Private homepage – Hans-Georg Michna

Global Positioning System

Hans-Georg Michna

Global Positioning System Information and Data for Germany and East Africa

Contents

• Nature Reserve Mapping Project
• GPS
• Data
• For Pilots: GPS Emergency Approaches
• Virtual Geocache on the Equator
• Send Mail

Links

• See the private homepage for information on travelling in east Africa.
• Read the story and download the routes for a 5 hour Bavarian mountain hike to the Baumgartenschneid.

Nature Reserve Mapping Project

History

This project began as the Nature Reserve Waypoint Project and asked contributors to send in waypoints of track or trail junctions. However, nobody came forward, so the project existed only in the form of two of my own waypoint collections.

However, meanwhile a technical detail changed. Newer GPS receivers, now usually smartphones, have a much larger track memory, and so there is a new opportunity to revive this project under a new name with some decisive advantages over the old one:

1. It is now even less work, namely almost no work at all, to collect the data. Just record the track while you drive or walk. But load the track from this page first, to benefit from the information.
2. The result is much more useful, because it does not only record arbitrarily chosen junctions but entire tracks or trails.
3. Smartphones can be used (see below).

The New Project Uses Tracks

So please join a new project to gather nature reserve GPS information. This is a collaborative project that aims at achieving a maximum of usefulness with a minimum of effort. The idea is that travellers record tracks. The names of all contributors will be mentioned in a list here, provided anybody volunteers.

You can take part only if you have a smartphone with suitable software, like Locus Free or My Tracks, or a newer GPS receiver with a big enough track point capacity.

Please send me an email when you need the tracks in a different file format.

Currently present are 7 nature reserves in Kenya, East Africa, namely Amboseli National Park, Lake Nakuru National Park, Masai Mara east of the Mara River, Samburu und Buffalo Springs game reserves, and the Tsavo East and West National Parks.

Currently available tracks

The links on the left side lead to incomplete, but convenient Google Maps renditions of the tracks for occasional, quick use on smartphones. The GPX File links on the right side can be used to download GPS files. They are complete and should be preferred not only for offline use.

In some areas, particularly Samburu, the Google Maps satellite map also shows many tracks, so check that as well, provided you have a sufficiently good Internet connection. If the tracks are clearly visible on the satellite map, they are often more complete.

To contribute actively, install Google's My Tracks program, Locus Map Free - Outdoor GPS, or any similar program that records GPS tracks, then send the recorded tracks to me, preferably in GPX format, but I can probably use any other common format too.

Procedure for smartphones in areas with Internet connection

These tracks are incomplete and not recommended, but they are a quick and convenient partial solution.

To use these track maps in Google Maps, even on your smartphone:

1. First make sure you have Google Maps installed. If not, install it from the Google Play Store.
2. Open this web page on your smartphone in your favorite web browser.
3. Tap on the area name in the Area column in the table above, which is the Google My Maps link.
4. If you get a choice, add it to My Maps or My Places or enable it permanently.
5. Repeat this procedure with other maps, if you like.

Please send me an email if this does not work for you or if these instructions need to be amended.

Procedure for smartphones in areas without Internet connection

Download the above GPX files before you lose your Internet connection.

Download and install Locus Maps Free - Outdoor GPS from Google Play Store or install any other mapping program that can show recorded tracks and waypoints provided as GPX files.

If you know a very good one that runs on the iPhone, please let me know by email, so I can add a recommendation here.

Import or open the GPX files you need and make sure they are visible on the map. For Locus Maps Free - Outdoor GPS put the files into the Locus/import folder and import them into the program's database for intensive use. Alternatively put them into the Locus/mapItems folder and activate them in the data menu for automatic import every time the program is started. That is a bit slower, but easier to handle. It is suitable for occasional or temporary use.

Procedure for Garmin GPS receivers

1. Download the track file.
2. Delete the entire track memory of your GPS receiver.
3. Use a recent version of MapSource or the newer BaseCamp (download from www.garmin.com) to upload the tracks into your Garmin GPS receiver or, if you have a different type of GPS receiver, discuss the technical side with me.
4. Set your GPS device up suitably, i.e. set the number of displayed trackpoints to the maximum. Set the track recording method and the track display to Auto and Wrap When Full and the track point density to Least Often to be able to store many more trackpoints.
5. Drive. Enjoy.
6. Before you leave the area, please contribute by reading the tracks from your GPS receiver and emailing them to me. Do not drive too far from the area before you do that, because that could overwrite the oldest relevant tracks.

I will replace the oldest ones here with your fresh ones and mention your name in a list of contributors.

Problems

1. No contributors. Please contribute to alleviate this problem. Meanwhile I'll keep feeding it with my own tracks.
2. I don't know yet how the various GPS receivers deal with the track segment names, but I hope it will just work. I'll test this as soon as I get to it.
3. Different GPS receivers. I don't know how the different track memory space of different receivers will work in the framework of this project. We'll see. But generally the usage is migrating over to smartphones, so specialized GPS receivers are no longer the best option in most cases.

GPS

GPS (Global Positioning System) is one of the technical marvels of our time. See www.gpsinformation.net for the best source of general GPS information plus a very good collection of Web links and see www.trimble.com/gps/ for an excellent illustrated and animated explanation of how GPS works. More info can be found at the following sites.

GPS Tutorials

www.edu-observatory.org/gps/tutorials.html
www.trimble.com/gps/index.html

NAVSTAR GPS User Equipment Introduction

www.navcen.uscg.gov/pubs/gps/gpsuser/gpsuser.pdf

Also see

https://titleloanasap.com/gps-revolution-for-automobiles
www.gpsy.com/gpsinfo/
http://home-2.worldonline.nl/~samsvl/
www.best.com/~williams/avform.html
http://vancouver-webpages.com/peter/

Introduction

www.edu-observatory.org/gps/tutorials.html
www.Colorado.EDU/geography/gcraft/notes/notes.html
www.groenveld.de/pub/article.php?artid=148 (Very good, detailed article on the GPS fundamentals in German language)

Books and Technical Documents

www.navcen.uscg.gov/gps/geninfo/default.htm
www.nima.mil/GandG/pubs.html
www.navtechgps.com/
www.edu-observatory.org/gps/gps_books.html

Waypoints, Maps & GIS

www.edu-observatory.org/maps/waypoints.html
www.edu-observatory.org/maps/maps.html
www.edu-observatory.org/gis/gis.html
www.edu-observatory.org/maps/utm.html

On May 1st, 2000, the US made a surprise move and switched off the dreaded Selective Availability (SA) distortion of the GPS sattelite signals. This instantly makes all existing GPS receivers much more precise without requiring any changes or upgrades to the devices. With good sattelite reception we now get a position error of less than 15 m with a probability of 95%. The altitude error remains bigger than the position error by a factor of roughly 1.5 but has now become usable for many more purposes for which it was too imprecise in the days of SA. There are no plans to switch SA back on.

The best GPS receiver for most purposes is a smartphone, Android or iPhone.

Data

In the descriptions and sometimes in the names of the waypoints you may occasionally find the following single or two letter abbreviations.

When both direction and graphical depiction are present, the graphical depiction always comes last.

Some of the approximately 350 east African waypoints may be inaccurate. Please do not rely on them too heavily and please try to verify or remeasure them and email me your results.

In addition, some of the east African waypoints are taken with a lower numeric accuracy or from unreliable sources. Many of the airport waypoints are up to one mile off, for various reasons. I found a few that were some 5 miles off until I corrected them. Sometimes the waypoint designated an airfield but was really positioned in a nearby town or lodge. In one case (Mt. Kenya Safari Club) an airfield waypoint turned out not to be an airfield at all but the mountain lodge itself. (Of course I have already corrected these, but some others will certainly still be inaccurate.)

Below you can download GPS-Waypoints for Germany and for East Africa with emphasis on Kenya and the surrounding areas. Most waypoints are intended for flying, and most of them are airports or airfields.

The Germany information was valid in the year 2000 and has been superficially checked, but not fully updated in 2002. There may have been a few changes meanwhile, so check at least those airports that you plan to use before you fly.

The Kenyan and East African waypoints contain some useful driving waypoints and routes (see description further down). The East Africa file is Kenya-centric, but contains a lot of airports farther from Kenya, reaching into the area E 25° to 45° and S 15° to N 15°.

The airspace files are for pilots and were apparently updated in 2010. Cross-check with current information before using them.

Specific information for the Kenya and East Africa waypoints

You can use Excel to load the text files and save them in different formats, like CSV. You can also use an editor, like the simple Windows editor, after that to replace commas with semicolons or vice versa for different national versions of Excel, because the data doesn't contain any commas or semicolons---these are only used as separators.

The following table defines the use of the symbols on the Garmin GPS devices. You can use these to delete waypoints by symbol on a Garmin GPS device or in the computer and thus separate the flying from the driving waypoints.

Special reporting points are available for the Nairobi Wilson northeast and southeast access lanes and some other places.

Northeast access lane inbound: NAI-N1 – NAI-N2 – NAIWIL
Southeast access lane inbound: NAI-S1 – NAI-S2 – NAIWIL
Prohibited area north of Wilson airport: NAI-P3
Points on the control zone boundary: NAI-N, NAI-NW, NAI-W
South corner of area 2 (if not using the southeast access lane): NAI-S

Mandatory reporting points for some German airports are similarly arranged, with the digit 1 always designating the outer reporting point of an access route. Occasionally, when an access route is curved and you have to turn at a point that is not a reporting point, I have inserted a waypoint at the turning point. Example: The Hannover departure route “Lima” uses the waypoints HAN – HAN-E2 – HAN-LX – HAN-L.

HAN is Hannover airport. HAN-E2 is a mandatory reporting point. Flying outbound, at HAN-LX you have to turn right (south) towards the next mandatory reporting point HAN-L, but HAN-LX itself is not a reporting point, only a course change point. Thus HAN has the + symbol I use for airports, HAN-E2 (like HAN-E1) and HAN-L have the symbol I use for mandatory reporting points, but HAN-LX has the symbol I use for other flying navigation points.

Here is the Nairobi Control Zone:

Nairobi Control Zone

The following table explains the east African driving routes. These routes are becoming obsolete and are being replaced by the tracks listed above and by the navigation capability of Google Maps. They are still explained here, just in case somebody wants to try them.

The routes beginning in Nairobi all use a shortcut from the western part of the city. If you start on Uhuru Highway in the center of the city instead, then you can simply drive north on Uhuru Highway through Westlands and continue straight in the direction to Naivasha and Nakuru until you meet the route. All routes use the turnoff to the old road down into the Rift Valley to Mai Mahiu, because this road is currently in a good state and more beautiful than the new road to Naivasha.

For Pilots: GPS Emergency Approach

Here are some thoughts on an emergency that can happen in a light aircraft when flying VFR and have a handheld GPS on board. Assume, for example, that you are flying VFR on top and your single engine fails. Another case in which a GPS can help might occur if you get trapped in clouds, but there you still have your engine at least, which makes it easier. Still the GPS can help.

In IFR-equipped aeroplanes you have very nice things like a big screen GPS, a flight director, etc. In a single engine plane with just a handheld non-aviation GPS you have much less, but with some ingenuity it should still be possible to fly some kind of workable approach.

Obviously, if you have a moment of time, you should declare an emergency immediately and keep telling the controller what you’re up to.

Assuming that you loaded at least all airfields near your planned route into the GPS receiver, you can quickly find the nearest airfield.

For simplicity the calculations and examples assume a (slow) gliding speed of 60 kt, because at this speed the numbers are very simple. If you really fly 70 kt, don’t worry. All our calculations cannot exactly account for your particular case anyway, so we are calculating roughly correctly and assume a sink rate of 800 ft/min. All heights are above ground, so with the common QNH altimeter setting you always have to deduct the height of the airfield from your altimeter reading.

Use the suitable special features of your GPS. For example, the Garmin GPSMAP 60/76/96 C/CS series has display fields for sink rate and sink rate to destination. Have these activated before you even take off. If you clicked on your desired emergency destination, then on Go To, and see that your required sink rate to destination is lower than your actual sink rate, you know you won't make it, so you have to do something.

Assuming that you don’t have much spare distance to soar and therefore have to try to make it to the airport without flying around aimlessly, but you still want to fly at least a short, straight final approach, one method could be this:

1. Airfield—Point your aircraft straight towards the nearest airfield and reduce your speed to no more and not much less than the maximum gliding distance speed. Don’t worry too much about the runway direction now. It is better to land anywhere, in any direction inside the airport, like diagonally on the runway or on the grass, than out in the bush.
2. Engine—Try to restart the engine. If this fails and if you have some more miles to fly, try to stop the windmilling propeller by setting it to maximum RPM if it is a constant speed propeller on a piston engine, then raising the nose and flying very slowly, but only for a short moment. Don’t lose too much height though. Don’t overdo it. Give up when you come too close to stalling speed, which is the end of green line minus some correction if you’re light. A windmilling propeller is an unwanted brake. If you still have the time, use the starter to rotate the propeller into a horizontal orientation to make propeller ground contact during the landing less likely. Switch the ignition off. 2003-10-06 – J. Carlos Goncalves sent the following hint: "If you have a constant speed propeller use coarse pitch—low RPM—to try to stop it. It did work, and seemed to be the only way, on the North American Harvard T-6 and Dornier DO-27. Otherwise it was very difficult to stop the propeller." Thanks, Carlos.
3. GPS Goto—Enter a Goto command for the airfield waypoint into your GPS, so you see the distance. Be sure to know the quickest method for that, which may involve pointing at the waypoint on the map display. On some GPS devices like the Garmin GPS 12 it may be enough to select the waypoint. And of course you have set your GPS to nautical miles before you even started, right?
4. Gyro—Quickly check and adjust your gyro compass.
5. Height—Calculate whether you have more than 800 ft of height above ground for each mile still to fly. Example: If you are 2 nm from the field and 2,000 ft above ground, you have 400 ft to spare (2,000 ft - 2 x 800 ft) and can use these to maneuver towards the actual runway direction and threshold. Remember though that you have only 2 minutes for this maneuver. When you have only 1,600 ft altitude above ground left, then you have to turn towards the airfield, otherwise you may not make it. 1 nm from the field is about the latest to fly any significant maneuvers. Any closer and you can only make some small, gentle turns, because you cannot fly any significant turns so short before the unavoidable landing. As usual, it’s the extra, spare height that counts. If you have much less than 800 ft per nm of distance, for example less than 500 ft per nm, you will most likely not reach the airfield. It may still be a good idea to fly towards it, because the area around it may be flatter than other areas.
6. Radio—Declare an emergency. Explain the situation briefly, but flying and navigating have priority.
7. Runway direction—Compare your flying direction against the runway direction. If the difference is much more than 90°, you’ll have to fly past the airfield and turn. You need extra height for that maneuver. Consider using the opposite runway direction.
8. Approach fix—Now you have to calculate a little. You want to know where the runway threshold and a suitable final approach fix is. Look at the directional gyro and find the runway direction. For example, if the runway is 24, look for the figure 24 on the gyro. That’s the far end of the runway. On the opposite side is your runway threshold. Change your flying direction a little towards that side. Look at the GPS map screen and imagine the runway on the waypoint in the same orientation it has on the directional gyro. 1 nm from the waypoint on the threshold side is your final approach fix, some 800 to 1,000 ft above the ground, depending, of course, on the wind as well. Look at the zoom factor, determine the (invisible) point on the GPS screen, and steer towards that approach fix.
9. Height—Check your height. Do you have height to spare? Depending on whether the runway direction is favorable or not, you need extra height for the maneuvering to your final approach. In the worst case, when you have to land from the opposite side, you need about 1,600 ft extra height from overflying the field to touchdown, because that’s 2 extra nm. Determine whether you have enough spare height for that. If you don’t, forget about the runway direction, fly straight to the airfield, and land, even if the direction is totally wrong.
10. Shortcut or detour—When you have flown some of the distance, like half, to your final approach fix, check your height again. If you have more height than you need, move the final approach fix out to, say, 2 nm from the field. In any case, turn further away from the direction to the field to lengthen your flight and lose height. If you're low, turn towards the field and move your final approach fix closer to the field, but if you’d have to move it closer than 1 nm, it’s better to give up on the approach fix altogether and aim for reaching the field in a gentle curve (or straight, if you find yourself too low).
11. Descent—When you reach your final approach fix, check your height again. If you have any more than 800 ft per nm still to fly, lower the flaps half way and trim. Check again quickly. If you’re still staying too high, don’t hesitate to lower the flaps all the way and trim again. Keep checking your height and, of course, speed. If you’re still high, sideslip. If even this is not enough, push the nose down a bit and fly to the side and back. If you’re 2,000 ft too high, fly a 360° rate 1 turn which should get you down almost 2,000 ft, but be very careful to end the turn when you’re flying towards the airfield again, which you can see on your GPS map display. If, however, you are too low, i.e. less than 800 ft per nm still to fly, immediately bring the flaps back up all the way while letting the nose drop a bit to gather the required speed, then fly directly towards the airfield at the optimal, longest distance gliding speed.

During all this quick maneuvering never forget to keep your speed at the proper approach speed. You don’t want a stall-spin accident now. And keep in mind that 1,000 ft too high is pretty bad, but still better than 10 ft too low.

If your directional estimate turns out to be inaccurate, you will notice after turning in that your flight direction is not exactly equal to the runway direction. If you have some extra height to lose, turn again to compensate for the discrepancy and fly an S-like course that ends again in the runway direction. Of course, as soon as you’re no longer perfectly sure that you can make it to the airfield, immediately turn in and fly directly towards the airfield.

You should never need this procedure when your engine is still running, but in the unlikely case that you do have to make something like an instrument approach on a handheld GPS, lower the required heights above ground to some 600 ft per nm of distance, which corresponds roughly to a 6° glide angle.

That’s a rough plan, but you may find that the mere thinking about it will prepare you for such an occasion. Let’s hope it will never happen, but be prepared anyway.

Virtual Geocache on the Equator

For general information on geocaching please see www.geocaching.com. The listing of this geocache on that site is here. For more information on travelling in Kenya please see http://michna.com/kenya.htm. For travel reports please see http://michna.com/kenya2019/ and others.

This is a description of the first equatorial divine (a fun abbreviation of “dividing line”) geocache, i.e. the first geocache placed where an integer meridian crosses the equator, which is at the same time the first virtual geocache. The coordinates are N/S 0° E 36°. Later these points were named, "confluence".

Due to the people who live in the area, it is not possible to actually stash away anything. Thus we have the first virtual geocache now. Approx. 40 m to the south of the meridian-equator crossing there was a tree, unfortunately now felled.

Whoever sends me an email with a credible description of the place will get entered into the virtual logbook for that geocache, published below.

A small hint—at first I went there the hard way, by pointing my jeep straight towards the point, off about 90° from the nearby main road, and driving straignt towards it. It’s only a few kilometers, but it took me hours of rather difficult driving including turning back once and crossing a river, where I had to drive through the water, then up a steep slope such that I was seriously worried about the jeep falling over backwards.

After finding the place, it turned out that there is at least one easier way to get there. Getting back to the road took me much less than an hour. A good map would help. So don’t do it the hard way. The shortest way is not always the fastest.

Twice I found it impossible to reach by car after it had rained.

But then I don’t expect this geocache to be found all too often, if ever. (Now that it has been found already several times, my preceding sentence, of course, looks overpessimistic.)

Since 2019-06-01 a sign is there, reading, "N0 E36". If you find the cache, please let me know by email whether the sign is still in place. People might take it away.

The virtual geocache logbook is here:

Send Mail

Please measure the waypoints again if you pass by and let me have your coordinates, so the accuracy can be improved. Of course I am always interested in more good waypoints and routes. Please click on the E-Mail symbol below to send me mail.

Private homepage – Hans-Georg Michna

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