Hello ..
I am planning to implement a differential GPS system using two Adafruit Ultimate GPS Breakout Modules found here:
https://www.adafruit.com/product/746?gc ... x8QAvD_BwE
When I plugged the module in, I managed to get NMEA Sentences.
The problem with NMEA Sentences is that they do not seem to reveal the individual satellite data (individual satellite positions and clocks) that are used to estimate the position.
In order to implement a differential GPS system, I need to extract more detailed information from the GPS module not just NMEA Sentences.
I am wondering if there is a way to extract:
1. arrival time of the satellite signal
2. reported position of the satellite
3. internal clock of the satellite when it sent the signal
for each individual satellite
If I have this detailed data, I can implement one of the many differential GPS algorithms existing in textbooks and research papers to get a very improved relative positioning between the two GPS modules.
Thank you very much for any help you can provide.
Regards ..
Obtaining raw satellite data from Adafruit Ultimate GPS Brea
Moderators: adafruit_support_bill, adafruit
Please be positive and constructive with your questions and comments.
- aaljurbua94
- Posts: 3
- Joined: Mon Jan 10, 2022 6:17 pm
- sj_remington
- Posts: 994
- Joined: Mon Jul 27, 2020 4:51 pm
Re: Obtaining raw satellite data from Adafruit Ultimate GPS
I suspect you mean RTK GPS, for cm-level accuracy, in which case you will need a different receiver module. Two of them, if you want to have your own base station, otherwise you need to sign up with a commercial provider of local RTK corrections.
The UBlox C94-M8P kit works well, and is reasonably priced.
Standard DGPS/WAAS/EGNOS corrections are built in to most modern GPS receivers, including the Adafruit GPS module you linked.
The UBlox C94-M8P kit works well, and is reasonably priced.
Standard DGPS/WAAS/EGNOS corrections are built in to most modern GPS receivers, including the Adafruit GPS module you linked.
- aaljurbua94
- Posts: 3
- Joined: Mon Jan 10, 2022 6:17 pm
Re: Obtaining raw satellite data from Adafruit Ultimate GPS
Hi sj_remington ..
Thank you very much for your prompt reply. You are right, what I need is something similar to RTK GPS.
I am wandering why do I need the kit? I do have two GPS modules and two raspberry pi devices, can't I program the two GPS modules to work as a RTK GPS system?
Thank you ..
Thank you very much for your prompt reply. You are right, what I need is something similar to RTK GPS.
I am wandering why do I need the kit? I do have two GPS modules and two raspberry pi devices, can't I program the two GPS modules to work as a RTK GPS system?
Thank you ..
- dlleigh
- Posts: 225
- Joined: Wed Jan 30, 2013 8:08 pm
Re: Obtaining raw satellite data from Adafruit Ultimate GPS
You need a GPS receiver than can output the pseudoranges to the satellites, The Ultimate GPS module cannot do that.
You should check out the uBlox device that was suggested.
You should check out the uBlox device that was suggested.
- sj_remington
- Posts: 994
- Joined: Mon Jul 27, 2020 4:51 pm
Re: Obtaining raw satellite data from Adafruit Ultimate GPS
The Ublox C94-M8P kit consists of two receivers with a convenient radio link, line of sight range of about 20 km. It may currently be unavailable, but contact Ublox to be sure.
The M8P receiver alone is available, https://www.u-blox.com/en/product/neo-m8p-series but has been superseded by the considerably more expensive ZED-F9P. Sparkfun has F9P breakout modules in stock.
The M8P receiver alone is available, https://www.u-blox.com/en/product/neo-m8p-series but has been superseded by the considerably more expensive ZED-F9P. Sparkfun has F9P breakout modules in stock.
Last edited by sj_remington on Mon Jan 10, 2022 8:08 pm, edited 1 time in total.
- aaljurbua94
- Posts: 3
- Joined: Mon Jan 10, 2022 6:17 pm
Re: Obtaining raw satellite data from Adafruit Ultimate GPS
Thank you very much guys. I appreciate your replies. I will probably get the kit, it seems that programming two Ultimate GPS modules in differential mode does not work.
Please be positive and constructive with your questions and comments.