A 
sensing system (11) includes a first 
radar sensing 
assembly (10; 3104, 3106; 4100, 4200) and an analysis 
system (18). The first 
radar sensing 
assembly (10; 3104, 3106; 4100, 4200) measures plural distances (12; 22, 30; 42, 50, 60, 70, 80; 4102, 4202) to a first target location (16) at different times using 
radar. The analysis 
system (18) receives the plural distances (12; 22, 30; 42, 50, 60, 70, 80; 4102, 4202) from the first radar sensing 
assembly (10; 3104, 3106; 4100, 4200) and quantifies movements of a target object (14) at the first target location (16) at the different times by calculating differences in the plural distances (10; 3104, 3106; 4100, 4200) measured by the first radar sensing assembly (10; 3104, 3106; 4100, 4200). The analysis 
system (18) generates one or more first quantified 
activity level values indicative of the movements of the target object (14) at the first target location (16) using the differences in the plural distances (12; 22, 30; 42, 50, 60, 70, 80; 4102, 4202) that are calculated.