added stuff for bluetooth

worked on resampling methods

sensors/beacon/BeaconMeasurement.h

@@ -48,6 +48,9 @@ public:
 
     /** get the rssi */
     float getRSSI() const {return rssi;}
+
+    /** set another signal strength */
+    void setRssi(float value){rssi = value;}
 };
 
 

sensors/beacon/BeaconMeasurements.h

@@ -24,11 +24,20 @@ struct BeaconMeasurements {
 
     /** remove entries older then 3000 ms*/
     void removeOld(const Timestamp latestTS) {
-        auto lambda = [latestTS] (const BeaconMeasurement& e) {
-            Timestamp age = latestTS - e.getTimestamp();
-            return age > Timestamp::fromMS(1000*3);
-        };
-        entries.erase(std::remove_if(entries.begin(), entries.end(), lambda), entries.end());
+
+        std::vector<BeaconMeasurement>::iterator it;
+        for (it = entries.begin(); it != entries.end(); ++it){
+            if(latestTS - it->getTimestamp() > Timestamp::fromMS(1000*3)){
+                entries.erase(it);
+            }
+        }
+    }
+
+    void add(const BeaconMeasurement& entry){
+        entries.push_back(entry);
+
+        //remove entries that are to old (3000ms)
+        removeOld(entry.getTimestamp());
     }
 
 };

sensors/beacon/setup/BeaconFingerprint.h

@@ -0,0 +1,103 @@
+#ifndef BEACONFINGERPRINT_H
+#define BEACONFINGERPRINT_H
+
+#include "../../../geo/Point3.h"
+#include "../BeaconMeasurements.h"
+
+#include <unordered_map>
+
+/**
+ * denotes a wifi fingerprint:
+ *	known position and 1-n measurements [wifi-scan on all channels] conducted at this position
+ *
+ * if more than one measurement is conducted, each AP is contained more than once!
+ */
+struct WiFiFingerprint {
+
+
+    /** real-world-position that was measured */
+    Point3 pos_m;
+
+    /** seen APs at the given location */
+    BeaconMeasurements measurements;
+
+    /** ctor */
+    WiFiFingerprint() {;}
+
+    /** ctor */
+    WiFiFingerprint(const Point3 pos_m) : pos_m(pos_m) {;}
+
+    /** ctor */
+    WiFiFingerprint(const Point3 pos_m, const BeaconMeasurements& measurements) : pos_m(pos_m), measurements(measurements) {;}
+
+
+    /** as each AP might be contained more than once (scanned more than once), group them by MAC and use the average RSSI */
+    BeaconMeasurements average() {
+
+        // group scans by MAC (all measurements for one AP)
+        std::unordered_map<MACAddress, BeaconMeasurements> group;
+        for (BeaconMeasurement& bm : measurements.entries) {
+            group[bm.getBeacon().getMAC()].entries.push_back(bm);
+        }
+
+        // create the output that contains the AP's average
+        BeaconMeasurements res;
+        for (auto& it : group) {
+            const BeaconMeasurements& apMeasurements = it.second;
+            BeaconMeasurement avg = apMeasurements.entries.front();			// average starts with a copy of the first entry (to get all data-fields beside the rssi)
+            for (int i = 1; i < (int)apMeasurements.entries.size(); ++i) {		// sum up all other entries [1:end]
+                avg.setRssi(avg.getRSSI() + apMeasurements.entries[i].getRSSI());
+            }
+            avg.setRssi(avg.getRSSI() / apMeasurements.entries.size());
+            res.entries.push_back(avg);										// add to output
+        }
+
+        // done
+        return res;
+
+    }
+
+    /** get all measurements for the given MAC */
+    std::vector<BeaconMeasurement> getAllForMAC(const MACAddress& mac) const {
+        std::vector<BeaconMeasurement> res;
+        for (const BeaconMeasurement& m : measurements.entries) {
+            if (m.getBeacon().getMAC() == mac) {res.push_back(m);}
+        }
+        return res;
+    }
+
+    /** serialize */
+    void write(std::ostream& out) const {
+        out << "pos: " << pos_m.x << " " << pos_m.y << " " << pos_m.z << "\n";
+        out << "num: " << measurements.entries.size() << "\n";
+        for (const BeaconMeasurement& bm : measurements.entries) {
+            out << bm.getTimestamp().ms() << " " << bm.getBeacon().getMAC().asString() << " " << bm.getRSSI() << "\n";
+        }
+    }
+
+    /** deserialize */
+    void read(std::istream& inp) {
+        std::string tmp;
+
+        // read the position
+        inp >> tmp; if ("pos:" != tmp) {throw "error";}
+        inp >> pos_m.x >> pos_m.y >> pos_m.z;
+
+        // number of entries
+        inp >> tmp; if ("num:" != tmp) {throw "error";}
+        int numEntries; inp >> numEntries;
+
+        // read the entries
+        for (int i = 0; i < numEntries; ++i) {
+            uint64_t ms; inp >> ms;
+            std::string mac; inp >> mac;
+            float rssi; inp >> rssi;
+            BeaconMeasurement bm(Timestamp::fromMS(ms), Beacon(MACAddress(mac)), rssi);
+            measurements.entries.push_back(bm);
+        }
+    }
+
+};
+
+
+#endif // BEACONFINGERPRINT_H