d. Radar Beacon Receiver 



This separate receiver allows continuous viewing and variable mixing 

 of the radar and video signal on the PPI display. With this unit, it is practical 

 to operate the radar and obtain a picture of a target area and simultaneously 

 obtain a brightened spot on the target indicating the position of a transponding 

 beacon within the target area . 



This system is adaptable to a standard radar. The electronic unit is 

 close coupled to the radar transceiver and is tied into the wave guide. A control 

 unit is mounted near the radar display. The control unit contains the necessary 

 adjustments for setting to the beacon frequency and spot brightening as required. 



3. ACCURACY 



The equipment has a fundamental instrumental accuracy of + 40 feet 

 as a maximum incremental error due to crystal characteristics and performance, 

 This standard of accuracy can be maintained up to maximum range, subject to 

 a satisfactory target being available. A fixed operation accuracy of + 80 feet 

 for 99.7% of cases is reported as the result of operational tests . 



For radar to beacon antenna heights of 45 feet and 10 feet respectively, 

 strong contact can be maintained out to 10 n.m . , steady response to 12 n.m . 

 and occasional response to 15 n.m. Sea state and atmospheric conditions will 

 modify these ranges . 



Strong contacts to beyond 30 miles have been documented. These 

 ranges have been repeated with no difficulty when the combined antenna heights 

 were 1000 feet. 



4. SUMMARY 



a. Precision Ranging Unit 



(1) Type of system: precision ship -positioniBg and ranging 

 system utilizing ship radar equipment. 



(2) Number of stations: two reflectors or transponding 

 beacons placed at either end of base line. 



(3) Range: out to normal ranges of radar being used. 



(4) Accuracy (instrumental): + 40 feet based on electronic 

 specifications . 



140 



artbur ai.lLittlcHlnr. 



