5hz GPS receivers

ShawJohn · 04-09-2007, 01:01 PM

Has anyone tried the 5hz GPS receivers.

I can't provide any links but I was reading yesterday that the likes of slow moving agricultural gear like combined harvesters use 5Hz GPS receivers to accurately crop a field.

This technology is publicly available, just don't ask me where?!?

2k1Toaster · 04-09-2007, 01:19 PM

By a farm irragator and hacks it gps receiver!

Never tried them, but I know that in Streets and Trips it doesn't make any difference (2006 version, havent tried '07) because the program is only set to update on 1Hz signal. If you had a 1Ghz gps signal, you would still only update at 1Ghz with most programs.

I have seen another thread on here with 5Hz where someone pointed to a link to buy. Pretty cheap too, like $100 to $120... Sparkfun maybe? I'll dig around. After all, that is what badgers do!

************************ EDIT ************************

Badger smarts win!

http://www.mp3car.com/vbulletin/gps/...hz-anyone.html

It is sparkfun.com: http://www.sparkfun.com/commerce/pro...ducts_id=8266#

Of course it is an OEM module, but meh. Good antenna reception and cheap-ish. $99

volum3rider · 04-09-2007, 04:40 PM

Yeah there are a few out there like this one

http://www.garmin.com/products/gps185hz/

But almost all gps programs for pc consumers are set to update at 1hz.

kevinlekiller · 04-09-2007, 05:07 PM

Quote: Originally Posted by 2k1Toaster

you would still only update at 1Ghz with most programs.

1Ghz

2k1Toaster · 04-09-2007, 05:14 PM

Quote: Originally Posted by kevinlekiller

1Ghz

Wow. My badger senses didn't even pick that one up. Ghz is a habit nowadays!

I want the 1Ghz GPS module! Sign me up!!!

henkbliek · 04-09-2007, 06:44 PM

Lucky you; GPS is already at 1.57542GHz.
Hope the extra 575MHz doesn't bother you

2k1Toaster · 04-09-2007, 07:16 PM

refresh rate, not carrier frequency!

Clintebb · 03-31-2008, 12:43 AM

i am also interested in this, is there any software that works with 5hz?

as for the software only working with 1hz, you will still see an improvement, i would think a very noticable improvement. most of that improvement would be noticed in speed accuracy and when stationary. i would like to throw one of the gps receivers from work into the car and give that a go, 25hz with beaconor other external corections

but for the $2000 i dont think its worth it

and a car doesnt need 2cm accuracy..

does anyone know about mapmonkey or freedrive, or more in particular destinator, if it works with 5hz or just 1?

DJiK · 03-31-2008, 02:22 AM

For those interested, I had mentioned a few advantages of the 5Hz GPS receivers in this thread.

mx270a · 04-06-2008, 04:30 PM

I'm playing with a Trimble 252 receiver, which sends location info at 10Hz. Yes, this is for farm use. The receiver lists for $5000, plus another $1500/year for Omnistar HP service. Accuracy is normally within 2-4 inches.

Cheap GPS receivers only listen to the L1 frequency. There is a L2 frequency that is encrypted, which is what the military uses. These more precise receivers can use the carrier signal of L2, but not the data inside it. The Omnistar correction is a differential correction service like WAAS, but newer and better.

For mapping, I can see the difference between a 1Hz WAAS receiver and a 10Hz Omnistar receiver. I don't think it would be that much help in a car.

A standard WAAS antenna will tell you which road you're on. A higher precision antenna should be able to determine which lane you're in. For example, if you need to take a certain exit off an Interstate, it could nag you if you're in the wrong lane.

The speed output isn't going to be much more accurate, and might be harder to read since it is being updated about as fast as you can see it. We're talking .1 and .01 MPH changes.

I have a Garmin 16 (1Hz WAAS) that is relatively calm when it isn't moving. Whatever heading it was reporting when it was moving is what it keeps reporting. On the other hand that Trimble 252, when sitting still, will report even the slightest bit of movement as a new heading and a speed. If you are looking at something in a perspective view, and the heading keeps changing, the display is going to keep re-rendering the view based on that new heading.

Marvin Hlavac · 04-06-2008, 05:09 PM

Signing my name using a fast GPS engine

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Yes, I agree, accuracy of a $50 GPS receiver is just fine for driving purposes - $5,000 would be an overkill

. And the maps in the navigation software we use are not that accurate anyway, so we wouldn't really benefit from better precision.

Nevertheless, it is interesting to see how good this technology can get - that's why I'm posting link to this YouTube video

Clintebb · 04-06-2008, 09:31 PM

Quote: Originally Posted by mx270a

I'm playing with a Trimble 252 receiver, which sends location info at 10Hz. Yes, this is for farm use. The receiver lists for $5000, plus another $1500/year for Omnistar HP service. Accuracy is normally within 2-4 inches.

Cheap GPS receivers only listen to the L1 frequency. There is a L2 frequency that is encrypted, which is what the military uses. These more precise receivers can use the carrier signal of L2, but not the data inside it. The Omnistar correction is a differential correction service like WAAS, but newer and better.

For mapping, I can see the difference between a 1Hz WAAS receiver and a 10Hz Omnistar receiver. I don't think it would be that much help in a car.

A standard WAAS antenna will tell you which road you're on. A higher precision antenna should be able to determine which lane you're in. For example, if you need to take a certain exit off an Interstate, it could nag you if you're in the wrong lane.

The speed output isn't going to be much more accurate, and might be harder to read since it is being updated about as fast as you can see it. We're talking .1 and .01 MPH changes.

I have a Garmin 16 (1Hz WAAS) that is relatively calm when it isn't moving. Whatever heading it was reporting when it was moving is what it keeps reporting. On the other hand that Trimble 252, when sitting still, will report even the slightest bit of movement as a new heading and a speed. If you are looking at something in a perspective view, and the heading keeps changing, the display is going to keep re-rendering the view based on that new heading.

I work for a company in australia importing, selling and servicing trimble GPS receivers ad other products. our receivers are using both the L1 and L2 frequencies, i dont believe its encrypted. i have heard there is going to be a new receiver released sometime that also can receive L5. but for now we are sing L1, L2, and glonass to give good coverage, for most customers either use omnistar an rtk base station.

as for the 1hz vs 10hz, it will make a significant diffrence on speed and positional accuracy for the car environment. the difference will not have any affect if you are driving at a constant velocity, (speed and direction). there is no difference in accuracy between the two, but the diference is noticed when changed occur, if you take a sharp left hand turn you can be on another straight before the receiver even starts to change its heading. with 10 hz it will follow the car's movements much more closely. with my receiver and i have used several different brands of and held receiversfor automotive use, they can take more than seconds to correctly show your heading after turning a corner. even though the navigation software only accepts 1hz, the gps receiver is still calculating at 10hz, and the software is taking ever 10th update, which will follow the car much moreclosely than a 1hz receiver.

and for speed, the precision (number of decimal places) of the speed isnt affected by the frequency of updates. with more updates you will have a much more smooth speed while accelerating and decellerating. comparing the speed readings from a car gps system to one of for example an ez-guide 500 with a 25hz autonomous receiver (uncorrected signal same as car receiver) as soon as the car starts moving the ez-guide instantly shows an acurate speed, and as soon as you stop or accelerate it accuratly follows your speed quite accuratly. with a car receiver you can be driving for one second before it even shows any speed change, and even still it may have started calculating your position 0.1second after you started to drive, so one second after you start to drive you are doing 20km/h but the receiver only shows 3km/h.

and using onmistar in a car environment would not work due the system omnistar is based on, it requires the receiver to be stationary for some time, up to 10-30 mins before it can have accurate corrections.

the reason for many had held receivers to be stable while stationary is they have software that if movement is below a tolerance the receiver will just show nothing. this is stop the speed and position constantly hopping around because of the low accuracy gps engine. receivers like this can be a problem if you are using it for walking as they can take up to a few hundred metres to update the position due to the slow walking pace i have one like this that only works for the car not walking. whereas another one i have constantly updates, so when stationary the speed is usually 1-2km/h

mx270a · 04-06-2008, 09:40 PM

Hmm. My understanding was that L1 was for civilian use, L2 was military use and had an encrypted data stream. Thus the data in L2 was useless, but the carrier signal itself could be used for timing.

The EzGuide 500 calculates GPS data at 25Hz? I thought it was at 10, and that the steering control was at 50Hz.

When does L5 become something we can use, and how much more precise is it going to be compared to what we're using today?

Clintebb · 04-06-2008, 09:58 PM

ahh i will check, from memory it was 25 but could be wrong, and 50hz steering corrections is right i think.

L5 i think is available now just there isnt any trimble receivers utilising it yet, or something like that, or it also could be that is still encrypted and not available forpublic use. i'm not sure exactly how much more accurate it will be, but it should improve autonomous gps accuracy. L1, L2, L5 all operate at different frequencies, therefore are affected by the atmosphere differently, so the receiver can calculate a more accurate position. that and recently and in the near future there are a lot of sats being sent into orbit, the russians in particular are launcing quite a few.

ShawJohn · 04-08-2008, 04:06 AM

As long as them Ruskies stick to launching satelites and stop their ****ing sneaky flights over the UK... T@ts!!!