year, we enhance our technology and today we are now building our own readers and of course building our own antennas. The motherboard for our G4 readers has some incredible design elements. It has a lot of redundancy, has an internal SSD drive for storing reads, supports Wi-Fi, USB and Ethernet, incorporates one of the most advanced battery designs in the world, has 5 microprocessors, and it uses about 1/3rd of the power of our previous products. While it can read at speeds up to 900 chips per second, we don't run it that fast unless we are timing a really fast event such as an airplane, motorcycle or auto race. For most running, triathlon, and cycling events...600 reads/second is more than adequate.

SO...now that you have earned your Masters in Electrical Engineering, let's get back to accuracy. In our own internal tests in our labs, we perform some crazy speed tests. For example, we have a rocket sled that can move at speeds up to 60mph for a distance of 30 feet. In one test, we placed 10 chips on the sled, spaced one inch apart from front to back. This simulates 10 runners crossing a finish line within one inch of each other. The sled flew past our antennas and we got every read. More important...we got the reads in the correct order. While the reads were separated by thousandths of a second, they were still in the right order! We also have a large RF chamber in our lab where we can simulate high density races and check to see if finish order is correct. We will place 3, 10 or even 20 chips within 3 to 24 inches of the finish line on the floor and then read the chips to determine the finish order. This test factors in the propagation delay, meaning the speed of the electrons going through the air. It makes sense if you think about it. Chips close to the finish line should take slightly less time to respond, when compared to chips 24 inches away. We do this by using very high-speed digital scopes that can capture the data. Then, we also do tests behind our building on a large paved area. In these tests, we use volunteers who run through our finish line. At the same time, we capture photos, using our PhotoVision product, down to 1,000th of a second. This allows us to time stamp the runners as they cross the finish line and compare that to the finish order Jaguar determined. Generally speaking, we are accurate to about 1 to 3 inches. So, what about the real world of race timing?

One of our most successful timers is Precision Race out in North Carolina. They've been with us for 14 years and they are truly experts in all things races. Bruce and Pat run the company and Bruce teaches engineering and product classes at our annual conference. He truly is one of the top experts in this industry. He times a lot of races including high-speed mountain bike events. He often shares photos showing 3 or 4 riders crossing a finish line within an inch of each other...meaning they are side by side and their tires are only 1 inch forward or behind the other rider. I would say that 95% of the time, Jaguar is spot on and gets the finish order correct. That's amazing considering the bikes are traveling at speeds up to 35mph. He has timed well over 1,000 races since joining our family and if you meet him, just ask about accuracy. He will tell you that Jaguar is incredibly accurate.

In closing, don't let someone tell you that RFID race timing can't be that accurate. At Innovative Timing Systems, we have spent millions of dollars on our engineering. We have perfected accuracy, which is why we received a prestigious award a couple of years ago for our inventions. Our best awards are when races thank us for delivering amazing results. Don't get me wrong...we don't always get 100% read success with perfect accuracy...but we're closing in on it. Now if we could just get the runners to wear their bibs properly!

I hope this information has been interesting to you.

Thanks!

Kurt Hansen
Founder and CEO of Innovative Timing Systems

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