Modesdeco 2 with SBS-3

[AntRivas]

Hi everyone,

I was interested in obtaining airspeed using SBS-3, so after looking for information I read that it is possible with Modesmixer2. Thus my first question is if this is true, because I'm starting and am not 100% certain.

However, I have downloaded modesdeco2 and modesmixer2 to start practicing but when running the following bat file:

@echo off
C:\Users\Antonio\Desktop\modesdeco2\modesdeco2.exe --gain 49.6 --freq-correction 62 --location 37.16:-5.93 --web 8088 --db C:\Users\Antonio\Desktop\BaseStation\BaseStation.sqb
PAUSE

And error appears indicating that "can't open device: sdr_open(): Bad file descriptor"

How could it be solved?

I have to say that I'm trying to learn as quickly as possible but it is a huge unknown world for me and I would be very grateful if you could help me.

Ah, and I'm using the last BS Firmware (119) and my OS is Windows 10.

Thank you for your help.

[AntRivas]

Hi everyone

I've read a lot of the posts and threads about the connection between BaseStation and Modesdeco2 but I have not achieved it.

I'm trying to connect BaseStation (I have a SBS-3) to Modesdeco2, as sergsero explained in this post https://radarspotting.com/forum/index.php/topic,8102.30.html

However, when I type "modesdeco2 --device-list" it returns that there is no available RTL devices. Do you know what RTL dongle is recommended to make it works?

Thank you so much

PD: I don't know if this point is decisive, but I'm using the USB connection between SBS-3 and PC (not the ethernet). When I get to configure this connection is when I want to transmit data through ethernet.

[IanH]

modeSdeco2 is used for connecting to a SDR dongle. So not relevant to you.

You can connect your SBS-3 directly to BaseStation - you don't need any other software.

Edit: just seen your first post - I need to read and understand that now. 

[Triple7]

Edit: just seen your first post - I need to read and understand that now. 

Likewise! I typed a response and then deleted it all. I will review again tomorrow.

Tim

[IanH]

If you expand the data in BaseStation (click the "Open" button), are you sure that airspeed is not shown?

I can see "Speed" but Ihave modified what is shown so possibly it is not the default setup.

[sergsero]

Hi AntRivas,

As noted above, modesdeco2 is used to work with other types of receivers and in your case is not required.

Further, it should be clarified what you mean by the term "airspeed". In aviation, there are several types of airspeed related to aircraft such as:

• Ground speed (GS) is the horizontal speed in which the aircraft moves relative to a fixed point on the ground.
• True airspeed (TAS) is the speed in which the aircraft moves relative to the surrounding air.
• Indicated airspeed (IAS) is the number displayed on the aircraft's airspeed indicator (ASI).
• Calibrated airspeed (CAS) is calculated from IAS and correcting it for measurement errors.
• The Mach number (M) is the speed of the aircraft divided by the speed of sound at that temperature of the surrounding air.

Native software of the SBS-3 receiver (basestation.exe) displays GS.

Modesmixer2 decodes and displays GS and TAS, IAS, M (for the currently used transponders, typically in the presence of a UP-signal from Mode S interrogators).

There is the following relationship between these speeds:
Indicated airspeed (IAS) +- instrument, position and calibration errors ---> Calibrated airspeed (CAS). For most people/airplanes/situations, CAS ~= IAS.

CAS (or ~= IAS) +- density correction ---> True airspeed (TAS).  It is always less than TAS.  The reason for this is that the ASI actually measures the dynamic pressure (or the pressure of the air moving over the wings). However, the dynamic pressure varies at different altitudes, and is proportional to the air density (Dynamic Pressure = half air density x velocity squared).  The air is thinner at altitude, so the dynamic pressure will be less for the same airspeed, which means IAS will reduce as you climb, regardless of the rate of movement, while TAS will be consistent.

TAS +- head/tailwind component (vector addition) ----> Ground speed (GS).

However, I think you are interested in the airspeed to get the wind parameters closest to point aircraft location. It is calculated inside the program using TAS and additional vector components of Track Angle and Heading.

Regards,
sergsero

[AntRivas]

Hi sergsero, IanH and Triple 7,

First of all, thank you for your attention and comments. They are very important because I'm starting and have lot of dudes  .

To clarify why I'm using SBS-3 I'm going to explain the purpose of the project I'm carrying out. The idea consists in using aircrafts as air weather stations, so we could obtain a more accurate measurements of windspeed and improve its prediction.

So, as sergsero has perfectly explained the most interesting "airspeed" for me would be the TAS. And I have to recognize my mistake due to I understood that BS only provides GS and reading ModeSMixer and ModeSDeco posts I thought they would be the solution 

Thank you so much again

[AntRivas]

If you expand the data in BaseStation (click the "Open" button), are you sure that airspeed is not shown?

I can see "Speed" but Ihave modified what is shown so possibly it is not the default setup.

Hi IanH

Sorry because my description was deficient. BS show GS but I'm interested in TAS and I thought I had to use a third application to get it.

Regards,
AntRivas