Fire - control radar A fire - control radar ( FCR ) is a radar which is designed specifically to provide information ( mainly target azimuth , elevation , range and velocity ) to a fire - control system in order to calculate a firing solution ( i . e . information on how to direct weapons such that they hit the target ( s ) ) . Such radars typically emit a narrow , intense beam of radio wave s to ensure accurate tracking information and to minimise the chance of losing track of the target . Some modern radars have a track - while - scan capability enabling it to function simultaneously as a fire - control radar and a search radar . This works either by having the radar switch between sweeping the search sector and sending directed pulses at the target to be tracked , or by using a phased - array antenna to generate two ( or more ) discrete radar beams and dividing them between both tasks . Operational phases . Fire - control radars operate in three different phases : Performance . The performance of a fire - control radar is determined primarily by two factors : radar resolution and atmospheric conditions . Radar resolution is the ability of the radar to differentiate between two targets closely located . The first , and most problematic , is gaining high range resolution . To do this in a basic fire - control radar system , it must operate at smaller pulse width . Bearing resolution is typically ensured by using a narrow ( one or two degree ) beam width . Atmospheric conditions , such as moisture lapse , temperature inversion , and dust particles affect radar performance as well . Moisture lapse and temperature inversion often cause ducting , in which RF energy is bent as it passes through hot and cold layers . This can either extend or reduce the radar horizon , depending on which way the RF is bent . Dust particles , as well as water droplets , cause attenuation of the RF energy , translating into a loss of effective range . In both cases , a lower pulse repetition frequency makes the radar less susceptible to atmospheric conditions . Countermeasures . Most fire - control radars have unique characteristics , such as radio frequency , pulse duration , pulse frequency and power . These can assist in identifying the radar , and therefore the weapon system it is controlling . This can provide valuable tactical information , like the maximum range of the weapon , or flaws that can be exploited , to combatants that are listening for these signs . During the cold war Soviet fire control radars were often named and NATO pilots would be able to identify the threats present by the radar signals they received . Surface based . One of the first successful fire - control radars , the SCR - 584 , was used effectively and extensively by the Allies during World War II for anti - aircraft gun laying . Since WWII , the U . S . Army has used radar for directing anti - aircraft missiles including the MIM - 23 Hawk , the Nike series and currently the MIM - 104 Patriot . Ship based . Examples of fire - control radars currently in use by the United States Navy : Aircraft based . After WWII , airborne fire control radars have evolved from the simpler gun and rocket laying AN / APG - 36 system used in the F - 86D to the Active Electronically Scanned Array based AN / APG - 81 of the F - 35 .