Shield　tunneling　under　rivers　often　requires　monitoring　riverbed　deformations　in　near　real-time.　However,　it　is　challenging　to　measure　riverbed　deformation　with　conventional　survey　techniques.　This　study　introduces　a　comprehensive　method　that　uses　the　Global　Positioning　System　(GPS)　of　the　USA　and　the　BeiDou　navigation　satellite　system　(BeiDou)　of　China　to　monitor　riverbed　deformation　during　the　construction　of　twin　tunnels　beneath　the　Hutuo　River　in　Shijiazhuang,　China.　A　semi-permanent　GPS　network　with　one　base　station　outside　the　river　and　six　rover　stations　within　the　river　was　established　for　conducting　near　real-time　and　long-term　monitoring.　The　distances　between　the　base　and　the　rover　antennas　are　within　two　kilometers.　The　network　was　continuously　operating　for　eight　months　from　April　to　December　2018.　The　method　is　comprised　of　three　components:　(1)　Monitoring　the　stability　of　the　base　station　using　precise　point　positioning　(PPP)　method,　a　stable　regional　reference　frame,　and　a　seasonal　ground　deformation　model;　(2)　monitoring　the　relative　positions　of　rover　stations　using　the　carrier-phase　double-difference　(DD)　positioning　method　in　near　real-time;　and　(3)　detecting　abrupt　and　gradual　displacements　at　both　base　and　rover　stations　using　an　automated　change　point　detection　algorithm.　The　method　is　able　to　detect　abrupt　positional-changes　as　minor　as　five　millimeters　in　near　real-time　and　gradual　positional-changes　at　a　couple　of　millimeters　per　day　within　a　week.　The　method　has　the　flexibility　of　concurrent　processing　different　GPS　and　BeiDou　data　sessions　(e.g.,　every　15　minutes,　30　minutes,　one　hour,　one　day)　for　diffident　monitoring　purposes.　This　study　indicates　that　BeiDou　observations　can　also　achieve　few-millimeter-accuracy　for　measuring　displacements.　Parallel　processing　GPS　and　BeiDou　observations　can　improve　the　reliability　of　near　real-time　structural　deformation　monitoring　and　minimize　false　alerts.　The　method　introduced　in　this　article　can　be　applied　to　other　urban　areas　for　near　real-time　and　long-term　structural　health　monitoring.