New Inmarsat Aero-H and H+ Decoder in Development

Another new decoder project is in the works. This is another Multi-Channel decoder for Aero but instead of just ACARS and CPDLC it does AMBE and LPC voice decode. The screenshot below shows call logging status output from the prototype decoder. Like the Aero-P project this decoder uses the same control or NCS channels that carries the ACARS/CPDLC traffic except this application focuses on call “following” and directs up to 8 other decoders for actual voice demodulation. Note the captured call highlighted in yellow below. That is a 519 second AMBE call that was classified as non-safety from the aircraft associated with ICAO address 7CF865, which happens to be an Airbus A-300 registered to the Royal Australian Air Force (RAAF). You can look it up yourself at airframes.org.

Status output from decoders.

Status output from decoders.

The AMBE algorithm for Aero is owned by DVSI and therefore requires licensed HW or SW. I am using licensed HW as shown below. This card was available from DVSI but may no longer be due to the inability for them to acquire all the legacy parts to build the boards! I purchased the board a couple years ago for a Mini-M project.

DVSI AMBE DSP Board.

DVSI AMBE DSP Board.

More updates later as the project continues development.This software is intended for commercial use so please don’t ask if you can download it.

Posted in Inmarsat, Projects Tagged ,

ISEE-3 Frequency Drift Measured

Based on the latest Horizons update by JPL (based on Arecibo observations) I have measured the frequency drift of the spacecraft TX frequency (transponder A RHCP). It appears to be drifting upward at a rate of 3.3 Hz per hour. Not bad for such an old spacecraft. This is unlocked carrier frequency measurement over a 3 hour period.

isee3_drift

Posted in Spacecraft Tagged ,

JPL Updates ISEE3 Horizon Data

Updated my Horizons data for ISEE-3 today and found this nice note:

UPDATE (2014-Jun-23):
Trajectory updated to JPL solution #32 (s32), based on 42 coarse Arecibo plane-of-sky angular measurements spanning May 22 – Jun 23 …

Upon updating things and re-acquiring the signal we have so far a solid signal tracking with little change to frequency. We will see how it performs in next few hours but previously we would observe a 3 Hz per hour change in the frequency. But of course that can just be the unlocked carrier drifting…

Here is screenshot just after re-acquisition.

Signal just after horizon updated.

Signal just after horizon updated.

Posted in Spacecraft Tagged ,

ISEE-3 Signal Getting Stronger

Each day the signal from the old but reliable ISEE-3 spacecraft gets stronger and stronger. I have updated the tracking software to log the signal strength over time.

Latest ISEE-3 Signal.

Latest ISEE-3 Signal.

It’s also very easy to see the signal without averaging as shown below. Paul (@uhf_satcom), over at uhf-satcom has also shown the signal can be found without Doppler correction using just a 1m dish.

ISEE-3 without averaging.

ISEE-3 without averaging.

Posted in Spacecraft Tagged ,

Antenna Tracking Software Updated

I developed this little application a couple years ago to manage shuttle passes for automated s-band reception/recording. I have started using it more for DSN now and so have updated it with some new features.

The tracker gets it’s Ephemeris data via a “Pipe” from other applications, in this case usually another piece of software that interfaces between NASA Horizon database and this application.

The tracker supports Green Heron Engineering controllers via 2 serial ports or an LVB controller via a single serial port.

Besides the usual “Auto Park” and common pointing angles I have added a “Delta” feature to help with off-pointing (validating a signal is coming from spacecraft) as well as spacecraft that are not really where Horizon says they are (ISEE-3) or in special cases like ACE (not in Horizons), where it’s at L1 but offset some number of degrees.

Here is screenshot of the updated application.

pTracker with new features.

pTracker with new features.

Remote operation with this little application allows reception of ACE using the delta controls – without it, i would have needed manual control over the tracking hardware.

ACE reception.

ACE reception.

Posted in Projects, Spacecraft Tagged

Mars Orbiter Mission (MOM) Signal Detected

It’s been an S-Band weekend here. Earlier today the Indian Spacecraft MOM was picked up by DF2MZ as well as UHF-Satcom at a distance of 107 Million km! By the time the spacecraft rose over California Goldstone had locked it up to their ground station and data was being transferred. The signal was well down into the noise, but using some amount of integration the signal was detectable (as shown below). After a few hours Goldstone stopped the data transfer and unlocked the signal, the signal immediately increased in strength and moved to the calculated Doppler target, where it remained for the evening. You see Doppler in the locked signal because the spacecraft is compensating for the Doppler (locking to the ground signal), where on the unlocked signal you don’t see any Doppler, this is because it is being compensated with software using NASA Horizon data. The exact unlocked frequency was 2292.960847 MHz.

MOM going from locked to unlocked.

MOM going from locked to unlocked.

Here is a nice website that gives you the real time status of the DSN (click on image to go to the site).

DSN Now.

Posted in Spacecraft Tagged

ISEE-3 (ICE) Spacecraft Detected

ISEE-3 (ICE) Spacecraft was detected today using a 1.2m dish at 2270.390831 MHz. The signal at this frequency was also simultaneously detected and confirmed by Paul over at UHF-Satcom. The detection was accomplished by integrating multiple FFTs with the spacecraft TX frequency corrected for Doppler. Without precise Doppler correction the signal would not be detectable – I confirmed by turning integration off. I also confirm target by off-pointing the dish confirming loss of signal in multiple directions. The Doppler correction is accomplished with an application that takes NASA Horizon data and calculates a real time adjustment to the TX frequency of the spacecraft. This adjusted “offset” is then used to update the SDR IF frequency. The software that makes this possible was written by r00t in .cz.

Below is a screenshot that pretty much sums things up.

Doppler correct ICE signal.

Doppler correct ICE signal.

Posted in Spacecraft Tagged ,

LRO on S-Band

The Lunar Reconnaissance Orbiter (LRO) is a nice S-Band (2271 MHz) signal coming from the moon to calibrate your dish. This is especially helpful if you need the accuracy for even higher frequencies where the beam-width is narrower. Below is a screenshot after optimization of LNA assembly, calibration of azimuth and elevation as well as adjustment of phase center of the feed.

lro

LRO wilth doppler and sidebands.

LRO wilth doppler and sidebands.

The LNA assembly and feed shown below is just temporary for this measurement. Normally the LNA is located a few meters away inside an equipment box but for this peaking i wanted to remove all feed line loss.

LNA / Feed Assembly for S-Band.

LNA / Feed Assembly for S-Band.

Posted in Spacecraft Tagged ,

Mars and Saturn in June

It’s getting hot and atmospheric conditions are not the best for astrophotography, however stacking 5000 images does help a bit with the variable focus.

Mars.

Mars.

Saturn.

Saturn.

Posted in Astronomy Tagged

Inmarsat Aero-P ACARS Multi-Channel Decoder

Inmarsat Aero-P includes an ACARS service for airlines to use while transiting the various ocean regions. This is much more reliable than HF ACARS. Inmarsat hosts 3-4 Aero-P control channels on L-Band for each ocean region. Each control channel is running OQPSK at 10.5K bits/s rate. This new decoder is actually 4 decoders in parallel and is capable of monitoring an entire ocean region. Currently both RFSpace SDR-IP and NetSDR is supported as well as the QSDR. The required bandwidth is 200 KHz. I can make this work with 190 KHz which would then add the SDR-IQ (with Ethernet server app) to the list of supported SDRs. As usual, this decoder interfaces over Ethernet. Below are a few screenshots of the working prototype.

Here is plot of the 4 channels from the IOR region. These are always on and continuous transmitting so they are easy to find.

IOR Aero-P Control Channels.

IOR Aero-P Control Channels.

The next screenshot is POR region. You can see the 3 Aero-P channels in the IQ Viewer in lower left. Above that are logging windows for each channel, in POR case, there are 3 channels. The other console window is the main decoder log, shows current SDR status, Signal Unit count, ACARS traffic count, CPDLC counts as well as log-on events. All traffic is sorted per aircraft and written to disk – so everything is archived.

POR Aero-P ACARS sample.

POR Aero-P ACARS Sample.

Here is a sample from UHF-Satcom for the AOR region (thanks Paul).

AOR region Aero-P ACARS sample.

AOR region Aero-P ACARS sample.

Here is a sample from another user monitoring IOR region.

IOR region Aero-P ACARS sample.

IOR region Aero-P ACARS sample.

There is support for streaming all TEXT ACARS messages over to Plane Plotter.

Aero-P ACARS on Plane Plotter.

Aero-P ACARS on Plan Plotter.

Below is screenshot of directory where messages are stored. You can see in this case there is some trouble with WIFI.

Sample logging.

Sample logging.

Support for ACARS Display was added, which is a step up from Plane Plotter IMO. You can see that ACARS Display will automatically look up the ICAO based on registration number.

ACARS Display Support.

ACARS Display Support.


If you click on one of the registration numbers (such as B-HKU) you will be brought to a website that will give you up to date information about that aircraft (as shown below).

Flight Lookup.

Flight Lookup.

Posted in Inmarsat, Projects, SATCOM Tagged ,