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Last update: April 12, 2024, at 07:29 AM
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     Chirp Sonar System Description

Department of Earth Science
 Allé gt. 41, N-5007 Bergen, Norway 
0.1 DRAFT - 29 Sept, 2021 OM OM -


Key specifications:

  • Vertical Resolution (depends on pulse selected): 6-10 cm
  • Penetration
    • In coarse calcareous sand: 6m
    • In clay: 80m
  • Towfish
    • Model: SB-424S ("424" means Transducer output from 4 to 24 kHz)
    • S/N: 37630
  • Topside unit:
    • Model 3100P
    • S/N: 37641



PROBLEM WITH WLAN CONNECTION TO TOPSIDE UNIT FROM WIN10 MACHINES: "It appears that most newer wireless network adapter drivers for Windows 10 do not support the connection type of our older topside wireless access points. There is no fix for this without changing hardware inside the topside. This means you will need a new wireless bridge in your topside. " --- Ref email from manufacturer 24 May, 2019.


Edgetech Chirp Sonar: LAPTOP / NOTEBOOK LIST, MAY 2019
Item # Sub-item Description Result Remarks
1 Dell ATG D630 (2008):

- Win XP (which is not updated anymore)
- Dell product web page
- Manuals:
-- Latitude D630 ATG Quick Reference Guide (PDF) -- also local copy
-- Latitude D630 ATG User's Guide (PDF) - also local copy
1.2 Windows Defender:
  • Update virus and spyware definitions
  • Run PC Scan, full type
- -
1.3 Microsoft Update   OK   -
1.4 USB/LAN interface adapter: Clas Ohlson P/N: 38-3732 -- LevelOne, type USB-0301, model AE222X1 -- User Manual (PDF) -- also local copy.

Required since built-in LAN port is defective.

1.5 Edgetech Discovery software: Discover V. 4.09 (2016):
- Select model "3100P" during installation.
  OK   -
1.6 External GPS: HOLUX M-215+

- Manufacturer: Holux
- Product link:
- Supplier: Amazon
- Download Driver and Manuals from here. Scroll down to the bottom, to section M-215+
- HOLUX M-215+ User Manual (local copy)
- HOLUX M-215+ Quick Guide (local copy)

1.7 GPS splitter software: Franson GPS Gate   OK   -
2 Dell Latitude 7480 (2018):
2.2 Windows Defender:
  • Update virus and spyware definitions
  • Run PC Scan, full type
- -
2.3 Microsoft Update - -
2.4 Edgetech Discovery software: Version installed = (2018) - -
2.5 External GPS: HOLUX M-215+

- Manufacturer: Holux
- Product link:
- Supplier: Amazon
- Download Driver and Manuals from here. Scroll down to the bottom, to section M-215+
- HOLUX M-215+ User Manual (local copy)
- HOLUX M-215+ Quick Guide (local copy)

2.6 GPS splitter software: Franson GPS Gate - -
3 NOTEBOOK: DELL Latitude 7212 "Rugged Extreme Tablet" (2019):

- Dell product web page
- Manuals:
-- Latitude 7212 Quick Start Guide (PDF) -- also local copy
-- Latitude 12 Rugged Extreme-nettbrett – 7212 Brukerhåndbok (PDF) - also local copy

- Built-in GNSS: u-blox, virtual COM port 7. Dedicated u-blox NEO-M8 GPS card
--- u-blox: NEO M8 series
--- Data Sheet -- also local copy
--- ''u-blox 8 / u-blox M8 - Receiver Description -- Including Protocol Specification -- also local copy Δ

- Micro serial to DB-9 (M) adapter

3.2 Windows Defender:
  • Update virus and spyware definitions
  • Run PC Scan, full type
- -
3.3 Microsoft Update   OK   -

A] --- USB/LAN interface adapter: Clas Ohlson P/N: 38-3732 -- LevelOne, type USB-0301, model AE222X1 -- User Manual (PDF) -- also local copy. Required since WIN10 WLAN device driver not compatible with wireless bridge inside Chirp Sonar Topside unit (it must be replaced).

B] --- USB-C (M) to USB 3.0 type A (F): Kjell & Co P/N: 69161

3.5 Edgetech Discovery software: Version installed = (2018):
- Download from here, section "Discover Software Available for Download"
- Select version: "Sub-bottom Discover Software (3100, 3200, 3300)":
- Select model "3100P" during installation.
  OK   -
3.6 External GPS: HOLUX M-215+

- Manufacturer: Holux
- Product link:
- Supplier: Amazon
- Download Driver and Manuals from here. Scroll down to the bottom, to section M-215+
- HOLUX M-215+ User Manual (local copy)
- HOLUX M-215+ Quick Guide (local copy)

3.7 GPS splitter software: Franson GPS Gate   OK   -
4 LAPTOP, BACKUP: DELL Inspiron 9400 (2006)
4.2 Microsoft Security Essentials:
  • Update virus and spyware definitions
  • Run PC Scan, full type
- -
4.3 Microsoft Update - -
4.4 Update Edgetech Discovery software: - Select "3200 Software"
5 SYSTEM TEST - using both primary and backup laptops


  • Topside unit (yellow PeliCase)
  • Chirp Towfish
  • GPS
5.1 Towfish functional test (limit Power Level to 10%)   OK   -
5.2 GPS test   OK   -
5.3 Recording test   OK   Only seen that *.JSF files are generated - content not examined.

Laptop screen resolutions


                Computer Industry Name 	  TV Industry Name
 1366 x 768 	HD (not Full HD) 	 
 1600 x 900 	HD+   Resolution of OM laptop 2013
 1920 x 1080 	Full HD 	             1080p
 1920 x 1200     Offered by Dell Inspiron 9400  ----   back up Chirp Sonar laptop.   This resolution seems to be minimum required.
 2304 × 1440 	Retina (Apple only) 	 
 2560 x 1440 	QHD / WQHD 	              2K
 2560 × 1600 	Retina (Apple only) 	 
 2880 × 1800 	Retina (Apple only) 	 
 3000 x 2000 	PixelSense (MS Only) 	 
 3200 x 1800 	QHD+ 	                      3K
 3840 x 2160 	UHD 	                      4K

Extra monitor:


Important - Machine ID -- not used anymore

To use the software, you have to enter a password (obtained from the manufacturer) which depends on your laptop computer ID code. The machine ID is generated by the MAC-address of the actice network adapter (this MAC adddress is unique). The computer ID code will be different if LAN and/or WLAN adapter is enabled or not. Our setup (as of August 2009) demands that both LAN and WLAN adapter be enabled.

IP-adddress of topside box is fixed at

Default IP address of topside box (yellow) is It's possible to connect to the yellow Topside unit by either WLAN or cabled LAN. The IP addresses for WLAN and LAN adapters must be:

  • WLAN:, netmask:
  • LAN:, netmask:

Both should not be active at the same time.

Discover SB software: Set IP- and Port-address, in order to communicate with Topside Unit

When using Discover SB(3200SW) on 3100P systems, set the Network settings under the Discover Control Panel to the following (in order to communicate with Topside Unit):

  • TCP/IP Address:
  • TCP/IP Socket: 1620
  • Enable Connection to Sonar box checked
Topside box default IP address
In Discover software, set Topside box default IP address and port number.

Enable GPS import in EDGETECH software

Select Sonar -> Control Panel -> Navigation. Enable proper COM port - in this case the second one, assigned to port 4. Ensure that speed is correct (here 4800 b/s). Also ensure that you select Coordinate Units: Lat Long from GLL/GGA Msg, as shown:

You will probably want to enable "Save Nav Track Data to File" and enter proper filename. It is assumed (but not confirmed!) that nav data is merged into SEG-Y headers, so you should have nav data even when the "Save nav track to file" is not enabled (must be checked!!!).

When EDGETECH software detects the GPS, corresponding status field will be updated (not red):


Transcription to SEG-Y

Options when recording data in SEGY format
Options when recording data in SEGY format.

It's recommended to store data in native JSF format as this format stores more parameters then SEGY. A transcription to SEGY is accomplished by recording in SEG-Y while simultaneously playing back the JSF-file in question. When selecting SEGY as record format, some additional SEGY options are enabled:

  • Represent seismic samples as either IBM floats, or IEEE floats. The (1) and (5) refers to the "Data sample format code" field in the SEGY binary header; "1" designates IBM floats, and "5" IEEE floats. The latter was first introduced in revision 1 of the SEGY standard; both formats should be equally suitable, but it's probably best to stick to the IBM float format to ensure no problems arise in any later processing of SEGY files in other software.
  • Select either ASCII or EBCDIC in first part of "Reel identification header" (the 3200 byte long "EBCDIC" part) of SEGY. If you want to adhere to the SEGY standard you should chose "EBCDIC".

To test the transcription we played back a JSF-file while recording in SEGY (using IBM floats and EBCDIC header). The SEGY file was succesfully imported into SeismicUnix, as shown here:

   [olem@uib5 sub-bottom-profiler]$ segyread endian=0 conv=1 tape=./testing.sgy | surange
   1+0 records in
   6+1 records out
   3200 bytes (3.2 kB) copied, 0.000323044 s, 9.9 MB/s
   959 traces:
   tracl    1 959 (1 - 959)
   tracr    1 959 (1 - 959)
   fldr     5168 6126 (5168 - 6126)
   tracf    1
   trid     1
   nvs      1
   nhs      1
   duse     1
   scalco   -100
   sx       1965730 1967901 (1965730 - 1967901)
   sy       21659301 21661921 (21661921 - 21659301)
   gx       1965730 1967901 (1965730 - 1967901)
   gy       21659301 21661921 (21661921 - 21659301)
   counit   2
   ns       10305
   dt       46
   gain     1
   igc      1
   corr     1
   sfs      2000
   sfe      15000
   slen     20
   styp     1
   year     2009
   day      174
   hour     9
   minute   14 22 (14 - 22)
   sec      0 59 (25 - 24)
   timbas   2

Navdata in SEGY file

When JSF files are transcripted into SEGY, navigation values are treated like this. First examine the counit (= coordinate unit) keyword; in the example above it's 2, which means that navigation data are stored as arch seconds. To convert to desimal degrees, the scalco value is needed; here it's -100, which means that coordinate values should be divided by 100.

E.g., the sx (source X-coordinate = Longitude) has minimum value 1965730. This values can be converted into decimal degrees:

  (1965730/100) / 3600 = 5.460361111 degrees

The sample JSF file has longitudes in the 5 deg 27 min range, so our conversion seems to be correct.

Nav track file - format, processing

Nav data can be stored by selecting "Save Nav Track Data to File" from "Navigation tab" within "Options" window.

Here is sample from one such Nav Track data file:

0  3684.4210   405.1333 165 0.0 0 7 2 48 -70.9 10    0.00 0
0  3684.4209   405.1333 248 0.0 0 7 2 50 -70.9 11    0.00 0
0  3684.4209   405.1332 218 0.0 0 7 2 52 -70.9 12    0.00 0
0  3684.4208   405.1332 281 0.0 0 7 2 54 -70.9 13    0.00 0
0  3684.4209   405.1332 271 0.0 0 7 2 56 -70.9 14    0.00 0
0  3684.4209   405.1332 258 0.0 0 7 2 58 -70.9 15    0.00 0
0  3684.4209   405.1332 271 0.0 0 7 3 0 -70.9 16    0.00 0
0  3684.4211   405.1334 61 0.0 0 7 3 2 -70.9 17    0.00 0
0  3684.4211   405.1336 24 0.0 0 7 3 4 -70.9 18    0.00 0
0  3684.4212   405.1336 46 0.0 0 7 3 6 -70.9 19    0.00 0

Format is described in file: "Appendix A Nav & Contour file formats.pdf" issued by Edgetech:

Field No. Field Name and Description Size Example
1 Target/Fix:
  • 0: Latitude/Longitude coordinates fix
  • 1: Latitude/Longitude coordinates target (left mouse click)
  • 2: Easting/Northing (X/Y) coordinates fix
Integer 0
2 Latitude (minutes) Float 3684.4210
3 Longitude (minutes) Float 405.1333
4 Course Integer 165
5 Speed Integer 4.0
6 Not used Integer 0
7 Hour (NMEA) Integer 23
8 Minute (NMEA) Integer 59
9 Second (NMEA) Integer 59
10 Reflection coefficient of Seafloor (dB) Float -70.9
11 Return Number Integer 13705
12 Fish height above seafloor tracker (meters or ms) Float 31.2
13 Not used Integer 0

In addition, nav data gets stored in two places within the JSF file. The raw NMEA message will be stored within the JSF file as a 2002 message. This is the same exact string that is sent from the GPS. The nav data will also be contained within the 80 message (sonar trace data) within the JSF file.

Reflection coefficient display

View reflection coefficient display in upper left corner of the display area by dragging the horizontal dividing line:

You must enter an offset value (try -40 dB) in the appropriate control control menu.


New GNSS receiver Sept 2021: "Navilock NL-8004U u-blox 8" (P/N: 62531)

Specifications, chip set information incl. NMEA telegram description

NMEA Telegrams from Navilock model NL-8004U (P/N: 62531)

Chipset is u-blox UBX-M8030. References:

Data sample from Navilock NL-8004U:

1st record, only at the beginning (when opening COM-port):

$GNTXT,01,01,02,u-blox AG -*4E
$GNTXT,01,01,02,HW UBX-M8030 00080000*60
$GNTXT,01,01,02,ROM CORE 3.01 (107888)*2B
$GNTXT,01,01,02,FWVER=SPG 3.01*46

Subsequent records:



RMC -- Recommended Minimum Data
  status:  V = Data invalid, A = Data valid
  spd: Speed over ground [knots]
  cog: Course over ground [degrees]
  mv: Magnetic variation value. Only supported in ADR 4.10 and later
  mvEW: Magnetic variation E/W indicator. Only in ADR 4.10 and later
  posMode: Mode Indicator
               N = No fix
               E = Estimated/Dead reckoning fix
               A = Autonomous GNSS fix
               D = Differential GNSS fix
               F = RTK float
               R = RTK fixed
  navStatus: Navigational status indicator
               V = Equipment is not providing navigational status information,
                   fixed field, only available in NMEA 4.10 and later
GNS -- GNSS fix data


  posMode: Positioning mode, see position fix flags description.
               1st character for GPS, 2nd character for GLONASS,
               3rd character for Galileo, 4th character for BeiDou
  alt: Altitude above mean sea level
  sep: Geoid separation: difference between ellipsoid and mean sea level
  diffAge: Age of diff corrections [seconds], null when DGPS is not used
  diffStation: ID of station providing diff corrections, null when DGPS is not used
  navStatus: Navigational status indicator
                V (Equipment is not providing navigational status information,
                   fixed field, only available in NMEA 4.10 and later)
GGA -- Global positioning system fix data


The NMEA specification indicates that the GGA message is GPS specific. However, when the receiver is configured for multi-GNSS, the GGA message contents will be generated from the multi-GNSS solution. For multi-GNSS use, it is recommended that the NMEA-GNS message is used instead.

  quality: Quality indicator for position fix, see position fix flags description [1]
              0 = No fix
              1 = Autonomous GNSS fix
              2 = Differential GNSS fix
              4 = RTK fixed
              5 = RTK float
              6 = Estimated/Dead reckoning fix
GSA -- GNSS DOP and Active Satellites


  • If less than 12 SVs are used for navigation, the remaining fields are left empty. If more than 12 SVs are used for navigation, only the IDs of the first 12 are output.
  • The SV numbers (fields 'svid') are in the range of 1 to 32 for GPS satellites, and 33 to 64 for SBAS satellites (33 = SBAS PRN 120, 34 = SBAS PRN 121, and so on).
  • In a multi-GNSS system this message will be output multiple times, once for each GNSS.
  opMode: Operation mode:
            M = Manually set to operate in 2D or 3D mode
            A = Automatically switching between 2D or 3D mode
  navMode: Navigation mode, see position fix flags description [1]
           Possible values for navMode:
              1 = No fix
              2 = 2D fix
              3 = 3D fix
  svid: Space Vehicle ID - Start of repeated block (12 times)
  PDOP: Position dilution of precision
  HDOP: Horizontal dilution of precision
  VDOP: Vertical dilution of precision
  systemId: NMEA defined GNSS System ID, see Signal Identifiers table [2]
            Only available in NMEA 4.10 and later
GST -- GNSS Pseudo Range Error Statistics


This message reports statistical information on the quality of the position solution.

  rangeRms: RMS value of the standard deviation of the ranges [meter]
  stdMajor: Standard deviation of semi-major axis (only in ADR 4.10 and later)
  stdMinor: Standard deviation of semi-minor axis (only in ADR 4.10 and later)
  orient: Orientation of semi-major axis (only in ADR 4.10 and later)
  stdLat: Standard deviation of latitude error [meter]
  stdLong: Standard deviation of longitude error [meter]
  stdAlt: Standard deviation of altitude error [meter]
ZDA -- Time and Date


  ltzh: Local time zone hours: 00 (fixed field)
  ltzn: Local time zone minutes: 00 (fixed field)

[1] Position fix flags description
[2] Signal Identifiers table


HOLUX M-215+

This unit appears as a COM-device. Since there are many new types of NMEA telegrams - and we are not sure if all telegram types output GNSS-quality data, we should split the GPS data stream and direct one for logging to disk, and the other to Chirp Sonar program. In that way we can post-process all raw navigation data - not only the (possible) sub-set that Chirp Sonar program deals with. (Many uncertain factors here !!)

Basic Specifications:

  • MTK MT3333 GPS/ GLONASS chipset
  • 66 parallel searching, 22 tracking channels
  • Receiver: L1, 1575.42 MHz
  • C/A code: 1.023 MHz
  • Update rate: 1Hz.
  • Antenna type: Built in patch antenna
  • Minimum Signal tracked: -165dBm
  • Dimension: 64.5 x 42 X 17.8 mm.
  • Weight: < 84g.
  • Waterproof: IPX7 ("X7" where second digit is seven; it means: Immersion, up to 1 m depth -- Ingress of water in harmful quantity shall not be possible when the enclosure is immersed in water under defined conditions of pressure and time (up to 1 m of submersion).
  • Operation temperature: -10 C to + 60 C
  • Store temperature: -20 C to + 70 C.
  • Operation humidity: 5% to 95% no condensing
  • Non DGPS (Differential GPS):
    • Position: 3.0 M CEP excluding SA
    • (Refer to MTK chip specification): Velocity: 0.1 M / sec.

NMEA protocol output V.3.01:

  • Protocol and interface Baud rate: 4800 bps
  • Data bit: 8
  • Parity: N
  • Stop bit: 1

Output NMEA telegrams

Description of NMEA telegrams: MT3333 Platform NMEA Message Specification For GPS+GLONASS_V1.00 (PDF) ---- also local copy

Message ID Meaning Rate
GPGGA Global Positioning System Fixed Data 1time/1sec
GPRMC ~ GNRMC Recommended Minimum Specific GNSS Data 1time/1sec
GPVTG Course Over Ground and Ground Speed 1time/1sec
GPGSA GNSS DOP and Active Satellites 1time/5sec
GPGSA GNSS DOP and Active Satellites 2time/5sec
GPGSV / GLGSV GNSS Satellites in View 1time/5sec

Sample data set


Upload GPS data and generate KML file, or Google Maps file

USB Extension cable

Protective box with IP44 rating, for USB connectors

The USB cable junction needs protection from the elements. Earlier we have used heat-shrink tube lined with glue - but then it will not be possible to disassemble the stuff. So this time we purchased a junction box that might be a bit over-sized, but in practice that is not a problem: Jula P/N: 402298

The box is rated IP44, where second digit indicates ingress protection:

"Water splashing against the enclosure from any direction shall have no harmful effect, utilizing either: a) an oscillating fixture, or b) A spray nozzle with no shield.
Test a) is conducted for 10 minutes. Test b) is conducted (without shield) for 5 minutes minimum."


Jula P/N: 402298


Using Nav data from survey vessel RV "Hans Brattstrøm"

Furuno GP-32 GPS / Chart Plotter

JRC model JLR-21 GPS Compass

RV "Brattstrøm" is furnished with following navigation equipment:

  • Furuno GP-32 GPS / Chart Plotter. Local GP-32 GPS Brochure.
    • From specifications:
      • Output: NMEA 0183, with following NMEA telegrams: AAM, APB, BOD, BWC, GGA, GLL, GTD, RMA, RMB, RMC, VTG, XTE, ZDA
      • Input: DGPS data in RTCM SC104 version 2.1 format
      • Position accuracy, GPS only: 10 meter (95%)
  • JRC model JLR 21 GPS Compass that also provides vessel heading/course in addition to position. Local JLR-21 brochure.
    • From specifications:
      • Output: 5 independent working NMEA0183 ports (that means RS232C): DT, THS, ROT, ZDA, GGA, VTG, RMC, GBS, DTM, GSA, GSV, GNS, MSS, GST, GLL, ALR, ATT, HVE
      • Input: DGPS RTCM SC-104 version 2.0 (type 1, 2, 9, 16) format
      • SBAS receiver: Built-in (WAAS/EGNOS/MSAS)
      • Position accuracy, GPS only: 12m 2drms (C/A code, HDOP=<4, SA OFF)

Determining COM port

When the GPS is attached to the computer via an USB port, you must determine which COM port the operating system assigned to the device (it can vary). You will later use this COM port information in the EDGETECH topside box control program, in order to activate GPS input to the software.

First select Start -> Control Panel, and then click DEVICE MANAGER, as shown below:

Then click on Ports (COM & LPT):

The GPS device is designated "PROLIFIC USB-TO-SERIAL COMM PORT". In this example, the operating system assigned Keep('COM4') to this device.

Verify operation of GPS

We use TeraTerm terminal program in this example. You can also use Window's own terminal program (HyperTerminal).

It's also prudent to verify correct operation of the GPS. Do that before you enable the GPS in the EDGETECH software.

Execute the TeraTerm terminal software. Select Setup -> Serial port:

Use COM port discovered in Control Panel, and set speed to 4800 b/s:

If the GPS works properly, you should see something like this (2011):

Then close the terminal program (or select File -> Disconnect). You are about to enable the GPS serial port in the EDGETECH software, and you cannot gave the same COM-port open in two programs (unless you have installed special software for that purpose, like Franson GpsGate).

Splitting GNSS COM-port data stream, so many applications can read Nav data

Differential GNSS correction data

It is most practical to use GNSS ("Global Navigation Satellite System") correction services provided by the Norwegian Mapping Authority. Their correction signals are received through internet connection. A roving GNSS receiver can then use GSM (or GPRS) mobile broadband. The receiver must also feed NMEA GGA-telegrams back, so the system can determine which of the fixed reference stations in the national network is most appropriate to base correction data on.

Many GNSS receivers have serial data RS232C interface. The serial port that is designated to receive correction data, can often also emit the required NMEA GGA telegram, thus only a single serial port must be interfaced to the internet.

The Norwegian Mapping Authority provides two types of GNSS correction services:

  • DPOS, giving decimeter accuracy
  • CPOS, giving centimeter accuracy

The accuracy provided by DPOS service is sufficient for geolocating marine seismic data that we collect.

DPOS / CPOS services provided by the Norwegian Mapping Authority

DPOS : Decimeter accuracy - preferred CPOS : Centimeter accuracy
DPOS Receiver requirements CPOS Receiver requirements

Sitat (quote):

  • For å oppnå den kvaliteten som er oppgitt på produktinformasjonsarket for DPOS-tjenesten, trengs en kodebasert GNSS-mottaker med faseglattingsteknikk. Disse GNSS-mottakerne er i stand til å utnytte informasjon i fasemålingene til å justere kodemålingene, slik at grove feil i kodemålingene blir avdekket.
  • Mottakeren må:
    • Ha inngang og håndteringsmulighet for RTCM-format, versjon 2.3
    • Kunne sende ut posisjonsinformasjon i form av NMEA GGA-strenger.
    • Ved mottak av data over GPRS/internett kunne håndtere dataprotokollen NTRIP.

Sitat (quote):

  • 2-frekvent GNSS-mottaker.
  • Mottakeren må ha en firmware-versjon som støtter bruk av virtuell referansestasjon (herunder mottak av meldingstype 59 i RTCM versjon 2.3 eller meldingstype 1032 i RTCM versjon 3). Det anbefales å alltid ha en nyere firmware-versjon.
  • Måleboka eller mottakeren må ha programvare som gjør det mulig å sette parametere for bruk av virtuell referansestasjon (VRS).
  • Roveren må være tilkoblet en ekstern datakilde (vanligvis et GSM-modem) gjennom en port med mulighet for sending og mottak av data. Roveren må kunne sende NMEA GGA-strenger og motta RTCM referansedata på denne porten. En del GNSS-mottakere har også innebygget GSM-modem.

DPOS/CPOS representatives

GNSS receiver suitable for D/CPOS correction

  • Manufacturer: Topcon
  • Model: MR-2
  • Datasheet: PDF
  • Signals Tracked
    • GPS: L1 C/A, L1C, L1P(Y), L2P(Y), L2C, L5
    • GLONASS: L1 C/A, L1P, L2 C/A, L2P, L3C
    • Galileo: E1, E5a, E5b, E5AltBoc
    • BeiDou: B1, B2
    • SBAS Corrections: WAA
  • Using two antennas, direction/heading can be determined. According to specifications, "Heading Accuracy" is 0.3 degrees/D, where D is inter-antenna distance in meters.
  • Topcon maskinstyring X63 GPS+ til gravemaskin

Finding and un-installing registered, but unused, COM ports

Quoting from this source:

  • First up, you'll have to open up a Command Prompt and in Windows 7 it has to be run as administrator. Open up the start menu and start typing in "Command" until the black C:\ icon appears. Right click and select Run as Administrator If you have some other version of Windows, you may not have to run as admin.
  • Now type in set devmgr_show_nonpresent_devices=1 (which is the magic command to show ghost devices) followed by start devmgmt.msc (which starts up the device manager).
  • Select "Show hidden devices" from the View menu.
  • You can now see every COM port you've ever made, and you can also now select which ones you want to uninstall so the COM port number can be recycled.


Step # Description Screenshot
1 On client Windows PC, click on lower left magnifying glass. Enter "software" in search field
2 Select "Software Center" program that appears
3 Scroll down to Python and install. Select Python version 2.7.x Click to enlarge.
4 Open terminal window and confirm that Python is installed on your computer. By convention, Python 2.7.x will be installed in local directory: c:\Python27. Since there is no PATH to that folder (unless you set environment variable), you have to specify the complete path to Python, when you want to invoke it. Click to enlarge.
5 If Python works fine, you should see similar display as screen shot to the right. Exit by typing exit(). Click to enlarge.
6 Now make a new working directory for processing nav data, and download raw data files and Python script (ref next section). In this example, folder is:


Click to enlarge.
7 Execute Python script - and redirect output to file called 'test.txt" using command:

c:\Python27\python.exe > test.txt

Click to enlarge.

Example nav data and scripts

Use these nav data from June 2017 survey as example. They are copied from survey's web page:

No. Folder on recording laptop1) Input file File time stamp Script Output file Map sample
1 C:\DATA\2017-JUNE\HB17-211 navtrack.dat001.nav 20.06.2017, 14:22:36 navtrack.dat001.nav.txt Link
2 C:\DATA\2017-JUNE\ navtrack.dat002.nav 22.06.2017, 07:51:30 navtrack.dat002.nav.txt Link
1) Recording laptop: Dell Inspiron 9400, S/N:


2019, January: Survey at "Byfjorden", Bergen

  1. New laptop, WIN 10:
  2. Backup laptop (that runs MS VISTA O/S):
    • Attempted to install latest Chirp sonar SW: But at least WIN7 is required. So earlier version: V. 4.09 was re-installed.
    • Connected GPS: OK --- detected as Keep('COM6'), within Sub-bottom Discover Software
    • Connection to yellow top side unit OK.
  3. Manuals, latest versions:

2018, June

2016, September ---- outdated - for reference only

Test # Sub-item Description Result Remarks
  • OS: Microsoft Vista Home Basic, 32 bit, Service Pack 2
  • CPU: Intel Core 2 Duo, P8400 @ 2.26 GHz / 2.26 GHz
  • RAM: 4 GByte
1.1 Microsoft Security Essentials:
  • Update virus and spyware definitions
  • Run PC Scan, full type
  OK   -
1.2 Microsoft Update   FAIL   Microsoft Update program does not get any updates - appears to be getting no response from Microsoft update server - but the other machine (running Vista Business) updated successfully (took very long time, though).
1.3 FIX for Microsoft Update problem   OK   Download "WSUS Offline Update" from here: First execute main program, then client program. Worked fine!
1.4 Update Edgetech Discovery software: Version installed = 4.09, and that is the latest as of 5 September 2016. (If update required, download from Edgetech Resource Center - "Discover Software Available for Download". Remove existing program version first [Start -> Control Panel -> Programs and Features]).   NOT REQUIRED   -
2 LAPTOP, BACKUP: DELL Inspiron 9400
  • OS: Microsoft Vista Business, 32 bit, Service Pack 2
  • CPU: Intel T2600 @ 2.16 GHz / 2.17 GHz
  • RAM: 2 GByte
2.1 Microsoft Security Essentials:
  • Update virus and spyware definitions
  • Run PC Scan, full type
  OK   -
2.2 Microsoft Update   OK   -
2.3 Update Edgetech Discovery software:   OK   Select "3200 Software"
3 SYSTEM TEST - using both primary and backup laptops


  • Topside unit (yellow PeliCase)
  • Chirp Towfish
  • GPS
3.1 Towfish functional test (limit Power Level to 10%)   OK   -
3.2 GPS test   OK   -
3.3 Recording test   OK   Only seen that *.JSF files are generated - content not examined.

2016, April

For the first time since we received the Edgetech Chirp Sonar system in 2008, is was deployed without prior system check-out. Main laptop (DELL Latitude E6400 ATG) DOA ("dead on arrival"). Here's repair report from our excellent IT support staff (ØN):

  1) Machine: DELL Latitude E6400 ATG
  2) Laptop had not been used since September 2015 ⇒ internal battery depleted ⇒ BIOS date/clock had to be set.
  3) Installed new BIOS version.
  4) Inside BIOS setup, HDD controller was in incorrect mode so HDD performance was poor. Fixed.
Correct setting : Mode = AHCI ("Advanced Host Controller Interface") 5) Outdated network driver caused machine to freeze after log in. Driver updated ⇒ problem fixed.

2015, September

Machine: DELL Latitude E6400 ATG:

  • OS (VISTA) updated
  • Many applications incl Microsoft Security Essentials updated
  • Virus scan: OK
  • New Edgetech software - ver 4.09 - placed in "C:\Edgetech\Discover Sub-Bottom 4.00\Discover-Sub-bottom.exe"
  • After one year inactivity the built-in battery (rechargeable) was depleted. All BIOS settings were thus lost. There is one setting related to ATA-disk configuration that must be adjusted in such cases (contect IT support / ØN to learn details).


Applies to both primary and back-up laptops:

  • OS (MS Vista) updated
  • Many applications incl anti-virus also updated
  • New Edgetech Chirp Sonar software "Discovery": Updated to version 4.08
  • Edgetech Chirp sonar documentation (PDFs) placed in desktop folder

Other GPS/GNSS receivers for evaluation 2018

New GNSS development 2018

Part of description of new GNSS development, excerpt from email 15 Feb 2018:

''..... det er ganske forstemmende å se hvilken posisjonsnøyaktighet en standard GPS-mottaker gir (ref denne figuren). Fabrikantene av enklere GPS-mottakere forsøker nå å skjule dette kjedelige faktum når oppgraderte produkter presenteres, ved å utelate spesifikasjonen som angår horisontal nøyaktighet når man IKKE har korreksjonsdata; i stedet oppgir de denne nøyaktigheten med litt kryptisk forbehold: "SBAS enable" - se figur 2 under. Dette er intet problem når man har kunnskap om de tekniske forhold som ligger bak. Så langt har det kun vært sensitiviteten som er forbedret - dvs mottakerens evne til å først finne GPS-signalet, og deretter følge det (dvs det er to slike spesifikasjoner; "tracking sensitivity" som vanligvis oppgis, og den er bedre enn den som trengs for å identifisere signalet i første omgang, kalt "acquisition sesnsitivity" ) - som gir en forbedret mulighet for å bruke GPS-mottakerne i "urban jungle", og med mye overdekning i form av "dense foliage".

Det nye nå er at chip-settene som brukes i rimelige satellitt-mottakere også kan behandle signaler fra GLONASS (det Russiske systemet), Galileo (det Europeiske) og BeiDou-2 (det Kinesiske), og dermed forbedre posisjonsnøyaktigheten mye for en helt frittstående mottaker (uten korreksjon). Men utviklingen er i en tidlig fase, og det er kun en av de fem dominerende chip-sett-fabrikantene som har signalisert at de kan fremstille kretser som kan behandle signaler fra alle de nevnte satellittsystemene (QTI med SiRFstarV 5e). Men bare det å kunne kombinere GPS og GLONASS vil øke nøyaktigheten mye. Og slike enheter skal finnes på markedet:

Vi burde anskaffe Holux M-215+ og BU353-W10 for å se om de levde opp til forventningene (kan kjøpe fra Amazon og få beløpet refundert - ikke funnet norske forhandlere så langt). Siden det er endel tid før Chirp sonar'n skal benyttes så bør dette gå bra.

Test results


US GlobalSat GPS GNSS Location Sensor BU-353W10

This is a very problematic receiver. It does not appear as a COM-port, but as a special device. So we cannot get a serial stream, as our chirp sonar software expects.

GlobalSat model BU-353S4

  • No IP-rating
  • Horizontal accuracy, only with SBAS enable - clearly misleading
  • Sensitivity spec very good (-163 dBm)

New USB based GPS, February 2018 -- Alternatives

GlobalSat mod. BU-353 does not work with Win10 (new primary laptop). So we have to purchase new GPS units (USB versions). Here are the alternatives.

Garmin model GPS 18x USB

NOTE: When you plug GPS 18x USB into computer running Win10, the operating system will get drivers from proper source. After some time, the unit appears as GARMIN device with Setup > Devices. So another piece of software is required - GpsGate Splitter from GpsGate. Download and install. Then data from GPS 18x USB will appear as virtual COM ports (by default, Keep('COM1')-4), which means many applications can simultaneously utilize the same data source. Very good.

Haicom HI-204III USB

  • Chipset: GSP3F -- SSiRF Star IV technology
  • HI-204III USB
  • Accuracy, position, 10 meters, 2D RMS
  • Tracking sensitivity: -159dBm (why is this stated in header, and not in section with specifications)
  • Norw. supplier: Nautisk Fritid
    "Haicom 204III er en 20-kanals GPS sensor for tilkobling til PC via USB. Vi har solgt hundrevis av disse gjennom mange år, og de er et anbefalt produkt som er enkle å installere, har et veldig godt satelittmottak og samtidig er robust. Haicom 204II er vanntett. Haicom 204III brukes til våre PC navigasjonssystemer slik som TIKI og Chart Navigator."

GPS splitter software

USB-based GPS unit - GlobalSat Model BU-353 - introduction ---- OBSOLETE - for reference only

GlobalSat mod. BU-353
GlobalSat mod. BU-353
  • Manufacturer: GlobalSat
  • Model BU-353 is obsolete - no longer in production.
  • Replaced by updated model BU-353S4; its specifications state: "Accuracy -> Position Horizontal: <2.5m 2D RMS SBAS Enable". SBAS ("Satellite-based augmentation systems") is not used in our application. The new chip-set (SiRF STAR IV) provides better receiver sensitivity: -163dBm compared to -159 dBm (4 dB improvement) compared to BU-353. Moreover, new chip set can handle 48 channels in parallell; 20 before. The first feature will improve reception indoors or in urban landscapes. The latter does not matter much as the number of visible GPS satellites are still limited any time. So the horizontal accuracy specifications will probably not show much improvement, if any at all. Anyway, horizontal accuracy with SBAS disables is not indicated for model BU-353S4.

GlobalSat Model BU-353 - Specifications ---- OBSOLETE - for reference only

Click to enlarge.

BU-353 specifications, from BU-353 "User's Guide" ver 2.3.

Testing BU-353 horizontal accuracy, WAAS disabled - showing location outliers ---- OBSOLETE - for reference only

  • From BU-353 specifications; Accuracy -> Position Horizontal:
    • 5m 2D RMS WAAS enabled
    • 10m 2D RMS WAAS disabled
  • WAAS = Wide Area Augmentation System - we do not use this correction method
  • "10m 2D RMS WAAS disabled" accuracy specifications is an RMS average; outliers can be fairly large as shown in plot below.

Checking Model BU-353 performance with SiRFDemo software ---- OBSOLETE - for reference only

Download latest SiRFDemo.exe software from

Click to enlarge.

SirfDemo test of GPS BU-353. Slecet first Data Source -> Activate source. Change to NMEA-mode by choosing Action -> Switch to NMEA mode (if the GPS was in binary mode for some reason).

GlobalSat Model BU-353 documentation ---- OBSOLETE - for reference only

GlobalSat Model BU-353 NMEA telegrams ---- OBSOLETE - for reference only

Example of NMEA telegrams sent by the BU-353. Notice how the $GPGGA, $GPGSA, $GPRMC telegrams appear every second, wheras the $GPGSV is transmitted at a lower rate.

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Page last modified on September 27, 2022, at 05:51 PM
Electronics workshop
Department of Earth Science - University of Bergen