I am thinking of using Semtech LR1110 for designing tracking device in field with LoRa. Since this one has GNSS & LoRa on SoC, so going with LR1110.
But I have a concerns about LR1110.
How can I use GNSS data to get accurate GPS location ?
Is there any open source (free) way to get GPS coordinates from GNSS data ?
Will I be able to connect device based on LR1110 to LoRa gateway ?
We do not know yet the API for the GNSS part so it is not really possible to answer. But it would be surprising if it is complex to get the actual location considering this is exactly the goal of the chip.
As for the connection to a LoRa gateway, you wonāt have any issue, the LoRa part is completely inter-operable with all the others LoRa chips.
For those interested in this device, from the contents of The Things Virtual Conference on April 16
Semtech - Deep dive into the new LR1110 chip
LoRa, WiFi and GNSS on a single chip. Experts will take a deep dive into the LR1110.
You would think so, GNSS is a term that describes the various āGlobal Navigation Satellite Systemsā in orbit such as GPS, GLONASS, Galileo, Beidou etc.
There are devices such as Mediateks that only receive the GPS satellites, but Ublox devices can receive GLONASS, Galileo, Beidou etc, so its more accurate to describe them as GNSS devices.
According to datasheet, the LR1110 cannot do the location calculation itself. It depends on back-end server:
The LR1110ās GNSS Geolocation System achieves low energy geolocation by offloading time- and compute-intensive operations to back-end system components.
The LR1110 features a fast and low-power GNSS scanner. The device captures a short portion of the signal broadcast by the GNSS satellites, and extracts the information required to calculate the device position - the pseudoranges. This information is aggregated into a NAV message which can be sent to a back-end system to compute the device position.
A low power GPS, does the location calculation very quickly, I would suggest the amount of power it uses to do the actual calculation is very low.
Sending the data somewhere else to do the calculation via LoRa you would think takes more power not less.
I can see that it might be useful in some applications to have the āpseudorangesā on a central server somewhere, but the device not having the capability to do its own location calculation, like a standard GPS, seems to be a bit odd.
Unless you use Kolmostarās magical jedi-200 module: https://www.kolmostar.com/products-low-power-jedi-200
Which, amazingly, claims to be able to send the ephemeris data in 50 bytes only every 12 hours! Needless to say I have not been able to get my hands on a module. I wonder if their algorithm has been licensed elsewhere.
I spoke with Semtech recently and was told you would have to implement your own GPS solver on a connected microcontroller if you wanted to operate in this way, since the LR1110 offloads this processing to reduce power consumption.
To the second question, yes, the LR1110 includes everything you need for multi-region LoRaWAN communication.
If youāre interested in testing it Iām going to be putting together some modules as soon as the part is available for sampling! I also wrote up a few posts that explain just how the device operates in terms of positioning.
There is a very technical video from Nicolas Sornin about th LR1110, for The things Network virtual conference: he addressed the question on why the chip is limited to pseudo-range (mainly the chip would need a lot more up-to-date information to be able to do the processing) : https://youtu.be/AQ1tSzmhDrg
He talks about the GNSS part around 25min, but the whole video is very interesting
Did anyone ever try to implement their own GPS solver on a connected microcontroller? Iām wondering what the footprint of the solver is and if maybe a Cortex M4 is able to accomplish this job.
Can you post in English ?
I suggest you contact Lacuna Space as they have experience regarding this subject and should be able to either help you or point you to a partner with the required expertise. Given the shroud of secrecy around the satellite LoRaWAN offerings there will not be a lot of expertise on this forum.
Keep in mind if you are working in areas with flammable gasses your device needs to conform to very strict safety requirements. (It should in no circumstance be the cause of ignition)
Yes, if by aerial you mean satellite
Yes, for Lacuna it does both as required.
Any standard antenna for LoRa & for GNSS, but if you want to include the satellite comms, then Iād strongly recommend using the one designed by the company providing the service unless you have exceptionally advanced RF antenna design skills.
This is not a question. LoRa or WiFi or BLE or Ethernet or ESP-now or LTE or Avian-over-IP are all communications systems. You have sensors for the gases you wish to detect. You then have a way of communicating that information back to where ever needs to know it. The two are not conditional on each other.
Using various sensors on hand with various radio modules on hand, I can solve this in hours. But adding any form of satellite comms is not going to be a part of that equation - there are too many variables around frequency of uplinks, time to relay messages, cost, the radio hardware and so forth.
Perhaps you could clarify what you believe satellite LoRaWAN would solve for you?
Thanks you for your answer
Thank you very much for your feedback. Furthermore, following this question āIs it possible to use LoRa terrestrial and LoRa aerial simultaneously on the LR1110 module?ā you answered me by saying āYes, if by antenna you mean satelliteā. Am I to understand from your answer that to do both LoRa terrestrial and LoRa aerial simultaneously on the LR1110 module, which already has a LoRa antenna, GNSS and Wifi, I would then need two LoRa antennas to be able to do both simultaneously? Thank you also for your clear answer on the fact that we can switch between two but I have a question to switch between the two is it necessary to do it in a soft or hardware way? If it is in a hardware way you advise what circuit? Regarding the antennas at what distance can we put them in relation to each other to avoid disturbances? if you have an idea of the lengths of the antenna line on the PCB if it is an omnidirectional antenna for LoRa and a patch for GNSS?
Iām also planning to size the antennas on Ansys to see how they behave. Thanks again for your answers
You could, but you can combine them in to one if you wish.
If you have two antennaās you will need an RF switch controlled by the software.
Itās hard to answer the rest of your questions. Itās not feasible to build your own device as the satellite services are somewhat unique and have differing requirements. And RF design is a whole art form as well as engineering in itās own right - not something that can be answered in mm as there are so many other factors.
Have you researched the way that LoRa using LR-FHSS to a satellite works before you design using Ansys?
Yes, I am currently investigating the type of modulation to better understand things. Additionally, I have a question because I feel like Iām missing some information. The question is as follows: what is the exact difference between aerial LoRa and terrestrial LoRa? Are they both on the same frequency band, i.e. 868MHz?
Thank you in advance for your answer.
Five minutes on google will answer the question.
ā This antenna has been successfully tested with the LacunaTM network which is operates at in the 865 MHz and 915 MHz bands. ā
But satellite LoRaWAN uses the s-band as well (2-4GHz)
Satellite goes up using LR-FHSS modulation for Lacuna with a delay between uplink & forwarding, terrestrial is standard LoRa going sideways. But again, itās so very dependent on the provider that itās hard to generalise.
Yes, the use the local channel plan - so 868 in the EU, 915 in US & AU.
Thank you so much for your response, which adds more clarification to what I have understood so far. Yes, in terms of the differences, it is true that it remains difficult to generalize, as I have seen many responses when I was providing responses on this question. Thank you also for the confirmation regarding the frequency band, as I thought the frequencies were different when it comes to terrestrial or aerial applications. Thank you very much.