diff --git a/pkg/producer/rpc.go b/pkg/producer/rpc.go
index c0c4e75..d0ff38d 100644
--- a/pkg/producer/rpc.go
+++ b/pkg/producer/rpc.go
@@ -3,7 +3,6 @@ package producer
 import (
 	"encoding/json"
 	"fmt"
-	"math"
 	"os"
 	"strings"
 
@@ -15,14 +14,16 @@ import (
 	"starwiz.cn/sjy01/image-proc/pkg/dem"
 )
 
+const FLT_EPSILON = 1.192092896e-07
+
 type RPC struct {
 	lineOffset, lineScale               float64
 	sampOffset, sampScale               float64
 	latOffset, longOffset, heightOffset float64
 	latScale, longScale, heightScale    float64
 
-	LineCoef   RPCModel
-	SampleCoef RPCModel
+	LineCoef RPCModel
+	SampCoef RPCModel
 
 	minH, maxH     float64
 	GCPs           []*GroundPoint
@@ -55,8 +56,8 @@ type RPCModel struct {
 // rational polynomial coeffients
 func NewRPC(r *Registrator, scene *Scene, rpb string) *RPC {
 	rpc := RPC{
-		elevationLayer: 4,
-		gridsize:       19,
+		elevationLayer: 5,
+		gridsize:       5,
 		registrator:    r,
 		scene:          scene,
 		rpb:            rpb,
@@ -92,8 +93,6 @@ func (rpc *RPC) init() {
 
 // 虚拟控制点
 func (rpc *RPC) generateVirtualGCP() {
-	log.Infof("Generating virtual GCPs, %d x %d x %d",
-		rpc.gridsize+1, rpc.gridsize+1, rpc.elevationLayer+1)
 	points := gridImage2(rpc.gridsize, rpc.gridsize,
 		rpc.scene.Height, rpc.scene.Width,
 		rpc.elevationLayer, int(rpc.minH), int(rpc.maxH))
@@ -137,10 +136,10 @@ func (rpc *RPC) RPC() error {
 	rpc.saveVec(strings.Replace(rpc.scene.Tiff, ".tiff", ".vec.txt", -1),
 		rowVec, colVec, latVec, lonVec, heightVec)
 
-	rpc.lineOffset = float64(rpc.scene.Height / 2)
-	rpc.lineScale = float64(rpc.scene.Height)
-	rpc.sampOffset = float64(rpc.scene.Width / 2)
-	rpc.sampScale = float64(rpc.scene.Width)
+	rpc.lineOffset = float64(rpc.scene.Height) / 2.0
+	rpc.lineScale = float64(rpc.scene.Height) / 2.0
+	rpc.sampOffset = float64(rpc.scene.Width) / 2.0
+	rpc.sampScale = float64(rpc.scene.Width) / 2.0
 	rowVec = normalize2(rowVec, rpc.lineOffset, rpc.lineScale)
 	colVec = normalize2(colVec, rpc.sampOffset, rpc.sampScale)
 
@@ -155,73 +154,42 @@ func (rpc *RPC) RPC() error {
 
 	// x = (B^T * B)^-1 * B^T * l, 其中 x = [a1..a20 b2..b20]^T
 	// 行参数
-	B := buildDesignMatrix(rowVec, latVec, lonVec, heightVec)
-	J, err := SolveNormalEquation(B, rowVec)
+	// B := setupSystemOfEquations(rowVec, latVec, lonVec, heightVec)
+	// J, err := SolveNormalEquation(B, rowVec)
+	log.Println("solving row coefficients")
+	J, err := solveCoefficients(rowVec, latVec, lonVec, heightVec)
 	if err != nil {
 		return err
 	}
 
 	// 列参数
-	D := buildDesignMatrix(colVec, latVec, lonVec, heightVec)
-	K, err := SolveNormalEquation(D, colVec)
+	// D := setupSystemOfEquations(colVec, latVec, lonVec, heightVec)
+	// K, err := SolveNormalEquation(D, colVec)
+	log.Println("solving col coefficients")
+	K, err := solveCoefficients(colVec, latVec, lonVec, heightVec)
 	if err != nil {
 		return err
 	}
 
-	for i := 0; i < 20; i++ {
+	rpc.LineCoef.NumCoefficients[0] = J[0]
+	rpc.LineCoef.DenCoefficients[0] = 1.0
+	rpc.SampCoef.NumCoefficients[0] = K[0]
+	rpc.SampCoef.DenCoefficients[0] = 1.0
+	for i := 1; i < 20; i++ {
 		rpc.LineCoef.NumCoefficients[i] = J[i]
-	}
-	rpc.LineCoef.DenCoefficients[0] = 1.0
-	for i := 20; i < 39; i++ {
-		rpc.LineCoef.DenCoefficients[i-19] = J[i]
+		rpc.LineCoef.DenCoefficients[i] = J[i+19]
+		rpc.SampCoef.NumCoefficients[i] = K[i]
+		rpc.SampCoef.DenCoefficients[i] = K[i+19]
 	}
 
-	for i := 0; i < 20; i++ {
-		rpc.SampleCoef.NumCoefficients[i] = K[i]
-	}
-	rpc.SampleCoef.DenCoefficients[0] = 1.0
-	for i := 20; i < 39; i++ {
-		rpc.SampleCoef.DenCoefficients[i-19] = K[i]
-	}
-
-	nameRPB := strings.Replace(rpc.scene.Tiff, ".tiff", ".sep.rpb", -1)
-	rpc.saveRPB(nameRPB)
-
-	r, c := B.Dims()
-	M0 := mat.NewDense(r, c, nil)
-	var BM0, M0D, M mat.Dense
-	BM0.Augment(B, M0)
-	M0D.Augment(M0, D)
-	M.Stack(&BM0, &M0D)
-	var L mat.Dense
-	L.Stack(rowVec, colVec)
-	coeffs, err := SolveNormalEquation(&M, mat.NewVecDense(rowVec.Len()+colVec.Len(), mat.Col(nil, 0, &L)))
-	if err != nil {
-		return err
-	}
-
-	for i := 0; i < 20; i++ {
-		rpc.LineCoef.NumCoefficients[i] = coeffs[i]
-	}
-	rpc.LineCoef.DenCoefficients[0] = 1.0
-	for i := 20; i < 39; i++ {
-		rpc.LineCoef.DenCoefficients[i-19] = coeffs[i]
-	}
-	for i := 39; i < 59; i++ {
-		rpc.SampleCoef.NumCoefficients[i-39] = coeffs[i]
-	}
-	rpc.SampleCoef.DenCoefficients[0] = 1.0
-	for i := 59; i < 78; i++ {
-		rpc.SampleCoef.DenCoefficients[i-58] = coeffs[i]
-	}
 	nameRPB0 := strings.Replace(rpc.scene.Tiff, ".tiff", ".rpb", -1)
 	rpc.saveRPB(nameRPB0)
 
 	projectedPoints := rpc.applyRFM(
 		mat.NewVecDense(20, rpc.LineCoef.NumCoefficients[:]),
 		mat.NewVecDense(20, rpc.LineCoef.DenCoefficients[:]),
-		mat.NewVecDense(20, rpc.SampleCoef.NumCoefficients[:]),
-		mat.NewVecDense(20, rpc.SampleCoef.DenCoefficients[:]),
+		mat.NewVecDense(20, rpc.SampCoef.NumCoefficients[:]),
+		mat.NewVecDense(20, rpc.SampCoef.DenCoefficients[:]),
 		rpc.GCPs,
 	)
 	name := strings.Replace(rpc.scene.Tiff, ".tiff", ".gcp_proj.txt", -1)
@@ -230,156 +198,19 @@ func (rpc *RPC) RPC() error {
 	return nil
 }
 
-func normalize(v *mat.VecDense) (*mat.VecDense, float64, float64) {
-	var vOff, vScale float64
-	vOff = mat.Sum(v) / float64(v.Len())
-	vScale = math.Max(math.Abs(mat.Max(v)-vOff), math.Abs(mat.Min(v)-vOff))
-	for i := 0; i < v.Len(); i++ {
-		v.SetVec(i, (v.AtVec(i)-vOff)/vScale)
-	}
-
-	return v, vOff, vScale
-}
-
-func normalize2(v *mat.VecDense, vOff, vScale float64) *mat.VecDense {
-	for i := 0; i < v.Len(); i++ {
-		v.SetVec(i, (v.AtVec(i)-vOff)/vScale)
-	}
-
-	return v
-}
-
-func buildDesignMatrix(vec, latVec, lonVec, heightVec *mat.VecDense) *mat.Dense {
-	n := latVec.Len()
-	// 设计矩阵 B = [ 20个分子系数 19个分母系数 ]
-	B := mat.NewDense(n, 39, nil)
-	for i := 0; i < n; i++ {
-		P := latVec.AtVec(i)
-		L := lonVec.AtVec(i)
-		H := heightVec.AtVec(i)
-		r_c := vec.AtVec(i)
-
-		B.Set(i, 0, 1)
-		B.Set(i, 1, L)
-		B.Set(i, 2, P)
-		B.Set(i, 3, H)
-		B.Set(i, 4, L*P)
-		B.Set(i, 5, L*H)
-		B.Set(i, 6, P*H)
-		B.Set(i, 7, L*L)
-		B.Set(i, 8, P*P)
-		B.Set(i, 9, H*H)
-		B.Set(i, 10, P*L*H)
-		B.Set(i, 11, L*L*L)
-		B.Set(i, 12, L*P*P)
-		B.Set(i, 13, L*H*H)
-		B.Set(i, 14, L*L*P)
-		B.Set(i, 15, P*P*P)
-		B.Set(i, 16, P*H*H)
-		B.Set(i, 17, L*L*H)
-		B.Set(i, 18, P*P*H)
-		B.Set(i, 19, H*H*H)
-		B.Set(i, 20, -L*r_c)
-		B.Set(i, 21, -P*r_c)
-		B.Set(i, 22, -H*r_c)
-		B.Set(i, 23, -L*P*r_c)
-		B.Set(i, 24, -L*H*r_c)
-		B.Set(i, 25, -P*H*r_c)
-		B.Set(i, 26, -L*L*r_c)
-		B.Set(i, 27, -P*P*r_c)
-		B.Set(i, 28, -H*H*r_c)
-		B.Set(i, 29, -P*L*H*r_c)
-		B.Set(i, 30, -L*L*L*r_c)
-		B.Set(i, 31, -L*P*P*r_c)
-		B.Set(i, 32, -L*H*H*r_c)
-		B.Set(i, 33, -L*L*P*r_c)
-		B.Set(i, 34, -P*P*P*r_c)
-		B.Set(i, 35, -P*H*H*r_c)
-		B.Set(i, 36, -L*L*H*r_c)
-		B.Set(i, 37, -P*P*H*r_c)
-		B.Set(i, 38, -H*H*H*r_c)
-	}
-
-	return B
-}
-
-// SolveNormalEquation 使用正规方程法求解最小二乘问题
-func SolveNormalEquation(A *mat.Dense, b *mat.VecDense) ([]float64, error) {
-	var At mat.Dense
-	At.Mul(A.T(), A) // At = A^T * A
-
-	// 求解 (A^T * A)^-1 * (A^T * b)
-	var AtInv mat.Dense
-	err := AtInv.Inverse(&At)
-
-	if err != nil {
-		// 岭估计方法调整法方程状态，使得矩阵非奇异，最小二乘平差可以收敛
-		r, c := At.Dims()
-		log.Infof("cannot inverse design matrix(%d*%d): %v", r, c, err)
-		log.Info("try to adjust design matrix with +kI, k=0.0000001")
-		k := 0.0000001 // [0.00000005, 0.000005]
-		I := mat.NewDiagDense(r, nil)
-		for i := 0; i < r; i++ {
-			I.SetDiag(i, k)
-		}
-		At.Add(&At, I)
-
-		err = AtInv.Inverse(&At)
-	}
-
-	if err != nil {
-		log.Infof("cannot inverse design matrix: %v, try SVD method", err)
-		// 计算矩阵的 SVD 分解
-		var svd mat.SVD
-		ok := svd.Factorize(&At, mat.SVDThin)
-		if !ok {
-			fmt.Println("SVD 分解失败")
-			return nil, fmt.Errorf("设计矩阵不可逆, SVD 分解失败: %v", err)
-		}
-
-		// 获取 U、Σ 和 V^T
-		var u, v mat.Dense
-		svd.UTo(&u)
-		svd.VTo(&v)
-		sigma := svd.Values(nil)
-
-		// 计算 Σ^+ (Sigma pseudo-inverse)
-		m, n := u.Dims()
-		sigmaInv := mat.NewDense(n, m, nil)
-		for i := 0; i < len(sigma); i++ {
-			if sigma[i] > 1e-10 { // 避免除以零
-				sigmaInv.Set(i, i, 1/sigma[i])
-			}
-		}
-
-		// 计算 V * Σ^+ * U^T
-		var temp mat.Dense
-		temp.Mul(&v, sigmaInv)
-		AtInv.Mul(&temp, u.T())
-	}
-
-	var Atb mat.VecDense
-	Atb.MulVec(A.T(), b) // Atb = A^T * b
-
-	var x mat.VecDense
-	x.MulVec(&AtInv, &Atb) // x = (A^T * A)^-1 * (A^T * b)
-
-	return mat.Col(nil, 0, &x), nil
-}
-
 func (rpc *RPC) Output() string {
 	var lineNumCoef, lineDenCoef, sampNumCoef, sampDenCoef string
 	for i := 0; i < 20; i++ {
 		if i < 19 {
 			lineNumCoef += fmt.Sprintf("\t\t%.15e,\n", rpc.LineCoef.NumCoefficients[i])
 			lineDenCoef += fmt.Sprintf("\t\t%.15e,\n", rpc.LineCoef.DenCoefficients[i])
-			sampNumCoef += fmt.Sprintf("\t\t%.15e,\n", rpc.SampleCoef.NumCoefficients[i])
-			sampDenCoef += fmt.Sprintf("\t\t%.15e,\n", rpc.SampleCoef.DenCoefficients[i])
+			sampNumCoef += fmt.Sprintf("\t\t%.15e,\n", rpc.SampCoef.NumCoefficients[i])
+			sampDenCoef += fmt.Sprintf("\t\t%.15e,\n", rpc.SampCoef.DenCoefficients[i])
 		} else {
 			lineNumCoef += fmt.Sprintf("\t\t%.15e", rpc.LineCoef.NumCoefficients[i])
 			lineDenCoef += fmt.Sprintf("\t\t%.15e", rpc.LineCoef.DenCoefficients[i])
-			sampNumCoef += fmt.Sprintf("\t\t%.15e", rpc.SampleCoef.NumCoefficients[i])
-			sampDenCoef += fmt.Sprintf("\t\t%.15e", rpc.SampleCoef.DenCoefficients[i])
+			sampNumCoef += fmt.Sprintf("\t\t%.15e", rpc.SampCoef.NumCoefficients[i])
+			sampDenCoef += fmt.Sprintf("\t\t%.15e", rpc.SampCoef.DenCoefficients[i])
 		}
 	}
 
@@ -497,57 +328,20 @@ func (rpc *RPC) saveVec(name string, rowVec, colVec, latVec, lonVec, heightVec *
 
 func (rpc *RPC) applyRFM(num_line, den_line, num_samp, den_samp *mat.VecDense, points []*GroundPoint) []*GroundPoint {
 	var res []*GroundPoint
-
 	for _, p := range points {
 		var r GroundPoint
-		r.Y = rpc.project(num_line, den_line, p.P, p.L, p.H)
-		r.Y = r.Y*rpc.lineScale + rpc.lineOffset
-		r.X = rpc.project(num_samp, den_samp, p.P, p.L, p.H)
-		r.X = r.X*rpc.sampScale + rpc.sampOffset
+		P := (p.P - rpc.latOffset) / rpc.latScale
+		L := (p.L - rpc.longOffset) / rpc.longScale
+		H := (p.H - rpc.heightOffset) / rpc.heightScale
+		r.Y = project(num_line, den_line, P, L, H)
+		r.X = project(num_samp, den_samp, P, L, H)
 		r.P = p.P
 		r.L = p.L
 		r.H = p.H
+		r.Y = (r.Y*rpc.lineScale + rpc.lineOffset)
+		r.X = (r.X*rpc.sampScale + rpc.sampOffset)
 		res = append(res, &r)
 	}
 
 	return res
 }
-
-func (rpc *RPC) localize(num, den *mat.VecDense, row, col float64) (P, L, H float64) {
-
-	return
-}
-
-func (rpc *RPC) project(num, den *mat.VecDense, P, L, H float64) (v float64) {
-	v = rpc.applyPoly(num, P, L, H) / rpc.applyPoly(den, P, L, H)
-	return v
-}
-
-func (rpc *RPC) applyPoly(poly *mat.VecDense, P, L, H float64) (v float64) {
-	P = (P - rpc.latOffset) / rpc.latScale
-	L = (L - rpc.longOffset) / rpc.longScale
-	H = (H - rpc.heightOffset) / rpc.heightScale
-
-	v = 0.0
-	v += poly.AtVec(0)
-	v += poly.AtVec(1) * L
-	v += poly.AtVec(2) * P
-	v += poly.AtVec(3) * H
-	v += poly.AtVec(4) * L * P
-	v += poly.AtVec(5) * L * H
-	v += poly.AtVec(6) * P * H
-	v += poly.AtVec(7) * L * L
-	v += poly.AtVec(8) * P * P
-	v += poly.AtVec(9) * H * H
-	v += poly.AtVec(10) * P * L * H
-	v += poly.AtVec(11) * L * L * L
-	v += poly.AtVec(12) * L * P * P
-	v += poly.AtVec(13) * L * H * H
-	v += poly.AtVec(14) * L * L * P
-	v += poly.AtVec(15) * P * P * P
-	v += poly.AtVec(16) * P * H * H
-	v += poly.AtVec(17) * L * L * H
-	v += poly.AtVec(18) * P * P * H
-	v += poly.AtVec(19) * H * H * H
-	return v
-}
diff --git a/pkg/producer/rpc_helper.go b/pkg/producer/rpc_helper.go
new file mode 100644
index 0000000..82e0222
--- /dev/null
+++ b/pkg/producer/rpc_helper.go
@@ -0,0 +1,382 @@
+package producer
+
+import (
+	"fmt"
+	"math"
+
+	log "github.com/sirupsen/logrus"
+	"gonum.org/v1/gonum/mat"
+)
+
+func normalize(v *mat.VecDense) (*mat.VecDense, float64, float64) {
+	var vOff, vScale float64
+	vOff = mat.Sum(v) / float64(v.Len())
+	vScale = math.Max(math.Abs(mat.Max(v)-vOff), math.Abs(mat.Min(v)-vOff))
+	for i := 0; i < v.Len(); i++ {
+		v.SetVec(i, (v.AtVec(i)-vOff)/vScale)
+	}
+
+	return v, vOff, vScale
+}
+
+func normalize2(v *mat.VecDense, vOff, vScale float64) *mat.VecDense {
+	for i := 0; i < v.Len(); i++ {
+		v.SetVec(i, (v.AtVec(i)-vOff)/vScale)
+	}
+
+	return v
+}
+
+func solveCoefficients(f, latVec, lonVec, heightVec *mat.VecDense) ([]float64, error) {
+	M := setupSystemOfEquations(f, latVec, lonVec, heightVec)
+	n := f.Len()
+	weights := mat.NewDiagDense(n, nil)
+	for i := 0; i < n; i++ {
+		weights.SetDiag(i, 1.0)
+	}
+	w2 := mat.NewDiagDense(n, nil)
+
+	iterations := 0
+	var x mat.VecDense
+	// var e0 float64
+
+	for iterations < 20 {
+		iterations++
+
+		// w2 = weights^2
+		for i := 0; i < n; i++ {
+			w2.SetDiag(i, weights.At(i, i)*weights.At(i, i))
+		}
+
+		// x = (M^T * w2 * M)^-1 * M^T * w2 * R
+		var MtW2 mat.Dense
+		MtW2.Mul(M.T(), w2)
+		var MtW2M mat.Dense
+		MtW2M.Mul(&MtW2, M)
+
+		invMtW2M, err := invertRPCMatrix(&MtW2M)
+		if err != nil {
+			return nil, err
+		}
+		var MtW2F mat.VecDense
+		MtW2F.MulVec(&MtW2, f)
+
+		x.MulVec(invMtW2M, &MtW2F)
+
+		numerator := mat.NewVecDense(20, nil)
+		denominator := mat.NewVecDense(20, nil)
+		numerator.SetVec(0, x.AtVec(0))
+		denominator.SetVec(0, 1.0)
+		for idx := 1; idx < 20; idx++ {
+			numerator.SetVec(idx, x.AtVec(idx))
+			denominator.SetVec(idx, x.AtVec(idx+19))
+		}
+
+		weights = setupWeightMatrix(denominator, latVec, lonVec, heightVec)
+
+		// residual = m.t()*w2*(m*tempCoeff-r);
+		// var temp0, temp1, residual mat.VecDense
+		// temp0.MulVec(M, &x)
+		// temp1.SubVec(&temp0, f)
+		// residual.MulVec(&MtW2, &temp1)
+		// var square mat.Dense
+		// square.Mul(residual.T(), &residual)
+		// residualValue := math.Sqrt(square.At(0, 0))
+		// if residualValue < 0.0001 {
+		// 	break
+		// }
+
+		// fmt.Printf("residual value: %.16f\n", residualValue)
+		// fmt.Printf("iterations: %d\n", iterations)
+
+		e := 0.0
+		for i := 0; i < n; i++ {
+			Rcal := project(numerator, denominator, latVec.AtVec(i), lonVec.AtVec(i), heightVec.AtVec(i))
+			e += math.Pow(Rcal-f.AtVec(i), 2)
+		}
+		e = math.Sqrt(e / float64(n))
+		fmt.Println("iterations:", iterations, "r error:", e)
+
+		if e < 1e-5 {
+			break
+		}
+
+		// dnum := mat.NewVecDense(20, nil)
+		// b0, b1 := true, true
+		// dden := mat.NewVecDense(19, nil)
+		// for i := 0; i < n; i++ {
+		// 	dnum.SetVec(i, math.Abs(numerator.AtVec(i)-numerator0.AtVec(i)))
+		// 	numerator0.SetVec(i, numerator.AtVec(i))
+		// 	fmt.Println("dnum:", i, dnum.AtVec(i))
+		// 	if dnum.AtVec(i) > 0.000001 {
+		// 		b0 = false
+		// 		break
+		// 	}
+		// }
+		// for i := 1; i < n; i++ {
+		// 	dden.SetVec(i, math.Abs(denominator.AtVec(i)-denominator0.AtVec(i)))
+		// 	denominator0.SetVec(i, denominator.AtVec(i))
+		// 	if dden.AtVec(i) > 0.000001 {
+		// 		b1 = false
+		// 		break
+		// 	}
+		// }
+
+		// if b0 && b1 {
+		// 	break
+		// }
+	}
+
+	log.Println("iterations:", iterations)
+
+	return mat.Col(nil, 0, &x), nil
+}
+
+func setupSystemOfEquations(Rn, latVec, lonVec, heightVec *mat.VecDense) *mat.Dense {
+	n := latVec.Len()
+	// 设计矩阵 B = [ 20个分子系数 19个分母系数 ]
+	B := mat.NewDense(n, 39, nil)
+	for i := 0; i < n; i++ {
+		P := latVec.AtVec(i)
+		L := lonVec.AtVec(i)
+		H := heightVec.AtVec(i)
+		r := Rn.AtVec(i)
+
+		B.Set(i, 0, 1)
+		B.Set(i, 1, L)
+		B.Set(i, 2, P)
+		B.Set(i, 3, H)
+		B.Set(i, 4, L*P)
+		B.Set(i, 5, L*H)
+		B.Set(i, 6, P*H)
+		B.Set(i, 7, L*L)
+		B.Set(i, 8, P*P)
+		B.Set(i, 9, H*H)
+		B.Set(i, 10, P*L*H)
+		B.Set(i, 11, L*L*L)
+		B.Set(i, 12, L*P*P)
+		B.Set(i, 13, L*H*H)
+		B.Set(i, 14, L*L*P)
+		B.Set(i, 15, P*P*P)
+		B.Set(i, 16, P*H*H)
+		B.Set(i, 17, L*L*H)
+		B.Set(i, 18, P*P*H)
+		B.Set(i, 19, H*H*H)
+		B.Set(i, 20, -L*r)
+		B.Set(i, 21, -P*r)
+		B.Set(i, 22, -H*r)
+		B.Set(i, 23, -L*P*r)
+		B.Set(i, 24, -L*H*r)
+		B.Set(i, 25, -P*H*r)
+		B.Set(i, 26, -L*L*r)
+		B.Set(i, 27, -P*P*r)
+		B.Set(i, 28, -H*H*r)
+		B.Set(i, 29, -P*L*H*r)
+		B.Set(i, 30, -L*L*L*r)
+		B.Set(i, 31, -L*P*P*r)
+		B.Set(i, 32, -L*H*H*r)
+		B.Set(i, 33, -L*L*P*r)
+		B.Set(i, 34, -P*P*P*r)
+		B.Set(i, 35, -P*H*H*r)
+		B.Set(i, 36, -L*L*H*r)
+		B.Set(i, 37, -P*P*H*r)
+		B.Set(i, 38, -H*H*H*r)
+	}
+
+	return B
+}
+
+// 构建权矩阵 [ 1/B ]
+func setupWeightMatrix(coeffs, latVec, lonVec, heightVec *mat.VecDense) *mat.DiagDense {
+	n := latVec.Len()
+	row := mat.NewDense(n, 20, nil)
+	result := mat.NewDiagDense(n, nil)
+	for i := 0; i < n; i++ {
+		P := latVec.AtVec(i)
+		L := lonVec.AtVec(i)
+		H := heightVec.AtVec(i)
+
+		row.Set(i, 0, 1)
+		row.Set(i, 1, L)
+		row.Set(i, 2, P)
+		row.Set(i, 3, H)
+		row.Set(i, 4, L*P)
+		row.Set(i, 5, L*H)
+		row.Set(i, 6, P*H)
+		row.Set(i, 7, L*L)
+		row.Set(i, 8, P*P)
+		row.Set(i, 9, H*H)
+		row.Set(i, 10, P*L*H)
+		row.Set(i, 11, L*L*L)
+		row.Set(i, 12, L*P*P)
+		row.Set(i, 13, L*H*H)
+		row.Set(i, 14, L*L*P)
+		row.Set(i, 15, P*P*P)
+		row.Set(i, 16, P*H*H)
+		row.Set(i, 17, L*L*H)
+		row.Set(i, 18, P*P*H)
+		row.Set(i, 19, H*H*H)
+
+		var B float64
+		for idx2 := 0; idx2 < 20; idx2++ {
+			B += coeffs.AtVec(idx2) * row.At(i, idx2)
+		}
+
+		result.SetDiag(i, 1/B)
+	}
+
+	return result
+}
+
+func invertRPCMatrix(At *mat.Dense) (*mat.Dense, error) {
+	var AtInv mat.Dense
+	err := AtInv.Inverse(At)
+
+	if err != nil {
+		// 岭估计方法调整法方程状态，使得矩阵非奇异，最小二乘平差可以收敛
+		r, c := At.Dims()
+		log.Infof("cannot inverse matrix(%d*%d): %v", r, c, err)
+		k := 0.0000001 // [0.00000005, 0.000005]
+		log.Infof("try to adjust matrix with +kI, k=%.8f", k)
+		I := mat.NewDiagDense(r, nil)
+		for i := 0; i < r; i++ {
+			I.SetDiag(i, k)
+		}
+		At.Add(At, I)
+
+		err = AtInv.Inverse(At)
+	}
+
+	if err != nil {
+		log.Infof("cannot inverse matrix: %v, try SVD method", err)
+		// 计算矩阵的 SVD 分解
+		var svd mat.SVD
+		ok := svd.Factorize(At, mat.SVDThin)
+		if !ok {
+			fmt.Println("SVD 分解失败")
+			return nil, fmt.Errorf("设计矩阵不可逆, SVD 分解失败: %v", err)
+		}
+
+		// 获取 U、Σ 和 V^T
+		var u, v mat.Dense
+		svd.UTo(&u)
+		svd.VTo(&v)
+		sigma := svd.Values(nil)
+
+		// 计算 Σ^+ (Sigma pseudo-inverse)
+		m, n := u.Dims()
+		sigmaInv := mat.NewDense(n, m, nil)
+		for i := 0; i < len(sigma); i++ {
+			if sigma[i] > 1e-10 { // 避免除以零
+				sigmaInv.Set(i, i, 1/sigma[i])
+			}
+		}
+
+		// 计算 V * Σ^+ * U^T
+		var temp mat.Dense
+		temp.Mul(&v, sigmaInv)
+		AtInv.Mul(&temp, u.T())
+	}
+
+	return &AtInv, nil
+}
+
+// SolveNormalEquation 使用正规方程法求解最小二乘问题
+func SolveNormalEquation(A *mat.Dense, b *mat.VecDense) ([]float64, error) {
+	var At mat.Dense
+	At.Mul(A.T(), A) // At = A^T * A
+
+	// 求解 (A^T * A)^-1 * (A^T * b)
+	var AtInv mat.Dense
+	err := AtInv.Inverse(&At)
+
+	if err != nil {
+		// 岭估计方法调整法方程状态，使得矩阵非奇异，最小二乘平差可以收敛
+		r, c := At.Dims()
+		log.Infof("cannot inverse design matrix(%d*%d): %v", r, c, err)
+		log.Info("try to adjust design matrix with +kI, k=0.0000001")
+		k := 0.0000001 // [0.00000005, 0.000005]
+		I := mat.NewDiagDense(r, nil)
+		for i := 0; i < r; i++ {
+			I.SetDiag(i, k)
+		}
+		At.Add(&At, I)
+
+		err = AtInv.Inverse(&At)
+	}
+
+	if err != nil {
+		log.Infof("cannot inverse design matrix: %v, try SVD method", err)
+		// 计算矩阵的 SVD 分解
+		var svd mat.SVD
+		ok := svd.Factorize(&At, mat.SVDThin)
+		if !ok {
+			fmt.Println("SVD 分解失败")
+			return nil, fmt.Errorf("设计矩阵不可逆, SVD 分解失败: %v", err)
+		}
+
+		// 获取 U、Σ 和 V^T
+		var u, v mat.Dense
+		svd.UTo(&u)
+		svd.VTo(&v)
+		sigma := svd.Values(nil)
+
+		// 计算 Σ^+ (Sigma pseudo-inverse)
+		m, n := u.Dims()
+		sigmaInv := mat.NewDense(n, m, nil)
+		for i := 0; i < len(sigma); i++ {
+			if sigma[i] > 1e-10 { // 避免除以零
+				sigmaInv.Set(i, i, 1/sigma[i])
+			}
+		}
+
+		// 计算 V * Σ^+ * U^T
+		var temp mat.Dense
+		temp.Mul(&v, sigmaInv)
+		AtInv.Mul(&temp, u.T())
+	}
+
+	var Atb mat.VecDense
+	Atb.MulVec(A.T(), b) // Atb = A^T * b
+
+	var x mat.VecDense
+	x.MulVec(&AtInv, &Atb) // x = (A^T * A)^-1 * (A^T * b)
+
+	return mat.Col(nil, 0, &x), nil
+}
+
+func localize(num, den *mat.VecDense, row, col float64) (P, L, H float64) {
+
+	return
+}
+
+func project(num, den *mat.VecDense, P, L, H float64) (v float64) {
+	v = applyPoly(num, P, L, H) / applyPoly(den, P, L, H)
+	return v
+}
+
+func applyPoly(poly *mat.VecDense,
+	P, L, H float64) (v float64) {
+	v = 0.0
+	v += poly.AtVec(0)
+	v += poly.AtVec(1) * L
+	v += poly.AtVec(2) * P
+	v += poly.AtVec(3) * H
+	v += poly.AtVec(4) * L * P
+	v += poly.AtVec(5) * L * H
+	v += poly.AtVec(6) * P * H
+	v += poly.AtVec(7) * L * L
+	v += poly.AtVec(8) * P * P
+	v += poly.AtVec(9) * H * H
+	v += poly.AtVec(10) * P * L * H
+	v += poly.AtVec(11) * L * L * L
+	v += poly.AtVec(12) * L * P * P
+	v += poly.AtVec(13) * L * H * H
+	v += poly.AtVec(14) * L * L * P
+	v += poly.AtVec(15) * P * P * P
+	v += poly.AtVec(16) * P * H * H
+	v += poly.AtVec(17) * L * L * H
+	v += poly.AtVec(18) * P * P * H
+	v += poly.AtVec(19) * H * H * H
+	return v
+}