# NEO-6M GPS Module Setup Guide

## Overview
The NEO-6M is a cost-effective GPS module that provides reliable positioning data for the Aniker anchor alarm system. This guide covers the basic setup and configuration of the NEO-6M with the ESP32.

## Module Features
- High sensitivity: -161 dBm tracking
- Time-To-First-Fix:
  - Cold start: 27s
  - Hot start: 1s
- Position accuracy: 2.5m CEP (Circular Error Probable)
- Velocity accuracy: 0.1m/s
- Operating temperature: -40°C to 85°C

## Physical Setup

### Power Requirements
- Input voltage: 3.3V DC
- Current consumption: ~45mA at continuous operation
- Backup power (optional): 2.0V to 3.6V for faster satellite acquisition

### Pin Connections
1. **Power Pins**
   - VCC → ESP32 3.3V
   - GND → ESP32 GND

2. **Communication Pins**
   - TX → ESP32 GPIO16 (RX)
   - RX → ESP32 GPIO17 (TX)

### Antenna Considerations
- The module comes with a ceramic patch antenna
- Place the antenna facing upward with clear view of the sky
- Avoid metal objects directly above the antenna
- Keep antenna away from sources of interference

## Initial Testing

### LED Indicators
- Power LED: Should be constantly on
- Signal LED: Will blink when receiving data from satellites

### Expected Behavior
1. When first powered on, the module will begin searching for satellites
2. Initial position fix may take 30-60 seconds in optimal conditions
3. Signal LED will begin blinking once satellites are acquired

## Troubleshooting

### Common Issues

1. **No Power LED**
   - Check 3.3V power connection
   - Verify ground connection
   - Check for short circuits

2. **No Signal Reception**
   - Ensure clear view of sky
   - Check antenna connection
   - Move away from sources of interference
   - Try outdoor testing first

3. **Intermittent Data**
   - Check wire connections
   - Verify baud rate settings
   - Check for interference sources

### Testing Tips
- First test outdoors with clear sky view
- Allow up to 5 minutes for first fix
- Use serial monitor to verify data reception
- Verify correct UART configuration

## Software Configuration

### Default Settings
- Baud rate: 9600bps
- Update rate: 1Hz
- NMEA messages: GGA, RMC, GSA, GSV

### Serial Communication
```rust
// Example configuration in Rust
let config = uart::config::Config {
    baudrate: 9600,
    data_bits: uart::config::DataBits::DataBits8,
    parity: uart::config::Parity::ParityNone,
    stop_bits: uart::config::StopBits::STOP1,
};
```

## Performance Expectations

### Typical Performance
- Time to first fix: 30-60 seconds
- Position accuracy: 2.5m (open sky)
- Update rate: 1Hz
- Operating temperature: -40°C to 85°C

### Environmental Factors
- Performance degrades under cloud cover
- Indoor operation is not reliable
- Metal objects can cause interference
- Marine environment considerations:
  - Salt spray protection needed
  - Weatherproofing recommended
  - Stable mounting required

## Future Improvements
- [ ] Add power saving modes
- [ ] Implement faster update rates
- [ ] Add configuration interface
- [ ] Optimize for marine use