Comments on: GPS Accuracy: HDOP, PDOP, GDOP & Multipath

By: GISGeography

GISGeography — Sat, 20 Sep 2025 13:43:45 +0000

In reply to Frank. Typically under 2.5 is considered good for most GPS applications. 1 to 1.5 is really good

By: Frank

Frank — Tue, 16 Sep 2025 17:36:18 +0000

Which is a range of good HDOP values.
Thanks
Frank

By: Boniface

Boniface — Tue, 09 Apr 2024 09:15:52 +0000

In reply to I. Rossi. as it approaches Zero it becomes better...the lesser the value of the number the better

By: GISGeography

GISGeography — Mon, 17 Jul 2023 02:10:53 +0000

In reply to John Morrison. They're different

By: John Morrison

John Morrison — Sun, 16 Jul 2023 23:57:03 +0000

Are HDOP, GDOP and PDOP different or the same?

By: DaveX

DaveX — Tue, 07 Mar 2023 03:16:05 +0000

PDOP is unitless — It is the ratio between the size of your positional error divided by the error in range from the satellites. If you don’t have good separation between the satellites, the range error bands overlap and you get high PDOP. If the satellites are well separated/orthogonal, then the range errors intersect better and PDOP approaches 1. On a football field with 18yd wide goalposts, there’s a a 2 yard square area that’s 13+/-1 yards from the goalposts (PDOP=~1) and wide 18x2yd crescent band that’s 100+/-1 yards from the goalposts (PDOP=~18)

By: Ashish Kumar

Ashish Kumar — Fri, 30 Dec 2022 07:51:36 +0000

Lower DOP (Dilution of Precision) value means better positional precision considering wider angular separation between the satellites which is used to determine the GNSS receiver unit’s position.

By: Seepheerd

Seepheerd — Wed, 14 Sep 2022 08:03:13 +0000

PDOP/GDOP is the Position of DOP and can be thought of as 3D positioning or the mean of DOP, and most often referred to in GPS accuracy:
HDOP is the Horizontal of DOP; VDOP is the Vertical of DOP, both together give the PDOP or GDOP (Leica and Trimble terminology)

By: JS Kim

JS Kim — Thu, 02 Jun 2022 07:23:59 +0000

I have a question for you.

I assume that the position of the receiver is fixed in the Cartesian coordinate system.
At this time, are the X,Y coordinates of the satellite position making up the minimum PDOP and the X,Y coordinates of the satellite location making the minimum HDOP the same?

Summary: I’m wondering if the HDOP value is also minimal at the location of the satellite with the minimum PDOP.

By: I. Rossi

I. Rossi — Mon, 09 May 2022 13:52:56 +0000

I don’t understand…

What is a good PDOP ???