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GNSS Devices in Mapping

Geostationary Satellites

GNS 2000 Plus

Key features

I finally found a small GNSS device that met my key criteria of;

  • handles GPS, Glonass and Galileo satellite constellations
  • small enough to affix to my helmet or hat for best satellites view
  • stores track data for later retrieval

Most either store data for later retrieval or transmit live via Bluetooth but don’t store. The GNS 2000 Plus does both if you select to transmit via Bluetooth. Bluetooth transmission is the default. Storing is effected by rapid Off-On after you turn on the only switch on the device. But make sure you observe the light pattern that confirms you are in storage mode. I find both methods work well.

Satellites in view

This was an eye opener. Without access to Galileo, in the forest I was sometimes getting (via Bluetooth GPS app) barely sufficient usable satellites for good performance.

Add in Galileo and total satellites visible was at least 22 with 12 in use. In general, more satellites in use means better accuracy. As the signal from one satellite in use deteriorates, the next best is swapped in.

What’s not so good?

I wanted a POI button on my GNSSr but very few have these. However, to my pleasant surprise I found that Bluetooth to a smart device with OruxMaps as the tracking app, gives me not just POI function but also easy capability for making notes directly.

It isn’t IPX rated for climatic conditions. However if rain is threatening I put it in a ziplock bag.

The GNS 2000 Plus records a track point to the device only every 5 seconds. However, data transmitted to a smart device via Bluetooth, whether or not also recording to the GNS device, gives 1 second intervals – in fact typically 3 records per second. See my correction post for further information.

When setting the function to record on the GNS device, carefully observe that the green light flashes quickly 3 times as the switching to effect this is time sensitive. [This section updated 24 May 2019 to note BT 1 second intervals – thanks Rob Plowright].

For mtbo I find 5 seconds acceptable. I am used to riding at 12 km/h or less while mapping (at a significant cost of disc brake pads) which means a track point every 17m. On detailed track I tend to go slower and at junctions I generally stop. For foot-o, the Bluetooth transmission gives detailed data and if desired, the GNS device recording can also be on as a backup.

Originally I was disturbed at the lack of ability to set various parameters. Now I am a convert to the simplicity.

Tracking against Trimble

The Lerderderg Track (Vic) trail was originally surveyed on foot in 2000 using a professional Trimble with mushroom antenna. So this is a very good standard against which to compare the GNS 2000 Plus while riding. The Trimble track was supplied smoothed. The pic shows a track portion.

GNS 2000 ride vs Trimble walk in bush

The GNS 2000 Plus was on my helmet thus giving it the same exposure to satellites as the Trimble mushroom antenna. I also wore on my wrist my Suunto Ambit 2S and it showed noticeably more variation. My interpretation is that the addition of Galileo satellite access has enabled the GNS 2000 Plus to virtually match the professional Trimble year 2000 model.

Not all plain sailing

Talking of plain sailing, this device was developed mainly for small plane including sail plane use – hence the 5 second interval. Geoff Peck and I worked on resolving a number of issues. These revolved around getting the track data from all of GPS Glonass, Galileo etc from the device through to a gpx or kml/kmz file format for OCAD.

We found the popular GPS Bluetooth app recommended by GNS 2000 Plus did not handle satellites other than GPS and Glonass! Eventually we came across GNSS Commahttps://www.facebook.com/pilablunder app which as you can see from the images above, handles data from all constellations. So we had the means of getting the data and GNSS Commander would also store it and even email it afterwards.

But I wanted the ability to manage the tracks on the phone, especially creating POIs with text info. Also on occasion having a background map whether online topo or my own orienteering or trail map. Many apps were presented but only one suited – OruxMaps. I originally looked at it askance as it had so many functions. But I found it very simple to set up and use for what I wanted. It also will upload your track to their website or GPSies.com or a few others. However, I just connect via cable to my PC and get it that way already in GPX format.

GNSS 2000 Plus with laptop

Judging by some online chat groups, it can be problematic getting a GNSS device to work with an OCAD on a laptop in the field.

So I did a test and found that using Bluetooth as COM6 at max rate on my PC made the connection. I then started OCAD 2019 Real-Time GPS. When I tried the Test function, data flowed through but an Invalid Data message displayed and stayed on for every record. However, I recalled that my trusty GPS Utility software found an invalid NMEA header in a GNS 2000 Plus file so guessed the error message might be staying on despite the rest of the data being OK.

So it proved and in live mode it worked fine. OCAD Inc should have fixed the persistent error message problem by now.


I have had a breakthrough with the Holux situation on windows 10.  
I started with installing the drivers below and my RCV-3000 now works with the ezTour software. Then to my amazement the 1200e now works also.
https://www.silabs.com/products/development-tools/software/usb-to-uart-bridge-vcp-drivers
I still can’t get the data off in Ocad although the real time gps works but this is not a major issue for me as the export can be done from eztour.

The above from Andrew Slattery for all those Holux GPSr users out there

GNS 2000 Plus In the field

The GNS 2000 Plus got a good workout in the final stages of preparing the Lerderderg Track map. I have since used it on other maps. I mostly ride with the device on my helmet. More recently while walking to check the map for the Daylesford permanent orienteering course, I fixed it to my cap using a combo of velcro strap and 2 safety pins.

GNS2000+ on hat

With my mobile strapped to the bike bar I mostly use Bluetooth – GNSS Commander – OruxMaps principally to enable recording of POIs on the mobile along with comments. I haven’t bothered to date with loading a map of the area into OruxMaps. When in mobile range I can use the generic online maps but find they are of little or no assistance.

Getting OCAD maps into OruxMaps is simply a matter of exporting in GeoTiff format (TIF including World file), then copying those two files into my mobile OruxMaps MapsFiles folder per image below.

OruxMaps files on mobile
map files in OruxMaps app on mobile

The wrap

Despite it’s apparent limitation of recording every 5 seconds, I have found the GNS 2000 Plus to be highly satisfactory for my use in developing mtbo maps and trail maps. When I used it in checking a foot-o map, I found that it delivered dramatically better results than the original mapper’s GPSr – checked via NearMap and my many prior mappings of those tracks over the years. So I believe it is quite likely at least as good as any other GNSSr in its price range – if there is such a thing.

Geoff Peck and I have been sharing experiences re access to Galileo, SBAS, Beidou etc on GNSS devices. We have managed to surmount a number of hurdles along the way and are pleased to share our experiences. Use the Comments section to ask and we will reply there to share with all users of this blog

I bought my GNS 2000 Plus, $175, from a company Geoff recommended – Melbourne based Oz Pilot. Their online shop doesn’t specify the GNS 2000 is the Plus tri-ceiver model, but just specify that in your order and that is what you will get.

Off course

Latest knOCAD post

Symbol Set Conversion warning.

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A Drone Goes Orienteering Mapping

Drone with camera

Drones in orienteering mapping?

This is not to claim that making orienteering maps is boring, as one dictionary suggests that a drone is  “A person who does tedious or menial work; a drudge” ….. on the contrary, anyone who knows me will know that I find the work stimulating and rewarding, and certainly not menial. Indeed making orienteering maps is one of my passions in life, and another (there are more!) is the theory of flight Continue reading A Drone Goes Orienteering Mapping

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A Bit of Latitude Crept into the Datum

Geostationary Satellites

Australia and New Zealand Datums

Thanks to our active tectonic plates, the datums of both countries are becoming rather outdatumed. For example, Australia has had about 1.5m of land mass shift from its 1994 position relative to the earth’s surface.

NZ has implemented its new datum NZGD2000 and projection NZTM2000.

On 1 January 2017, Australia’s first step in a multi-year process is heralded by implementation of GDA2020.  The second stage is in 2023.

In Switzerland we are changing too from CH1903 to LV1995. So the reference system in Switzerland we are using is more than 100 years old and it takes more than 20 years from the new measurement to changing to the new reference system. — from Gian-Reto at OCAD Inc.

Background

The latest Australian official advice re the datum changes is on the ANZLIC Committee on Surveying and Mapping website for GDA2020

Also worth reading is this presentation from RMIT.

NZ Map Grid

For New Zealand datum change see the NZ Land Information website for NZGD2000

OCAD Co-ordinate Systems

The OCAD co-ordinate system combines datum with the country map grid. e.g. GDA94 Zone 55.

OCAD Inc already has in place the new NZ co-ordinate system based on NZGD2000.

When the Australian parameters are available, they will do the same for GDA2020.

Transforming from Old to New

Very simple. Under the Map | Transform menu you select Change Co-ordinate System, then select the new co-ordinate system and it is done.


Geostationary satellite image source Wikipedia

Not entirely unrelated

GPS registers most accurate signal yet. NASA aerospace analysts recently calculated the signal-in-space accuracy of GPS to 38 centimeters. Good news for farmers and auto-drive car developers. Read more and also click the image at top of that reading for GPS info you might not be aware of.

 

 

 

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Auto Generated Orienteering Maps for WOC 2016

Topo socks

Really? Auto generated orienteering maps?

Well yes and no. Read all about it on the WOC Sweden 2016 website. If you haven’t seen such maps before you will be surprised if not amazed. Continue reading Auto Generated Orienteering Maps for WOC 2016

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Thumbs Up for InReach SE Satellite Communicator

geospatial

InReach SE delivers every 10 minutes

InReach SE night-O route
InReach SE night-O route

Two more bush tests of the InReach SE and it worked flawlessly in ‘tracking’.

The image at right is of the waypoints during a 3 hour night orienteering event. I was able to watch from home in real time as Anitra orienteered. The InReach was set to deliver a location for every 10 minutes.

As a user of Route Gadget, I had to keep reminding myself that the straight lines between waypoints mean absolutely nothing in terms of actual route. In fact, although the term ‘track’ is used in the manual, what it delivers on the screen is really the same as a ‘route’ in GPSr terms.

Battery life

Over the course of the 3 hours (plus probably 30 minutes prior and post event), it used just 6% of battery capacity. This is considerably better than SPOT 2. The quid pro quo is that the InReach weighs 190 gms vs SPOT 2’s 120 gms and InReach is 4cm taller including aerial.

However, in our case it will normally be used when mapping, bush walking and trail riding thus the difference in weight and size is not consequential. Critically, InReach works for us whereas SPOT 2 does not.

InReach SE carry
InReach SE carry

Surprising performance

For the night orienteering event, the InReach was in a waist-belt pocket with just half the aerial poking out as in the image at left. It didn’t miss a beat. Even when SPOT 2 was working well in the first 2 years we had it, it had to be fully exposed and preferably off the body to work well.

However, continuous tracking is important only if you want to follow on the internet the route of a person using the device. If you are interested purely in the SOS aspect, then all the device has to do is deliver a single waypoint at that time. I am confident the InReach SE will, but based on our SPOT 2 experience, I cannot be confident that SPOT 3 would work in the terrain and vegetation where we normally operate.

We are now a lot more comfortable again with the other partner being out in the bush for solo mapping, bush walking and trail riding. We recommend InReach SE as a safety device at least for we older solo bush venturers who are susceptible to more serious injury in a fall and the like. And for adventurers like Alastair Humphreys riding the world or rowing the Atlantic, who have an audience that is interested in their progress.

2019 update

Increasingly we are both out in the bush at the same time in different areas. So we are buying another InReach. This time the Mini which is lighter at 100g and smaller at 99 x 52 x 26mm. Also cheaper at $499 (plus the usual communication plan).

On our InReach SE, we use the Recreational Satellite subscription plan. However we will trial the Freedom plan on our Mini on the basis that because both of us are not always out at the same time then it will not be used as often as the SE.

I note that Spot has released model X which like InReach, is a 2 way communicator. Price is the same as InReach Mini. I still would not go back to Spot down south for reasons mentioned above. I gave my old Spot to a geologist nephew and he uses it frequently in northern Australia and Timor-Leste. It works very well up there.

Footnote: I do not receive any commercial benefit from promoting use of Garmin InReach. I do benefit from knowing that promoting satellite emergency communicators might save an orienteer’s life but much more likely, provide comfort to family back home.