Multilateration Reliability.
Unlimited Listeners.
4D1's Precise Indoor Positioning System uses multilateration for predictable, reliable, accurate 3D positioning.
Multilateration works by triangulating signals from multiple reference points, or beacons, to accurately determine the precise location of a tracker, providing robust and reliable positioning information. Multilateration serves as the linchpin for the reliability of GPS, and 4D1 leverages it to ensure accurate, dependable positioning even in complex, changing environments.
4D1 trackers are listen-only, which means our Precise Indoor Positioning System supports unlimited users.
Multilateration positioning systems typically use one of two architectures:
Listen-only: Beacons transmit and trackers receive.
User Broadcast: Trackers transmit and beacons receive.
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High-user applications stand to gain from a listen-only approach, like that of GPS, as this architecture seamlessly supports an unlimited number of users. While user broadcast methods reduce tracker complexity, inherent bottlenecks with network congestion limits the number of users that can be supported.
Ultrasonic Accuracy.
Spread Spectrum Resiliency.
Using ultrasonic signals, 4D1's Precise Indoor Positioning System delivers reliable, sub-centimeter positioning in all three dimensions without algorithm constraints.
The speed of sound is one million times slower than the speed of light. Positioning systems using time difference techniques can measure distances exponentially more precisely with sound compared to radio methods, like Ultra Wideband.
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This weakness of radio-based Real-Time Location Systems (RTLS) results in location accuracy of several decimeters at best and only in two dimensions (X and Y) when height constraints are applied. When operated in 3D, the accuracy of radio-based RTLS is inflated to several meters.
Using spread spectrum signals, 4D1's Precise Indoor Positioning System can operate without disruption in noisy environments.
Even though environmental noise typically tapers off in the ultrasonic band, some industrial equipment may intentionally or inadvertently emit ultrasonic noise. This noise has the potential to jam ultrasonic-based systems, underscoring the importance of sophisticated signal processing to prevent disruption. By efficiently distributing signals across a wide range of the ultrasonic frequency band, spread spectrum techniques mitigate the impact of interference and provide more reliability than narrow band approaches.
With The Scalability of CDMA.
4D1 beacons use CDMA spread spectrum signals to support large scale, high performance deployments.
Time difference of arrival systems also use different protocols to differentiate between broadcast signals:
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Time Differential Multiple Access (TDMA): allocates specific time slots to each broadcasters.
Code Differential Multiple Access (CDMA): assigning unique codes to each broadcaster.
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TDMA approaches are typical of narrowband systems that broadcast over a central frequency, which is shared by transmitting at different times. This presents a significant weakness - low scalability due to limited, finite timeslots having to be divided among all broadcasters. Spread spectrum systems, on the other hand, can use CDMA which allows multiple broadcasters to transmit simultaneously and continuously. This facilitates efficient and simultaneous transmission without the need for fixed time slots resulting in unlimited scalability.
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