ubx-cfg
Static ESP Testing - Phase 1
Overview
The objective of phase 1 was to determine the relative performances of GLONASS and Galileo. The SYRAC GPS devices were configured to use GPS + GLONASS or GPS + Galileo, and various sample rates - 10 Hz, 15 Hz, 20 Hz.
The tests were started on 2026-07-09 @ 0003 and the duration was more than 9 hours. The results showed that GPS + Galileo outperformed GPS + GLONASS, regardless of the sample rate.
Configurations
The following device configurations were tested, and the time distributions obtained from GPS Speedreader.
| ID | Constellations | Rate | Max Sats | ESP | Observed time distribution (ms) | Drops? |
|---|---|---|---|---|---|---|
| SY1 | GPS + GLONASS | 10 Hz | 32 | 160 MHz | 99: 3, 100: 336950, 101: 3 | - |
| SY2 | GPS + Galileo | 10 Hz | 32 | 160 MHz | 99: 34, 100: 336334, 101: 34 | - |
| D3 | GPS + GLONASS | 15 Hz | 32 | 240 MHz | 65: 1, 66: 2280, 67: 498181, 68: 2282 | - |
| D1 | GPS + Galileo | 15 Hz | 32 | 240 MHz | 65: 1, 66: 2264, 67: 497605, 68: 2266 | - |
| D5 | GPS + GLONASS | 20 Hz | 32 | 240 MHz | 50: 672969, 51: 11, 99: 11 | Y |
| D2 | GPS + Galileo | 20 Hz | 32 | 240 MHz | 50: 673429, 51: 4, 99: 4 | Y |
| S3 | GPS + Galileo + GLONASS | 10 Hz | 32 | 160 MHz | 99: 4, 100: 336891, 101: 4 |
Notes:
- The 20 Hz devices (D5 and D2) both dropped frames during this test, but not in huge numbers
- Various time intervals were observed, due to the way the M10 handles clock drift
Statistics
Click the GPY filenames for charts showing SOG, Sats, HDOP, and sAcc.
| File | Description | Mean | Median | Stddev |
|---|---|---|---|---|
| SY2_2607090003.gpy | GPS + Galileo @ 10 Hz | 0.043 | 0.039 | 0.024 |
| S3__2607090003.gpy | GPS + Galileo + GLONASS @ 10 Hz | 0.045 | 0.041 | 0.024 |
| D1_2607090003.gpy | GPS + Galileo @ 15 Hz | 0.051 | 0.049 | 0.028 |
| SY1__2607090003.gpy | GPS + GLONASS @ 10 Hz | 0.054 | 0.051 | 0.029 |
| D2__2607090003.gpy | GPS + Galileo @ 20 Hz | 0.057 | 0.052 | 0.031 |
| D3__2607090003.gpy | GPS + GLONASS @ 15 Hz | 0.060 | 0.056 | 0.032 |
| D5_2607090004.gpy | GPS + GLONASS @ 20 Hz | 0.064 | 0.060 | 0.034 |
GPS + Galileo (green) clearly outperformed GPS + GLONASS (orange) @ 10 Hz.
GPS + Galileo (green) clearly outperformed GPS + GLONASS (orange) @ 15 Hz.
GPS + Galileo (green) clearly outperformed GPS + GLONASS (orange) @ 20 Hz.
The same was also evident in the median values for SOG.
The performances from the perspective of standard deviation were ordered in much the same way as the mean values.
Observations
- Time To First Fix (TTFF) was quite variable, and some devices needed quite some time
- Warm up periods are significant, so analysis excludes the first 30 mins and last 5 mins
- 10 Hz was slightly more accurate than 15 Hz, and 15 Hz was slightly more accurate than 20 Hz
- Dropped frames were observed @ 20 Hz… slightly more for GLONASS (11) vs Galileo (4)
- No evidence of M10 “balanced” power mode issues in SOG
Conclusions
- GPS + Galileo outperforms GPS + GLONASS… certainly at this latitude
- 10 Hz
- GPS + Galileo = 0.043 kt
- GPS + GLONASS = 0.054 kt
- 15 Hz
- GPS + Galileo = 0.051 kt
- GPS + GLONASS = 0.060 kt
- 20 Hz
- GPS + Galileo = 0.057 kt
- GPS + GLONASS = 0.063 kt
- 10 Hz
- Additional satellites improve HDOP, but no huge gains beyond 24 satellites