暂时使用星下点坐标作为图像左上角坐标

pkg/auxilary/aux.go

@@ -0,0 +1,46 @@
+package auxilary
+
+import (
+	"os"
+
+	log "github.com/sirupsen/logrus"
+)
+
+// 卫星时间起点 北京时间 2000-01-01 20:00:00
+var (
+	ReferenceTime2000 = 946728000
+)
+
+func ExtractAux(auxfile string) ([]*AuxFrameHead, []*AuxFocalBox, []*AuxPlatform, error) {
+	data, err := os.ReadFile(auxfile)
+	if err != nil {
+		log.Println("read aux data from", auxfile, "error:", err.Error())
+		return nil, nil, nil, err
+	}
+
+	var afh []*AuxFrameHead
+	var afb []*AuxFocalBox
+	var aps []*AuxPlatform
+
+	for i := 0; i < len(data); i += 24 + 128 + 512 {
+		if i+24+128+512 > len(data) {
+			break
+		}
+		var head AuxFrameHead
+		head.Decode(data[i : i+24])
+		afh = append(afh, &head)
+
+		var box AuxFocalBox
+		box.Decode(data[i+24 : i+24+128])
+		afb = append(afb, &box)
+
+		var plat AuxPlatform
+		plat.Decode(data[i+24+128 : i+24+128+512])
+		aps = append(aps, &plat)
+	}
+
+	log.Printf("extract %d aux frame heads, %d aux focal boxes, %d aux platforms from %s",
+		len(afh), len(afb), len(aps), auxfile)
+
+	return afh, afb, aps, err
+}