What is "dwell time"

n. 1 (context chiefly engineering English) The period of time that a system or element of a system remains in a given state. 2 (context military English) The duty time soldiers have at their domestic home base between foreign deployments.

In the military, dwell time is the amount of time that service members spend in their home station between deployments to war zones, or to dependent restricted tours. Dwell time is designed to allow service members a mental and physical break from combat and to give them time with their families. It is an important component of long term military readiness.

Dwell time may refer to:

• Dwell time (information retrieval), a relevance indicator measuring the time the user remains at a search result after a click
• Dwell time (military), time service members spend in home station between deployments to war zones, or to dependent restricted tours
• Dwell time (radar), the time that an antenna beam spends on a target
• Terminal dwell time, in transportation, the time a vehicle spends at a scheduled stop without moving
• Service time, in queueing theory

Dwell time (T) in surveillance radar is the time that an antenna beam spends on a target. The dwell time of a 2D–search radar depends predominantly on

• the antenna's horizontal beam width θ, and
• the turn speed n of the antenna (in rotations per minute or rpm, i.e. 360 degrees in 60 seconds = multiplied by a factor of 6).

Dwell time is calculated by:

$$T_D = \frac{\theta_{AZ}}{6 \cdot n} \quad\quad \text{(in seconds)}$$

In information retrieval, dwell time denotes the time which a user spends viewing a document after clicking a link on a search engine results page (SERP). Dwell time is the duration between when a user clicks on a search engine result, and when the user returns from that result, or the user is otherwise seen to have left the result. Dwell time is a relevance indicator of the search result correctly satisfying the intent of the user. Short dwell times indicate the user's query intent was not satisfied by viewing the result. Long dwell times indicate the user's query intent was satisfied.

The dwell time in GNSS is the time required to test for the presence of a satellite signal for a certain combination of parameters. A GNSS satellite can be detected if it is present or not on a sky through a search process, based on correlation of a received signal with a reference signal stored in the receiver.

The dwell times are associated with the performance of a certain detector. They can be classified into single dwell times, when the decision is taken in one step, and multiple dwell times, when the decision is taken in two or more steps.