## 7 Experimental Description and Result Analysis  
Our proposed integrated architecture is examined through a live test which was collected by a ground vehicle in an operational traffic environment in Malaga, Spain and is publicly available online [13]. The IMU and monocular forward-looking camera sensors were rigidly fixed on the vehicle rooftop. In order to provide a truth reference solution, three RTK GPS receivers were installed on the vehicle to generate centimeter-level positioning and orientation solutions. In total six drive segments have been accomplished, however the corresponding truth references were vulnerable to limited signal qualities. The _Campus_0L_ segment had full range availability of truth reference and contains most common ground vehicle dynamics, such as acceleration, deceleration, stillness, forward driving, cornering, _etc._, and it is therefore adopted in this paper to test our integrated design. Other sensors utilized during the drive test, such as laser scanners, are disregarded. Table 1 presents some basic information of the overall drive test. In attempt to keep the recorded data from all sensors available during the whole test, we deliberately remove the beginning of the dataset when the vehicle was keeping static and the sensors were being powered on sequentially. The timespan in Table 1 is, consequently, approximately 20 s shorter than in the actual case. Figure 5: Flowchart of the proposed EKF-based architecture. Table 2 lists the individual IMU sensor specification of Xsens MTi enclosure [37]. Although this product enables 3D axes-based magnetometer to compensate for gyroscope drift, we ignore the magnetic field data and just make use of the 6-DOF raw angular rate and specific force measurements. Table 3 summarizes the major intrinsic calibration parameters from the camera. There were actually two cameras of the same model mounted at both sides in front of the vehicle rooftop. Without loss of generality, only the left camera is employed in this paper and parameters in Table 3 are, accordingly, derived from the left one. The parameters \(f_{x}\) as well as \(f_{y}\) denote the location of the principal point by means of pixel element on the image plane. The focal length is, similarly, defined in terms of pixel element in both x and y axes, and is hence depicted as \(c_{x}\) and \(c_{y}\). The remainder of the parameters in Table 3 are radial and \begin{table}
\begin{tabular}{c c} \hline \hline \multicolumn{2}{c}{_CAMPUS-0L_ **test details**} \\ \hline Data-collection time (UTC) & 2008/11/09, 10:07:57 \\ Distance of travel & 1,139 m \\ Timespan & 322 s \\ IMU make/model & Xsens MTi \\ IMU output rate & 100 Hz \\ Camera make/model & AVT Marlin F-131C \\ Image frame rate & 7.5 Hz \\ Image resolution & 1,024 \(\times\) 768 \\ Truth output rate & 100 Hz \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Basic information of the live drive test (Reproduced with permission from [13]). \begin{table}
\begin{tabular}{c c} \hline \hline \multicolumn{2}{c}{**Gyroscope**} & **Accelerometer** \\ \hline Drift rate & 1 deg/s & 0.02 m/s\({}^{2}\) \\ Noise & 0.05 deg/s/Hz & 0.002 m/s\({}^{2}\)/kHz \\ Bandwidth & 40 Hz & 30 Hz \\ Misalignment & 0.1 deg & 0.1 deg \\ Scale factor & — & 0.03\% \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Gyroscope and Accelerometer specification of Xsens MTi enclosure (Reproduced with permission from [37]). \begin{table}
\begin{tabular}{c c} \hline \hline \multicolumn{2}{c}{**AVT Marlin F-131C camera**} \\ \hline \(f_{x}\)(pixel) & 923.5295 \\ \(f_{y}\)(pixel) & 922.2418 \\ \(c_{x}\)(pixel) & 507.2222 \\ \(c_{y}\)(pixel) & 383.5822 \\ \(k1\) & \(-0.353754\) \\ \(k2\) & 0.162014 \\ \(p1\) & \(1.643379\times 10^{-3}\) \\ \(p2\) & \(3.655471\times 10^{-4}\) \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Intrinsic camera parameters of the camera in use (Reproduced with permission from [13]). tangential distortions, respectively.