Sensor grid
A sensor grid was a large collection of sensors.

In 2371, the upper sensor grid of Deep Space 9 failed. Chief Miles O'Brien told Benjamin Sisko he would have it operational again by the morning of the next day. ()

The Dominion had installed a sensor grid in the Soukara system by 2374. In that year, Worf and Jadzia Dax found that there were three gaps in the grid, all located in an asteroid field. They had a secondary sensor grid, forming a sensor perimeter round the Soukara base that too was required to be penetrated. With some adjustments to their tricorder, they were able to bypass the Dominion encryption lockouts and link into the sensor grid, after which time they were able to mask their lifesigns, but simultaneously making the tricorder useless for any other function. ()

See also 
Tachyon detection grid
Sensor technology