One of the top challenges within the Internet of Things is to know where each thing is. Devices that were stationary and plugged in have become roamable, portable and fully mobile. Locating where these devices are has become a challenge. Below are the top technologies that can help locate your IoT device.
- Global Navigation Satellite System (GNSS). GNSS is an umbrella term that encompasses the Global Positioning System (GPS), GLONASS and BeiDou. Initially developed for military use, GNSS uses signals transmitted from a constellation of satellites to accurately calculate location and real time anywhere on Earth’s surface. Widely available in every mobile phone and most automobiles, GNSS is a top contender application within the IoT. The challenge will be receiver sensitivity, especially when considering overall power consumption of IoT devices. Due to dissipation through the atmosphere, GNSS receivers must be extremely sensitive in order to operate. In the critical path is the antenna. Specifically designed to receive weak circularly polarized GNSS signals, antennas should be finely tuned to match the exact frequency band of satellite transmitters. If properly matched to the antenna, the GNSS receiver can discern signals as low as -150dBm.
- Radio Frequency Identification (RFID). There is no doubt that RFID is a top location and tracking technology. With tens of billions of units deployed every year, RFID is used in applications from retail to servers. The primary benefit of RFID is its ability to harness the RF backscatter energy from the reader and redirect in order to transmit its identification back to the reader. Absorbing all necessary power from the receiver RF transmission eliminates the need for a battery, making an RFID tag entirely passive with unlimited lifespan. However, it comes as no surprise that the IoT has additional demands. Most RFID applications are involved in tracking items whose position is already known. In other words, the application is not attempting to locate. Rather it only attempts to identify. Because the IoT involves small, roamable and out-of-sight devices, RFID must develop a longer range. Tracking these items requires RFID with meters of range and robustness that allows the tag to operate on various materials including on metal. RFID tags for the IoT are truly a new breed that greatly outperform their low cost retail predecessors.
- Ultra Wide Band (UWB). This underdog location based technology should not be underestimated. Known as Real Time Locating Systems (RTLS), the technology enables the highest resolution of location, often down to centimeters. If you need accuracy, this is the system to use. For the IoT, where a device may be anywhere, the importance of known precise location cannot be understated. Industrial robotics, warehousing, agriculture and factory automation can be steered accurately using RTLS, making this a top technology to use in the IoT.
- Radar. Radar has been in use since the 1940s and helps the Allies win World War II. Now it is employed in automobiles, drones and robots. Radar is an excellent option for locating something within a known range. Operating in the 10’s of GHz, these systems were out of reach for low cost and low power devices. Today’s advanced radar technologies are available at a more cost effective point, making radar a true option for the IoT.
- Infrared (IR). IR systems may allow the best accuracy while consuming very low power—a recipe that is perfect for the IoT. While IR systems can also be simple to design and very low cost, there is a catch—line of sight. If you can count on the line of sight, this is the system to use. However, with independently roamable devices, this line of sight may be a rare luxury.
- Ultrasound. Ultrasound is an age-old technology that can effectively be used to locate a device. It may be passive where the sound bounces off the device. Or the device may generate its own beacon. Simple, low cost and potentially low power, ultrasound can be an excellent option. What is the drawback? We live in a audio world. Interference and blocked paths can easily put this technology out of business.
The IoT is pushing the limits of technology every day with unique requirements. Being able to locate a device around the globe, in a parking lot or within a narrow range of focus has become a necessary endeavor. Each of these technologies have their specific strengths. In reality, many IoT devices will employ multiple of these technologies with RF varieties becoming more dominant.
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