HGLRC M100 Pro GPS Altitude is off by 46 meters

Hi, we have bunch of HGLRC M100 Pro GPS modules. When we test, it was displaying 1050 meters for alt in the GPS_RAW_INT message. The real altitude is 1004 meters. With other GPS modules we tested, it is displayed correctly like in the GEPRC M10Q.

Also I checked other things, like alt_ellipsoid in the GPS_RAW_INT is reporting the same value as alt field unlike GEPRC and intended behavior.

It does not send status text like “HW: 000A000” but GEPRC does. It displays many satellites inside like 15 which we never saw with GEPRC.

We connected them to u-center 2 software it displays UBX-MON-VER message correctly same as GEPRC but it does not display most of the messages even we poll them manually like UBX-MON-RF and UBX-SEC-UNIQID which is strange.

I’m no GPS expert but something suspicious with those modules. And we tested like 5 of them and all same.

I already sent an email to support@hglrc.com 4 days ago and there’s no answer.

What can I do?