###### Abstract  
Global navigation satellite systems play a significant role in the development of intelligent transport systems, where the estimation of the vehicle's position is a key element. However, in strongly constrained environments such as city centers, the definition of quality metrics and the assessment of positioning performances are challenges to be addressed. Due to the variability of different urban scenarios, the modeling of the dynamics as well as the architecture of the positioning platform, which might embed other sensors and aiding means to the GNSS unit, make it hard to define unambiguous positioning metrics. Performance assessment through analytical models and simulators can be ineffective in terms of cost, complexity, and general validity and scalability of the results. This paper shows how a record and replay approach can be an efficient solution to grant fidelity to a realistic scenario. This work discusses advantages and disadvantages with emphasis on the case study of harsh scenarios. Such an approach requires proper data collections that allow the replay phase to test the GNSS-based positioning terminals. This paper presents the results obtained on a set of field tests related to different scenarios, selected as representative for the key performance indicators assessment. GNSS; SDR; record and replay; GNSS receiver testing; RF front-end ArticleBenefits and Limitations of the Record and Replay Approach for GNSS Receiver Performance Assessment in Harsh Scenarios  
[PERSON], [PERSON], [PERSON], and [PERSON] 1  
1 Department of Electronics and Telecommunications, Politecnico di Torino, 10129 Torino, Italy; [EMAIL_ADDRESS]  
2 Finnish Geospatial Research Institute (FGI), Geodeetinrinne 2, 02430 Masala, Finland; [EMAIL_ADDRESS]  
2018  
targeting full connectivity with other cars and infrastructure enabling the so-called vehicle-to-vehicle (V2V) and vehicle-to-Infrastructure (V2I) communications [4]. Given this picture, the GNSS receiver performance assessment in the framework of the road environment is a key point in the development process of smart transportation that exploits the ITS technology. As part of a more complex positioning unit that we define in the following as a GNSS-based positioning terminal (GBPT), the standalone GNSS performance is often hidden since only the final position is of concern to the users. However, GNSS is still an essential part of the GBPT since many other systems provide solutions that are relative to an absolute GNSS position (e.g., inertial navigation systems, INS), or are used either to refine or aid the GNSS solution, with several possible levels of hybridization. Therefore, it is important to assess the performance of GNSS standalone in such an environment, in order to be able to define a basis for the integration with other sensors and with the communication layer. This paper addresses the problem of GBPT testing, focusing on the specific GNSS performance, for the performance evaluation in terms of the typical key performance indicators (KPIs) of the ITS sector [5]. The evaluation should be performed by means of statistical assessments, providing scenario-independent results of general validity. This is almost impossible in diverse and variable environments (e.g., urban). GNSS performance can be quite different in small and large cities, depending, for example, on the height of the surrounding buildings, on the width of the streets, and on a plethora of other environmental features. The record and replay technique proposed in this paper is derived from the software-defined radio (SDR) paradigm [6]. It relies on raw digitized samples of the GNSS signals collected in the field that can later be re-modulated into a signal that can be fed to any commercial receiver under test. A variety of commercial devices can record and replay GNSS signals. Some of them can also record a range of additional signals, synchronised to the GNSS input, increasing the level of playback realism [7; 8].