Benefits and Limitations of the Record and Replay Approach for GNSS Receiver Performance Assessment in Harsh Scenarios

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.

On the Use of an Ultra-Tight Integration for Robust Navigation in Jammed Scenarios

“…Moreover, it enables the possibility of capturing a specific event from the real world and then replay as many times as desired under exactly the same conditions, for deeper and refined analyses. Interested readers can find more details on [20][21] where the topic is discussed thoroughly supported by the presentation of experimental results.…”

A Controlled-Environment Quality Assessment of Android GNSS Raw Measurements

“…Different Android devices and the GNSS antenna transmitting simulated GNSS signals are clearly visible in the left pictures reported in Figure 6. The transmission and reception of GNSS signals was pursued according to the Record and Replay paradigm [11]. A block scheme of the setup is shown in Figure 7.…”

“…The study allowed to determine the quality of the measurements without the presence of multipath and external spurious signals. The tests were performed by means of the record-and-replay technique [11] applied to simulated GNSS signals by means of an IFEN TM NavX hardware signal generator and constellation simulator. Positioning solutions were evaluated with different carrier-smoothing algorithms to reach high precision and verify the performance of the obtained navigation solutions.…”

“…For this, the Klobuchar ionospheric model using broadcast ephemeris and the Hopfield troposphere model were implemented. For a fair comparison, a common subset of satellites were selected for all the smartphones, including GPS signals with PRN 1,10,11,14,18,22,27, and 32. Even though data collection was performed simultaneously and at the same location, it was not possible to ensure that all satellites were always in a tracking state for all the smartphones and, thus, to guarantee perfectly equal conditions.…”

Dynamic Performance Evaluation of Various GNSS Receivers and Positioning Modes with Only One Flight Test

“…Even if the time correlation of GNSS signals between multiple test sessions is high, different trajectories or attitudes might induce large differences in GNSS signal quality. Post-processing RINEX (receiver independent exchange format) data from various receivers can be one of the good options for evaluating the characteristics of receiver measurements in a dynamic environment [7,8]. This method is suitable for evaluating the measurement quality of each receiver and for analyzing the performance of known or newly developed algorithms, but it has limitations in evaluating the performance of commercial receivers whose detailed positioning algorithms are not disclosed.…”