As an open-source project, all source code and hardware plans are [http://cvs.savannah.gnu.org/viewvc/paparazzi/paparazzi3/hw/ freely available on the CVS Server] for anyone to produce, use, modify, and redistribute in accordance with the [http://www.gnu.org/licenses/gpl.txt GPL License Agreement] which requires only that the open-source nature of the project be maintained by all who redistribute it.

We encourage the distribution of hardware for profit or otherwise and invite any users with paparazzi-related hardware to post links and purchasing information on this page. Please use the [[Talk:Get_Hardware&action=edit|Discussion Tab]] to describe your experiences with any of these vendors.

<hr>

 
 
= [http://www.fmadirect.com FMA Direct] =
[[image:1888.gif|thumb|400px|FMA Direct]]
FMA is a good source of low cost IR sensors.
* [http://www.fmadirect.com/Detail.htm?item=1778&section=20 X-Y Sensor]
* [http://www.fmadirect.com/Detail.htm?item=1888&section=47 Z-Sensor]

 
= HALFBASE removed by Anton on 10/07/2008. Multiple people have claimed fraud. No delivery of product confirmed yet =
Some people have had problems with Halfbase. For more information see [http://lists.gnu.org/archive/cgi-bin/namazu.cgi?query=%22Order+from+HALFBASE%22&submit=Search&idxname=paparazzi-devel this thread] in the mailing list.
'''PLEASE READ BEFORE ORDERING'''.
There is more than 80% received their Products, in which 50% have received in timely Manner!
~ Most importantly, No fraud indeed! ~
Please contact BAE systems ( Global defence and aerospace, for military )
Blake, Alex - Alex.Blake@baesystems.com ( Would offer you reference about me!)

Jeffrey Szeto

 

There is no proof for the 80% he is claiming. If you are still very willing to order from HALFBASE because of their attractive low prices then do have a look at the thread, the link of which is mentioned above. There is hardly anyone in there who has recieved the order from HALFBASE, also after they get your money, they just stop responding back. I am still waiting for my order from last 5 Months.

Mohit Mundhra
 

Mr. Szeto - swindler.

Vladimir Khudyakov

= [http://mantiselec.com/paparazzi.html Mantis Electronics] =
[[image:lot1.jpg|thumb|400px|Mantis Electronics]]
Mantis Electronics is pleased to offer assembled Tiny 2.11, IR boards, GPS modules, USB-TTL interface boards, 3-Axis I2C/SPI accelerometer boards, and accessories for immediate order.
Our boards are solder paste stencilled, reflow soldered and 100% tested.
<h3>Our Items:</h3>
<ul>
<li>Tiny 2.11 assembled with LEA-4P and GPS antenna: $250 ($260 with Molex Picoblade connectors)
<li>2-Axis IR board with IR sensors: $75
<li>1-Axis IR board with IR sensors: $55
<li>u-blox LEA-4P GPS module: $75
<li>USB<->TTL Serial board: $15 (useful for programming and telemetry)
<li>3-Axis I2C/SPI accelerometer board: $35
<li>MLX90247 IR sensors: $12
<li>Tiny 2.11 bare PCB: $10
<li>2-Axis IR bare PCB: $5
<li>1-Axis IR bare PCB: $5
</ul>
Current lead time for orders is 3 weeks. USA shipping is $6. International shipping is $15.
 Please see our website [http://mantiselec.com/paparazzi.html http://mantiselec.com/paparazzi.html] to order.

 
= [http://chebuzz.com/paparazzi CheBuzz Paparazzi] =
CheBuzz Paparazzi is proud to become the first reseller of Paparazzi equipment in the EU. That means faster shipping, no packages getting stuck in customs, and no having to pay import duties! All of the equipment is hand-built for the moment, so all equipment is thoroughly tested. Your equipment is guaranteed to work upon arrival.
<h3>My Current Offerings:</h3>
<ul>
<li>Tiny 2.11 assembled with LEA-5H and GPS antenna: $225
<li>2-Axis IR board with IR sensors: $60
<li>1-Axis IR board with IR sensors: $40
<li>Picoblade to servo adapter: $2.50 each
<li>Tiny 2.11 bare PCB: $5
<li>Small Horizontal IR Sensor PCB: $3
<li>Slim Vertical IR Sensor PCB: $3
<li>U-blox LEA-5H GPS module: $60
<li>MLX90247 IR sensors: $10
</ul>
 My [http://chebuzz.com/paparazzi website] is not yet up, but should be shortly. Until that time, please contact me at chebuzz@gmail.com
 Orders will be shipped within 2 days of receiving payment. I will gladly accept payment in euros.

 
= [http://www.olimex.com/pcb/ Olimex] =
[[image:pcb-green.jpg|thumb|400px|Olimex PCBs]]
Fast PCB Prototypes
[http://www.olimex.com/pcb/ www.olimex.com/pcb]

 
= [http://www.ppzuav.com/ PPZUAV] Get it now without issues. =
[[image:BUNDLE2BASIC.jpg|thumb|400px|PPZUAV]]
<h3>Our Items</h3>
*[http://ppzuav.com/osc/catalog/product_info.php?products_id=59 Tiny2.11 Autopilot] 
*[http://ppzuav.com/osc/catalog/product_info.php?products_id=60 TWOG Autopilot] 
*[http://ppzuav.com/osc/catalog/product_info.php?products_id=74 Paparazzi design external GPS units] 
*[http://ppzuav.com/osc/catalog/index.php?cPath=12 RF modems] 
Confused what to buy? We have bundles ([http://ppzuav.com/osc/catalog/product_info.php?products_id=68 Tiny2.11 Bundle] and [http://ppzuav.com/osc/catalog/product_info.php?products_id=71 TWOG bundle]) to make it easier for you to get what you need quickly.

We know it's hard to decide what to get, what you need to do etc. so we do quite a bit to help ensure when your parts arrive they are pre-programmed and include cables you'll need. These steps include:
<ol>
<li>We load the bootloader
<li>configure the GPS module (LEA-5H Tiny2.11 we also update the GPS Firmware to the latest from u-blox)
<li>We load a sample tiny2.11 program into it.
<li>We verify it runs the program (LED1/RED flashes)
<li>Then acquires a 3D fix (LED2/GREEN flashes).
</ol>
* For TWOG orders we load the USB Boot Loader for you before shipping. 
* For Paparazzi GPS orders we update the u-blox firmware and load the Paparazzi GPS configuration file AND include the cable to connect it to the TWOG 
Our goal is for you to focus on learning paparazzi not trying to determine if your autopilot is working. This means you can use the USB programming cable (included) and load your aircraft configuration as soon as you receive your Autopilot. 

Please eMail '''sales@ppzuav.com''' with any questions or special requests before you place your orders. We return emails as quickly as possible. If it's an easy question within hours. More complex or longer explanation requests may take some time to read then write your answer so be patient.

[http://www.ppzuav.com/osc/catalog Visit the PPZUAV WebStore to see the latest offerings.]
-----
Important Information about [[PPZUAV_SHIPPING]]
 

= [http://www.sparkfun.com Sparkfun] =
[[image:P1030095.jpg|thumb|400px|Sparkfun]]
Sparkfun is a great source of miscelaneous electronics like:
* Gyros
* Accelerometers
* Pressure sensors
* Ultrasonic distance sensors
* Temperature/humidity sensors
* USB to Serial converters
* LEDs
* Etc.

Sensors/GPS

2008-10-07T17:07:19Z

Chebuzz: /* Other potential source of u-blox GPS */

{| align=right
|-
| __TOC__
|}

==Overview==
[[Image:U-blox_color_warm_60.gif|100px]]

Paparazzi autopilots are designed around the popular [http://www.u-blox.com u-blox] brand of receivers.

*Features:
**Small size
**Excellent performance
**4Hz position update rate

The '''[[Tiny]]''' features an onboard LEA series GPS receiver and patch antenna, while '''[[Classix]]''' and '''[[Previous_Autopilots|AVR-based]]''' boards require an external receiver+antenna such as the [[#Paparazzi_Stand-alone_GPS_Receivers|Paparazzi GPS]] or [[#u-Blox_SAM-LS_GPS_Smart_Antenna|SAM-LS]]. Please note that the receivers must be configured (prior to use with the autopilot) as indicated below. Both modules have proven reliable and robust.

{|align = center
|-
|[[Image:Lea big.jpg|200px|thumb|center|u-blox LEA GPS Receiver]]
|[[Image:Ublox_SAM-LS.jpg|200px|thumb|center|u-blox SAM-LS GPS receiver (w/built-in Smart Antenna)]]
|}

'''Note:''' The proprietary UBX protocol is used as it offers more information and efficiency than the universal NMEA protocol. The protocol is parsed in <tt>sw/airborne/gps_ubx.c</tt>. Other GPS brands would require a similar parsing file to be written for NMEA or other proprietary protocols.

==GPS Receivers==

===u-Blox LEA Series Receivers===
[[Image:Lea big.jpg|100px|thumb|right|u-blox LEA]]
The '''[TWOG_v1|TWOG]''', '''[[Classix]]''' and '''[[Previous_Autopilots|AVR-based]]''' boards require an external GPS module and antenna. The '''[[Tiny]]''' features an integrated receiver and antenna. Either type is designed for [http://www.u-blox.com/ u-blox] 4 and 5 series GPS receivers and the proprietary UBX binary protocol. An external battery or capacitor is typically used to enable the GPS to retain data while powered off for significantly faster signal re-aquisition. Any of the LEA-4 and LEA-5 series receivers can be used including the less expensive LEA-4A, 4S, 5A and 5S models as the special boot configuration code required for these models is already written.

*4Hz Position update rate
*Supports active or passive antennas
*Supports [http://en.wikipedia.org/wiki/DGPS DGPS], [http://en.wikipedia.org/wiki/WAAS WAAS], [http://en.wikipedia.org/wiki/EGNOS EGNOS], and [http://en.wikipedia.org/wiki/MSAS MSAS]
*Low position [http://paparazzi.enac.fr/wiki_images/Gps_rx_noise.pdf noise] figure
[[Image:TINY_1.3_MCU_BOTTOM.JPG|thumb|center|250px|LEA-4P installed on the Tiny]]
 

===Paparazzi Stand-alone GPS Receivers===
[[Image:Ppzgps13_800.jpg|100px|thumb|left|Paparazzi GPS13]]
[[Image:LEA5HExternalModulePinout.jpg|250px|thumb|right|LEA-5H Full Board Pinout]]
There are currently two (LEA-based) stand-alone, GPS receiver + antenna, prototype boards in development; the first one is based on the Sangshin 13mm patch antenna. 
The second is based on the Sarantel helix antenna. Drawings for both are available from the [http://cvs.savannah.gnu.org/viewcvs/paparazzi/paparazzi3/hw/ CVS]
Version 1 (V1) BOM is here.. Please post any pics you might have and check this for accuracy 
[http://paparazzi.enac.fr/wiki_images/Gps_13_BOM.xls V1 BOM.xls] 
[http://paparazzi.enac.fr/wiki_images/TinygpsBOM.txt Eagle Parts List Output.txt] 

If this needs fixing don't be shy, fix away.

 

===NAVILOCK NL-507ETTL===
[[Image:Navilock NL-507ETTL.jpg|thumb|left|NAVILOCK NL-507TTL]]
The NAVILOCK NL-507TTL u-blox TTL Modul 60416 features an LEA-4 series receiver and 25mm patch antenna on a 30mm x 30mm board.
* Datasheet: [http://www.navilock.de/download/Dokumente_SLASH_Sonstiges/60415_-_Datenblatt_u-blox_GPS_Module/481 http://www.navilock.de/download/Dokumente_SLASH_Sonstiges/60415_-_Datenblatt_u-blox_GPS_Module/481]
* Purchase: Available for 28€ at [http://www.amazon.de/Navilock-NL-507TTL-u-blox-TTL-Modul/dp/B0011E6VQG www.amazon.de]
 

===SPK GS406===
[[Image:GS406.jpg|thumb|left|SPK GS406 with LEA-5]]
[http://www.sparkfun.com/commerce/product_info.php?products_id=8889 Sparkfun] sells a nice small module featuring the newer 5-series receiver and the highly rated Sarantel antenna for about $90. The design is based around the active version of the Sarantel instead of the more appropriate passive model and there's some potentially tricky soldering involved to get around the ribbon cable but the price is great for this hardware.
 

===u-Blox C04-5H Reference Design===
[[Image:abavimage.jpg|100px|thumb|left|u-blox C04-5H]]
u-Blox sells a complete module with antenna for around $200 and will also provide complete schematics, BOM, and PCB files for free if you wish to make your own. Two versions are offered, one with an 18mm patch antenna and the other with the Sarantel P2 helical antenna.
See [http://www.u-blox.com/products/c04_5h.html http://www.u-blox.com/products/c04_5h.html] for more info.
 

====Connecting external receivers to Classix, 1.2.1, Lite, and RoboStix boards====

The u-blox receivers require 3.3v power and all current models have 5V tolerant data lines. The best way to connect to the SAM-LS is to remove the bottom case and solder the 4 wires directly to the TIM-LL module (GND (pin 1) ,VCC (pin 2),TX (Pin 5),RX (pin 4)) check the TIM-LL datasheet for pinout diagrams. The Classix and Lite boards feature a 3.3V regulator to power the GPS.

===Sourcing from u-blox===

u-blox keeps tight control over the distribution of their products. They must be obtained DIRECTLY from their own reseller offices. These offices may not be available in your area, for example Canada does not have a reseller. Sample quantities can be obtained from uBlox but overnight or 2 day shipping is required which drives the cost up considerably. While it is a large hassle obtaining these devices, it is undoubtedly worth it.

Talking with ublox sale for two years, Confirmed, that Order is possiable Directly from ublox, by knowing what project it was for & how was it to be use. After long reply waiting time, the answer was: - YES, but at least 2K-3K in volume, otherwise they're not interested. Like to share the order ? It is 500pcs/Roll.

===Other potential source of u-blox GPS===

There seems to be a few alternative source of u-blox GPS out there. They are considerably cheaper then the samples u-blox offers (at least in america). We didn't buy from these sources yet. Do not take this as a recommandation, we do not know the level of service they offer, etc.

If you do order from any of them, please update this page with your feedback.

Here's a few link worth exploring:
*http://www.rfdesign.co.za/pages/5645456/Products/GPS-Products/Antaris-4-Modules.asp
*http://www.comet.srl.ro/shop/info.html?ID=6195 ( Link error )
*http://www.expedienttech.com/product.htm ( Singapore )
*Halfbase removed by CheBuzz due to claims of fraud and non-response from the owner

==GPS configuration using U-Center==

[[Image:U-center_screencap.jpg|thumb|u-center configuration software]]
[http://www.u-blox.com/products/u_center.html U-Center] is a very comprehensive freeware program intended for the configuration and evaluation of u-blox receivers.
* [http://www.u-blox.com/products/u_center.html Download u-center]

* Note: You must [[Compiling#USB_flashing|install the UART tunnel]] to enable direct access to the built-in GPS on the [[Tiny|Tiny]].
* Note: You can run u-center on Linux by installing "wine" ([http://www.winehq.org/site/download-deb Installation of Wine]) and setting up com1 as /dev/ttyUSB0 See Info on wine for "dosdevices" setup. Just download the u-setup.exe and run it with wine, follow prompts. This has been tested with Ubuntu7.10 and Ubuntu 8.04 so far.
* Note: You will need a driver for your FTDI cable if you run u-center on Windows, which can be found [http://www.ftdichip.com/Drivers/D2XX.htm here].
The u-blox and Tiny UARTs both operate at 3.3V TTL levels and are 5V TTL tolerant. You must use a level shifter such as the common MAX232 to connect these devices to a standard PC serial port. The easiest and most recommended method is to connect to a USB port instead of serial with the $20 [http://www.ftdichip.com/Products/EvaluationKits/TTL-232R.htm FTDI USB-TTL converter cable] available from Digikey, Mouser, or direct from FTDI. Other similar converters are available from [http://www.pololu.com/products/pololu/0391/ pololu] / [http://www.sparkfun.com/commerce/product_info.php?products_id=199 sparkfun] or [http://shop.halfbase.com/product_info.php/products_id/54 Halfbase]. A stand-alone GPS such as the SAM-LS will require clean 3.3V/50mA power and a common ground with the TTL converter.

* U-blox occasionally releases firmware updates. Log on to the u-blox website using ''paparazzi'' for username & password to view or download the latest firmware images. There have 'never' been any updates released for the Antaris-4 series used in the Tiny.

Start U-center and choose your com port from the pull down list under the connect button near the top left corner of the window. Choose your baudrate from the pull down box to the right of the connect button or select the auto-baud button to the right of that. U-blox default is 9600 baud. This must be changed to 19200 or higher to accomodate the 4Hz update rate.
 [[Image:U-center_buttons.jpg|connect, baud, and autobaud buttons]]
 

===Uploading the Configuration File===
Download the appropriate configuration file below and use u-center to load in onto your receiver. Under the ''Tools'' menu, choose ''GPS configuration''. Be sure the box 'Store configuration into BBR/Flash' is checked and hit the button ''File>>GPS''. A few errors and retries are normal, but a significant number of errors may indicate a poor connection and the software will notify you if it is unable to send all the data successfully.
* [[Media:Tiny_LEA-4P-v6.zip|LEA-4P]]
* [[Media:Tim-LL-V5.zip|TIM-LL]]
* [http://paparazzi.enac.fr/wiki_images/Tiny_LEA-5H-v5.zip LEA-5H (For Use w/ Firmware V5 ONLY!)]

===Manual Configuration===
If you prefer to setup your receiver manually or have a model not listed above, here are instructions to configure your receiver in u-center.
Open the message window (menu View->messages view) to start the configuration process by changing the following settings:

====LEA-4P====

1. Right Click on the '''NMEA''' Icon and choose '''disable child'''
2. Choose UBX->CFG->NAV2(Navigation 2) - set it to use '''Airborne 4G''' (tells the Kalman filter to expect significant changes in direction)
3. UBX->CFG->PRT - set '''USART1''' to '''38400bps''' (must match the value in your [[Airframe_Configuration#Hardware_definitions_-_Makefile|Airframe file]])
4. Change the baudrate of U-Center to 38400bps if the connection is lost at this point
5. UBX->CFG->RXM(Receiver Manager) - change '''GPS Mode''' to '''3 - Auto''' (Enabling faster bootup only if signal levels are very good)
6. UBX->CFG->RATE(Rates) - change the '''Measurement Period''' to '''250ms''' (4 Hz position updates)
7. UBX->CFG->SBAS : '''Disable''' (SBAS appears to cause occasional severe altitude calcuation errors)
8. UBX->NAV (not UBX->CFG->NAV): double click on '''POSUTM, SOL, STATUS, SVINFO, VELNED.''' They should change from grey to black
9. UBX->CFG->CFG : '''save current config''', click '''"send"''' in the lower left corner to permanently save these settings to the receiver

====LEA-5H====

1. Right Click on the '''NMEA''' Text on top of the tree and choose '''disable child messages'''
2. Choose UBX->CFG->NAV5(Navigation 5) - set it to use '''Airborne 8 <4G'''. This tells the Kalman filter to expect significant changes in direction.
Note that this setting is only good for faster moving airplanes. For a fixed position hovering heli, 'pedestrian' setting is better
3. UBX->CFG->PRT - set '''USART1''' to '''38400bps''' (must match the value in your [[Airframe_Configuration#Hardware_definitions_-_Makefile|Airframe file]])
4. Change the baudrate of U-Center to 38400bps if the connection is lost at this point
5. UBX->CFG->RATE(Rates) - change the '''Measurement Period''' to '''250ms''' This gives a 4 Hz position update since 4 x 250ms is one second.
6. UBX->CFG->SBAS : '''Disable''' (SBAS appears to cause occasional severe altitude calcuation errors)
7. UBX->NAV (not UBX->CFG->NAV): double click on '''POSLLH, SOL, STATUS, SVINFO, VELNED.''' They should change from grey to black
(add the flag -DGPS_USE_LATLONG in your [[Airframe_Configuration#Hardware_definitions_-_Makefile|Airframe file]]) also make sure you set tiny_2_1_1.h if you have the latest boards Tiny/TinyWOG)
8. UBX->CFG->CFG : '''save current config''', click '''"send"''' in the lower left corner to permanently save these settings to the receiver

* Cycle the power and verify that the new configuration was saved
* To reset the receiver to the factory defaults go to ''UBX->CFG->CFG'', select 'Revert to default configuration', and click ''Send'' at the bottom left corner. To permanently save these values choose 'Save current configuration' and click ''Send''.
* To backup the configuration to a file on your PC: under the tools menu, choose GPS configuration, then click GPS>>file. This file can be re-loaded in a similar manner to configure additional identical receivers. Be sure the box 'Store configuration into BBR/Flash' is checked when reloading a configuration file to make the changes permanent.
* To update the firmware on a LEA-5H get u-center >= 5.03, revert the GPS receiver to the default configuration, get an appropriate image from u-blox (fitting your receivers serial number), find the flash identification flash.txt file in the u-center install directory and be prepared to wait a long time.

#NOTE: If you have a Tiny with LEA-5H module you must use u-center and manually setup the parameters as shown above (at least switch to 38400 baud manually before transferring the configuration file).
#NOTE: POSUTM is not available on LEA-5H. Instead, use POSLLH. Additionally, add the flag -DGPS_USE_LATLONG in the makefile section of the airframe xml file.

===Reset to Default Settings===
The GPS module can be reset to its original default settings by pulling BOOT_INT high(3.3V) during a power cycle ([http://www.u-blox.com/customersupport/gps.g4/ANTARIS4_Modules_SIM(GPS.G4-MS4-05007).pdf Antaris Manual, p. 122]). It may be required after a wrong firmware upgrade or a bad configuration change.

===DGPS (Differential GPS)===
Differential GPS is any method of improving GPS accuracy by comparing the GPS-indicated position of a nearby location to the known value and transmitting any error to the mobile unit. DGPS was originally created as a means of bypassing the deliberately introduced inaccuracies in civilian GPS signals. The original method used low frequency ground radios to relay correction data to the mobile unit and is still used today at airports, shipping ports, and even individual farms. Satellite Based Augmentation System (SBAS) is a modern form of DGPS where the ground stations relay correction data to a GEO-Stationary satellite, which then relays it to the mobile unit on standard GPS frequencies eliminating the need for a separate radio reciever. SBAS is currently available in 3 regions, [http://www.environmental-studies.de/Precision_Farming/EGNOS_WAAS__E/3E.html WAAS, EGNOS, and MSAS] though only WAAS is officially operational. U-blox receivers support all common varieties of DGPS [http://www.u-blox.com/customersupport/gps.g3/ENGOS_Issues(GPS.G3-CS-04009).pdf read the u-blox SBAS application note].
* It is important to note that DGPS methods only improve the ''accuracy'' of the position calculation, not the ''precision''. Since Paparazzi navigation is typically performed relative to the power-on location, any static error that could be corrected with DGPS is irrelevant.

====WAAS issues====
WAAS has been officially operational and "suitable for safety-of-life applications" since 2003. The default setting of all u-blox receivers ignores WAAS correction data and only uses the WAAS satellites for regular navigation like any other satellite. U-blox recommends further limiting this setting to exclude any stray EGNOS/MSAS satellites in North America, and completely disabling all SBAS functions for use outside North America. In 2006 one formerly reliable Paparazzi aircraft began having great GPS problems and displaying very erratic altitude calculations, disabling WAAS immediately resolved the issue and this phenomenon was recreated several times for verification. Turns out a new WAAS satellite was being added to the system and the others were being moved that week for better distribution. Our advice is to completely disable WAAS.

====EGNOS issues====
EGNOS is officially in "testing mode" and no claims of reliability are made. The [http://www.u-blox.com/customersupport/faq_antaris u-blox FAQ] states the following:
* "Do you see issues with EGNOS?"
*:"Yes. Although the data transmitted by the EGNOS satellites are usually good and valuable (e.g. during the solar storms in autumn 2003), they can sometimes be very unreliable, for example when system tests are performed. As an example, u-blox has noticed erroneous range information (up to three hundred kilometers) on various EGNOS satellite over the last few months [2006]."

===Further Reading===

The u-blox [http://www.u-blox.com/customersupport/antaris4_doc.html System Integration Manual] covers a lot of GPS theory as well as product specific topics.

== Antenna options for the Tiny and Paparazzi GPS units ==

The '''[[Tiny|Tiny 1.1]]''' features a 28mm square ground plane intended to be centered below the [[#Sangshin_13mm_Patch|Sangshin 13mm patch antenna]]. Much better performance has been seen with the 18mm antennas and an augmented ground plane. The ground plane is a critical part of the antenna affecting not only the gain and polarization characteristics but also the center frequency of the system. Users are advised to expand the ground plane to approximately 36mm square, centered on the ceramic portion of the antenna (not the pin). This can be done with copper foil soldered to the vias of the existing ground plane.
[[image:gps_antenna_comparison.jpg|thumb|500px|left|SAM-LS 25mm / Emtac 20mm / Emtac 18mm / Sangshin 18mm / Sangshin 13mm / Sarantel P2]]
 

=== Sangshin 18mm Patch ===
[[image:Sangshin_18mm.jpg|thumb|Sangshin 18mm x 4mm 1580Mhz]]
The Sangshin KSA-ST1580MS18 antenna has proven to offer the best performance of the currently available options. These are available from any Sanshin distributor such as [http://www.rfmw.com rfmw] ([http://www.rfmw.com/PortalProductDetail.aspx?ProdId=232436&fmt=1 here]) and cost approximately $6.50/ea. in small quantities.

 

=== EMTAC 18mm Patch ===
[[image:Emtac_18mm.jpg|thumb|Emtac 18mm x 4mm 1580Mhz]]
Offering identical performance to the Sangshin in a less attractive package is the Emtac 18mm antenna. The part number for the standard 1580MHz 18x18x4mm is ANA1580T18D40 and is not listed on their website. Other frequencies are available on a special order basis and the 1584Mhz has proven to outperform all other frequencies when used with a 36mm ground plane and no radome. The use of a radome (any material covering the antenna) or a larger ground plane should theoretically favor even higher frequencies.

'''Availability'''

* [http://www.transplantgps.com/modules.html TransplantGPS] in MN, USA. The 1580Mhz models are usually available at a cost of $3.55ea but there may be a minimum order requirement of ~$50 USD.
* [http://www.onefastdaddy.com/catalog/product_info.php?products_id=43 PPZUAV] ~$10.00 USD (no min. order requirement)
 

=== Sangshin 13mm Patch ===

[[image:Sangshin_13mm_onboard.jpg|thumb|Sangshin 13mm x 4mm 1580Mhz]]
Part of interest: '''[http://www.sangshinec.com/eng/patch_spec.htm KSA-ST1580MS13]'''

The Tiny 0.99 (not 0.9) and 1.1 were designed around this antenna but users are advised to install 18mm units for better performance.

Size: 13 x 13 mm 
Center Frequency: 1580 MHz 
Bandwidth: 5 MHz 
@Fo: -15 dB 
GAIN (dBi): 0 dBi 
Ground Plane: 50 x 50 mm 

'''Available From'''

[http://www.systroninc.com/ Systronic INC.] - Alberta, Canada
 

=== Emtac 20mm Patch ===

[[image:Salvaged_20mm_onboard.jpg|thumb|Emtac 20mm x 4mm]]
The Tiny 0.9 was designed around this 1583Mhz antenna and performed extremely well. Emtac has replaced this with an 18mm model that they claim offers even better performance.

* Obsolete
 

=== Sarantel GeoHelix-P2 ===

[[image:Geohelix-p2.jpg|thumb|Sarantel Geohelix P-2 1575Mhz]]

This antenna is popular among UAV designers due to it's natural rejection of other radio frequencies such as those originating from the modem or video system as well as it's improved rejection of signals reflected from the ground. U-blox recommends this antenna and features it in their [http://www.u-blox.com/news/sarantel.html reference design]. Frequency and polarization are not dependent upon ground plane geometry so this antenna is sold only in the true GPS frequency of 1575Mhz.
The geometry makes this antenna very inconvenient to mount, especially in an airplane. Some very non-scientific testing has been done with one of these antennas connected to a Tiny with a short length of 50 Ohm coax above a 120mm square of ungrounded aluminum foil and performance was adequate. The helical design should theoretically outperform a patch in the air, but not on the ground, so any organized comparison will be difficult. Possibly the most important aspect of this antenna is it's natural RFI filtering, which should be evaluated further.

* [http://www.sarantel.com/products/geohelix-p2 GeoHelix-P2] Passive GPS Antenna [[http://www.sarantel.com/downloads/specifications/geohelix-p2.pdf datasheet]]

'''Availability'''

* Sarantel @ cost of approx $18 USD each (active versions available for ~$40)
 
* [http://www.onefastdaddy.com/catalog/product_info.php?products_id=40&osCsid=709e839698120c5cd324072b77d67cc1 PPZUAV]