Fringe fitting was performed for the August 3rd and July 2nd observations. Both observations used the Hobart, Katherine and Yarragadee 12m antennas, whilst the July 2nd observation also featured Ceduna. Following this, the phase calibrator scans were correlated. As shown in Table 1, two phase calibrators were used for each experiment. For the August 3rd observation, the J2229-0832 scans were all detected, though the J2240-0836 scans were too weak to be detected along any baseline for the scan lengths used. Similarly for the July 2nd observation, J2211-1150 was too weak to be detected, whilst J2211-1328 was stronger, though only definitively detected along baselines including the larger Cd antenna. The single band delay was nominal on all of the detected scans, indicating a successful fringe fitting.
The August 3rd observation was used for subsequent spacecraft correlation due to the successful natural source correlations along all baselines. The Duev, Sekida & Fukushima, and spacecraft ranging models [21] were all used separately to generate the near-field model, with negligible differences in the single band delay of less than 0.1 nanoseconds, though the Duev model was used for the final product. The correlation had a significant single band delay despite the nominal single band delay in the phase calibrator scans. For example, the first JUICE scan had a single band delay of 251.149 ns along the Hb-Ke baseline with left-left polarisation, whilst the phase calibrator scans had single band delays of less than 0.01 µs.
After testing a numerous combination of spectral resolutions, integration times and kernels with negligible change, the source of error is likely to have arisen either from the error in the telescope pointing offset compared to the spacecraft’s actual position, or errors in the SPICE JUICE kernel due to inaccuracies in the orbital modelling. Further experiments and validation of the spacecraft positions in CASA/AIPS will determine which of these errors has caused this.
AIPS was used to produce images of the spacecraft and the phase calibrator source. An image of the phase calibrator source is shown in Fig. 4. The image shows the compactness of the source and its suitability to be used as a reference source for these types of experiments. An image of JUICE is shown in Fig. 5. In the plot, the power spectra of the signal have been overlaid to the dirty image of the spacecraft. The spacecraft is far away from the phase centre, due to errors on the orbit. That is expected, since the number of observations and tracking data is limited during the cruise phase.

[Figure: Figure 4: Image of J2229-0832 produced from the phase calibrator scans of the August 3rd]

experiment with the Aid of Dr Sándor Frey. Hb, Ke and Yg were used, which shows the resolved source at the expected position with an extended feature and minimal structure.

[Figure: Figure 5: Image of JUICE produced from the August 3rd observation with the aid of Dr Ross Burns. The spacecraft image is displayed with an overlay of its spectra, with the narrow tone at the expected spacecraft frequency confirming the source as JUICE.]

Previous studies imaging spacecraft with the PRIDE VLBI technique were published only two years after observations were taken, due to the complexity of the observations and the development of the technique [2, 14]. We have achieved the data compilation, processing and production of images in only 3 months, with a plethora of software packages used.
All of the calibrations and corrections from the Observation Technique section have been conducted in order to produce these images. We detected JUICE despite its coordinates being erroneous by several kilometres, which is normal during cruise phase; spacecraft orbits become much more precise when orbiting planets. However, this further demonstrates the ability of PRIDE to contribute to the orbital modelling. Work is ongoing to precisely determine the magnitude of these errors and incorporate it into the orbit predictions.