This　paper　proposes　a　novel　method　for　identifying　carriage　errors.　A　general　mathematical　model　of　a　guideway　system　is　developed,　based　on　the　multi-body　system　method.　Based　on　the　proposed　model,　most　error　sources　in　the　guideway　system　can　be　measured.　The　flatness　of　a　workpiece　measured　by　the　PGI1240　profilometer　is　represented　by　a　wavelet.　Cross-correlation　analysis　performed　to　identify　the　error　source　of　the　carriage.　The　error　model　is　developed　based　on　experimental　results　on　the　low　frequency　components　of　the　signals.　With　the　use　of　wavelets,　the　identification　precision　of　test　signals　is　very　high.