FrankE
a2c9e575a2
- worked on about everything - grid walker using plugable modules - wifi models - new distributions - worked on geometric data-structures - added typesafe timestamps - worked on grid-building - added sensor-classes - added sensor analysis (step-detection, turn-detection) - offline data reader - many test-cases
93 lines
2.2 KiB
C++
93 lines
2.2 KiB
C++
#ifndef WIFIPROBABILITYGRID_H
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#define WIFIPROBABILITYGRID_H
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#include <fstream>
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#include "../../math/Distributions.h"
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#include "../../data/Timestamp.h"
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#include "WiFiProbability.h"
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/**
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* probability is calculated by comparing pre-calculated wifi-signal-strengths
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* attached to each grid-node with a given WiFiMeasurements data structure
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*/
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class WiFiObserverGrid : public WiFiProbability {
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private:
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/** base-sigma to use for comparison */
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float sigma = 8.0f;
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/** additional sigma-per-second (measurement age) to*/
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float sigmaPerSecond = 1.5;
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public:
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/** ctor with uncertainty */
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WiFiObserverGrid(const float sigma) : sigma(sigma) {
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;
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}
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/**
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* get the given GridNode's probability.
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* compares the predicted signal-strengths stored on the given node
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* with the provided WiFi measurements
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*/
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template <typename Node> double getProbability(const Node& n, const Timestamp curTime, const WiFiMeasurements& obs) const {
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double prob = 0;
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// process each observed measurement
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for (const WiFiMeasurement& measurement : obs.entries) {
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// determine the age for this measurement
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const Timestamp age = curTime - measurement.getTimestamp();
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// sigma grows with measurement age
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const float sigma = this->sigma + this->sigmaPerSecond * age.sec();
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// the RSSI from the scan
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const float measuredRSSI = measurement.getRSSI();
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// the RSSI from the model (if available!)
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const float modelRSSI = n.getRSSI(measurement.getAP().getMAC());
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// no model RSSI available?
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if (modelRSSI == 0) {continue;}
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// compare both
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const double p = Distribution::Normal<double>::getProbability(measuredRSSI, sigma, modelRSSI);
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// adjust using log
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prob += std::log(p);
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}
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//return std::pow(std::exp(prob), 0.1);
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return std::exp(prob);
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}
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/** gnuplot debug dump */
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template <typename Node> void dump(Grid<Node>& grid, const Timestamp curTime, const WiFiMeasurements& obs, const std::string& fileName) {
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std::ofstream out(fileName);
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out << "splot '-' with points palette\n";
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for (const Node& n : grid) {
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const float p = getProbability(n, curTime, obs);
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out << n.x_cm << " " << n.y_cm << " " << n.z_cm << " " << p << "\n";
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}
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out << "e\n";
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out.close();
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}
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};
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#endif // WIFIPROBABILITYGRID_H
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