GNSS Dead Reckoning — Sensor Fusion Filter not necessary?

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My question might be a bit off-topic but I don’t know where else to ask.

When I do have a GNSS Module with integrated IMU and Dead Reckoning, for example, the Ublox ZED – F9K.

Does it still make sense to use a Filter for fusing GNSS and IMU / Odometry data or is that not necessary as the Module is handling that for me?

Or will the Dead Reckoning just enhance the precision after applying a Filter even more?imusensor-fusionfilterdead-reckoninggnssshareedit  follow  flag asked 14 hours agoStrohhut11133 bronze badges

• Ah, let me google and see if I can answer you question. I first skimmed the following ZED-F9K Product Summary: u-blox.com/sites/default/files/… – tlfong01 1 hour ago   
• I also read the module product sheet from Sparkun and made a features summary: “GPS-RTK2 Board (ZED-F9P) Product Sheet – SparkFun”: mouser.hk/new/sparkfun/sparkfun-gps-rtk2-board (1) TTFF = 25s (cold), 2s (hot); (2) Horizontal accuracy = 2.5m (without RTK), 10cm (with RTK); (3) Nag rate = 25Hz max – tlfong01 50 mins ago   
• I then browse the SparkFun GNSS 23 Products Catalog: sparkfun.com/categories/tags/gnss, and the GPS-RTK ZED-F9R Dead Reckoning Breakout – SparkFun US$300 sparkfun.com/products/16344. – tlfong01 41 mins ago   
• I also skimmed SparkFun’s “GPS-RTK Dead Reckoning ZED-F9R Hookup Guide“: learn.sparkfun.com/tutorials/…. – tlfong01 35 mins ago   
• I then read SparkFun’s Hookup Guide: “GPS-RTK Dead Reckoning ZED-F9R Hookup Guide (Python and Arduino)“: learn.sparkfun.com/tutorials/…. – tlfong01 31 mins ago    
• SparkFun’s tutorials are always very newbie friendly. If it has a guide for Arduino, then it should be of middle difficulty level. If it has a tutorial for python, then I think it should be as easy for Rpi python programmers. I once used Rpi python to access data from uBlox uCenter and found everything straightforward. (1) GPS taking long time to fix out in the open – EE SE, 2020sep03, Viewed 2k times electronics.stackexchange.com/questions/519711/…. /to continue, … – tlfong01 15 mins ago   
• (2) Rpi Neo-6M/7M/8M GPS Module Setup/Fix/Update Problems – Rpi SE 2020jun18 raspberrypi.stackexchange.com/questions/113544/…. – tlfong01 15 mins ago   

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Question

Is it necessary to use any filter to fuse Ublox ZED-F9K’s GNSS and IMU/Odometry data?

Answer

My answer is NO, for the following reasons:

(1) GNSS and IMU are independently developed modules with matured software. It is unlikely for the vendor to “fuse” them at the hardware level. A more efficient method is to let the MCU/SBC to talk to either or both guys using I2C, or UART and I2C.

(2) uBlox uCenter uses very simple, text based NMEA0183 protocol, and update rate is of the order of 25Hz, so the user can easily pass the slow GNSS data to IMU for processing.shareeditdeleteflag answered just nowtlfong0110111 bronze badge New contributoradd a comment