Reviewer #1:

The paper presents a smartphone-based localization system using a particle filter to incorporate different probabilistic models. The comments and suggestions as follows:

1. The authors mention that "a setup-time of under 120 min for the complete building" in abstract. But I don't find any context about the setup-time in the whole paper. How does the "under 120 min" calculate? How long does the navigation mesh for the whole buliding take? How long does the 42 WiFi beacon installation take? How does the measuremnet of the reference points take? etc. The authors should give the details.
-> 120 museum has enough power outlets, requires it for the vitrinen... (am anfang von den experimenten was dazu schreiben)
-> 120 was misleading. the 120 min war bezogen auf onside setup.. however, we have now addded how the system is setup and what step took what time. 

2. The authors mention that the historical buildings "environments that are not built with localization in mind or do not provide any wireless infrastructure". But the WiFi beacons still need to be plugged into the power outlets. That means the whole building need 42 available power outlets. Does the WiFi beacon install in special position? I think the historical buildings don't have enough power outlets or the power outlets don't be available in a suitable position, maybe there is no power outlets at all in the whole corridor for example. 

3. The authors meation that "This leads to problems for methods using received signal strengths indications (RSSI) from Wi-Fi or Bluetooth, due to a high signal attenuation between different rooms". However the WiFi beacon this paper used will meet the same issues, the authors also use the RSSI of the WiFi beacons? How does the WiFi beacon avoid the high signal attenuation between different rooms?
-> We clarified this statement within the text. The text passage you mentioned should not refer to the beacons, but to our used optimization method, see line xxx to xxx. As you correctly stated, the beacons are not able to avoid high signal attenuation. However, as they are very cheap (less then 10 $), we are able to increase the coverage by identifying weak spots. This makes the localization system a bit more independent, e.g. if some building should provide its own Wi-Fi infrastructure. 

4. The authors mention that an optimization scheme can avoid inaccuracies that "outdated fingerprints caused by changes of the environment or inaccurate building plans". However the paper also use the recent RSSI measurements of nearby AP’s and signal strength predictions and "Each reference location was scanned 30 times (≈ 25 s scan time) using a Motorola Nexus 6 at 2.4 GHz band only". How can the reference poits to deal with the changes of the environment? Only 25 scan for each poit at the setup? I can't find any special details to deal with the environment changing issues.
-> Thank you very much for pointing this out. Your concerns are valid. This was a misformulation within the introduction of the paper. We have improved the relevant section of the text and made the basic statement clearer. Please refer to line xxx and xxx.

5. The author mention that "Such buildings are often full of nooks and crannies, what makes it hard for dynamical models using any kind of pedestrian dead reckoning (PDR)","the error accumulates not only over time, but also with the number of turns and steps made". So "Thus, this paper presents a robust but realistic movement model using a three-dimensional navigation mesh based on triangles". However, Why does the three-dimensional navigation mesh can deal with the turns and steps error? The author should give the more detail description. The navigation graph uses 30*30 grid-cell, the navigation mesh uses triangles. But I don't find very clear that how does the triangles plan? More triangles can improve the accuracy or not? Why the the ground floor need 320 triangles? This the minimum?
-> We completely changed the transition part, describing how both, graph and nav-mesh are generated automatically, based on the building's floorplan. The number of required triangles strongly depends on the building's layout. 320 were required for the building presented within the picture.


6. The authors emphasize that "The goal of this work is to propose a fast to deploy and low-cost localization solution, that provides reasonable results in a high variety of situations". But for the 2500m2 building they used 42 WiFi beacon. I don't think the number is few. Is the whole 42 beacon necessary? The author should discuss the impact of the number of WiFi beacon. How many are the reference poits? What's the impact of the density of the reference points? If the authors want to emphasizen the fast deploy and low-cost, they should give more detail discussion, also the "high variety".
-> 2500m2 sind nur die bereiche in denen gelaufen werden kann. ohne den innenhof. die zahl ist also etwas verwirrend... 
