13 days ago •
is focused on TX operations for Low Earth Orbit (LEO) satellites. Most
satellites in those orbits transmit signals in relatively low power
(compared to GSO satellites). 100mW to 2W is a typical range for LEO.
Given that power output and our RX assembly (yagi + dvb dongle for
reception) a Low Noise Amplifier can really improve our RX capabilities.
decided that LNA would be an integral part of our RX assembly early on,
but we could not easily find something that would meet our requirements
(bands, noise figure, cost, size etc). After browsing and researching a
lot of different options out there, we stumbled upon LNA4ALL.
 is a great project by 9A4QV. The amplifier is built around
Mini-Circuits PSA4-5043+ E-PHEMT Ultra Low noise MMIC amplifier
operating from 50 MHz to 4 GHz. Small SOT-343 package combine low noise
and high IP3 performance with internal match to 50 ohms. With 20 Euros
as a pricetag, this was the LNA we were looking for.
are using our 5V output from the regulator we have inside SatNOGS as
VCC for the LNA (required a tiny bit of modification) and the LNA is
connected in line between our RX dongle and the antenna (using SMA
tests are showing great improvement in our reception (tested against a
variety of bands, encoding and satellites) making this LNA an
irreplaceable part of our project.
shielding and housing should be in place, so we designed  and 3d
printed quickly a housing for this LNA. Some grounded aluminum tape
makes up for a shield.
More tests will follow, and we are designing new antennas and evaluating their matching.
15 days ago •
as a project has been concieved as many Satellite Ground Station
implementations (like the v0.1 which is ready) coupled together under a
global Network that would enable anyone to utilize SatNOGS as a single
platform for observations.
UX idea is simple. An observer/astronomer/maker/hacker accesses our
global Network via a web interface. Then she provides details about the
observation that she would like to schedule like, which satellite, which
band, what timeframe, which encoding etc. Then, having all the info ,
the system calculates the possible observation windows, on the available
Ground Stations connected to the Network for the given timeframe
(taking into account any tool, location and time constrains). Once the
observer confirms the proposed "observation job" then it gets sent as a
job to each Ground Station (GS) job queue to be executed when it has to.
are gathering observations, decoding/recording them and sending them
back to the Network, making them available to the observer (and the
Here is a glimpse into the initial DB Schema of the Network (not all attributes are populated in the tables)
general design of the Network part of SatNOGS constitutes a typical
many-to-many scheduling problem (many observers to many ground stations)
Interestingly enough projects have been developed for observations
planning and scheduling on satellites like Hubble (HST) Projects like
SPIKE  and ASPEN . Those are examples of many-to-one scheduling
system s and we have been looking around for implementations that would
be similar to our proposed one. Unfortunately we haven't found anything
closely related, thus we are building the Network part from scratch.
the expertise of our software people, we are building the application
part on Django (python), and relying on rest APIs for communication with
our ground stations. The first iteration of the network will be focused on a client-pull approach (versus a server-push) to eliminate any network restrictions.
challenges towards the global network are interesting. Given the
data-heavy approach of the network (imagine all observations from all
stations stored and indexed) we expect data storage to be a serious
challenge. We are evaluating deep-storage as an approach to this, and we
welcome any feedback or ideas around that.
15 days ago •
For v0.2 of our ground station we have been working on consolidation of our electronics trying to minimize size and upgrade the components. Combined with the current minimized approach for the gear assemblies, this will enable us to deliver a smaller more rigid and reliable ground station.
The electronics that needed to be fitted in are the following:
* An Arduino. We selected Pico for the size advantage
* Two stepper drivers. We are using Pololu compatible A4983 based stepper drivers.
Agis (our electronics expert) designed an integrated board to fit everything in. Here is the result:
And the schematic:
We are printing the PCB as we speak and will be posting a new log with the construction and testing.