IoT localization technologies

A concise guide to modern IoT localization technologies, their mechanisms, trade-offs, and real-world applications.

Table of content

Introduction

Comparison of different technologies

Sentinum products and the integrated detection methods.

Intelligent use of different tracking technologies for energy optimization.

What does the term "GNSS" mean?

Localization with WIFI SSID Scan

GNSS Scan 

GPS functionality

eDRX: On the way to the interrogable tracker 

Ultrawideband 

Tracking in LoRaWAN® 

Tracking via the "Cell Locate" mobile network

Introduction 

Selecting the right localization technology is critical for battery-powered IoT devices, influencing their battery life, accuracy, and reliability. Key options include GNSS for precise outdoor tracking (high accuracy but energy-intensive), Wi-Fi and BLE for efficient indoor positioning (low energy but moderate accuracy), LoRaWAN® ideal for large-scale outdoor use with cloud-assisted, low-power localization, and Cellular localization offering global reach with moderate accuracy.

The best technology choice depends on balancing accuracy needs, environment suitability, coverage, energy efficiency, and maintenance considerations to ensure practical, long-lasting IoT solutions

Comparaison of different technologies 

Technology	Range under good conditions (m)*	Range under poor conditions (m)	Power Consum-ption	Sustainibility for Indoor Tracking	costs
BLE scanning (not implemented, on request)	1 – 3	5 - 10	Low	High	Medium
WIFI SSID Scanning	1 – 5	5 – 20	Low	High	Medium
GNSS (GPS, Glonass, BeiDou, Galileo)	3 - 5	5 - 10	High	Not suitable	High
Mobile radio localization via triangulation or radio cells	10 – 150	150 to several kilometers	Low	Low	Low
GNSS Scan	1 – 10	10 - 200	Low	Not suitable	Medium
UWB	<0,1 – 0,3	0,3 – 0,5	Low	Sehr Hoch	Medium
Tracking Via LoRaWAN***	200 – 500	500 - 1500	None	Practically not suitable	Low

Sentinum products and the integrated locating procedure 

In general, all LoRaWAN® devices can be located via the LoRaWAN®. This requires gateways with GPS synchronization.
As of Q2 2025, the Apollon-Q and Juno series in the Sentinum product portfolio are equipped with extended tracking functions.
Localization via BLE function can be activated on request.

Item number	Radio standard	WIFI SSID Scan	GNSS Scan	GNSS	Cell Locate
S-JUNO(-iX)-LOEU-TRACK	LoRaWAN®	✔	✔	X	X
S-JUNO(-iX)-LOEU-TH-TRACK	LoRaWAN®	✔	✔	X	X
S-JUNO(-iX)-NBM1-TRACK-2	Cellular	✔	X	✔	✔
S-JUNO(-iX)-NBM1-TRACK-3	Cellular	✔	X	✔	✔
S-JUNO(-iX)-NBM1-TH-TRACK-2	Cellular	✔	X	✔	✔
S-JUNO(-iX)-NBM1-TH-TRACK-3	Cellular	✔	X	✔	✔
S-JUNO(-iX)-MIOTY-TRACK	mioty®	✔	X	✔	X
S-JUNO(-iX)-MIOTY-TH-TRACK	mioty®	✔	X	✔	X
S-(i)APOQ-LOEU-T-ACC	LoRaWAN®	✔	✔	X	X
S-(i)APOQ-LOEU-TR-ACC	LoRaWAN®	✔	✔	X	X
S-(i)APOQ-NBM1-T-ACC	Cellular	✔	X	✔	✔
S-(i)APOQ-NBM1-TR-ACC	Cellular	✔	X	✔	✔

Smart use of different tracking technologies for energy optimization 

We combine various tracking technologies for precise and energy-efficient location
determination: WiFi SSID scan, GNSS, GNSS scan and Cell Locate. Each of these
technologies has specific strengths that we use flexibly and depending on the situation.

• The WiFi SSID scan detects available WiFi networks in the vicinity and determines a position based on known SSID locations. This method is extremely energyefficient and enables fast location updates - ideal in urban areas with dense Wi-Fi coverage.

• GNSS (Global Navigation Satellite System, e.g. GPS) offers very precise positioning,but is very energy-intensive in comparison. GNSS is therefore only activated when other methods do not provide sufficiently accurate data.

• The GNSS scan only collects satellite data and optimizes the position calculation without permanently maintaining an active GNSS session. This also saves a considerable amount of energy compared to permanent GNSS use.
• Cell Locate enables positioning based on mobile radio cells. This method is available globally and provides a rough but continuous location determination even if there is no WLAN or GNSS signal.

Intelligent control and prioritization - such as the preferred use of WiFi scans - can significantly reduce the device's energy consumption. Only when WiFi or cell positioning is not sufficient does the device automatically switch to GNSS or other more precise methods. All tracking strategies and fallback mechanisms are individually configurable so that the best balance between energy efficiency, accuracy and availability can be selected for different applications and regions.
Even if individual technologies vary depending on the environment, this flexible combination
enables virtually seamless and detailed route recording worldwide.
We also offer suitable solutions for indoor scenarios in which GNSS signals are often
unavailable or inaccurate. The WiFi SSID scan and the use of known indoor access points
make it possible to reliably the position even inside buildings. Optionally, indoor
positioning can be supplemented by additional technologies such as Bluetooth Low
Energy (BLE) beacons or inertial sensors.This enables precise location determination even in complex environments such as shopping
centers, airports or industrial halls - seamlessly integrated into the existing tracking concept.

What does the term " GNSS" means? 

GNSS stands for "Global Navigation Satellite System" and refers to a satellite-based system for global positioning and navigation. It comprises various national and international satellite networks such as the American GPS (Global Positioning System), the European Galileo, the Russian GLONASS and the Chinese BeiDou. A GNSS receiver on earth receives signals from several satellites simultaneously. Among other things, these
signals contain information about the exact time and position of the respective satellite. The receiver can calculate the distance to each individual satellite from the transit times
of the signals - i.e. the time it takes for the radio signal to travel from the satellite to the receiver. With the help of at least four such satellites, the receiver can determine its own position in three dimensions (longitude, latitude and altitude) as well as the exact time. 

GNSS thus enables worldwide, independent and continuously available positioning with an accuracy that can range from several meters to a few centimeters, depending on the type of receiver, environment and technology used. In modern applications, so-called multiGNSS receivers are often used, which simultaneously use several systems such as GPS, Galileo and GLONASS in order to increase accuracy, availability and reliability. Today, GNSS is used in a wide range of areas - from navigation in vehicles, aircraft and ships to surveying and agriculture, IoT devices, smartphones and autonomous systems.

Localization with WIFI SSID scan 

Which Sensors WIFI SSID scan?

In the Sentinum product portfolio, parts of the Juno and Apollon-Q series are equipped with a WIFI SSID scan function. The Cellular and mioty® products are equipped with a 2.4 GHz and 5 GHz WIFI SSID scan for the evaluation of up to 20 MAC addresses, the LoRaWAN® products with a 2.4 GHz WIFI SSID scan for up to six addresses: 

Item number	Radio Standard	2,4 GHz Scan	5 GHz Scan	Maximum number of MAC addresses
S-JUNO(-iX)-LOEU-TRACK	LoRaWAN®	✔	X	6
S-JUNO(-iX)-LOEU-TH-TRACK	LoRaWAN®	✔	X	6
S-JUNO(-iX)-NBM1-TRACK-2	Cellular	✔	✔	20
S-JUNO(-iX)-NBM1-TRACK-3	Cellular	✔	✔	20
S-JUNO(-iX)-NBM1-TH-TRACK-2	Cellular	✔	✔	20
S-JUNO(-iX)-NBM1-TH-TRACK-3	Cellular	✔	✔	20
S-JUNO(-iX)-MIOTY-TRACK	mioty®	✔	✔	20
S-JUNO(-iX)-MIOTY-TH-TRACK	mioty®	✔	✔	20
S-(i)APOQ-LOEU-T-ACC	LoRaWAN®	✔	X	6
S-(i)APOQ-LOEU-TR-ACC	LoRaWAN®	✔	X	6
S-(i)APOQ-NBM1-T-ACC	Cellular	✔	✔	20
S-(i)APOQ-NBM1-TR-ACC	Cellular	✔	✔	20

How does WIFI SSID scanning work 

Wi-Fi SSID scan-based localization uses the detection of Wi-Fi networks in the environment to the location of a device. It uses the signal strength (RSSI) of the Wi-Fi signals to estimate the distance to the various access points (APs). This technique is often used indoors where GPS signals may unavailable or inaccurate. 

Essentially, the localization process works as follows:

1. Activation of the SSID scan: The device starts with a passive Wi-Fi scan, during which it listens for all beacon frames emitted the access points (APs) in the vicinity. These beacon frames contain the SSID (the name of the network), the BSSID (the MAC address of the AP) and the signal strength of the received signal (RSSI). 
2. . Measuring the signal strength: The RSSI (Received Signal Strength Indicator) is measured for each signal received. This signal strength indicates how strongly the signal from the access point is received by the device. A higher RSSI usually means that the device closer to the corresponding access point.
3.  Comparison with known positions: To determine the position of the device, the measured RSSI values are used in combination with the known positions of the access points. This is done using methods such as triangulation or trilateration, in which the distances to at least three or more access points are calculated are calculated. Based on these calculations, the device can determine its position on a map or in a room. 
4. Position determination: The data collected from the access points is analyzed to determine the most likely position of the device. This is done taking into account the signal strength and the known positions of the access points. Modern algorithms can also further refine the localization by taking into account additional factors such as environmental conditions or the movements of the device
5. osition display: Once the device has determined the position, this is displayed to the user on a map or in a corresponding user interface. If required, the accuracy of the position can also be updated in real time based on further SSID scans and changing signal strengths.

Advantages and applications of WI-FI based localization 

• High accuracy indoors: As GPS signals are often weak or non-existent indoors, Wi-Fi scanning offers an excellent alternative to indoor positioning.
• Simple implementation: As many buildings are already equipped with Wi-Fi networks, localization via Wi-Fi can be implemented with minimal additional effort.
• Cost-effective: Wi-Fi-based localization requires no additional hardware investment if Wi-Fi access points are already available.

This localization approach is particularly advantageous in indoor navigation systems, asset tracking or fleet management, as it enables precise positioning, even without the use of expensive GPS systems. 

Positioning technology based on Wi-Fi SSID scanning is used in a variety of applications where a rough to medium level of positioning accuracy is required and existing WiFi infrastructure can be used. A device records the names (SSIDs) and signal strengths (RSSI) of the surrounding Wi-Fi networks without connecting to them. This information can used to estimate where the device is located - either by comparing it with an existing Wi-Fi database (e.g. from Google or Apple), by prior fingerprinting or with the help of a self-built Wi-Fi mapping model.

This technology is used, for example, for indoor localization in buildings, such as shopping malls, airports or large office complexes, where GPS signals only available to a limited extent or not at all. Wi-Fi scanning is also used in logistics and asset tracking to track the location of devices or goods within warehouses or on company premises - often in combination with other technologies such as BLE or LoRaWAN. In smartphones andwearables, the method is used to enable location-based services such as map navigation, geofencing or location sharing, even if there is no mobile network connection. 

Another typical use case is supportive positioning for battery-powered IoT devices where GNSS would be too energy-intensive. Here, the Wi-Fi scan can help to determine a sufficiently precise position without draining the battery too much.

load. Due to the wide availability of WLAN networks and the possibility of estimating a position even without an active network connection, Wi-Fi SSID scanning represents a flexible, cost-effective and energy-saving alternative or supplement to classic GNSS or cellular positioning systems. 

Dependence on accuracy 

Wi-Fi localization accuracy varies from 1–20 meters depending on environment and system setup.

Key factors:

• RSSI behavior: Signal strength doesn’t scale linearly with distance. Obstacles like walls and electronics can distort it.

• AP distribution: Accuracy improves with three or more well-placed access points.

• Environmental impact: Materials like metal or dense structures can reflect or block signals, reducing precision.

• Algorithm quality: Machine learning and calibration-based systems can enhance accuracy by adjusting for environmental noise.

• Network visibility: Hidden SSIDs and interference from other networks limit available data and reduce positioning reliability.

Despite these variables, Wi-Fi scanning remains a versatile and often accurate method—especially when GPS isn’t viable.

Why WI-FI SSID scanning makes sense for JUNO 

The Juno with Wi-Fi SSID scanning is ideal for indoor or urban positioning where GNSS underperforms. Combining Wi-Fi, GNSS, and cellular improves accuracy.

Juno benefits:

• Supports active/passive scans on 2.4 and 5 GHz bands.

• Energy-efficient for battery-powered devices.

• WPA3 security support.

• Excellent for indoor detection.

• Leverages existing Wi-Fi infrastructure.

• Extends device lifespan compared to GNSS use.

Juno can evaluate signals from up to 20 access points, delivering location accuracy between 3–20 meters, depending on context.

GNSS Scan 

Function of GNSS Scan 

GNSS (Global Navigation Satellite System, e.g., GPS) offers very precise positioning but is energy-intensive. GNSS is activated only when other methods lack sufficient accuracy.

Wi-Fi SSID scan accuracy typically ranges from 1 to 20 meters and depends heavily on signal strength (RSSI), environmental conditions, and the number of accessible access points. Open spaces yield higher accuracy (1-5 meters), while complex indoor environments lower it (5-20 meters). More well-distributed access points improve accuracy through triangulation. Environmental obstacles and interference from electronic devices can further affect accuracy. Additionally, advanced algorithms and visibility of Wi-Fi networks significantly influence the precision of Wi-Fi localization. Overall, Wi-Fi scanning offers flexible, energy-efficient positioning when GNSS is unavailable or too demanding.

How GNSS Scan Works: GNSS scan uses satellites from systems like GPS, Galileo, GLONASS, or BeiDou to determine positions. A GNSS receiver scans visible satellites, calculates device position from received signals, and sends data to a cloud platform. This method allows precise localization with low energy use, activating the receiver only when required.

Accuracy typically ranges between 2.5 to 10 meters using standard GPS, and improves to 1-3 meters when combining multiple GNSS systems. In difficult environments, such as urban canyons or heavy obstructions, accuracy can decrease to between 10 and 50 meters.

• Signal Reception: The GNSS receiver (e.. in the smartphone) receives radio signals from at least four GNSS satellites (e.g. GPS, Galileo, GLONASS).
• Time of flight  Measurement: Each signal contains a time stamp. The receiver measures how long the signal took to travel from the satellite to earth (transit time).
•  Distance estimation : The distance to each satellite is calculated from the signal transit time (distance= speed of light× transit time).
• Position Calculation (Trilateration): Using the distances to at least four satellites, the receiver can calculate its own location (longitude, latitude, altitude) and the exact time by calculating the intersection points of the spheres around the satellites. 
• Corrections: Errors due to the atmosphere, satellite orbits or clocks are partially corrected by algorithms or additional systems (such as DGPS or SBAS). 

GNSS Scan and LoRa® Cloud

The LoRaWAN® devices such as the Juno Tracker or the Apollon-Q are based on the LoRa® Edge LR1110 chipset and send the GNSS scan information on port 199. The data is sent to databases such as the LoRa® Cloud, where the latitude and longitude coordinates are calculated. The coordinates are then returned to the network server via standardized interfaces.

Sentinum offers such a service. You can simply send the data to our servers and we will do the rest for you. Just give us a call. 

If you want your own integration, the following links will help you:
Connecting TTI with the LoRa Cloud: LoRa Cloud| The Things Stack for LoRaWAN®
Connecting Chirpstack to the LoRa Cloud: LoRa Cloud - ChirpStack open-source LoRaWAN®
Network Server documentation 

LoRa Cloud Homepage: Semtech LoRa Cloud

Example for the TTI integration: 

To connect The Things Stack (TTI) - the LoRaWAN® platform from The Things Industries - with the Semtech LoRa Cloud, you need to set up an integration so that data, z. e.g. GNSS scans, are correctly transmitted to the LoRa® Cloud and processed. The LoRa® Cloud performs tasks such as geolocalization, GNSS conversion, Wi-Fi positioning or modem services.

1. Activate Semtech LoRa Cloud 

• Go to https://lora-developers.semtech.com.
• Create an account or log in.
• Under LoRa Cloud→ Modem Services you will find your token (API key), which you must enter later in TTI.

2. Set up integration in The Things Stack

Log in to The Things Stack Console (e.g. https://eu1.cloud.thethings.industries/).
• Open the device you want to connect.
• Go to Integrations→ Webhooks.
• Click on Add Webhook and Semtech LoRa Cloud as the template. 

3. Configure webhook 

• Fill out the form:
  o Base URL: Is automatically suggested by TTI.
  o Token: Enter your API key from the LoRa Cloud here.
  o Activate the desired services, e.g:
  ▪ Modem Services (for GNSS and Wi-Fi scans).
  ▪ Geolocation (for TDOA/RSSI).
  o You can also send GNSS or Wi-Fi data, depending on the device type.

4. Adapt payload formats (if necessary) 

• Make sure that your end device uses the expected payload structure for Semtech
  LoRa Cloud Services (e.g. the format provided by Semtech's LoRa Basics
  Modem).

5. Check data

• As soon as your device sends position data (e.g. GNSS raw data), this is forwarded to the LoRa Cloud via TTI.
• The response from the LoRa Cloud is then sent back to the end device or your application via TTI. 

Test & Monitoring:

• Use the Live Data view in TTI to see whether data is being transmitted.
• In the Semtech Cloud, you can see whether requests are arriving and being processed.
•  Check the response packets with the geodata (latitude, longitude) and position accuracy

GPS Mode of operation 

GPS (Global Positioning System) is a satellite-based navigation system that makes it
possible to determine the exact position on earth. It consists of at least 24 satellites
orbiting the earth at an altitude of around 20,000 kilometers. These satellites continuously
send out signals containing information about their current position and the exact time at
which the signal was sent. Each satellite is equipped with an atomic clock that is extremely
precise. 

A GPS receiver, which is installed in devices such as smartphones, navigation systems or
other GPS-enabled devices, receives these signals. In order to determine its own position,
the receiver requires signals from at least four satellites. As soon as the signals are
received, the receiver measures the time it took for the signal to travel from the satellite to
the receiver. As the light propagates at a constant speed, the receiver can calculate the
distance to each satellite.

With the distances to at least three satellites, the receiver can the position on the earth's
surface using triangulation. A fourth satellite helps to calculate the altitude (the Z
coordinate) and correct any errors. The accuracy of the GPS position on the number of
satellites received and the quality of the signal. The accuracy is best in open areas without
obstacles such as tall buildings or trees. In urban mountain canyons or in bad weather,
signal interference can affect the accuracy. 

To further improve accuracy, differential GPS (DGPS) is used in many cases. Stations are
installed at fixed, known points on the earth which send correction data to the mobile GPS
receivers in order to increase the accuracy to a few centimetres. 

In addition to the American GPS system, there are also other global navigation satellite
systems (GNSS) such as GLONASS (Russia), Galileo (Europe) and BeiDou (China), which are
often used together with GPS to improve the accuracy and availability of positioning.

EDRX: On the way to the Interrogable tracker 

The dream of a tracker that is constantly listening and can be actively interrogated is
becoming a reality. The eDRX function helps to make this a reality.
eDRX (Extended Discontinuous Reception) allows a mobile device to switch to an energy-saving "sleep mode" after a data transmission, in which it does not constantly communicate with the mobile network. Normally, mobile devices have to check at short intervals whether the network has new messages for them (e.g. incoming commands or updates). These frequent checks cost energy, even if there no new data.
With eDRX, these check intervals are significantly extended: a sensor can be set so that it only listens for new network messages every minute or even hour. During idle periods, the device's receiver largely switches off, which drastically reduces energy consumption. As soon as the set eDRX phase ends, the sensor "wakes up", listens briefly for new messages and can then go back to sleep if nothing important has been received. The location of the device can be queried via a message from the network to the sensor.

The device remains registered with the network - it is not completely offline - but only reduces its active readiness to receive data. This is ideal for applications where the device mainly sends data itself (e.g. location, sensor readings) and only rarely needs to be reachable.

eDRX cycles can last from seconds to hours (depending on the network operator and the application). The higher the eDRX frequency, the higher the quiescent current consumption of the device. It is therefore crucial to carefully define the required polling frequencies and always set these in relation to the intended service life of the device.

ULTRAWIDEBAND

ltra-wideband (UWB) is a modern radio technology for high-precision positioning, which is used particularly indoors. Positioning is achieved by transmitting extremely short and broadband radio signals in the frequency range from around 3.1 to 10.6 GHz. These signals have a very high time resolution, which means that the transit time of the signal - i.e. the time it takes to travel from a transmitter to a receiver - can be measured extremely accurately. Based on this time measurement, the distance between two devices can be calculated with an accuracy of typically 10 to 30 centimeters, in some cases even less than 10 centimeters.

UWB positioning works using two main methods: two-way ranging (TWR) and time difference of arrival (TDoA). In two-way ranging, a mobile device (also known as a tag) sends a radio signal to a permanently installed receiver (anchor). This responds and the tag measures the time required for the outward and return journey. The distance can be calculated from this time, taking into account the constant propagation speed of the radio waves. The TDoA method works slightly differently: here the tag only transmits a signal that is received by several anchors simultaneously. The minimum time difference with which the signal arrives at the different receivers is used for the triangulated calculation of the position. This method enables particularly energy-efficient applications, as the tag does not have to actively respond and the computing work is carried out on the server side.

A typical UWB positioning system consists of several permanently installed anchors with known positions and mobile tags that are attached to objects, people or vehicles. The position is calculated by a central positioning software that continuously processes the signals. UWB is characterized not only by its high accuracy, but also by its low latency, which makes it ideal for real-time applications - for example in industrial production, logistics centers or for access control in buildings. Even in complex environments with a lot of metal or other radio sources, UWB remains very reliable due to its high robustness against interference. The typical range indoors is between 30 and 100 meters, depending on the antenna configuration and the structural conditions. This makes UWB an extremely powerful solution for precise, secure and energy-efficient indoor tracking.

Tracking in LoRaWAN®

Tracking in the LoRaWAN® network works by end devices (so-called nodes) transmitting radio signals that are received by several LoRaWAN® gateways. The exact position of the device is not determined directly by the device itself, but by evaluating the signals received in the network or in a special positioning platform (e.g. the Semtech LoRa® Cloud). There are various methods for determining position, which can be combined depending on the application and infrastructure.

A frequently used approach is the so-called TDOA method (Time Difference of Arrival).Here, the network measures the time difference with which a radio signal from a LoRaWAN® device arrives at various gateways. As radio signals propagate at the speed of light, these minimal time differences can be used to derive distance differences to the gateways. If at least three gateways receive the same signal, the position of the device can be calculated by triangulation. This calculation is performed centrally in the LoRaWAN® Network Server or in a connected cloud solution. The accuracy of TDOA is usually in the range of around 200 to 1000 meters, depending on gateway density, synchronization and environmental conditions. 

The TDOA (Time Difference of Arrival) method in the LoRaWAN® network works on a principle similar to triangulation, or more precisely, it is a variant of multilateration. The position of a device is not calculated directly from the signal strengths (as with the RSSI method), but from the time differences of a radio signal at several gateways.

When a LoRaWAN® end device (node) sends a message, this signal is received simultaneously (or almost simultaneously) by several gateways within range. Each of these gateways notes with extremely high time resolution exactly when signal arrived. As the radio signal propagates at the speed of light, differences in the nanosecond range already make a measurable difference in the calculated distance.

By calculating the time differences with which the signal arrives at the various gateways, the system can calculate circles (or hyperbolas) with possible positions of the device. The more gateways receive the signal, the more accurately the intersection of these hyperbolas can be  determined - i.e. the actual position of the device. This method requires at least three synchronized gateways to calculate a two-dimensional position (latitude/longitude). 

Are special gateways required?

A special type of gateway is required for tracking in the LoRaWAN® via TDOA:
These must be GPS-synchronized or have another precise time synchronization (e.g. PTP - Precision Time Protocol) so that the time stamps for receiving the signal are exact and comparable.
Standard LoRaWAN® gateways without time synchronization cannot provide reliable TDOA data, as even the smallest deviations in time recording would lead to large errors in position determination.

Accuracy

The accuracy of TDOA depends heavily on the density and distribution of the gateways, the quality of the time synchronization and the environment (e.g. reflections). Typically, it is in the range of 200 to 1000 meters, in ideal conditions even better. In urban environments, it can be affected by multipath effects (reflections). 

TDOA for indoor tracking:

Indoor tracking with the TDOA method in the LoRaWAN® network is theoretically possible, but in practice it is very limited and usually not recommended when it comes to precise localization buildings. Here are the reasons in detail:

Why TDOA is problematic for indoor applications:

1. Radio wave distortion due to obstacles Walls, ceilings, furniture and other objects cause strong attenuation, scattering and reflections of radio signals. This changes the effective propagation time of the signal, which leads to massive accuracy errors with a method based on time
differences such as TDOA.
2. Multipath propagation (Multipath) Radio signals not only reach the gateways directly, but often also via reflections. These signals arrive with a minimal delay and distort the time measurement, making the position calculation inaccurate.
3. Difficult gateway placement For meaningful TDOA tracking, there must be at least three gateways with a clear line of sight to the device - this is difficult to achieve in buildings. Even large buildings are often only covered by one gateway, which does not allow TDOA
positioning.
4. Synchronization suffers from poor GPS reception GPS synchronization of gateways is often not possible or unreliable indoors, which ruins the basis for TDOA. Without exact time synchronization, the entire method does not work.

When TDOA works indoors with restrictions:

• In very large halls, airport terminals or open logistics areas with good gateway coverage.

• If additional technologies are used for error correction (e.. algorithms that recognize multipath effects).

• In combination with other localization technologies such as Bluetooth, UWB or WiFi to compensate for failures or inaccuracies.

Tracking the mobile radio network "Cell locate "

Mobile phone positioning works by a mobile device communicating with the mobile phone network via its radio signal, and the network then calculates the approximate location based on various parameters. Here is an overview of the most important methods:

The accuracy of positioning via mobile radio depends heavily on the method used, the network coverage and the environment. The power consumption is very low compared to other technologies.