It is important to understand how smartphones work, what they do, and how this information about you is captured.
Introduction
All of us carry these small computers in their pockets. Can you imagine the power that you hold within your Smartphone was more computing power than the computers which brought astronauts to the moon? One of the main questions is that what kind of data is your cell phone picking up? That's what we are talking about today.
According to Android documentation: "The Android platform supports three broad categories of sensors:
- Motion sensors: These sensors measure acceleration forces and rotational forces along three axes. This category includes accelerometers, gravity sensors, gyroscopes, and rotational vector sensors.
- Environmental sensors: These sensors measure various environmental parameters, such as ambient air temperature and pressure, illumination, and humidity. This category includes barometers, photometers, and thermometers.
- Position sensors: These sensors measure the physical position of a device. This category includes orientation sensors and magnetometers."
(Link: https://developer.android.com/guide/topics/sensors/sensors_overview.html)
Motion Sensors
According to SparkFun, accelerometer an is a: " Accelerometers are devices that measure acceleration, which is the rate of change of the velocity of an object." (Link: https://learn.sparkfun.com/tutorials/accelerometer-basics). Basically, for mobile devices, it is less about the rate of acceleration with respect to the orientation of the screen. Gravity sensors (and the gyroscope) work with the accelerometer to determine which way the cell phone is pointed and orient the screen in that direction.
Environmental Sensors
Each type of meter has a specific function:
| Item | Description | Link |
|---|---|---|
| Barometers | Meteorology. any instrument that measures atmospheric pressure. | www.dictionary.com/browse/barometer |
| Photometers | The measurement of the intensity of light or of relative illuminating power | www.dictionary.com/browse/photometry |
| Thermometers | An instrument for measuring temperature, often a sealed glass tube that contains a column of liquid, | https://en.wikipedia.org/wiki/Thermometer |
Position Sensors
"Position sensors are useful for determining a device's physical position in the world's frame of reference. For example, you can use the Geomagnetic Field Sensor in combination with the accelerometer to determine a device's position relative to the magnetic north pole. You can also use these sensors to determine a device's orientation in your application's frame of reference. Position sensors are not typically used to monitor device movement or motion, such as shake, tilt, or thrust (for more information, see Motion Sensors).
The geomagnetic field sensor and accelerometer return multi-dimensional arrays of sensor values for each SensorEvent. For example, the geomagnetic field sensor provides geomagnetic field strength values for each of the three coordinate axes during a single sensor event. Likewise, the accelerometer sensor measures the acceleration applied to the device during a sensor event. For more information about the coordinate systems that are used by sensors, see Sensor Coordinate Systems. The proximity sensor provides a single value for each sensor event. Table 1 summarizes the position sensors that are supported on the Android platform."
The geomagnetic field sensor and accelerometer return multi-dimensional arrays of sensor values for each SensorEvent. For example, the geomagnetic field sensor provides geomagnetic field strength values for each of the three coordinate axes during a single sensor event. Likewise, the accelerometer sensor measures the acceleration applied to the device during a sensor event. For more information about the coordinate systems that are used by sensors, see Sensor Coordinate Systems. The proximity sensor provides a single value for each sensor event. Table 1 summarizes the position sensors that are supported on the Android platform."
(Link: https://developer.android.com/guide/topics/sensors/sensors_position.html)
"This article lists Android devices that support raw global navigation satellite system (GNSS) measurements as well as tools to log and analyze GNSS data. You can find the tools in the GPS Measurement Tools repo on GitHub, which includes the GNSS Logger APK and the GNSS Analysis app for Linux, Windows, macOS, and the Installation and User Manual.
Original equipment manufacturers (OEMs), developers, and researchers can make use of the tools in this page to test new phone designs, validate functionality, develop new algorithms, evaluate improvements to the GNSS system implementation as well as building value added apps." (Link: https://developer.android.com/guide/topics/sensors/gnss.html)
"Depending on the device, raw GNSS measurements can include all or some of the following data:
- Pseudorange and pseudorange rate.
- Navigation messages.
- Accumulated delta range or carrier.
- Hardware (HW) clock."
(Link: https://developer.android.com/guide/topics/sensors/gnss.html)
Conclusion
It is important to understand how smartphones work, what they do, and how this information about you is captured. Understanding what your cellphone is capturing about you is the first step in protecting yourself from unwanted attacks.
