# Magnetometer Sensor in the Litreture
###### tags: `bibliography`
Magnetometer sensor is used in different applications in the literature. The following is the list of the papers that use magnetometer sensors. The list will be updated.
## Co-location Detection
Co-location detection can be done using different sensors such as GPS. However, GPS is not useful to determine the coexistence within a couple meters. An alternative is the magnetometer sensor that has good precision and has less energy consumption than GPS. In the following papers, it has been shown that smartphone magnetometer readings exhibit high linear correlation when two phones coexist within a short distance.
The main application is for detecting co-located people in case of epidemic contagious diseases transmission by using geomagnetic field sensor on the smartphones. People who are within the transmissible distance from an infected person might be identified as a potential infected.
* [An Unsupervised Learning-Based Spatial Co-Location Detection System from Low-Power Consumption Sensor](https://www.mdpi.com/1424-8220/21/14/4773)
* [Co-location epidemic tracking on London public transports using low power mobile magnetometer](https://ieeexplore.ieee.org/abstract/document/8115963)
* [Detecting outdoor coexistence as a proxy of infectious contact through magnetometer traces](https://ietresearch.onlinelibrary.wiley.com/doi/10.1049/el.2017.2454)
* [Co-location Detection System Using Mobile Magnetometer Data](https://ieeexplore.ieee.org/abstract/document/9289619)
* [A Smartphone Magnetometer-Based Diagnostic Test for Automatic Contact Tracing in Infectious Disease Epidemics](https://ieeexplore.ieee.org/abstract/document/8626091 )
## Authentication
In the following papers (exept the last one), a ring shaped magnet (or other shapes such as a rod or a pen) is used for interaction between the user and mobile phone. The idea is that the user has to wear this ring and moves it around the device. As a result of this movement, the integrated compass on the mobile phone is affected. Then, authentication is done based on comparing the similarity between the new signature and the pre-recorded templates.
It can be used either for interaction of the user with the mobile phone (such as accepting and rejecting calls) or authentication.
* [Magnetic signatures in air for mobile devices](https://dl.acm.org/doi/abs/10.1145/2371664.2371705)
* [MagiThings: Gestural Interaction with Mobile Devices Based on Using Embedded Compass (Magnetic Field) Sensor](https://www.igi-global.com/chapter/magithings/133749)
* [MagRing: Semi-biometric Interaction Utilizing Magnetic Ring Based-on Static Authentication of Magnetometer Sensor in Smartphone](http://www.advancesinmech.com/index.php/am/article/view/161)
* [FingerAuth: 3D magnetic finger motion pattern based implicit authentication for mobile devices](https://www.sciencedirect.com/science/article/abs/pii/S0167739X17326006)
* [MagiTact: interaction with mobile devices based on compass (magnetic) sensor](https://dl.acm.org/doi/abs/10.1145/1719970.1720048)
* [Lightweight non-distance-bounding means to address RFID relay attacks](https://www.sciencedirect.com/science/article/abs/pii/S0167923617301215)
-A mutual authentication protocol against relay attacks in RFID systems
-Evaluate the use of ambient conditions in RFID authentication protocols
-Use magnetometer readings in a mutual authentication protocol
## Pairing
* [MagPairing: Pairing Smartphones in Close Proximity Using Magnetometers](https://ieeexplore.ieee.org/abstract/document/7347440):
-Pairing smartphones by correlating magnetometer readings
-User needs to tap for a few seconds
-Pairing time: 4.5 seconds
-S ensitivity: few centimeters
## Navigation
The idea is to use magnetometer data for navigating in the absence of GPS data. The information about changes in the value of the local magnetic field can be used for this purpose. It requires the production of precise survey maps of magnetic anomalies which is a barrier to adoption of these solutions.
* [Magnetic field mapping as a support for UAV indoor navigation system](https://ieeexplore.ieee.org/abstract/document/7999535 )
* [Indoor waypoint navigation via magnetic anomalies](https://ieeexplore.ieee.org/abstract/document/6091315 )
## Localization
In the following papers, magnetometer sensor is used to find user’s location. GPS, Wi-Fi, NFC, and Bluetooth also work, but the problem with these techniques is that they identify location with meter resolution which is not accurate for indoor localization.
The idea comes from the creatures in nature, including butterflies, newts, and mole rats, that use the Earth's inherent magnetic field for navigation. The approach involves a location fingerprinting methodology that takes advantage of the presence of magnetic field anomalies inside buildings. To do the localization, first, magnetic field measurements should be taken throughout the building. Then, user’s location is estimated through the best estimator for each zone of the building. Compared to other localization approaches (e.g., camera-based, LIDAR-based), there exist far fever privacy concerns when sensing the indoor environment's magnetic field.
Some of the solutions involve the usage of accelerometer and gyroscope sensors as well. It is mainly because true north (or magnetic north) is unknown and additional sensors are used to detect the direction of gravity.
* [mPILOT-Magnetic Field Strength Based Pedestrian Indoor Localization](https://www.mdpi.com/1424-8220/18/7/2283)
* [MagicFinger: 3D Magnetic Fingerprints for Indoor Location](https://www.mdpi.com/1424-8220/15/7/17168)
* [How feasible is the use of magnetic field alone for indoor positioning?](https://ieeexplore.ieee.org/abstract/document/6418880 )
* [Characterization of the indoor magnetic field for applications in Localization and Mapping](https://ieeexplore.ieee.org/abstract/document/6418864 )
* [Magnetic maps of indoor environments for precise localization of legged and non-legged locomotion](https://ieeexplore.ieee.org/abstract/document/6696459)
* [Indoor location sensing using geo-magnetism](https://dl.acm.org/doi/abs/10.1145/1999995.2000010)
* [My Magnetometer Is Telling You Where I've Been?: A Mobile Device Permissionless Location Attack](https://dl.acm.org/doi/abs/10.1145/3212480.3212502)
* [Nature-inspired position determination using inherent magnetic fields](https://www.worldscientific.com/doi/abs/10.1142/S2339547814500149 )
## Sensor Identification
The identification/fingerprinting of a sensor (and consequently of the mobile phone) is possible through the exploitation of differences/imperfections in the magnetometer sensor.
* [The identification of mobile phones through the fingerprints of their built-in magnetometer: An analysis of the portability of the fingerprints]( https://ieeexplore.ieee.org/abstract/document/8167855)
* [A Survey of Techniques for the Identification of Mobile Phones Using the Physical Fingerprints of the Built-In Components]( https://ieeexplore.ieee.org/abstract/document/7902125)
## Magnetic Signal Leakage Detection
These papers shows the data leakage from isolated, air-gapped computers to nearby smartphones (even in a Faraday cage because a compass still works inside a Faraday cage) by using their magnetometers. The method is based on exploitation of the magnetic field generated by the computer's CPU. In ODINI paper, a malware is presented which controls the low frequency magnetic fields emitted from the infected computer by regulating the load of the CPU cores.
* [MAGNETO: Covert channel between air-gapped systems and nearby smartphones via CPU-generated magnetic fields]( https://www.sciencedirect.com/science/article/abs/pii/S0167739X2030916X)
* [Covert channels using mobile device's magnetic field sensors](https://ieeexplore.ieee.org/abstract/document/7428065)
* [ODINI: Escaping Sensitive Data From Faraday-Caged, Air-Gapped Computers via Magnetic Fields](https://ieeexplore.ieee.org/abstract/document/8820015)
* [Youtube Demo](https://www.youtube.com/watch?v=h07iXD-aSCA) (more from their cyber security labs [videos](https://www.youtube.com/channel/UCjCSvlOcENVup0Xeiim1u0g/videos))