Recordings of Artemis I LunaH-Map with the Allen Telescope Array on 2022-11-16

This dataset contains IQ recordings of the X-band 8451.7 MHz MHz telemetry signal from the Artemis I LunaH-Map cubesat. The recording was done on 2022-11-16, about seven hours after launch. Antennas 1a and 5c from the Allen Telescope Array were used in dual XY (linear) polarization.

The hardware configuration was as follows: the antennas were connected to RFCB LO d, which was tuned to a frequency of 8451.5 MHz and used an output IF of 512 MHz. A USRP N321 and a USRP N320 were connected to the IF output of the RFCB. The USRP N321 digitized both polarizations of antenna 1a, while the USRP N320 digitized both polarizations of antenna 5c. The USRPs used an external 10 MHz reference and PPS coming from the observatory distribution system, and LO sharing was set up among all the channels. The IQ sample rate of the USRPs was 1.92 Msps, and a GNU Radio flowgraph was used to record IQ data to disk. The GNU Radio flowgraph stored the IQ data for each channel as 16-bin integers in the GNU Radio metatata file format, with detached headers.

After recording, the data was converted to SigMF format. The detached headers are also provided in the dataset (they have the .hdr extension).

There are two recordings in this dataset. In the first one, LunaH-Map is transmitting a PCM/PM/bi-phase-L signal at approximately 48 kbaud. In the second one, LunaH-Map is transmitting a PCM/PM/NRZ signal at approximately 255 kbaud.

Since the second recording doesn't have good enough SNR for error-free decoding with a single antenna, the two antennas were beamformed by determining the correct complex amplitude, delay and frequency offsets for the two antennas, and by correcting these parameters before adding the signals. The beamformed signal is provided in the HMAP_2022-11-16T15:16:06_beamform SigMF dataset. In this dataset, the signal polarization has been synthesized by finding the correct amplitude and phase offset between the X and Y channels of each antenna, and adding coherently both channels before beamforming.