Tagged: kerberossdr

April 25, 2019

KerberosSDR Batch One End of Stock, Batch Two Preorders Available

If you weren't aware, KerberosSDR is our recently released 4x Coherent RTL-SDR which can be used for tasks such as direction finding and passive radar. KerberosSDR was successfully crowdfunded over on Indiegogo, and we have recently completed shipments to all backers. Currently there is only about 20 units of the batch one production left in stock.

We are currently offering discounted preorders for batch two units on Indiegogo which we expect will be ready to ship in July or hopefully earlier. If you are interested, please order soon to avoid missing out as the price will be raised again once we are shipping. Batch two will be the same as batch one except for some minor changes. For example we have decided to convert the microUSB port into a USB-C port as we have found that there are many very poor quality microUSB cables on the market which could cause issues for users. USB-C cables are generally of a higher quality.

More information about KerberosSDR is available on the Indiegogo page.

KerberosSDR Updates

Since our last post on this blog about KerberosSDR we have made some enhancements to the software.

The KerberosSDR code is now fast enough to run at 1-2 Hz update rates for direction finding and passive radar on a Raspberry Pi 3 B+.
There is now a web interface, so the KerberosSDR can be controlled via a WiFi hotspot and internet browser. Useful for use on the Pi 3 and Tinkerboard.

For future updates we are currently working on several new features:

Filters to remove low confidence DoA results on the Android app.
A secondary heatmap type display on the Android app based on signal strength, for two direction finding indications.
Methods to determine the center of multiple bearing intersection points.
Further enhancements to processing speed, possible improved results from processing gain and possible better accuracy from improved DoA algorithms.

Within the next few weeks we will also release full tutorial videos that will show how to set up and use the KerberosSDR for direction finding and passive radar with a Raspberry Pi 3 or Tinkerboard. If you prefer a text based explanation we already have a guide up at rtl-sdr.com/ksdr.

Below is an image that demonstrates the KerberosSDR direction finding Android app. A user of KerberosSDR has also submitted two of his own screenshots that show that he was able to determine the location of a GSM transmitter with a linear antenna array.

KerberosSDR Direction Finding Results. Multiple data points collected during a drive, with bearings pointing towards the TX tower (red marker). Circular array of whip antennas used at freq. 858 MHz.

April 10, 2019

SignalsEverywhere: KerberosSDR Direction Finding Video Tutorial

Over on his YouTube channel SignalsEverywhere, Corrosive has uploaded a new video about setting up a KerberosSDR for direction finding. KerberosSDR is our new 4-input Coherent RTL-SDR that was crowdfunded on Indiegogo, and has now shipped to all backers. With KerberosSDR applications like direction finding and passive radar are possible. If you're interested, there are still about 70 units available in this batch. After that a second batch will be available in a few months.

In the video he goes over the full set up procedure, from setting up his chosen computing platform (a Raspberry Pi 3) to connecting up the KerberosSDR, connecting to it's web interface, calibrating, setting up the antennas, and then demonstrating some direction finding with four whip antennas on his car and a HackRF used as a signal source.

Radio Direction Finding Equipment KerberosSDR Coherent 4 x RTL SDR RDF Setup

Watch this video on YouTube

January 11, 2019

KerberosSDR Updates: Demo Software Speed Improvements, Android App, Manufacturing Updates

If you weren't already aware, over the past few months we've been working with the engineering team at Othernet.is to create a 4x Coherent RTL-SDR that we're calling KerberosSDR. A coherent RTL-SDR allows you to perform interesting experiments such as RF direction finding, passive radar and beam forming. In conjunction with developer Tamas Peto, we have also had developed open source demo software for the board, which allows you to test direction finding and passive radar. The open source software also provides a good DSP base for extension.

If you're interested and missed out in the early campaign, don't worry we still have about 250 units left from this batch for sale at a price of $140 + shipping over on our Indiegogo Campaign.

Demo Program Updates

Over the past few weeks we've been working on a few code speed improvements to the demo software, and we now believe that it should be fast enough to run on a Pi 3 B+ at decent update rates. In particular the passive radar display frame rate has been improved and we're able to get about 1 FPS on a Tinkerboard now.

We will soon release the full code, but for now you can see the main two libraries developed by Tamas' that are used in the KerberosSDR code. These libraries contain the direction finding and passive radar processing algorithms.

pyAPRIL - Python Advanced Passive Radar Library. Available on PyPi and GitHub

pyArgus - Python Beamforming and Direction Finding Algorithms. Available on PyPi and GitHub.

Android Direction Finding Companion App Updates

Over the holidays we've been working on a simple companion Android app for the direction finding feature. Using the GPS and/or compass sensors on the Android phone, and the transmitter bearing given by the KerberosSDR we can plot a bearing towards the transmitter that we are tuned to.

The phone connects to a laptop/SBC WiFi hotspot running the KerberosSDR Linux software, and reads the bearing via a simple php HTML server.

Driving around with the KerberosSDR gives better results than when stationary as we can take multiple readings at different points which helps to average out multipath distortions.

In the image below we used a linear antenna array of four dipoles attached to the windscreen of a car. KerberosSDR was tuned to a TETRA transmitter at 858 MHz.

We drove down a street and then back up it. The red lines indicate the direction of the car as determined by GPS, the blue lines indicate the forward direction towards the transmitter, and the green lines the reverse direction. (a linear antenna array won't know if the transmitter is in front or behind it).

You can see that the majority of blue/green lines point towards the TETRA transmitter which we've marked with a red location marker at the known location.

KerberosSDR Results from a Linear Antenna Array of Dipoles

Getting a bearing from GPS requires that you are moving. However if you are stationary it is also possible to use the compass sensor in the Android app, but Android compass sensors are not particularly accurate.

We also tested the app with a circular array of antennas and found it to work well too. A circular array has the benefit over a linear array of providing only one direction towards the detected signal, but may be more susceptible to multipath issues. In our test the circular array was simply four magnetic whips placed on top of a car.

KerberosSDR using Whip Antennas in a Circular Array on a Vehicle

This time we then drove around for a longer time while logging the data in the Android app. We can see that the majority of blue lines point towards the known transmitter location. Blue lines pointing away from the transmitter may be due to multipath or a briefly incorrect GPS heading (e.g. during a turn). Sometimes reflections or refractions of the signal can be more likely to be picked up if the direct path to the transmitter is really blocked. However if you have enough data points from driving around, it becomes much more clear where the actual transmitter is.

KerberosSDR Results from the Circular Array

Manufacturing Updates

We now have some pictures of the boards being manufactured at the factory. Unfortunately we are behind our initial shipping target of mid-Jan due to the previous unexpected payment delays from Indiegogo, and because of this we may hit the Chinese New Year holidays which could delay us further as factories take a 2 week holiday starting late Jan. We're really hoping to have them shipped off just before then, but we don't know if we can beat the clock. I know some of you are anxious to get started with KerberosSDR, and so I do apologize for the delay.

KerberosSDR in it's metal case (no screen printing yet)

November 22, 2018

An Overview on RF Direction Finding with RTL-SDRs

Thanks to K2GOG of the Hudson Valley Digital Network for writing in a sharing with us his latest blog post which is a useful overview of some direction finding techniques that can be used with RTL-SDR dongles. RF direction finding is the act of using a radio to determine the physical location of a signal.

In his post K2GOG mentions our successfully crowd funded KerberosSDR which will be shipping in January next year. KerberosSDR is our 4x coherent RTL-SDR, and one possible application is to use it as a four antenna phase coherent direction finder. K2GOG explains the phase coherent concept in his post quite elegantly.

While looking over KerberosSDR, K2GOG was also reminded of another direction finding technique called heat mapping which can be performed with a single RTL-SDR. This process involves driving around with an RTL-SDR and GPS logger, measuring the signal power as you drive and combining it the current GPS coordinates. From that data a heat map can be generated, which shows where the signal is the strongest, and therefore where the likely source is. The RTLSDR Scanner application by eartoearoak makes doing this easy, and in his post K2GOG provide a short tutorial on setting it up.

A heatmap generated by K2GOG with an RTL-SDR, GPS and RTLSDR Scanner.

November 12, 2018

Final Day to Pre-Order a Discounted KerberosSDR

Today is the last day to pre-order a KerberosSDR in our Indiegogo campaign! More information also available on our KerberosSDR page.

First, we'd like to thank all those who've pre-ordered a KerberosSDR unit already. The response has been overwhelming, and we've raised so much more than we originally thought. Thanks to your support, we've been able to immediately fund continued development on the open source demo software. We aim to release the software when we ship, and we'll have another update then. On the Hardware side, we've already begun ordering some components, and have started prototyping the metal enclosure that will come stock on all KerberosSDR units. We are still on track for a late December/early January shipping date.

If you haven't pre-ordered yet, get in quick as the campaign and pre-order discount ends today! Although all 600 early bird discounts have been taken, it is still possible to pre-order KerberosSDR for $125. Afterwards, the price will rise to a maximum of $150.

Over the next month of manufacturing we intend to begin releasing tutorials that show how to use the board and demo software for passive radar and direction finding experiments. We'll also show some other use cases, like how KerberosSDR could be used as four separate RTL-SDRs for monitoring multiple frequencies simultaneously.

KerberosSDR with Calibration Board Attached (Metal Enclosure with SMA connectors Not Shown)

November 6, 2018

KerberosSDR: One Week of Discounted Preorders Remaining

Just a reminder that one week remains in the KerberosSDR Indiegogo campaign. This is your last chance to grab a KerberosSDR at a discounted preorder price. And at the time of posting there are still 50 "second early bird" units remaining at a discounted price of only $115 USD.

More information available on our KerberosSDR page, and the Indiegogo page.

Updates

Due to the higher than anticipated number of preorders, we have been able to immediately fund further work on improving the demo software, and will be able to continue to work on improving it throughout this and next year. First on the agenda is improving the code buffering structure and DSP processing speed. Shortly after we'll be looking at adding additional features to aide with calibration and direction finding.

We have also now begun ordering parts, begun prototyping the metal enclosure, and have finalized the PCB. Manufacturing is on track to begin shortly after the campaign ends.

October 14, 2018

KerberosSDR Now Available for Pre-order on Indiegogo

We're happy to announce that KerberosSDR is now available for pre-order on Indiegogo.

As promised we announced the release to KerberosSDR mailing list subscribers first, so that they'd be the first to get the initial discounted early bird units. However due to much higher than expected interest, we have released a few "second early bird" units at a still discounted price of $115 + shipping. We're only going to release 300 of these so get in quick before the price jumps up to $125. Our pre-order campaign will last 30 days, and afterwards the retail price will become $150.

More information available on our KerberosSDR page, and the Indiegogo page.

KerberosSDR Main Board (Metal Enclosure with SMA connectors Not Shown)

September 27, 2018

More KerberosSDR Passive Radar Demos

KerberosSDR is our upcoming low cost 4-tuner coherent RTL-SDR. With four antenna inputs it can be used as a standard array of four individual RTL-SDRs, or in coherent applications such as direction finding, passive radar and beam forming. More information can be found on the KerberosSDR main post. Please remember to sign up to our KerberosSDR mailing list on the main post or at the end of this post, as subscribers will receive a discount coupon valid for the first 100 pre-order sales. The list also helps us determine interest levels and how many units to produce.

In this post we're showing some more passive radar demos. The first video is a time lapse of aircraft coming in to land at a nearby airport. The setup consists of two DVB-T Yagi antennas, with KerberosSDR tuned to a DVB-T signal at 584 MHz. The reference antenna points towards a TV tower to the west, and the surveillance antenna points south. Two highlighted lines indicate roughly where reflections can be seen from within the beam width (not taking into account blockages from mountains, trees etc).

The second video shows a short time lapse of a circling helicopter captured by the passive radar. The helicopter did not show up on ADS-B. On the left are reflections from cars and in the middle you can see the helicopter's reflection moving around.

We are expecting to receive the final prototype of KerberosSDR within the next few weeks. If all is well we may begin taking pre-orders shortly after confirming the prototype.