Position Tracking vs. Position Sensors? Distinction Matters in Terminology and TechJanuary 18, 2020 by Tyler Charboneau
Position trackers and position sensors are fundamentally different. Yet sometimes outside of engineering spaces, we hear the terms used interchangeably. Here's why the distinction matters.
For engineers, issues of terminology are anything but trivial.
One striking example where terminology is commonly used incorrectly is with position trackers and position sensors. While these terms refer to fundamentally different technologies, consumers often discuss the two interchangeably.
For engineers, though, the distinctions between the hardware in position trackers and position sensors is the difference between apples and oranges. While they can sometimes be used in tandem, it's essential from a design perspective to discuss them as entirely separate hardware.
In this article, we'll discuss those differences—not only the definitions of position tracking and position sensors but also in core technologies and applications.
Defining Position Tracking
Position tracking technology does exactly as it suggests: it traces an object’s location at a specific period of time. You’re likely familiar with common positioning systems like GPS, Europe’s GNSS/Galileo, and GLONASS.
GPS III. Image (modified) used courtesy of GPS.gov
Position tracking systems do rely on hardware, but that hardware's exposure to its environment is limited. That said, a device’s surroundings play a large role in tracing position accurately. The effectiveness of GPS in major cities can diminish due to building density or device movement indoors. These systems and other trackers rely on satellites, cell towers, or localized geofencing to function properly.
The U.S. airforce recently made strides in GPS technology when setting satellite vehicle number-74 “healthy and active,” meaning that the satellite can now be used by military and civilian GPS worldwide.
According to Lockheed-Martin, the new satellite, part of the GPS III family, was designed by engineers to have “three times better accuracy and up to eight times improved anti-jamming capabilities than their predecessors, and a design life extending 25 percent longer than the newest GPS satellites on-orbit.”
Military personnel set satellite vehicle number-74, the first iteration of GPS Block III vehicles, as "healthy and active" from Schriever Air Force Base in Colorado. Image used courtesy of Sgt. Matthew Coleman-Foster, U.S. Air Force
Position tracking often involves triangulation, a process that pinpoints a location using three points of reference. Radio frequencies between these geographical landmarks (towers or satellites) are averaged to a specific point—the location of the position tracking device. In this way, tracking helps establish an object’s position within a larger system.
That’s not to say localized indoor tracking isn’t possible. Many warehouses and manufacturing facilities use these same networks to track equipment throughout the day. Position tracking systems are also adept for mapping rooms, facilities, and transit routes for different electronics.
Some companies, like Accuware, use a hybridized system for tracking and sensing. This mapping-and-positioning method employs a camera as a sensor. The camera also enables continuous tracking in a 3D space.
System architecture of Sentinel, an Accuware tracking and sensing security system. Image used courtesy of (PDF) Accuware
Other position tracking systems require a GPS chip or cellular radio. GPS relies on signals and thus piggybacks on components that may send or receive transmissions.
Defining Position Sensors
Position sensors gather data about an object's immediate environment. They can work in unison with other sensors or independently.
ASM’s (not to be confused with ams) magnetostrictive position sensor comes in an “ultra-flat” package and can measure up to 5,750 mm away from itself. Image used courtesy of ASM
Sensors provide contextual readouts for users or can support added device functions based on the information they gather. For instance, position sensors can tell advanced electronics or machinery how various components are moving in relation to one another. This helps regulate proper function and may even diagnose electromechanical problems.
One example of this is ams’ inductive motor control position sensor, the AS5715R. ams claims that this sensor is built specifically for motors (up to 480 000rpm) with low and high pole-pair counts without losing resolution. Because the device is said to reduce torque ripple and increase the efficiency of motor control, ams also suggests the sensor for safety-critical and automotive applications.
Block diagram of AS5715R. Image used courtesy of ams
Another example is your mobile phone’s proximity sensor. During a call, your device’s screen will shut off when it reaches a certain distance from your ear. This prevents you from accidentally hanging up or activating another function that may disrupt your conversation.
The popular Roomba vacuum uses proximity sensors to navigate your home’s nooks and crannies. Many commercial maintenance robots use localization sensors to assess their environments and inspect accordingly.
Common Tracking Systems and Sensors
The fundamental technologies behind trackers and sensors differ. However, there is some overlap since electrical components can fill a dual role. Here are some examples:
Common tracking technologies and components
- RF transmitters
- Cellular radios
- 3D mapping using computer vision
- Onboard camera systems
- Ultra-wideband networks and 5G
Common position sensors and components
- Proximity sensors
- IR diodes
- Onboard camera systems
- Light-based sensing systems, like LiDAR
- Displacement sensors
- Extension sensors
- Ultra-wideband networks and 5G
Notice the overlap of ultra-wideband (UWB) between position tracking technology and position sensors. UWB is gaining popularity in open and unobstructed spaces indoors. This approach is adept at gathering position data and assessing that position within a pre-mapped space.
NXP offers its own UWB technology. Image used courtesy of NXP
This reading can be continuous as long as the device isn’t hindered by other objects. UWB relies on light transmission between two points and is thus a time-of-flight system. Positioning is determined by light beam transit time between two sensors or nodes.
Displacement sensors and extension sensors are used with machinery. They measure positioning in objects like forklifts, lifters, driverless systems, transport cranes, telescoping parts, and even extendable tables. You can imagine, then, that this technology is integral to many industrial applications.
Setting the Record Straight
It’s entirely possible that many confuse tracking and sensing because both technologies are essential in designing contextually-aware products.
Tracking is a great way to monitor equipment, yet it draws much of its functionality from external components like those in towers, satellites, and networking sensors. Tracking is also hardware dependent. It requires cooperation between more moving parts, which makes tracking more systematic in nature. Sensors allow devices to be “smarter” while supplementing other functions.
Using the correct terminology, especially between these two terms, is absolutely essential. It’s still worth noting that these technologies are often complementary to a degree. Many hardware components have overlapping importance, highlighting just how intricate our modern devices truly are.
What other technical terms do you see used imprecisely or even incorrectly? Does misunderstandings in terminology ever disrupt your work? Share your experiences in the comments below.