RaceCapture GPS: Difference between revisions

Latest revision as of 17:25, 10 July 2024

GPS is a complex and sensitive system that can be affected by many different factors. Number of satellites, nearby radios, weather, terrain and obstructions all affect GPS data. To get the best GPS signal and quality, use these tips.

Use 10Hz for best balance of performance / accuracy

If you are at a track that has lots of elevation changes, obstructions (bridges, hills, buildings, etc), keep the update rate at 10Hz.

25 and 50Hz can be used when you have clear horizon to horizon view all around, with minimal obstructions and terrain- such as flat plains or desert terrain.

Clear view of sky

Make sure the GPS antenna is mounted in a location with a full view of the sky. The best place is on the roof of your car, or under the front or rear window.

Ensure GPS system is powered up for 15-30 minutes before racing

When first powered up, GPS systems download almanac data from the satellite constellation, and this takes about 15-30 minutes. For optimal performance, ensure the RaceCapture is powered up well before your event.

Understand the GPS quality indicator channels

GPSQuality - Indicator of the type of GPS fix obtained:
- 0: No fix
- 1: Fix in progress
- 2: 2D fix
- 3: 3D fix
- 4: 3D fix with dead reckoning active (if supported by device)

GPSSats - Number of satellites in view used for calculating position

GPSDOP - Dilution of Precision - indicates overal positional quality. learn more
- < 1 Ideal
- 1-2 Excellent
- 2-5 Good
- 5-10 Moderate
- 10-20 Fair
- 20 Poor

Check torque on GPS antenna connector

RaceCapture/Pro and RaceCapture/Apex: Ensure the GPS antenna is properly torqued to 5-6 inch/lbs (just beyond finger tight)

Check Satellites in view and DOP

If you're suspecting marginal GPS conditions, ensure you log the Satellites (satellites in view) and DOP (Dilution of Precision) channels and see if that correlates with any GPS errors.

GPS interfence

Electrical or radio systems can cause interference if the radio's transmitting frequency (or it's harmonic frequency) is close to GPS bands (~1300MHz). If you notice GPS accuracy problems or speed glitches coinciding during transmission of in-car radios, it's recommended you switch your radios to a channel further away from the GPS band.

You can also move the GPS antenna further away from the transmitting antenna.

Diagnostic procedure for radio system and GPS interference

Start by spacing the radio antenna as far away as practically possible from the GPS antenna.

Then, while the car is static (not racing / moving) - watch the GPS speed indicator while keying the mic in the car. If you see the GPS speed jump or show values - coinciding with the keying of the mic - then your radio is interfering. Change the channel of the radio until the problem goes away.

Note: Low cost / budget radios may have poorly designed RF sections that spill across frequency bands - if you run into this issue, then you would need to switch to a better quality radio.

Use latest RaceCapture firmware

We continually add improvements to RaceCapture/Pro firmware to improve all functionality, make sure you are on the latest version. Download firmware here

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 GPS is a complex and sensitive system that can be affected by many different factors. Number of satellites, nearby radios, weather, terrain and obstructions all affect GPS data. To get the best GPS signal and quality, use these tips.
-===Lower the update rate if uneven terrain, track obstructions or inclement weather===
+===Use 10Hz for best balance of performance / accuracy===
-If you are at a track that has lots of elevation changes, obstructions (bridges, hills, buildings, etc), lower the update rate to 10hz.
+If you are at a track that has lots of elevation changes, obstructions (bridges, hills, buildings, etc), keep the update rate at 10Hz.
+* 25 and 50Hz can be used when you have clear horizon to horizon view all around, with minimal obstructions and terrain- such as flat plains or desert terrain.
 ===Clear view of sky===
-Make sure the GPS antenna is mounted in a location with a full view of the sky. The best place is high up on the top of the car.
+Make sure the GPS antenna is mounted in a location with a full view of the sky. The best place is on the roof of your car, or under the front or rear window.
-===Away from transmitting devices===
+[[file:RaceCapture_Pro_MK3_antenna_install.png]]
-GPS antennas can be affected by other transmitting devices such as radios and phones. Be sure to place the GPS antenna as far away from them as possible.
-===Use latest RaceCapture/Pro firmware===
+===Ensure GPS system is powered up for 15-30 minutes before racing===
+When first powered up, [https://en.wikipedia.org/wiki/Time_to_first_fix GPS systems download almanac data from the satellite constellation], and this takes about 15-30 minutes. For optimal performance, ensure the RaceCapture is powered up well before your event.
+===Understand the GPS quality indicator channels===
+* '''GPSQuality''' - Indicator of the type of GPS fix obtained:
+** 0: No fix
+** 1: Fix in progress
+** 2: 2D fix
+** 3: 3D fix
+** 4: 3D fix with dead reckoning active (if supported by device)
+* '''GPSSats''' - Number of satellites in view used for calculating position
+* '''GPSDOP''' - Dilution of Precision - indicates overal positional quality. [https://en.wikipedia.org/wiki/Dilution_of_precision_(navigation) learn more]
+** < 1 Ideal
+** 1-2 Excellent
+** 2-5 Good
+** 5-10 Moderate
+** 10-20 Fair
+** 20 Poor
+===Check torque on GPS antenna connector===
+* RaceCapture/Pro and RaceCapture/Apex: Ensure the GPS antenna is properly torqued to 5-6 inch/lbs  (just beyond finger tight)
+===Check Satellites in view and DOP===
+If you're suspecting marginal GPS conditions, ensure you log the Satellites (satellites in view) and DOP (Dilution of Precision) channels and see if that correlates with any GPS errors.
+===GPS interfence===
+Electrical or radio systems can cause interference if the radio's transmitting frequency (or it's harmonic frequency) is close to GPS bands (~1300MHz). If you notice GPS accuracy problems or speed glitches coinciding during transmission of in-car radios, it's recommended you switch your radios to a channel further away from the GPS band.
+* You can also move the GPS antenna further away from the transmitting antenna.
+====Diagnostic procedure for radio system and GPS interference====
+Start by spacing the radio antenna as far away as practically possible from the GPS antenna.
+Then, while the car is static (not racing / moving) - watch the GPS speed indicator while keying the mic in the car. If you see the GPS speed jump or show values - coinciding with the keying of the mic - then your radio is interfering.  Change the channel of the radio until the problem goes away.
+* '''Note:''' Low cost / budget radios may have poorly designed RF sections that spill across frequency bands - if you run into this issue, then you would need to switch to a better quality radio.
+===Use latest RaceCapture firmware===
 We continually add improvements to RaceCapture/Pro firmware to improve all functionality, make sure you are on the latest version. [[RaceCapturePro_Downloads|Download firmware here]]