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GPS, not firing PositionReceived event


#1

Hi, just trying out the GPS Module with Hydra and never getting the PositionReceived event

just the InvalidPositionReceived and NMEASentenceReceived

The light is constant on the GPS module, not sure if that just indicates power, versus signal?


gps.NMEASentenceReceived += new GPS.NMEASentenceReceivedHandler(gps_NMEASentenceReceived);
gps.PositionReceived += new GPS.PositionReceivedHandler(gps_PositionReceived);
gps.InvalidPositionReceived += new GPS.InvalidPositionReceivedHandler(gps_InvalidPositionReceived);
gps.Enabled = true;


The NMEASentenceReceived is firing with the following:

$GPRMC,V,N53
$GPVTG,N
30
$GPGGA,0,00,99.99,48
$GPGSA,A,1,99.99,99.99,99.99
30
$GPGSV,1,1,0079
$GPGLL,V,N
64

Thanks in advance.


#2

I havent gotten a chance to use this module, so I’m not sure if there is an issue with it and the Hydra, but it is confirmed to work on the Spider. Here is a sample project that might help you out: http://www.netmf.com/gadgeteer/showcase.aspx?showcaseid=2

Down in the comments, there is some information that might help you out:

[quote]The GPS is seeing no satellites. So you need to move the antenna near a window that can see the sky. I was able to get a connection from inside the house by putting the antenna on a window seal.

The data you are seeing is National Marine Electronics Association formatted data. http://www.gpsinformation.org/dale/nmea.htm
So in the GPGGA sentence the fifth word 00″ is number of satellites being tracked. So you have none. [/quote]

and


#3

Like Steven, I’ve used the GPS module successfully on FEZ Spider, but haven’t tested it on my Hydra.

I’m waiting on another USB Client DP module (which finally shipped…yay!), and once I have that, I’ll be able to test stuff like this more readily on my Hydra.

I was able to get a decent signal indoors, but when I tested, it was in a room with a couple of very large windows nearby, so that probably helped.


#4

How long have you waited for a valid position message? It can take a long time for a GPS to find a set of satellites the first time it is turned on. Usually, after finding a set, the chip stores the frequencies. The next time it powers on it uses the stored set as a starting point, to speed up capture.

Of course, I assume that you are testing at a location that acceptable satellite reception. :wink:


#5

Thanks Guys,

I took it out into the garden and left it there for 10 minutes hoping it was just a connection issue.

But doesn’t look like it is, would be grateful if someone could try it out on there Hydra.

Nothing other than my display seems to work :frowning:

Regards

John


#6

I’ll try it real quick and see what happens.


#7

Thanks Steven,

What results did you find.


#8

I couldn’t get a valid signal from a Spider or a Hydra from my desk. I’ll be trying from a better location soon.


#9

I found that I needed a wide-open view of the sky in order to get a valid position with the GPS module. Even in my tree-filled yard it was tough.

Also, it takes about two minutes to acquire a fix on the GPS satellite. Once the fix is acquired, it’s quite stable - I was even able to walk around inside with it. It makes me appreciate how much work the assistive-GPS feature does for phones.


#10

Thanks Kerry,

Yes im convinced the device is working, otherwise im gathering i woudnt get any NMEA data.

According to some sources, standalone GPS can take up to 12.5 minutes to acquire enough information to gain a fix.

Im going to try again tonight after work.


#11

Hi all, so did some further investigation tonight,

Mainly looking at the GPGSV sentences (Satellites in View)

When I first connect the antenna, I get plenty of data coming through, up to 5-7 satellites, however after a few seconds it degrade back down to 0.

if i disconnect and reconnect it does the same thing.

Is this is dodgy module? Or am i missing something

start:

$GPGSV,1,1,0079
$GPGSV,1,1,00
79
$GPGSV,1,1,0079
$GPGSV,1,1,00
79
$GPGSV,1,1,00*79

Tweak the cable:

$GPGSV,1,1,01,13,267E
$GPGSV,1,1,01,13,07
7D
$GPGSV,1,1,01,13,077D
$GPGSV,3,1,10,02,24,03,22,05,23,06,25
78
$GPGSV,3,2,10,10,25,11,24,12,25,13,267B
$GPGSV,3,3,10,15,25,16,24
7A
$GPGSV,3,1,10,02,20,03,19,05,19,06,2179
$GPGSV,3,2,10,10,20,11,21,12,22,13,22
78
$GPGSV,3,3,10,15,21,16,207A
$GPGSV,3,1,10,02,16,03,11,05,16,06,17
7E
$GPGSV,3,2,10,10,17,11,17,12,19,13,1878
$GPGSV,3,3,10,15,18,19,25
7A
$GPGSV,1,1,03,12,11,16,28,19,227C
$GPGSV,1,1,03,12,10,16,26,19,19
7B
$GPGSV,1,1,03,12,10,16,22,19,1375
$GPGSV,1,1,03,12,09,16,17,19,09
70
$GPGSV,1,1,02,12,10,19,0879
$GPGSV,1,1,02,12,08,19,08
70
$GPGSV,1,1,01,12,0873
$GPGSV,1,1,00
79
$GPGSV,1,1,00*79


#12

what happens if you leave it running for 10+ minutes?


#13

Not a lot I left it out in the open for about 20-25 minutes, never seen once the PositionReceived fire :frowning:

I once seemed be be able to get constant $GPGSV good sentences,but then it just went back to the old

$GPGSV,1,1,0079
$GPGSV,1,1,00
79
$GPGSV,1,1,0079
$GPGSV,1,1,00
79


#14

I the pigtails and block just the antenna?

Thinking i could find another antenna if so,


#15

Solved

Hi all I finally got my first fix last night, and I’m not talking the drug induced kind ;).

I tweaked the pig tail connector for the central pin of the antenna, it wasn’t making good contact, left it on a windows seal getting some good $GPGSV sentences and within a few minutes it got a fix.

Thanks for everyone’s help.


#16

@ KartAssist

Glad you finally got it working. As I recall, the first fix seemed to take forever for mine, but once it got a fix, it was pretty responsive thereafter.