Added PassPredict program

.hgignore

@@ -4,6 +4,7 @@ Debug\*
 *.o
 RunTest
 SatTrack
+PassPredict
 *.txt
 *.orig
 *.a

Makefile

@@ -24,7 +24,11 @@ SATTRACK=SatTrack
 SATTRACKSOURCES=SatTrack.cpp
 SATTRACKOBJECTS=$(SATTRACKSOURCES:.cpp=.o)
 
-all: $(SGP4LIB) ${TESTPROG} ${SATTRACK}
+PASSPREDICT=PassPredict
+PASSPREDICTSOURCES=PassPredict.cpp
+PASSPREDICTOBJECTS=$(PASSPREDICTSOURCES:.cpp=.o)
+
+all: $(SGP4LIB) ${TESTPROG} ${SATTRACK} ${PASSPREDICT}
 
 ${SGP4LIB}: ${OBJECTS}
 	${AR} -rcs -o $@ ${OBJECTS}
@@ -35,8 +39,11 @@ ${TESTPROG}: ${SGP4LIB} ${TESTPROGOBJECTS}
 ${SATTRACK}: ${SGP4LIB} ${SATTRACKOBJECTS}
 	${CC} ${SATTRACKOBJECTS} ${LDFLAGS} -static -L. -lsgp4 -o $@
 
+${PASSPREDICT}: ${SGP4LIB} ${PASSPREDICTOBJECTS}
+	${CC} ${PASSPREDICTOBJECTS} ${LDFLAGS} -static -L. -lsgp4 -o $@
+
 .cpp.o:
 	$(CC) $(CFLAGS) $< -o $@
 
 clean:
-	rm -rf *.o ${SGP4LIB} ${TESTPROG} ${SATTRACK}
+	rm -rf *.o ${SGP4LIB} ${TESTPROG} ${SATTRACK} ${PASSPREDICT}

PassPredict.cpp

@@ -0,0 +1,151 @@
+#include "Observer.h"
+#include "SGP4.h"
+
+#include <iostream>
+
+Julian FindCrossingPoint(const CoordGeodetic& user_geo, SGP4& sgp4, const Julian& initial_time1, const Julian& initial_time2, bool finding_aos) {
+
+    Observer obs(user_geo);
+    Eci eci;
+
+    bool searching = true;
+    unsigned int loop_count = 0;
+
+    Julian time1 = initial_time1;
+    Julian time2 = initial_time2;
+
+    Julian middle_time = time1 + (time2.GetDate() - time1.GetDate()) / 2.0;
+
+    while (searching && loop_count < 25) {
+
+        sgp4.FindPosition(&eci, middle_time);
+        CoordTopographic topo = obs.GetLookAngle(eci);
+
+        if (topo.elevation > 0.0) {
+
+            if (finding_aos) {
+                time2 = middle_time;
+            } else {
+                time1 = middle_time;
+            }
+        } else {
+
+            if (finding_aos) {
+                time1 = middle_time;
+            } else {
+                time2 = middle_time;
+            }
+        }
+
+        /*
+         * when two times are within a second, stop
+         */
+        if (((time2.GetDate() - time1.GetDate()) * kSECONDS_PER_DAY) < 1.0) {
+            searching = false;
+        }
+
+        middle_time = time1 + (time2.GetDate() - time1.GetDate()) / 2.0;
+        loop_count++;
+    };
+
+    return middle_time;
+}
+
+void AOSLOS(const CoordGeodetic& user_geo, SGP4& sgp4, const Julian& start_time, const Julian& end_time) {
+
+    Observer obs(user_geo);
+    Eci eci;
+
+    bool first_run = true;
+    Julian previous_time = start_time;
+
+    Julian aos_time;
+    Julian los_time;
+    bool found_aos = false;
+    bool found_los = false;
+
+    for (Julian current_time = start_time; current_time <= end_time; current_time.AddMin(1.0)) {
+
+        sgp4.FindPosition(&eci, current_time);
+        CoordTopographic topo = obs.GetLookAngle(eci);
+
+        if (topo.elevation > 0.0) {
+            /*
+             * satellite is above horizon
+             * and its the first run, so just use start_time
+             */
+            if (first_run) {
+
+                aos_time = start_time;
+                found_aos = true;
+                found_los = false;
+
+                /*
+                 * not the first iteration and satellite has
+                 * gone above horizon, so find AOS
+                 */
+            } else if (!found_aos) {
+
+                aos_time = FindCrossingPoint(user_geo, sgp4, previous_time, current_time, true);
+                found_aos = true;
+                found_los = false;
+            }
+        } else {
+            /*
+             * if satellite now below horizon and have found previous AOS
+             * find LOS
+             */
+            if (found_aos) {
+
+                los_time = FindCrossingPoint(user_geo, sgp4, previous_time, current_time, false);
+                found_aos = false;
+                found_los = false;
+                std::cout << "AOS: " << aos_time << ", LOS: " << los_time << std::endl;
+            }
+        }
+
+        first_run = false;
+        previous_time = current_time;
+    }
+
+    if (found_aos && !found_los) {
+
+        los_time = end_time;
+        std::cout << "AOS: " << aos_time << ", LOS: " << los_time << std::endl;
+    }
+}
+
+int main() {
+
+    CoordGeodetic geo(51.37322, 0.089607, 0.05);
+    Tle tle("STS 134                 ",
+            "1 37577U 11020A   11146.50425755  .00016213  00000-0  10821-3 0   213",
+            "2 37577  51.6484 271.9502 0003400 321.9646 127.1023 15.75523823  1551");
+    SGP4 sgp4(tle);
+
+    Julian start_date;
+    Julian end_date(start_date);
+    end_date.AddDay(10.0);
+
+    /*
+     * generate 10 day schedule
+     */
+    AOSLOS(geo, sgp4, start_date, end_date);
+
+    return 0;
+#if 0
+    Eci eci;
+
+    while (1) {
+        Julian now;
+        sgp4.FindPosition(&eci, now);
+        CoordTopographic topo = obs.GetLookAngle(eci);
+        CoordGeodetic geo = eci.ToGeodetic();
+        std::cout << now << " ";
+        std::cout << topo << " ";
+        std::cout << geo << std::endl;
+    };
+
+    return 0;
+#endif
+}