Recently some attention has been given to a type of sequential detection 

 in which the statistical testing procedure ajid the radar transmission and reception 

 characteristics are programmed to change between pulses or groups of pulses. 

 The general form of this type of multiple-stage detection is outlined in figure 1. 



NEXT BEAM 

 POSITION 

 If all stage-1 cells have noise-only decisions 



STAGE 1 



If any 



ale 



STAGE 2 



If any 



If all stage-2 cells he 



noise-only decisions 



STAGE / 



('■ 



.1, 





, m): 



Tra 



ns 



miss.o 



ns 



of the /th 



- stage 



typ 



e are 



con 



tin 



ued un 



til 



for each 



th 



stage resolut 



ion 



ce 



II a 





deci sion 



s 



each 



ed. 



The 



two 



po 



ssible 





deci sions 



pe 



r eel 



ar 



e "noise 



o 



ily " ar 



d 



"alarm." 



















Announce signal decisions and 

 take appropriate actions. 



Figure 1. Multiple-stage detection with a maximum of m stages. 



An electronically scanned antenna points, once each on every scan, in a number 

 of different directions. For any given stay of the beam, stage-(/ -i- 1) testing occurs 

 only if stage-! testing indicates that a signal might be present. The antenna beam 

 stays in a given position until a final decision is made as to the presence of any 

 targets in that sector. Note that in this type of multiple-stage test, final signal 

 decisions can be made only in the final stage, while a final decision that no signal 

 is in any resolution element can be made in any stage. Some of the many possible 

 degrees of freedom in the design of each stage are the following. 



1. Range resolution, number and placement of range bins 



2. Doppler resolution, number and frequency coverage of filters 



