The basic principle behind the track-before-detect(TBD)scheme was introduced

and an overview of the studies on state-of-art TBD methods was then presented.The paper paid special attention to the following TBD methods:dynamic programming

recursive Bayesian filtering

finite set statistics

histogram probability multi-hypothesis tracking

and also the relevant applications.Finally

some key issues to enhance the precision and robustness of dim target detection and tracking are indicated based on the progress of the existing research

which deserve more attention of the researchers' for solution.These include:performance analysis and evaluation of the existing TBD methods

the TBD solutions for closely-spaced and/or maneuvering dim targets

multi-sensor fusion for the TBD problem

joint target detection

tracking and classification(JDTC) for dim targets

and so on.