HP 29 GPS: the view from 9865 meters!

[Geoff Quickfall]

Hello all and Bernhard for reigniting the LED magic.

I took my HP 29E IR GPS to work this week. A flight from Vancouver, Canada to Beijing, China and return. I wanted to see the GPS functioning on the flight deck but had some reservations about the reception inside the flight deck.

The flight deck is surrounded by wiring, metal and other good EM producers and blockers, hence the need for external antennae. Also the windcreens are different then normal car or cabin windshields. They are two panes of treated glass with a middle layer of liquid vinyl. The liquid vinyl is heated by a transparent aluminum (Star Trek). For more on this:

Heated windshields.

Back to the flight deck, the heated windshields also block external EM. iPads have made their way onto the flight deck, company issue of course, containing manuals and etc but also a GPS which gives dynamic overlay of aircraft position on various charts. However, the iPad is situated on a g-force bracket suctioned cupped to the side window. This allows the reception of satellite data from one direction, the aircraft shielding any info from the other side. It is not uncommon to have one pilot receiving SAT data and the other pilot (other side) not.

So back to the HP 29E IR GPS. In the following photos you will see it is placed near the window ipad bracket on a clip board. All the way to Beijing it failed to receive any data or even a glimmer of sensing. Disappointed but not unhappy I figured the tiny antenna was just not up to the task. After all my iPad GPS was locked onto at least three satellites giving me positional overlay information.

So I was relegated to taking pictures of the HP 29 in Beijing in the ground outdoors.

Well, I tried again on the way home and Success! Locked on to 9 satellites and all info conincided with flight deck instrumentation. Even ran a distance remaining program (Bernhard routine modified) to take dynamically changing latitude and longitude, present position coordinates and compare them to destination fixed point coordinates. The program runs them through the routine and displays the distance remaining in nautical miles to destination which is updated as quickly as the routine runs. I will post avideo at YouTube.

Bernhard, a hearty thanks! For those that don't know what an HP 29E IR GPS is:

• 29 E refers to an enhanced HP 29. The calculator is capable of storing and recalling thirty 98 line programs as well as 20 constants and blocks of registers containing constants required for programs. It also allows merging of sequential or non sequential programs to be called by others allowing thirty 98 lined programs to be merged into one large routine; similar to the merge command on the HP 67. In fact I have three routines totalling over 200 lines each acting as one program seamlessly calling each other!
• The IR means it infrared prints to the HP 8224a or b portable printer.
• GPS, well that's obvious isn't it :-)
  

Anyhow, here are the pictures somewhere near Alaska at a pressure altitude of 33,000'

Indication that 3 or more satellite signals are being received and displaying ZULU (GMT) time:



Current latitude:



Current longitude:



Speed in knots:



Speed in kph:



Heading, actually true track for an aircraft or boat which may head one way but track differently.



Altitude in meters which does. It correspond to the aircraft altitude as we fly at pressure altitudes with all aircraft using the same setting (standard 29.92" or 1013.2hPa)



Accuracy (horizontal dilution of precision):



Number of satellites detected:

[PANAMATIK]

Hi Geoff,

Thanks for these sensational photos! An HP-29E on a flight deck over Alaska, a calculator designed 40 years ago, capable of communicating with modern satellites, the only LED bubble display worldwide which shows real time GPS positions, and can handle them in a running programm, the speed of 850 km/h, the height above ground nearly 10000 m, this is beyond anything my own GPS calculator will ever display. And I never got more than 8 satellites on earths surface, another superlative.

Now the only thing missing is the southern hemisphere, no HP-29E or HP-25E GPS yet showed a latitude with "S" (aka 5) in the display.

Only superlative, which I could beat you so far is my GPS position in february in northern norway.

http://www.hpmuseum.org/forum/thread-782...l#pid69138

I'm glad I choose the most sensitive GPS module which I could find of this size.
But why didn't you get satellite conatct on the first fly? Perhaps because you started the calculator, while already flying with high speed? Or the place inside the airplane was different and somehow shielded. But it worked perfectly on the second flight.

Who will be the first, who takes an HP-29E or an HP-67E GPS into space, like in the times of the the Apollo-Soyuz project in 1976. I think they had an HP-65 for doing astronomical/navigational calculations. Does the GPS system show altitudes above 100 km ?

I'm really happy about the success!

Bernhard

[Geoff Quickfall]

Of course, you have access to GPS satellites on the ground, line of sight, so almost an entire hemisphere depending on satellite availability. In the aircraft you are down to what is in the field of view from that window and that field of view would be very restrictive.

I have seen iPads with GPS mounted in opposite sides of the flight deck one receiving the other not.

I positioned and started the HP 29 the same way on both flights so I don't think that was an issue. I did manage to get a fix on the other side of the dateline, but lighting was low on the flight deck and the image is a bit blurry. I will upload the longitude photo with an E for east but south will have until July.

[Paul Dale]

(06-01-2017 08:29 PM)PANAMATIK Wrote:  Does the GPS system show altitudes above 100 km ?

Military grade GPS units will. Civilian ones are artificially limited to a maximum altitude of 18 km and a maximum speed of 1,000 knots (sometimes both, sometimes either).

These limits are imposed by software, so it is possible to remove them from some GPS devices by updating their firmware.

Pauli

[PANAMATIK]

(06-01-2017 10:40 PM)Paul Dale Wrote:  

(06-01-2017 08:29 PM)PANAMATIK Wrote:  Does the GPS system show altitudes above 100 km ?

Military grade GPS units will. Civilian ones are artificially limited to a maximum altitude of 18 km and a maximum speed of 1,000 knots (sometimes both, sometimes either).

These limits are imposed by software, so it is possible to remove them from some GPS devices by updating their firmware.

Pauli

That's interesting. I knew only of the software imposed position inaccuracy, which is deactivated for civilian areas today, but of course from military view height and speed would be important informations for enemy missiles. From mathematical view GPS could provide altitudes high above (on the other side of) the GPS satellites up to many thousands of kilometers to get positions relative to earth, until distances are too far to get high angles between them. But I assume no GPS satellite will direct its signals away from earth, it would be a waste of transmission power.

I don't know what happens in the HP-29E GPS when more than 1000 knots are displayed (see picture no digit left), Geoff, please keep below this barrier.

Bernhard

[Paul Dale]

(06-02-2017 06:01 AM)PANAMATIK Wrote:  That's interesting. I knew only of the software imposed position inaccuracy, which is deactivated for civilian areas today, but of course from military view height and speed would be important informations for enemy missiles.

This would be Selective Availability. This used to be enabled and it intentionally degraded the GPS position for civilian use. It was turned off about 2000 and I don't think it has been turned on again.

For military use, there is an extra signal broadcast which supposedly provides ten times the accuracy. This signal is encrypted, so most GPS receivers can't decode it. The carrier wave from this signal can be used to improve the fix on a civilian GPS by some clever trickery.

There have been localised GPS black outs since selective availability was turned off. The war in Georgia against Russia is an example. This prompted the Russians to update and complete their GLONASS constellation. Good receivers will use both GPS and GLONASS signals (& the European Galileo ones).

Quote:I don't know what happens in the HP-29E GPS when more than 1000 knots are displayed (see picture no digit left), Geoff, please keep below this barrier.

Geoff's planes don't go anything like that fast. 1000 knots is well into the supersonic range.


Pauli

[Dieter]

(06-02-2017 06:42 AM)Paul Dale Wrote:  

(06-02-2017 06:01 AM)PANAMATIK Wrote:  That's interesting. I are displayed (see picture no digit left), Geoff, please keep below this barrier.

Geoff's planes don't go anything like that fast. 1000 knots is well into the supersonic range.

Maybe the same limitation applies to 1000 km/h – which is still below Mach 1.

And finally, although there is no Concorde today, maybe Geoff will be able to fly one of these so that we will get at least past the 1000 km/h mark. ;-)

Dieter

[Guenter Schink]

(06-02-2017 07:55 AM)Dieter Wrote:  

(06-02-2017 06:42 AM)Paul Dale Wrote:  Geoff's planes don't go anything like that fast. 1000 knots is well into the supersonic range.

Maybe the same limitation applies to 1000 km/h – which is still below Mach 1.

And finally, although there is no Concorde today, maybe Geoff will be able to fly one of these so that we will get at least past the 1000 km/h mark. ;-)

Dieter

1000 km/h isn't a problem at all. All you need for that is enough tailwind. Around 100kts would be sufficient. No drama. The maximum tailwind I ever had was something like 280kts obverhead northern Labrador.
Günter

PS: It's the ground speed that counts

[Geoff Quickfall]

Best I have done is Mach .86 (True airspeed of 490 kts) plus a tailwind in November, from Tokyo to Vancouver in the jet stream was 720 ground speed. GPS is ground speed.

As Günter says, 1000kph is easy, 720kts = 1333kph!

geoff

Got a good video of the functions and some routines using Bernhard's GPS and dynamic functions.

Another picture:

[PANAMATIK]

(06-02-2017 01:00 PM)Geoff Quickfall Wrote:  Best I have done is Mach .86 (True airspeed of 490 kts) plus a tailwind in November, from Tokyo to Vancouver in the jet stream was 720 ground speed. GPS is ground speed.

As Günter says, 1000kph is easy, 720kts = 1333kph!

geoff

It seems that I have to update the actual HP-29E GPS firmware version to show 4 digit numbers for speed kph, and 5 digit numbers for altitude meters. Promised!

But I will not show 3 digit numbers of satellites, because it is only a 66 channel receiver.

Bernhard

[Geoff Quickfall]

Good to here about the fix :-)

So far best reception number of satellites has been 11.

Geoff

[BobVA]

Cool! How'd the batteries hold up?

[Paul Dale]

(06-02-2017 03:00 PM)PANAMATIK Wrote:  But I will not show 3 digit numbers of satellites, because it is only a 66 channel receiver.

Two digits is more than sufficient. Each positioning constellation has about 30 satellites. Using data from all four existing constellations isn't going to use all of the channels, let alone reach three digits. About half of the satellites are visible at any one time and receivers usually don't use satellites close to the horizon -- the receivers I worked on defaulted to only use satellites over thirty degrees above the horizon (I think -- it's been a few years).

This is assuming that the receiver is even capable of handling all four constellations.


Pauli

[Etienne Victoria]

Geoff, sorry for hijacking the thread :-)

And now, the awesome view of an HP-29 GPS at 103 meters !!!

This GPS function is amazing and very nicely integrated in the calculator function set !

Congratulations Bernhard !

The 29 GPS in on the right ; can anybody spot the differences with Geoff's 29C ? ...apart from the altitude :-)))

Cheers

Etienne




Edited multiple times to convince the picture to appear in the post.

[rprosperi]

(07-11-2017 07:30 PM)Etienne Victoria Wrote:  can anybody spot the differences with Geoff's 29C ? ...apart from the altitude :-)))

Geoff's photos are no longer visible, as least for me. Each has a message about updating the account for hosting. (maybe Geoff's cool post has generated too much interest...)

[Eric Rechlin]

(07-11-2017 08:02 PM)rprosperi Wrote:  

(07-11-2017 07:30 PM)Etienne Victoria Wrote:  can anybody spot the differences with Geoff's 29C ? ...apart from the altitude :-)))

Geoff's photos are no longer visible, as least for me. Each has a message about updating the account for hosting. (maybe Geoff's cool post has generated too much interest...)

Photobucket has changed to a non-free image hosting service, requiring anyone who wants their images to be restored to pay a $400/year subscription. Quite frankly, I don't know why anyone has used Photobucket for years, because they have long been a poor service.

I've been using imgur for a while (probably about 8 years) for hosting images I post to forums, and while they have gone downhill they haven't pulled anything anywhere near this bad yet.

Hopefully Geoff has backups of his images so he can rehost them elsewhere and then update his posts.

[Etienne Victoria]

oops, sorry I didn't notice,

Geoffs's pictures must have stayed in my newsreader's cache.

Hope he can put them back online.

Etienne

[PANAMATIK]

(07-11-2017 07:30 PM)Etienne Victoria Wrote:  The 29 GPS in on the right ; can anybody spot the differences with Geoff's 29C ? ...apart from the altitude :-)))

I can't invoke your image for some reason, but I probably know what difference you mean. However I will not tell.

Bernhard

[Etienne Victoria]

The reason is that I miserably failed in embedding the picture.

I hope I have fixed it now.

Thank you for your great work...and thanks for not telling :-)

Etienne

[rprosperi]

(07-12-2017 11:29 AM)Etienne Victoria Wrote:  The reason is that I miserably failed in embedding the picture.

I hope I have fixed it now.

Etienne - FYI - The photo I see in your original post above is the same as the one from 2 days ago - 3 Woodstocks side-by-side. I've refreshed to be sure it's not a cached image and it still appears the same.