Radiolocation

Radiolocation, also known as radiolocating or radiopositioning, is the process of finding the location of something using radio waves. This method is very helpful because it lets us discover where objects are without needing to see them directly.

One common type of radiolocation is called radar. Radar sends out radio waves and listens for them to bounce back, helping us know where things like airplanes or ships are. Radiolocation is also used to find hidden things, such as buried cables, water mains, and other important public utilities underground.

Radiolocation is similar to something called radionavigation, where a person or device finds its own position using radio waves. Both of these are types of radiodetermination. Radiolocation is also important in special systems known as real-time locating systems (RTLS), which help track valuable items in real time.

Basic principles

We can find where something is by looking at the radio waves it sends out or reflects. These waves might come from the object itself or bounce off it, like in radar. For example, a stud finder can use radio waves to locate studs in a wall.

There are different ways to figure out location using radio waves. One way looks at how strong the signal is compared to when it started. Another way checks how long it takes for the signal to arrive. By using several receivers in known places, we can estimate where the signal came from even if we don’t know when it was sent. We can also find direction by using antennas that point in specific ways. All these methods help us pin down a location more accurately.

Mobile phones

Main article: Mobile phone tracking

Radiolocation helps find where a mobile phone is by using special towers called base stations. This is often done by measuring distances between radio towers using methods like angle of arrival (AOA) or time difference of arrival (TDOA).

These methods work best when there is a clear view between towers, but they can still help even in tricky places like mountains or cities with tall buildings. Some phone networks use the phone itself to find its location, similar to how GPS works. This helps emergency services know exactly where someone is when they call for help. People can also choose to share their location for other helpful services, but this is usually turned off by default to keep their information safe.

International regulation

A Radiolocation service (short: RLS) is defined in the rules set by the International Telecommunication Union's (ITU) Radio Regulations. It is a special kind of service used to find the location of something using radio waves, but not for figuring out where you yourself are.

This type of service is grouped under the radiodetermination service. It includes things like a Radiolocation-satellite service. There are also different kinds of stations used, such as Radiolocation mobile station and Radiolocation land station.

Satellites

Radiolocation-satellite service (short: RLSS) is defined as a special type of communication service used to find locations through radio waves. This service can also include the connections needed for it to work.

The radiolocation-satellite service includes three main parts:

• Earth radio stations
• Feeder links and
• Space radio stations

For example, military radar sensors in satellites on Earth operate within this service.

Examples of radio stations in the radiolocation-satellite service

Frequency allocation

The use of radio frequencies for this service follows rules set by the International Telecommunication Union. These rules help make sure everyone uses the radio spectrum in a coordinated way. Each country decides how to use these frequencies, which can be done in different ways.

Example of frequency allocation

Stations

Land station

A radiolocation land station is a special type of radio station that helps find the location of things using radio waves. It is not meant to move around. These stations are part of the radiolocation service and follow rules set by the International Telecommunication Union (ITU).

These stations can be part of different services, like radiodetermination or radionavigation. Some examples of land stations include:

• German Radar Wurzburg Riese (FuMG 65)
• ALTAIR (ARPA Long-Range Tracking and Instrumentation Radar)
• NASA Wallops Flight Facility Radar
• Antenna radar L band TAR Finland
• 50 Feet dish Antenna of a 3 kW C band Radar
• Intelligence-gathering phased array radar FPS-108 COBRA DANE
• Phased array radar AN/FPQ-16 PARCS
• Skyguide radar, Hochwacht in Boppelsen on Lägern (Switzerland)

Mobile station

A radiolocation mobile station is another type of radio station that also helps find locations using radio waves, but it is designed to be used while moving or stopping at different places. Like land stations, these also follow the ITU rules and can be part of various services.

Some examples related to mobile stations include:

• Nike Hercules IFC radars LOPAR and the tracking radars (MTR, TTR, TRR)
• Weapon control radar