First of all, Happy New Year Community ... We wish you a Happy flight year !
Good news for Solo owners, we just released 2 versions of Solo GPS to replace your factory GNSS. One with u-blox NEO-M8N or NEO-M8T and one with u-blox NEO-M8P
u-blox NEO-M8P is the smallest high precision RTK GNSS (Real Time Kinematics) module available on the market and TINY RTK is the first global solution for u-blox NEO-M8P. The RTK algorithms are pre-integrated into the module. As a result, size and weight are significantly reduced, and power consumption is five times lower than existing solutions, thus cutting costs and improving usability dramatically.
Following a high demand for an integrated solution for UAV users, we jointly achieved with u-blox and PX4 a version specially designed for this purpose : TinyRTK Drone Edition. The boards include patch antennas and a battery-powered base. Base can stream differential data to ground control station through a BLE module.
KEY FEATURES :
Centimeter‑level GNSS positioning for mass market, based on U-Blox M8P
Integrated Real Time Kinematics (RTK) for fast time‑to‑market
Smallest, lightest, and best energy‑efficient RTK module
MAVLink protocol encapsulation through u-blox NINA-B1 Bluetooth Low Energy module
Connectors: USB, JST-GH
Compass : HMC5983
Power : LiPo 1S compatible / USB with integrated charger
Size: 50 x 50 mm
Weight : 24g
Why this architecture?
it is small and consumes little energy
base can be standalone, wireless, rechargeable and located on a good sky view spot regardless of ground control station's position
base is compatible with 1S LiPos, rechargeable by USB with integrated charger
rover module is supported by Pixhawk
base module : encapsulation within MAVLink protocol is under development (some developers have already got our boards, we will keep sending them to all)
rover includes a compass (HMC5983)
patch antenna included to avoid additional integration costs
Support us in our Indiegogo campaign and do not hesitate to ask any question !
As we are so happy about our national football team, Drotek will offer a 5% discount on our entire store for people who sign up at euro.drotek.co before kick-off (Sunday 9 pm, French time).
If France wins it will become a 10% discount!
People who sign up can also choose to prognosticate on the score, those who get it right will get an additional reward!
SMARTNAV L1 RTK field test results, as promised. Please have a look at this previous post before reading.
The reference trajectory will be displayed in dark blue whereas SMARTNAV's output will be displayed as :
- red for "single" solutions (when RTK is not available)
- yellow for "float" solutions
- green for "fix" solutions (maximum accuracy)
So first we will review all the points listed in the previous post.
Height differences
It is common knowledge that GNSS tend to output poor vertical position accuracy due to the low vertical spacing of satellites. We wanted to check whether RTK could enhance this.
Standard deviation is about 4 meters. This is not bad considering the "low VDOP" of satellites and the measurement conditions.
Bridges and tunnels
The idea behind this test was to monitor how receiver would deal with successive acquisitions/losses of satellites.
Receivers loses lock completely under bridges and tunnels. Reacquisition is quite fast and even if there are some glitches convergence is fast.
Large roundabouts
The trajectory is very good here, due to the open sky view. But it is difficult to measure repeatability under those conditions.
Urban canyon
The most difficult environment, really small roads with high buildings.
Here the output is not correct at all. The receiver has a hard time calculating the solution. Even the reference trajectory is not precise at all. This is normal considering the conditions, glitches go up to hundreds of meters.
Leafy streets
We wanted to know whether trees affect position stability or not.
At the moment we drove under the trees, they were masking the sky completely. We can easily see that solution is not robust in this kind of area.
Repeatability
Repeatability was difficult to measure with the car, because it is difficult to make sure to follow the same path several times in an urban area. So we did another test. SMARTNAV was placed on a square table, calculating real-time RTK solutions. Baseline was about 10 meters. SMARTNAV was moved around table's edge several times, always following the same path.
It is very easy to reproduce the same path. Here the accuracy is under 5 cm.
Accuracy/precision
In open sky conditions, accuracy is always better than 20 cm.
However, when conditions are difficult, offsets as high as 1 meter can be observed. Offsets tend to appear after a glitch is observed. A time of convergence shows up after a glitch to come back to the reference trajectory.
In stationary, this is the position calculated by SMARTNAV.
This is the position calculated by L1/L2 AsteRx (without inertial hybridation).
There does not seem to be much precision difference between the two.
Availability
NRTK (SMARTNAV real time) availability :
- Fix : 27%
- Float : 62.5%
- Single : 10.5%
L1/L2 (post-processed) availability :
- Fix : 50.6%
- Float : 46.1%
- Single : 3.2%
L1/L2 is much more available than L1, which means it will be more robust in difficult environments or longer baselines.
First conclusions :
- RTK in urban areas is not a pipe dream
- reacquisitions are fast
- excellent precision/accuracy in open sky views
- still quite strong in "medium" environments (could be enhanced by hybridation with an IMU or a better software cycle slip detection)
- not reliable when sky view is heavily obstructed
- L1/L2 does not look more precise than L1, but it is more robust and available
Drotek has taken L1 RTK devices on the field under difficult conditions to see how they really perform.
Drotek, based in Toulouse (France) has had the opportunity to test SMARTNAV L1 RTK with laboratory grade devices. This test has been run in straight collaboration with GUIDE (GNSS Usage Innovation and Development of Excellence), a testing laboratory for satellite geolocation (http://www.guide-gnss.net/)
It is now quite clear that L1 RTK performs really well in open sky “easy” environnements. But we wanted to test its real performance in more difficult environments.
GUIDE is a equipped with a GBOX, a “black box” containing an aeronautical grade Inertial Measurement Unit and a multicontellation L1/L2 AsterX receiver. The unit constantly logs GNSS L1/L2 raw data + inertial measurements. The two datasets are then merged to output a precise reference trajectory.
The antenna is place on the roof of a car.
We set up two devices on the car ( + GBOX) :
one standalone SMARTNAV (with its own antenna), logging raw data for post-processing
one SMARTNAV connected to car’s antenna splitter, processing real-time NRTK (VRS) with Teria network corrections
The environments we wanted to test were the following :
height differences (>10%)
bridges and tunnels
large round abouts
housing estate
urban canyon
leafy streets
With this test, we will try to answer the three following questions :
Repetability : is solution precise in an absolute or relative way? Are we able to reproduce it over time?
Precision/Accuracy : how precise/accurate is the solution?
Availability : is L1 as reliable/available as L1/L2?
A lot of actors of the L1 low-cost RTK market have been emerging these months. U-Blox plays a relevant role in the miniaturization of GNSS chips for mass-market. Drotek and U-Blox are collaborating in order to produce the most reduced RTK board.
Market has shown that there are clearly two types of customers :
the ones who like plug-and-play boards, but who still like to dig into hardware/software, eager to collaborate on any aspect. This is why we have created SMARTNAV RTK (http://drotek.io/1PodT25)
the others who only want simple-approach and reduced-form factor products without paying any attention to technical details. This why we are integrating M8P on our boards.
For the first tests we have used our XXL board and placed M8P on it. (http://drotek.io/1SQ5hCo) This version of M8P is capable of handling both base and rover states.
So we configured base in order to deliver RTCM correction messages over a 433 MHz radio link and rover to receive them. These are the first results :
We got to “float” position without any problem, and deviation map showed great results in this first short test!
Drotek is ready to manufacture, waiting for U-Blox first delivery! At this stage we still do not have pricing information.
We recently talked about physical characteristics of our SMARTNAV-RTK GNSS and we now want to introduce the features of the application installed on the device that makes SMARTNAV-RTK plug and play for the average person and easily customizable for advanced users.
RTKLIB Web Console was developed in order to make the use of RTKLIB more user-friendly. We’ve totally rethought the way of using RTKLIB and your SMARTNAV-RTK GNSS can be managed exclusively from Web Console. No need for remote logins to your device to configure additional parameters or for shell script executions … all you need is Web Console.
Here is a short presentation of available features :
ARCHITECTURE
Application architecture is as below :
- The Front-end uses AngularJS Framework
- And the Back-end uses NodeJS Framework
The design is totally web responsive; it means that the application supports many devices.
SATELLITES MONITORING FEATURES
This tab shows you the quality of GNSS signals, it can help you finding a good position for the base :
- RTK Satellites chart shows SNR for common satellites between base and rover
- BASE Satellites chart shows signal-to-noise ratio for the base
MAP FEATURES
Map page is useful for monitoring the quality of solution in real-time. Choose your scale and visualize the deviation map where you can read position variations over time.
CONFIGURATION TOOL
From this page you can choose the mode you want to run (rover or base) and manipulate all the parameters available for RTKLIB.
Preloaded configuration files are accessible but you can create your own one and save it.
LOG MONITORING
Consult log files from Web Console.
ADMINISTRATION TOOL
Administration tools for SmartNav-RTK :
- Control status and manipulate RTKLIB service
- Export logs files without using any third-party application
- Sync system time with GPS Time.
- Update system with the latest release of SMARTNAV-RTK firmware.
SMARTNAV-RTK
For the moment SMARTNAV-RTK is only available in XL version but the light version is on the rails and will be available soon.
Due to user demand, we’ve updated our XL price list so that you can buy unit one by one and without any antenna. Don’t forget to add a second unit for the first order ;-)
The source code will be available at the end of the week; we progressively migrate our work through github, sorry for the delay.
Drotek, French tech start-up is proud to release its L1 RTK GNSS ! RTK technology allows to enhance GNSS positioning and to go down to centimeter level precision.
We have seen a lot of RTK boards coming up. However we have witnessed no good integration for the UAV segment and no performance enhancement in difficult environments.
This is why we decided to develop a solution to cope with these issues. Drotek is specialized in electronic design for UAVs and has put all its expertise in designing this board, jointly with French National Center for Space Studies (CNES) and French Institute for Aeronautics and Space (ISAE).
What is RTK for?
RTK technology uses corrections from a second GNSS receiver (called “base”, the other mobile receiver is called “rover”) in order to correct errors that lead to meter level precision. It has been used for a long time by surveyors, but at a very high cost. Today we want to trivialize this technology.
Our two years spent on developing this product have led us to focus on several points, such as connectivity, signal quality, EMI, real-time, etc...
We have compared our system’s performance with dual frequency receivers (in blue, Rover : Septentrio AsteRx 3 L1/L2 + Novatel geodesic antenna in RTK with base Trimble NetR9 + TRM59800), and it is pretty astonishing!
RTK works well in clean open-sky environments, but we like to test our device in difficult scenarios. Urban canyon is stil a pipe dream, but some route on ground robot in medium-hard environment (buildings, trees…) gives pretty good results :
Comparison between single GPS (red) and RTK : have a look at the left side under the tree. Single position gets highly contaminated by multipath, whereas the big ground plane and the Tallysman antennas filter it quite well :
Comparison between RTK Drotek (orange) and another open-source RTK solution (yellow) :
Base correction data can be sent through serial port with 3DR Radio types but also through cabled or wireless Internet for those want to get rid of range limitations. All drivers and server programs are already in the board. The following table sums up the different possible ways of communication between rover and base.
We are currently developing LoRa based transmitters, hoping that these will fulfill our expectations (we are quite excited about them!). Coming soon.
We truly believe in open-source community, but this board has also been designed to work “as is”. All boards will be delivered flashed and ready-to-use, with really little configuration, mainly for non-advanced users who would wish to get to precision without spending too much time on understanding how it works. Our wiki will explain everything step-by-step, but will also provide support on using RTKLIB graphical tools for post-processing and analyzing data. Do not forget to check our Github, we will publish in it really soon!
All our boards are stamped “Made in France”, we pay a lot of attention to the devices we manufacture in our French factory. Our motto is open source and open hardware, we work this way and we will stay this way. We want sell the atoms not the bits.
The package will be available in our site for pre-ordering. The expected release date is in one month, with a price of 699 € excluding VAT.
Our website is currently being redesigned, hope you will appreciate the new one! There will be plenty of content on how to use all the devices we manufacture, from little sensors to big boards!
Some additional exciting results :
This picture depicts the precision you can expect with good conditions, amazing!
A little demonstration (shot yesterday!) :
We modified an Iris+ drone, removed its GPS and replaced it by our board. Take-off is manual, and as soon as the drone lifted we triggered Return To Launch mode. The drone succeeded in landing on the table approximately 1 out of 2 times. It touched the table with at least two feet each time we tried the procedure. Wind conditions were quite gentle but with a fair amount of gusts. Even if the board provides precision, there has been a lot of work on the controller’s PIDs to achieve this result!
We used a Netgear WiFi router to transmit raw data from the base to the rover, using Edison's WiFi. Base was connected in Ethernet to the router, everything powered by a 4S LiPo and a 12V power module.
We will offer a board to the person who comes up with the coolest name for the device !
