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Ten questations about hitarget sensorrs

10 سوالی  که ممکن است در رابطه با سنسور  Hi-Target برای شما مطرح شود

  1. چگونه سنسور راریجستر کنم ؟

Device >  Connect Device > Register

 

پس از وارد شدن به صفحه ریجستر تنها کافیست کد 24 رقمی دریافت شده را وارد نمایید و کلید OK را بفشارید .

 

  1. من به سنسور متصل شده ام اما خطای زیادی دارم . دلیل آن چیست ؟

در این حالت ممکن است به دو دلیل باشد :

  • دستگاه شما ماهواره به حد کافی نگرفته باشد( یا از تاریخ کد ریجستر شما گذشته باشد ) .
  • به دلیل ضعیف بودن اینترنت و یا استفاده از اکانت شما توسط شخص دیگر ! در این حالت شما پیغام RTK FIX را در منوی شناور نمیبینید و پیغام های Float , SDGPS , DGPS را ممکن است مشاهده نمایید.
  • در صورت استفاده از سامانه های اینترنتی از جمله شمیم ، مجددا (Source Node (Mount Point خود را فراخوان و SET کنید.
  • از صحت و درستی تایم زون خود اطمینان حاصل نمایید :        Project > Project Setting
  • Elevation Mask را بررسی کنید.

 

  1. در پیاده سازی میخواهم نقاط آماده شده از قبل را به کنترلر وارد کنم برای این مسئله چه کاری باید انجام بدهم ؟

 

برای وارد کردن نقاط جهت پیاده سازی به کنترلر شرایط زیر باید رعایت شود ؛
در قالب تکست تمامی نقاط باید جمع آوری شود وترتیب آن به شیوه زیر است :

Pt,Y,X,Z,Desc

  • تذکر : رعایت ترتیب Y , X  بسیار حائز اهمیت است . بین مولفه ها نیز باید کاما باشد .

 

پس از آنکه فایل تکست شما با ترتیب فوق در قالب تکست آماده شد.کافیست آن را در یک فولدر قرار داده و آن را  در پوشه ZHD  قرار دهید .

برای Import  آن وارد سربرگ Project  میشوید و طبق مراحل زیر پیش میروید :

Data Transfer > Stake Out > Mark >  > Open Text Folder and Select (xxx.txt) File > OK

 

  1. برای آنکه بتوانم پیکان جهت را بر روی نقشه در پیاده سازی فعال کنم باید چه کاری انجام داد ؟تنها کافیست مسیر زیر را دنبال کنید :


Stake Point > Configure> Stake > Show Offset On Map > On

 

 

  1. ارسال فایل به کامپیوتر شخصی از طریق رابط USB به چه صورت است ؟

پس از اتصال رابط کاربری به PC ، تنظیمات مربوطه زیر را در کنترلر انجام دهید .
1- هنگامی که USB به کامپیوتر متصل میشود در قسمت ابزارک آن دو پیغام مشاهد میکنید با کشیدن زبانه به سمت پایین میتوانید اطلاعات جدید را ببینید .

2- با انتخاب گزینه   وارد رابط کاربری USB  میشوید پس آن را بر روی  USB Storage بگذارید.
سپس با انتخاب  و فعال کردن گزینه  خواهید توانست به کارت حافظه و حافظه داخلی دسترسی پیدا کنید .

پس از طی این مراحل وارد My Computer  شده و با انتخاب درایور شناخته شده توسط سیستم وارد آن شوید . کلیه موارد مربوط به نرم افزار Hi-Survey Road  در پوشه ZHD قرار دارد .

 

 

  1. من برداشت انجام داده ام و تمامی مراحل انجام یک پروژه صحیح را درست طی نموده ام اما به هنگامی خروجی با خطای No Data مواجه میشوم علت چیست ؟

 

در این مورد شما کافیست ابتدا در نرم افزار یک پروژه جدید بسازید ، پس از آن وارد File Manager دستگاه کنترلر شوید با انتخاب Phone Storage وارد حافظه داخلی کنترلر شوید، طبق مسیر زیر پیش بروید :

ZHD > Project > Road > پروژه ای که در خروجی گرفتن از آن با مشکل مواجه شدید را انتخاب کنید  > Copy “Gps.raw”

 

فایل Gps.raw را پس از کپی در پروژه ایی که از قبل ایجاد کرده بودید Replace(جایگزینی) کنید .

حال کافیست دوباره وارد نرم افزار شده و پروژه ی جدیدی که ایجاد شده و فایل Gps.raw در آن جایگذاری کرده اید را طبق مسیر زیر process نمایید :

 

Project > Raw Date > More > Process

 

هم اکنون خواهید توانست نقاط را مشاهده نموده و در Data Transfer  از آن خروجی بگیرید .

 

 

  1. میخواهم سنسور را ریست کنم ، چه کاری لازم است که انجام دهم ؟

 

V90 Plus : دستتان را بر روی دکمه ی پاور سنسور نگاه دارید ، پس از گذشت سه ثانیه صدای دینگ دانگ را خواهید شنید در این لحظه دستتان را از دکمه پاور جدا نکنید و منتظر بمانید که صدای دینگ دانگ دوم را نیز بشنوید پس از شنیدن صدای دینگ دانگ دوم دستتان را از پاور جدا کنید در این لحظه سنسور ریست میشود .

 

Qbox8 و V100 : همانند V90 Plus می باشد با این تفاوت که بجای شنیدن صدای دینگ دانگ شما باید به چراغ های آن دقت کنید . دستتان را بروی پاور دستگاه نگه دارید پس از گذشت سه ثانیه دستگاه همه ی چراغهای آن یکبار چشمک میزند ، در این لحظه دستتان را از پاور جدا نکنید و منتظر بمانید مرحله ی اول باری دیگر تکرار شود پس از آن میتوانید دستتان را از پاور جدا کنید . به هنگام ریست دستگاه مرتبا چشمک های قرمز و سبز میزند پس از آنکه ریست انجام شود دستگاه به حالت قبل باز میگردد . (تقریبا 7ثانیه )

V30 :  برای ریست V30  با نگه داشتن دکمه F1  به مدت 6 ثانیه دستگاه ریست میشود.

 

  1. میخواهم سنسور را آپدیت کنم . چه کاری لازم است که انجام دهم ؟

 

برای آپدیت سنسور کافیست ابتدا توسط کابل سنسور را به کامپیوتر متصل کنید ، دو درایور شناخته میشود با نام های Update و Static  .

فایل آپدیت سنسور را بدون تغییر در نام آن در درایور شناخته شده سنسور با نام Update   ، قرار دهید .
پس از اتمام این مرحله لازم است یکبار سنسور را خاموش و روشن کنید. هنگامی که سنسور روشن میشود به طور اتوماتیک شروع به نصب فریم ور کرده پس از شنیدن صدای Installation Sucsses  سنسور راه اندازی میشود. پس از طی این مراحل یکبار سنسور را ریست کنید .

  • تذکر : این شرکت هیچ گونه تضمینی درصورت بارگذاری فایل اشتباه و بروز هرگونه مشکل برای دستگاههایی که غیر از نماینده اصلی خریداری شده و وارد ایران شده است است را ندارد.

 

 

 

 

  1. چرا بعد از بارگذاری نقشه DXF ، آنرا در پشت زمینه نمی بینیم؟

حتما اگر نیاز به نمایش نقشه و نقاط خودتان هست باید در مسیر زیر رفته و گوگل مپ را خاموش کنید:

Survey > Configure > Display > Online Map => None
&
Color Map => On

 

 

  1. چرا در صفحه نمایش بجای مختصات به ما با واحد طول و عرض جغرافیایی نمایش می دهد؟

برای نمایش دادن مختصات بصورت X,Y کافیست یک لحظه بر روی طول و عرض کلیک کرده تا اتومات به حالت مختصات برگردد.

  • توجه داشته باشید که حتما  باید زون منطقه را درست تنظیم کرده باشد که در مسیر زیر می باشد:

Project > Project Setting

 

 

Different Messages In The nTrip RTCM3 System

The various messaging lists in the NTRIP RTCM3 system include :

Message Name & Usage CommentaryMessage
Experimental Messages
The messages in this range are temporary value assignments used by the RTCM SC-104 committee to develop and validate new messages before formal adoption and assignment of a permanent value.
100~1
L1-Only GPS RTK Observables
This GPS message type is not generally used or supported; type 1004 is to be preferred.
1001
Extended L1-Only GPS RTK Observables
This GPS message type is used when only L1 data is present and bandwidth is very tight, often 1004 is used in such cases (even when no L2 data is present).
1002
L1&L2 GPS RTK Observables
This GPS message type is not generally used or supported; type 1004 is to be preferred.
1003
Extended L1&L2 GPS RTK Observables
This GPS message type is the most common observational message type, with L1/L2/SNR content. This is the most common message found.
1004
Stationary RTK Reference Station ARP
Commonly called the Station Description this message includes the ECEF location of the antenna (the antenna reference point (ARP) not the phase center) and also the quarter phase alignment details. The datum field is not used/defined, which often leads to confusion if a local datum is used. See message types 1006 and 1032. The 1006 message also adds a height about the ARP value.
1005
Stationary RTK Reference Station ARP with Antenna Height
Commonly called the Station Description this message includes the ECEF location of the antenna (the antenna reference point (ARP) not the phase center) and also the quarter phase alignment details. The height about the ARP value is also provided. The datum field is not used/defined, which often leads to confusion if a local datum is used. See message types 1005 and 1032. The 1005 message does not convey the height about the ARP value.
1006
Antenna Descriptor
A textual description of the station ID (a number) and the antenna “descriptor” which is used as a model number. The descriptor can be used to look up model specific details of that antenna. See 1008 as well.
1007
Antenna Descriptor and Serial Number
A textual description of the station ID (a number) and the antenna “descriptor” which is used as a model number, and a (presumed unique) antenna serial number. The descriptor can be used to look up model specific details of that antenna. See 1007 as well.
1008
L1-Only GLONASS RTK Observables
This GLONASS message type is not generally used or supported; type 1012 is to be preferred.
1009
Extended L1-Only GLONASS RTK Observables
This GLONASS message type is used when only L1 data is present and bandwidth is very tight, often 1012 is used in such cases.
1010
L1&L2 GLONASS RTK Observables
This GLONASS message type is not generally used or supported; type 1012 is to be preferred.
1011
Extended L1&L2 GLONASS RTK Observables
This GLONASS message type is the most common observational message type, with L1/L2/SNR content. This is one of the most common messages found.
1012
System Parameters
This message provides a table of what message types are sent at what rates. This is the same information you find in the Caster Table (this message predates NTRIP). SNIP infers this information by observing the data stream, and creates Caster Table entries when required. This message is also notable in that it contains the number for leap seconds then in effect. Not many NTRIP devices send this message.
1013
Network Auxiliary Station Data
Contains a summary of the number of stations that are part of a Network RTK system, along with the relative location of the auxiliary reference stations from the master station.
1014
GPS Ionospheric Correction Differences
Contains a short message with ionospheric carrier phase correction information for a single auxiliary reference station for the GPS GNSS type. See also message 1017.
1015
GPS Geometric Correction Differences
Contains a short message with geometric carrier phase correction information for a single auxiliary reference station for the GPS GNSS type. See also message 1017.
1016
GPS Combined Geometric and Ionospheric Correction Differences
Contains a short message with both ionospheric and geometric carrier phase correction information for a single auxiliary reference station for the GPS GNSS type. See also messages 1015 and 1016.
1017
RESERVED for Alternative Ionospheric Correction Difference Message
This message has not been developed or released by SC-104 at this time.
1018
GPS Ephemerides
Sets of these messages (one per SV) are used to send the broadcast orbits for GPS in a Kepler format.
1019
GLONASS Ephemerides
Sets of these messages (one per SV) are used to send the broadcast orbits for GLONASS in a XYZ dot product format.
1020
Helmert / Abridged Molodenski Transformation Parameters
A classical Helmert 7-parameter coordinate transformation message. Not often found in actual use.
1021
Molodenski-Badekas Transformation Parameters
A coordinate transformation message using the Molodenski-Badekas method (translates through an arbitrary point rather than the origin) Not often found in actual use.
1022
Residuals, Ellipsoidal Grid Representation
A coordinate transformation message. Not often found in actual use.
1023
Residuals, Plane Grid Representation
A coordinate transformation message. Not often found in actual use.
1024
Projection Parameters, Projection Types other than Lambert Conic Conformal
A coordinate projection message. Not often found in actual use.
1025
Projection Parameters, Projection Type LCC2SP (Lambert Conic Conformal)
A coordinate projection message. Not often found in actual use.
1026
Projection Parameters, Projection Type OM (Oblique Mercator)
A coordinate projection message. Not often found in actual use.
1027
Reserved for Global to Plate-Fixed Transformation
This message has not been developed or released by SC-104 at this time.
1028
Unicode Text String
A message which provides a simple way to send short textual strings within the RTCM message set. About ~128 UTF-8 encoded characters are allowed.
1029
GPS Network RTK Residual Message
This message provides per-SV non-dispersive interpolation residual data for the SVs used in a GPS network RTK system. Not often found in actual use.
1030
GLONASS Network RTK Residual
This message provides per-SV non-dispersive interpolation residual data for the SVs used in a GLONASS network RTK system. Not often found in actual use.
1031
Physical Reference Station Position
This message provides the ECEF location of the physical antenna used. See message types 1005 and 1006. Depending on the deployment needs, 1005, 1006, and 1032 are all commonly found.
1032
Receiver and Antenna Descriptors
A message which provides short textual strings about the GNSS device and the Antenna device. These strings can be used to obtain additional phase bias calibration information.
1033
GPS Network FKP Gradient
A message which provides Network RTK Area Correction Parameters using a method of localized horizontal gradients for the GPS GNSS system.
1034
GLONASS Network FKP Gradient
A message which provides Network RTK Area Correction Parameters using a method of localized horizontal gradients for the GLONASS GNSS system.
1035
Not defined at this time
This message has not been developed or released by SC-104 at this time.
1036
GLONASS Ionospheric Correction Differences
Contains a short message with ionospheric carrier phase correction information for a single auxiliary reference station for the GLONASS GNSS type. See also message 1039.
1037
GLONASS Geometric Correction Differences
Contains a short message with geometric carrier phase correction information for a single auxiliary reference station for the GLONASS GNSS type. See also message 1039.
1038
GLONASS Combined Geometric and Ionospheric Correction Differences
Contains a short message with both ionospheric and geometric carrier phase correction information for a single auxiliary reference station for the GLONASS GNSS type. See also messages 1037 and 1037.
1039
BDS Satellite Ephemeris Data
Sets of these messages (one per SV) are used to send the broadcast orbits for the BeiDou (Compass) system.
1042
Not defined at this time
This message has not been developed or released by SC-104 at this time.
1043
QZSS Ephemerides
Sets of these messages (one per SV) are used to send the broadcast orbits for QZSS in a Kepler format.
1044
Galileo F/NAV Satellite Ephemeris Data
Sets of these messages (one per SV) are used to send the Galileo F/NAV orbital data.
1045
Galileo I/NAV Satellite Ephemeris Data
Sets of these messages (one per SV) are used to send the Galileo I/NAV orbital data.
1046
SSR GPS Orbit Correction
A state space representation message which provides per-SV data. It contains orbital error / deviation from the current broadcast information for GPS GNSS types.
1057
SSR GPS Clock Correction
A state space representation message which provides per-SV data. It contains SV clock error / deviation from the current broadcast information for GPS GNSS types.
1058
SSR GPS Code Bias
A state space representation message which provides per-SV data. It contains code bias errors for GPS GNSS types.
1059
SSR GPS Combined Orbit and Clock Correction
A state space representation message which provides per-SV data. It contains both the orbital errors and the clock errors from the current broadcast information for GPS GNSS types. Note these are given as offsets from the current broadcast data.
1060
SSR GPS URA
A state space representation message which provides per-SV data. It contains User Range Accuracy (URA) for GPS GNSS types.
1061
SSR GPS High Rate Clock Correction
A state space representation message which provides a higher update rate than message 1058. It provides more precise data on the per-SV clock error / deviation from the current broadcast information for GPS GNSS types.
1062
SSR GLONASS Orbit Correction
A state space representation message which provides per-SV data. It contains orbital error / deviation from the current broadcast information for GLONASS GNSS types.
1063
SSR GLONASS Clock Correction
A state space representation message which provides per-SV data. It contains SV clock error / deviation from the current broadcast information for GLONASS GNSS types.
1064
SSR GLONASS Code
A state space representation message which provides per-SV data. It contains code bias errors for GPS GLONASS types.
1065
SSR GLONASS Combined Orbit and Clock Corrections
A state space representation message which provides per-SV data. It contains both the orbital errors and the clock errors from the current broadcast information for GLONASS GNSS types.
1066
SSR GLONASS URA
A state space representation message which provides per-SV data. It contains User Range Accuracy (URA) data for GLONASS GNSS types.
1067
SSR GLONASS High Rate Clock Correction
A state space representation message which provides a higher update rate than message 1064. It provides more precise data on the per-SV clock error / deviation from the current broadcast information for GLONASS GNSS types.
1068
Reserved for MSM
This Multiple Signal Message type has not yet been assigned for use.
1070
GPS MSM1
The type 1 Multiple Signal Message format for the USA’s GPS system
1071
GPS MSM2
The type 2 Multiple Signal Message format for the USA’s GPS system
1072
GPS MSM3
The type 3 Multiple Signal Message format for the USA’s GPS system
1073
GPS MSM4
The type 4 Multiple Signal Message format for the USA’s GPS system
1074
GPS MSM5
The type 5 Multiple Signal Message format for the USA’s GPS system
1075
GPS MSM6
The type 6 Multiple Signal Message format for the USA’s GPS system
1076
GPS MSM7
The type 7 Multiple Signal Message format for the USA’s GPS system, popular.
1077
Reserved MSM
This Multiple Signal Message type has not yet been assigned for use.
1078
Reserved MSM
This Multiple Signal Message type has not yet been assigned for use.
1079
Reserved MSM
This Multiple Signal Message type has not yet been assigned for use.
1080
GLONASS MSM1
The type 1 Multiple Signal Message format for the Russian GLONASS system
1081
GLONASS MSM2
The type 2 Multiple Signal Message format for the Russian GLONASS system
1082
GLONASS MSM3
The type 3 Multiple Signal Message format for the Russian GLONASS system
1083
GLONASS MSM4
The type 4 Multiple Signal Message format for the Russian GLONASS system
1084
GLONASS MSM5
The type 5 Multiple Signal Message format for the Russian GLONASS system
1085
GLONASS MSM6
The type 6 Multiple Signal Message format for the Russian GLONASS system
1086
GLONASS MSM7
The type 7 Multiple Signal Message format for the Russian GLONASS system
1087
Reserved MSM
This Multiple Signal Message type has not yet been assigned for use.
1088
Reserved MSM
This Multiple Signal Message type has not yet been assigned for use.
1089
Reserved MSM
This Multiple Signal Message type has not yet been assigned for use.
1090
Galileo MSM1
The type 1 Multiple Signal Message format for Europe’s Galileo system.
1091
Galileo MSM2
The type 2 Multiple Signal Message format for Europe’s Galileo system
1092
Galileo MSM3
The type 3 Multiple Signal Message format for Europe’s Galileo system
1093
Galileo MSM4
The type 4 Multiple Signal Message format for Europe’s Galileo system
1094
Galileo MSM5
The type 5 Multiple Signal Message format for Europe’s Galileo system
1095
Galileo MSM6
The type 6 Multiple Signal Message format for Europe’s Galileo system
1096
Galileo MSM7
The type 7 Multiple Signal Message format for Europe’s Galileo system
1097
Reserved MSM
This Multiple Signal Message type has not yet been assigned for use.
1098
Reserved MSM
This Multiple Signal Message type has not yet been assigned for use.
1099
Reserved MSM
This Multiple Signal Message type has not yet been assigned for use.
1100
SBAS MSM1
The type 1 Multiple Signal Message format for SBAS/WAAS systems
1101
SBAS MSM2
The type 2 Multiple Signal Message format for SBAS/WAAS systems
1102
SBAS MSM3
The type 3 Multiple Signal Message format for SBAS/WAAS systems
1103
SBAS MSM4
The type 4 Multiple Signal Message format for SBAS/WAAS systems
1104
SBAS MSM5
The type 5 Multiple Signal Message format for SBAS/WAAS systems
1105
SBAS MSM6
The type 6 Multiple Signal Message format for SBAS/WAAS systems
1106
SBAS MSM7
The type 7 Multiple Signal Message format for SBAS/WAAS systems
1107
Reserved MSM
This Multiple Signal Message type has not yet been assigned for use.
1108
Reserved MSM
This Multiple Signal Message type has not yet been assigned for use.
1109
Reserved MSM
This Multiple Signal Message type has not yet been assigned for use.
1110
QZSS MSM1
The type 1 Multiple Signal Message format for Japan’s QZSS system
1111
QZSS MSM2
The type 2 Multiple Signal Message format for Japan’s QZSS system
1112
QZSS MSM3
The type 3 Multiple Signal Message format for Japan’s QZSS system
1113
QZSS MSM4
The type 4 Multiple Signal Message format for Japan’s QZSS system
1114
QZSS MSM5
The type 5 Multiple Signal Message format for Japan’s QZSS system
1115
QZSS MSM6
The type 6 Multiple Signal Message format for Japan’s QZSS system
1116
QZSS MSM7
The type 7 Multiple Signal Message format for Japan’s QZSS system
1117
Reserved MSM
This Multiple Signal Message type has not yet been assigned for use.
1118
Reserved MSM
This Multiple Signal Message type has not yet been assigned for use.
1119
Reserved MSM
This Multiple Signal Message type has not yet been assigned for use.
1120
BeiDou MSM1
The type 1 Multiple Signal Message format for China’s BeiDou system
1121
BeiDou MSM2
The type 2 Multiple Signal Message format for China’s BeiDou system
1122
BeiDou MSM3
The type 3 Multiple Signal Message format for China’s BeiDou system
1123
BeiDou MSM4
The type 4 Multiple Signal Message format for China’s BeiDou system
1124
BeiDou MSM5
The type 5 Multiple Signal Message format for China’s BeiDou system
1125
BeiDou MSM6
The type 6 Multiple Signal Message format for China’s BeiDou system
1126
BeiDou MSM7
The type 7 Multiple Signal Message format for China’s BeiDou system
1127
Reserved MSM
This Multiple Signal Message type has not yet been assigned for use.
1128
Reserved MSM
This Multiple Signal Message type has not yet been assigned for use.
1229
GLONASS L1 and L2 Code-Phase Biases
This message provides corrections for the inter-frequency bias caused by the different FDMA frequencies (k, from -7 to 6) used.
1230
Proprietary Messages4001-4095
Assigned to: Ashtech
The content and format of this message is defined by its owner.
4095
Assigned to: Trimble Navigation Ltd.
The content and format of this message is defined by its owner.
4094
Assigned to: NovAtel Inc.
The content and format of this message is defined by its owner.
4093
Assigned to: Leica Geosystems
The content and format of this message is defined by its owner.
4092
Assigned to: Topcon Positioning Systems
The content and format of this message is defined by its owner.
4091
Assigned to: Geo++
The content and format of this message is defined by its owner.
4090
Assigned to: Septentrio Satellite Navigation
The content and format of this message is defined by its owner.
4089
Assigned to: IfEN GmbH
The content and format of this message is defined by its owner.
4088
Assigned to: Fugro
The content and format of this message is defined by its owner.
4087
Assigned to: inPosition GmbH
The content and format of this message is defined by its owner.
4086
Assigned to: European GNSS Supervisory Authority
The content and format of this message is defined by its owner.
4085
Assigned to: Geodetics, Inc.
The content and format of this message is defined by its owner.
4084
Assigned to: German Aerospace Center, (DLR)
The content and format of this message is defined by its owner.
4083
Assigned to: Cooperative Research Centre for Spatial Information
The content and format of this message is defined by its owner.
4082
Assigned to: Seoul National University GNSS Lab
The content and format of this message is defined by its owner.
4081
Assigned to: NavCom Technology, Inc.
The content and format of this message is defined by its owner.
4080
Assigned to: SubCarrier Systems Corp. (SCSC) The makers of SNIP
The content and format of this message is defined by its owner.
4079
Assigned to: ComNav Technology Ltd.
The content and format of this message is defined by its owner.
4078
Assigned to: Hemisphere GNSS Inc.
The content and format of this message is defined by its owner.
4077
Assigned to: International GNSS Service (IGS)
The content and format of this message is defi
ned by its owner.
4076
Assigned to: Alberding GmbH
The content and format of this message is defined by its owner.
4075
Assigned to: Unicore Communications Inc
The content and format of this message is defined by its owner.
4073
Assigned to: Mitsubishi Electric Corp
The content and format of this message is defined by its owner.
4072

Concept and Comparison Of VRS , MAX , iMAX , FKP , NEAREST in GPS Networks

Concept and Comparison Of VRS , MAX , iMAX , FKP , NEAREST in GPS Networks

VRS:

The virtual reference station (VRS), or virtual base station (VBS), idea, introduced by Trimble, is that a base station is artificially created in the vicinity of a rover receiver. All baseline-length-dependent errors, such as abnormal troposphere variation, ionospheric disturbances and orbital errors, are reduced for this VRS. The rover receiving VRS information has a lower level of these errors than a distant base station. The VRS is calculated for a position, supplied by the rover during communication start-up, with networking software. The VRS position can change if the rover is far away from the initial point. The format for sending the rover’s position is standard NMEA format. Most rovers receive VRS data for a calculated base station that is within a couple of metres away. The VRS approach requires bi-directional communication for supplying the rover’s position to the networking software.

MAX:

For broadcast communication mediums, pre-defined cells, which may be created manually by the network operator, can be used to transmit master-auxiliary corrections, known as MAX, to the rovers. The rover user can connect to the correction service that is most relevant for their geographic location. Depending on the size of the network, multiple cells can be defined to optimise the transmission of data by reducing the number of stations that are contained in the correction messages. In the case of two-way communications, Leica GPS Spider will automatically select the optimum sites for the cell used to generate master-auxiliary corrections for each rover. This correction service is referred to as Auto-MAX. By choosing the most appropriate cell configuration, Auto-MAX corrections minimise the bandwidth required to transmit the corrections. The master station is always chosen as the station nearest to the rover. The auxiliaries are chosen from the surrounding stations to provide the best possible set of corrections for the rover’s position. With Auto-MAX even the largest reference networks can be fully serviced with a single communication channel. The MAX corrections contain the full information from the cell and therefore provide the maximum level of accuracy and reliability for the rover. With MAX, the network operator has to ability to transmit corrections using both two-way and broadcast communication technologies.

iMAX:

The iMAX idea, introduced by Leica Geosystems, is that networking software corrections, based on the rover’s position, are calculated as with VRS. However, instead of calculating the base station observations for the provided position, or another position closer to the base station, original observation information is corrected with the calculated corrections and broadcast. VRS works so that although the rover is unaware of errors the VRS is taking care of, there still might be ionospheric remains in the base station observations. iMAX provides actual base station position information. The rover may assume the base station is at a distance and open its settings for estimation of the remaining ionospheric residuals. The iMAX method may trigger the rover to open its settings further than required since the networking software removes at least part of the ionospheric disturbances. However, compared to VRS above, this approach is safer since it notifies the rover when there might be baseline-length-dependent errors in the observation information. iMAX requires bi-directional communication to the networking software for supplying the base station observation information.

FKP :

With FKP methodology, a model of the distance dependent errors (“Flächen-Korrektur-Parameter” FKP) is transmitted to the rover. The interpretation of the FKPs and the individualization of the corrections are done at the rover, i.e. the rover can for itself compute the individualized corrections in the same way as VRS/PRS or alternatively use its own algorithms, which might be better adjusted to the RTK algorithms of the rovers. Thus the FKP method provides to the rover more information than VRS method, so that the rover in principal can get more from the received data. FKPs describe the (horizontal) gradients of the corrections. The correction of a (real) reference station is used in combination with the FKPs to compute the individualized corrections for the rover position.

In the simplest case the FKPs describe a linear dependency of the corrections from the position (linear FKP). The FKPs then define an “inclined plane” for the corrections, centered at the (real) reference station. Per satellite and per frequency two parameters (inclination in North-South and in West-East) are required. FKP models of higher order are possible. Note that the validity of linear FKP is limited to about 100km radius, due to the fact that the physical error sources would lead to noticeable non-linear effects over longer distances.

NEAREST :

In this case, the system remains the same as a base and rover mode and acts as a single station, and the rover device is connected to the nearest reference station and takes corrections.

It is suggested that you use this method if you are out of the network.