In a recent post, I compared an L1/L2 u-blox F9P receiver paired with a u-blox ANN-MB antenna against a Quectel L1/L5 LC29HEA receiver paired with a very low cost L1/L5 antenna from Waveshare ($17 + shipping). I did this to get the combined cost of receiver and antenna down to an absolute minimum. The performance of this combination was reasonably good in challenging conditions but noticeably lower quality than simultaneous results from the u-blox receiver and antenna. At the time, I did not explore how much of this reduced performance was due to the lower cost receiver and how much was due to the lower cost antenna.
After publishing the post I was contacted by a representative from Quectel. He mentioned that they have done comparison testing between the LC29HEA and the u-blox F9P and have found the results to be more similar than my results if antennas of equal quality are used in the testing. He specifically recommended the Quectel YB0017AA L1/L5 antenna as being very similar to the u-blox ANN-MB antenna in size and performance. This antenna is available on AliExpress for $22 + shipping so is only marginally more expensive than the Waveshare antenna that I used. It’s also available from Digikey for a little higher price but faster shipping. I ordered the antenna from Digikey and after it arrived, repeated the previous comparison to the u-blox hardware using the new antenna.
Here’s a photo of the three antennas, the Waveshare L1/L5 on the left, the Quectel L1/L5 in the middle, and the u-blox ANN-MB on the right. As you can see, the Quectel antenna is more similar in size and shape to the u-blox antenna.
To start, I did some signal strength (C/No) comparisons between the Quectel and Waveshare antennas using the C/N0 values reported by the receivers. I expected the larger Quectel antenna to show higher C/N0 measurements but I was unable to detect a consistently measurable difference between the two.
However, when I repeated the simultaneous RTK measurement collection with the u-blox hardware and the Quectel hardware in a moderately challenging environment in my backyard with a mixture of tree cover and obstruction from the house, the Quectel results this time were noticeably closer in performance to the u-blox baseline. More detailed testing would likely bring up differences between the two, but with my single, somewhat unrigorous test, the results were close enough that I was not able to discern that one performed better than the other.
Here are the results from the Quectel receiver and antenna :
Here are the results from the u-blox receiver and antenna:
Fix rates were very similar between the two solutions at 84% for the u-blox and 88% for the Quectel. I would not consider this difference significant, especially since I suspect based on the previous comparison that the Quectel is a little more prone to false fixes.
Below is a plot of the distance between the two solutions when both were fixed. The two antennas were 34 cm apart, so the distance of each point from a circle of radius 34 cm indicates the combined error from both solutions. The number and magnitude of the errors are noticeably smaller than in a similar comparison for the previous experiment.
The large deviations in the vertical axis between the two solutions we saw in the previous comparison (shown on the left below) are not present in this comparison (shown on the right), again indicating fewer and smaller errors.
Overall, I consider both solutions quite qood considering the challenging conditions.
By the time you add the extra shipping for ordering the antenna separately from the receiver, the combined cost for receiver and antenna increases from $63 for the previous configuration to $81 for the new configuration, but given the improvement in performance, I suspect this is well worth it and is still significantly less expensive than the u-blox alternative.
Note that this and the previous comparison were made using the real-time internal RTK solutions from the receivers at a 5 Hz sample rate. For those more interested in PPK (post-processing) solutions using RTKLIB, this receiver may not be a good choice. So far, I have not been able to configure the receiver to output raw RTCM3 observations at greater than 1 Hz. 1 Hz is fine for static solutions but too slow in most cases for kinematic solutions.
Overall though, for anyone primarily interested in real-time RTK solutions for static or moving rovers, or post-processed solutions for static rovers, I would definitely suggest considering the Quectel LC29HEA module as a potential lower cost alternative to the u-blox F9P.
If you have worked with the LC29H and would like to share your thoughts and experiences, please leave a comment below.
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