辅助数据拟合

pkg/auxilary/image_time.go

@@ -0,0 +1,62 @@
+package auxilary
+
+import (
+	"fmt"
+	"os"
+)
+
+// PAN 16 行 / MSS 4 行 图像对应 1 行辅助数据记录，需要单独计算图像行时间
+type ImageTime struct {
+	auxT []*auxT
+}
+
+type auxT struct {
+	Tutc float64
+	Row  int
+}
+
+func NewImageTime() *ImageTime {
+	return &ImageTime{
+		auxT: make([]*auxT, 0),
+	}
+}
+
+func (it *ImageTime) Extract(aps []*AuxPlatform) {
+	var sec, microsec uint32
+	for i, ap := range aps {
+		if ap.UTCTimeSec != sec || ap.Microsecond != microsec {
+			sec, microsec = ap.UTCTimeSec, ap.Microsecond
+			t := float64(ap.UTCTimeSec) + float64(ReferenceTime2000) + float64(ap.Microsecond)/1e6
+			it.auxT = append(it.auxT, &auxT{Tutc: t, Row: i})
+		}
+	}
+}
+
+// Interp 内插出成像时刻
+// 参数: imgrow 图像行号 cross 图像跨度 aps 辅助平台列表
+// 返回值: 成像时刻(UTC seconds)
+func (it *ImageTime) Interp(imgrow int, cross int) (float64, float64) {
+	// 内插出成像时刻
+	u := int(imgrow / cross)
+	var u1, u2 *auxT
+	for i, a := range it.auxT {
+		if a.Row > u {
+			u1 = it.auxT[i-1]
+			u2 = a
+			break
+		}
+	}
+	dt := (u2.Tutc - u1.Tutc) / float64(cross*(u2.Row-u1.Row))
+	t := u1.Tutc + dt*float64(imgrow-u1.Row*cross)
+	return t, dt
+}
+
+func (it *ImageTime) Print(n int, cross int) {
+	f, _ := os.Create("log/image_time.txt")
+	defer f.Close()
+	for i := 0; i < n; i++ {
+		t, dt := it.Interp(i, cross)
+		s := fmt.Sprintf("%d %f %f\n", i, t, dt)
+		f.WriteString(s)
+	}
+}