Measurement of static precision of various GPS receivers

Czech Republic, November 2014, Dan Barta. All data in ZIP pack.

1.1Introduction

Theme of this article is measure of static precision GPS over autoritatie surveypoint with autoritative CUZK know coordinates.

This article reports my results from measurement of static precision of various field GPS devices on fixed control points with known coordinates.

 

  1. 1.Neighborhood of the point ZHB239  

  2. 2.A detailed view of the GPS receiver placed on a stone bollard at the survey point. 

  3. 3.Topcon HiPer GGD with computer FC-100 and a mobile phone during a field record. 

 

 

For the basic measurements, I selected one of the fixed control points of State Administration of Land Surveying and Cadastre (ČUZK), TL-4302, ZM-50 24-34, SMO-5 121201, ZHB nr. 239 in Brno city (more info):

000943022390 ETRS-89: B=49 10 27.3133 L=16 33 46.2048 H(el.)=337.19

 S-JTSK: Y=601684.95 X=1162703.86 H(Bpv)=292.44

1.2GPS receiver

Table 1: Hardware used in the field experiment.

company, product

type

software

chipset

released

number of chanells

GNSS

EGNOS (avalaible/used)

other

 

Haicom, HI-406BT

BT module

TrekBuddy 0.9.#

SiRF III

2006

20

GPS L1

yes/no

SIRF-SN

src src2

Sony, Xperia M C1905

mobile phone

Android 4.1.2, GPX Logger 1.1.3

?

2013

?

GPS L1+GLONASS L1

yes/no

A-GPS

src

Garmin, eTrex30

outdoor GPS

3.0

? Teseo II

2013

?

GPS L1+GLONASS L1

yes/no

-

src src2

Topcon, HiPer GGD, FC-100

geodetic GPS

TopSurf 6.04.03

Euro-112

2003

40

GPS L1/L2

yes/no

CZEPOS

src

 

 

1.3Measurement and precision

Measure was made in 09-10/2014 because is not possible by technical problems completed in same time. Every receiver was started in cold and keep it 15 min. Measure is in WGS-84, compare of resolution is in projection UTM33N via GDAL (except HiPer GGD in S-JTSK with grid transformation via INSPIRE).

The measurements were taken in September and October 2014. Due to technical issues I was not able to run all the devices simultaneously. Every receiver was cold-started and waited 15 minutes prior to any measurement. Coordinates were taken in WGS-84, in order to assess precision I converted the data to UTM33N via GDAL (except HiPer GGD in S-JTSK with grid transformation via INSPIRE).

 

Table 2: Results of basic measurements

measure

product

Poin nr. ČÚZK

settings

max XY [m]

max Z[m]

RMSE XY [m]

RMSE Z [m]

start UTC

duration

track points number

1

eTrex30

239

GPS L1, EGNOS off

2,8

19,2

1,6

12,5

05.09.14 18:10

30 min

1800

2

eTrex30

239

GPS L1/GLONASS L1, EGNOS off

4,5

3,3

2,7

3,1

05.09.14 06:30

30 min

1800

3

HI-406BT

239

GPS L1, EGNOS off, SiRF Static Navigation off

4,7

12,6

3,0

10,7

05.09.14 06:30

30 min

1800

4

Xperia M C1905

239

GPS L1/GLONASS L1, EGNOS off, A-GPS used

7,2

61,6

4,3

53,6

03.10.14 06:10

30 min

727

5

HiPer GGD, FC-100

239

GPS, RTK, PHASE FIXED, ref. station TUBO

0,016

0,027

-

-

08.09.14 22:02

< 1 min

2

 

 

1.4Advanced measurement with Topcon HiPer GGD

 

Measure is in WGS-84, compare of resolution is in S-JTSK with grid transformationvia INSPIRE is in table 3.

Advanced measurements were performed on additional control points. Coordinates were taken in WGS-84 and transformed to S-JTSK using grid transformation via INSPIRE. The results are given in Table 3.

 

Survey Accuracy using Topcon method RTK for L1 (source):

 H: 15mm + 1,5ppm × D

 V: 30mm + 1,5ppm × D

 

Table 3: Advance measurements with Topcon over 5 ZHB points

datetime

survey point

type RTK

dX [m]

dY [m]

dH [m]

dXY [m]

2014-09-08 18:29:02

ZHB201

PHASE_DIFF_FIXED

-0,027

0,005

-0,012

0,027

2014-09-08 19:00:22

ZHB206

PHASE_DIFF_FIXED

-0,009

-0,002

-0,031

0,009

2014-09-08 19:15:42

ZHB204

PHASE_DIFF_FIXED

-0,029

-0,016

-0,004

0,033

2014-09-08 19:18:19

ZHB204

PHASE_DIFF_FIXED

-0,024

-0,017

-0,006

0,029

2014-09-08 19:41:47

ZHB205

PHASE_DIFF_FIXED

0,002

0,027

-0,081

0,027

2014-09-08 19:44:21

ZHB205

PHASE_DIFF_FIXED

0,000

0,022

-0,080

0,022

2014-09-08 19:56:55

ZHB239

PHASE_DIFF_FIXED

0,015

0,006

-0,027

0,016

2014-09-08 19:59:15

ZHB239

PHASE_DIFF_FIXED

0,004

0,014

-0,027

0,015

max

0,081

0,033

 

 

Specific maeasure for testing precision of FLOAT RTK method and fake authoritative coordinations of ZHB216 is in the table 4.

Precision of measurements performed using the FLOAT RTK method and results from detection of a point with errorneously declared coordinates are given in table 4.

 

Table 4: Measurements of specific siuations a) RTK with FLOAT and b) false coordinates of the point ZHB216

datetime

survey point

type RTK

dX

 [m]

dY

[m]

dH [m]

dXY [m]

2014-09-08 18:35:17

ZHB201

PHASE_DIFF_FLOAT

 

-0,168

0,605

2,290

0,628

2014-09-08 18:58:27

ZHB206

PHASE_DIFF_FLOAT

-0,130

-0,697

-2,099

0,709

2014-09-08 22:02:49

ZHB216

PHASE_DIFF_FIXED

buggy official coord of ZHB216

-1,557

-1,587

0,014

2,223

2014-09-08 22:03:55

ZHB216

PHASE_DIFF_FIXED

buggy officia coord of ZHB216

-1,551

-1,592

0,006

2,223

 

1.5Conlusion

The precision of the field GPS device Garmin eTrex30 was <5m in XY position , <15m in height , the effect of including GLONASS was not clearly demonstrable.

The precision of bluetooth module Haicom HI-406BT was <5m in XY position , <15m in height .

The precision of Andiod phone-mobile Xperia M was <10m in XY position , ~50m in height .

The precision of geodetic GPS Topcon HiPer GGD, using RTK FIX was <0,05m in XY position , <0,1m in height . Using the RTK FLOAT method, the precision fell to <1,0m in XY position , <3,0m in height . During the experiment, I detected a control point with errorneously declared coordinates (ZHB 216) and reported it to CUZK via the appropriate web form.

 

Czech Republic, November 2014, Dan Barta. All data in ZIP pack.

 

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