Structural　monitoring　and　engineering　surveys　that　use　the　Global　Positioning　System　(GPS)　have　traditionally　performed　using　a　so-called　carrier-phase　double-difference　method　in　data　processing.　The　method　requires　at　least　one　reference　GPS　station　to　be　continuously　operated　in　the　field　during　the　monitoring　period.　The　stability　and　data　quality　of　the　reference　station　would　directly　affect　the　accuracy　of　displacement　measurements　at　the　rover　station.　Furthermore,　it　becomes　increasingly　difficult　to　maintain　ideal　reference　stations　in　urban　environments.　This　article　introduces　a　method　for　using　stand-alone　GPS　units　to　conduct　millimeter-accuracy　structural　deformation　monitoring　for　poststudy　or　for　near　real-time　structural　health　monitoring.　Two　years　of　continuous　GPS　observations　obtained　from　two　high-rise　buildings　in　Beijing　were　used　to　depict　the　detailed　method.　The　method　comprises　three　steps:　(1)　solving　GPS　antenna　positions　with　respect　to　a　global　reference　frame　(IGS08),　(2)　establishing　a　stable　local　reference　frame　and　transforming　the　global　positions　into　the　local　reference　frame,　and　(3)　deriving　a　regional　seasonal　model　and　correcting　GPS-derived　positional　time　series　with　the　regional　model.　It　is　concluded　that　2-　to　3-mm　horizontal　accuracy　and　5-　to　7-mm　vertical　accuracy　can　be　achieved　for　daily　solutions　with　the　proposed　method　in　the　Beijing　metropolitan　area.　The　key　products　from　this　study　are　the　Stable　Beijing　Reference　Frame　(SBJRF)　and　the　local　seasonal　model　for　GPS-derived　(vertical)　positional　time　series.　SBJRF　will　be　incrementally　improved　and　periodically　updated　to　synchronize　with　the　update　of　the　IGS　reference　frame.　The　general　theory　and　method　presented　in　this　article　could　be　applied　to　other　urban　areas　for　conducting　structural　health　monitoring　in　near　real　time.