Questions tagged [satellite]

Circuit design for satellites differs because of the space environment, which includes designating for vacuum, large temperature swings, and radiation tolerance. Satellite circuits should be able to handle latch ups and Single Event Upsets (SEU's) from radiation that ionizes silicon channels and recover from faults.

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GSM/GPS Performance difference between a vehicle tracker and mobile phone

I have used a vehicle tracking device (details attached below) and I have noticed something strange. I am actually comparing a mobile phone with a vehicle tracking device as both have GSM (SIM cards) ...
1 vote
62 views

Measuring Doppler and Doppler rate at a receiver

I am simulating receiving a digital signal, QAM modulation, raised cosine pulses... from a satellite to a receiver on the ground. I wanted to honestly simulate measuring the Doppler and Doppler rate ...
1 vote
83 views

What is the maximum relative speed at which wireless protocols can operate? (Doppler shift)

Let's take Wi-Fi and UWB. What determines in these standards their robustness to Doppler shift? The most obvious is the range of carrier frequency tolerance. But in both standards this range is ...
107 views

Computation Doppler shift in ppm

I am computing Doppler shift for different flying platforms and after my first presentation, it was suggested to revise in ppm. I compute always in Hz and have never heard even about this unit until ...
444 views

How is Doppler beam sharpening and synthetic aperture forming the same thing?

There's a quote here from Carl Wiley, the inventor of synthetic aperture radar: "I had the luck to conceive of the basic idea, which I called Doppler Beam Sharpening (DBS), rather than Synthetic ...
499 views

I'm working on a cubesat project intended to operate in low earth orbit. We're considering a few different options for our flight computer, ranging from Raspberry Pi to something like STM32L476. ...
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Radius of footprint vs altitude: math equation

I want to compare footprint size/beam size of satellite and plot “radius of footprint vs. altitude” variation. ( my main reference( see above) is 3GPPTR38_821/Solutions for {NR} to support non-...
47 views

How to compute a data rate "loss"?

I am studying 6G communication. There are a lot of publication about it, frequency, latency, BW and other KPIs.[1],[2] Now one of the most popular research topics is an integration non-terrestrial ...
1k views

How to compute propagation delay of satellite

In the table propagation delays of different satellite system are given. I want to reproduce the data of this table. According to my understanding, propagation delay is $$\tau =\frac{D}{V},$$ where \\$...
2k views

What are the limitations of USB in aerospace (especially microsatellites)?

I have just joined a startup company that builds microsatellites. But I am quite new to the aerospace field. I noticed that to connect components with the onboard computer we use many electrical ...
62 views

How to compute link budget in a system with aero/space-borne integration

I am studying a system in 5G which are represented as a combination terrestrial and non-terrestrial network (including satellite segments or HAP/LAP) [5G NTN] it is a unified terrestrial aerospace ...
1 vote
453 views

Why this grounding scheme?

The NASA technical book about grounding in spacecraft (NASA-HDBK-4001) (I believe the question may be relevant for any other terrestrial application) mentions this grounding scheme for subsystems: ...
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How to choose a wrap (station) antenna for space application?

I am looking for my research project a wrap (station) antenna. It is assumed that the antenna works in space (lunar) environment. The total dose for my device is 30 – 50 krad. Gain 3-5 dBi. Frequency ...
1 vote
95 views

Is this how cable networking works? [closed]

I am studying about how cable networks transmit data to various TV channels on our TV screen. It is fascinating to see how they work. After studying different articles online, I have made points as to ...
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I want to compute link budget in free space laser communication. My input parameters: wave length 700 nm, transmitter aperture: 0,88/0,15/0,2 m, receiver aperture: 0,3/0,5/1 My results: I have a ...
1 vote
142 views

Modulator in lasercom: from theory to practice

Hello everyone! We are working on a realisation of an optical modulator and have a doubt. Mr Noel Miller posted already a question, but it was suggested this community. I will repost his question ...
1 vote
280 views

Output back off of a high power amplifier (HPA)

We are selling S-band HPAs for satcom applications. A customer needs to obtain key RF characteristics of the S-Band HPA, specifically the wideband frequency response of carriers as a function of ...
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Why don't GPS satellites experience power outage more often than they should?

With the advent of smartphones I would believe that there's this huge exponential growth in number of GPS receivers around, and by now there should be an unaccountable number of devices on earth ...
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1 vote
2k views

How does the 4th satellite in GPS know the time offset?

Going through the working of GPS technology, I came to know that at least 4 satellites must be visible to solve for the location with considerable accuracy. Going through most of the resources, I can ...
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101 views

Arduino : send data via satellite (or other solutions) without GSM [closed]

I'm a researcher. I'm looking to build a very tiny embedded system with low power consumption. I must send data from the desert and above the ocean. To do that I think that my single option is to use ...
1 vote
157 views

Where would be the best place to start looking for information on developing a bootloader using 2 microcontrollers for a CubeSat?

I am an engineering student who has just begun working on a CubeSat project for my design class. We are working on the OBC, specifically looking at developing a bootloader at this time. The OBC ...
1k views

Help with calculating frequency offset

A 10 MHz TXCO is driving a receiver’s front end and has a frequency deviation of 10 ppm. It drives a direct downconversion RF front-end mixing the L5 frequency. What is the frequency offset at ...
357 views

Does satellite radio use AM or FM or both? [closed]

Somehow, I cannot find an answer anywhere... I am guessing both... Several actual satellites had FM in their names, so perhaps that is a clue, but I want to know for sure...
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How does being exposed to strong radiations effect nanosatellite electronics equipment?

I'm on paper designing a nanosatellite power system. The satellite would be orbiting in LEO. And I am wondering how and what type of radiation would affect its electronics. The system has a ...
86 views

Typical rms values for random jitter in satellite communication

I'm trying to find typical values for random jitter in satellite communication and I'm not really finding any values in any documents. Most of the time I only find definitions for different jitter ...
221 views

Is building a long range wifi antenna to connect to the up and coming starlink internet possible? [closed]

I want to try to convert a residential satellite dish into a long range wifi antenna to theoretically see if I can connect to the up & coming starlink internet that is being released in Canada and ...
211 views

Antenna Array - Hundreds of elements forming thousands of beams - How?

How would an antenna array of 100 elements be able to form 5000+ simultaneous beams? Or do I have it wrong, there would only be a maximum 100 beams from the 100 elements at any one time and those ...
225 views

Troubleshooting NOAA double cross antenna

I've been trying to recive NOAA automatic picture transmission (APT) pictures for a year now. I never got a picture with V-dipole, so I decided to build a double cross antenna. I used 75 ohm coax ...
928 views

How do I move a motor to a desired angle using a motor encoder?

So I have this project, the goal is basically to be able to make a motor move to rotate a set of gears and move a panel attached to a hinge to a desired angle. I have a motor encoder attached to the ...
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How does satellite TV get through in rain?

How does satellite TV get through in rain? I read somewhere that satellites make use of KU band to transmit data, we have heavy rainfall in various times of the year but even during those times TV ...
76 views

Satellite array antenna beamforming - basic intuition help

When you see a satellite coverage region on the earth, the array antennas form tens of circles (small coverages) in a large coverage. My question is whether all these small circle coverages exist at ...
53 views

Does DiSEqC require a DC bias?

The DiSEqC (Di[gital] S[attelite] Eq[uipment] C[ontrol] specification (bus_spec.pdf within https://www.eutelsat.com/files/PDF/DiSEqC-documentation.zip) describes a tone-based serial data bus that can ...
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I came across these broadcasting vans recently in London. The antenna that's deployed I think is a Vislink Advent uplink antenna, similar to this model, designed to transmit to satellites for ...
253 views

Do you really need a satellite dish to communicate with satellites?

I'm doing a project where I have ground sensors that detect seismic activity and report their GPS coordinates via APRS if seismic activity is detected. I'd like to do the APRS over satellite. The ...
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Can anyone explain Phantom Power and, specifically, how it's used in satellite television systems?

Although I spent many years in the electrical field, I specialized in Electrical Metrology (a long time ago). Bearing this in mind, I really know very little about satellite television system theory. ...
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1 vote
73 views

Source generator for Satellite Tuner input

I need to design a source generator for a TV factory. They want to automatize the functional tests by applying a test module to the TV's at the end of the production line. All the peripherals of the ...
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